Update on Tomosynthesis

May 17, 2022

Article in Auntminnie

Reminder: Tomosynthesis (or 3D mammography) is a radiological imaging technique that reduces the effect of superimposition of breast tissue as it reconstructs a three-dimensional image of the breast from several low-dose X-rays acquired from different projection angles.

This technique was heavily promoted about 10 years ago. Therefore, a review is done after 10 years of hindsight in the media "AuntMinnie.com."

This is a community website for radiologists and professionals in the medical imaging industry. According to this rather collaborative media that connects radiologists, business managers, and industry professionals to "meet, do transactions, research and collaborate," tomosynthesis has clearly disappointed.

Many questions and doubts about the benefit of using this technique have been raised previously:  https://pubmed.ncbi.nlm.nih.gov/30816931/

- tomosynthesis does not reduce false alarms
- the additional use of tomosynthesis does not reduce interval cancers
- tomosynthesis would increase overdiagnosis
- the benefits of tomosynthesis are not clear

1° Cancer detection

Digital mammography alone has been compared with digital mammography + tomosynthesis (a higher-radiation combination): matched studies* have shown that the addition of tomosynthesis made it possible to find more cancers: 8.8 per 1000 women compared with 6.4 per 1000. But in other unmatched studies*, the difference was narrower, 5.7 cancers detected per 1000 women versus 4.5.

* Matching consists of setting up pairs (1 case and 1 control) with the same characteristics (e.g., age) to compare the results while avoiding potential confounding factors. The groups are thus "balanced" on these characteristics.

2° Recall rates

What about recall rates? The recall rate refers to false alarms during screening, i.e., suspicions of cancer that will not be confirmed, but only after recalling the patients who will need to have other complementary explorations before deciding on these suspicions. Here again, the data vary according to the study conducted.

Based on the March 2022 study summarized here, repeated breast cancer screening with 3D mammography only modestly decreases the risk of having a false-positive result compared with standard digital mammography.

What can we learn from this study?

The risk of a false-positive result was lower when screening was performed every two years instead of every year and in the case of non-dense breasts and older women.
However, the difference was modest, and the reduction in false positives by using 3D mammography was only 2.4% compared to standard mammography.

3°How effective are synthetic mammography images?

In 2012 an opening was made for 'synthetic imaging,' which records a single radiological acquisition and therefore delivers a single dose of radiation, thus avoiding the over-irradiation caused by 3D mammography**.

But are the synthesized images an effective alternative to digital mammography images? Clinical results of effectiveness tests of synthesized mammographic images are unfortunately mitigated. Overall, the results between synthesized images are equivalent to digital mammography, although the latter has a better resolution.

**Classically, 2D mammography and 3D tomosynthesis acquisitions are used in combination. This results in a significant increase in the X-ray dose delivered. The X-ray doses delivered by combining 2D mammography and tomosynthesis are about twice the dose of 2D mammography alone.
Synthetic 2D tomosynthesis is an alternative, obtained by reconstruction from 3D acquisitions only; it avoids the joint use of 2D mammography and thus reduces the delivered dose.

4° Does tomosynthesis reduce mortality?

Does tomosynthesis result in a reduction in mortality? According to this article in Autminnie.com, a survey of eight studies conducted between 2016 and 2021 investigated whether tomosynthesis reduces rates of interval cancers (cancers not caught by screening because they occur between two mammograms) compared with digital mammography alone. Interval cancers are often very aggressive and occur quickly, thus missed by screening. They are correlated with mortality because their intrinsic aggressiveness endangers the survival of women, often because of their metastatic potential.

It was found that tomosynthesis does not impact the rate of interval cancer.

In conclusion

Ten years after its use, the benefits of tomosynthesis may be much more modest than clinicians initially expected. In conclusion, this technique is finally similar to digital mammography with no proven advantage.

Even if the detection rate of tomosynthesis seems slightly better, the benefit of this technique remains an open question. If this moderate improvement in cancer detection is gained at the cost of increased overdiagnosis, we cannot conclude that the benefit/risk ratio is favorable.

As usual, the major concern is the information provided to women, as tomosynthesis is sometimes performed in radiology offices without the knowledge of the patient who comes for a routine mammogram, who does not benefit from it and is exposed to unnecessary over-irradiation.

Also read: https://www.bmj.com/content/366/bmj.l4506




Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Evaluation of information on screening, the situation in Italy, French parallel, and hope…

Synthesis Dr. C.Bour, May 11, 2022

https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-022-01718-w

According to the authors of this Italian study published in BioMed Central (BMC, a scientific journal) on April 22, 2022, information about overdiagnosis showed a notable increase in 2021 compared with 2014. However, the frequency of this information in the documents aimed at women was still low, probably because it is both the most recent and harmful risk for women. Therefore, not all health operators are aware of overdiagnosis. If they are aware of it, they might avoid reporting the information in public documents for fear of dissuading women from undergoing screening. Moreover, many reports of overdiagnosis are unclear.

It is difficult not to find a parallel with the situation regarding information in France.

This situation of insufficient information for women persists for many reasons.

One of the most frequently reported justifications is that providing information on potential harms could reduce adherence to screening.

Method and results

As information provided to women on the benefit-risk balance is still highly biased, F. Atténa (Department of Experimental Medicine, University of Campania "Luigi Vanvitelli") and her collaborators have decided to evaluate documents addressed to the general female public and published on the Internet by the Italian national and regional public health services.

Information on false positives and false negatives, biopsy-proven false positives, interval cancer, overdiagnosis, radiation exposure, and mortality risk reduction was analyzed. In addition, quantitative data were investigated.

The 2021 situation was compared with the 2014 situation.

Overdiagnosis and biopsy-proven false-positive results were the least reported risks of screening (20.1% and 10.4%).
Compared to the 2014 information, the 2021 information showed some improvements. The most marked improvements concern overdiagnosis. The declarations of this adverse effect increased from 8.0 to 20.1%.
Concerning the number of false positives proven by biopsy, there is also an increase in the information from 1.4 to 10.4%.
But quantitative data remained scarce in 2021.

The authors conclude with the evidence of moderate improvements in information observed from 2014 to 2021.

However, information about breast cancer screening in materials for women published on Italian websites remains too sparse.

A previous shocking Italian study from 2020

A study published in September 2020 by Italian authors moved us: this economic study explained how to effectively manipulate women to make them participate ever more in organized breast cancer screening by mammography. The authors then congratulated themselves with confusing cynicism on the effectiveness of manipulation techniques: by withholding information from women in the invitation letters, insisting on a negative effect and a potential danger of not participating in screening, by "limiting the cognitive overload of women" (sic), it would be possible to increase participation in screening significantly.

This kind of unethical study can explain, among other things, the persistence of misinformation of women and biases in the information, which are constantly renewed, as seen in this BMC study mentioned above.

A problem common to many countries, including France

Danish authors analyzed how health authorities can subtly influence citizens to participate in cancer screening programs: https://cancer-rose.fr/en/2021/04/20/methods-of-influencing-the-public-to-attend-screenings/

The researchers identified and analyzed several "categories of influence," i.e., several methods that can be used to push the public to undergo screening.

In a systematic table, we find that information bias is used in many countries, among which we find European countries like Italy, corroborating the finding of this BMC study, Spain, and also France, where biased information from the National Cancer Institute (INCa) is present in two of the systematic categories. See the table: https://cancer-rose.fr/wp-content/uploads/2021/04/Supplementary-Tables-Rahbak-et-al-210421.pdf

The INCa's disregard for information to women culminates with the qualification of the scientific controversy of screening as "fake news ." (Cf https://cancer-rose.fr/en/2021/06/24/press-release-cancer-rose/)

Hope for improvement and consideration of overdiagnosis

A position of French sociologists on the "health projects" of the next government can be read in the article "The main topics for the next Minister of Health" published in the media 20Minutes; they are alarmed by the overdiagnosis of organized screening (in the section "Prevention").

We can read:

 "We must be wary of organized screenings; it can generate overdiagnosis, criticizes Frédéric Pierru (doctor in political science, a sociologist at the CNRS, research fellow (CR-CNRS), works at the Center for Political and Social Administrative Studies and Research (CERAPS), attached to the University of Lille). This is an individualistic, medicalized, and poor vision of prevention". He believes that it would be more effective to put resources back into maternal and child protection centers (PMI), school medicine, occupational medicine...

"Effective prevention would mean addressing diet, stress, alcohol..." says Daniel Benamouzig (sociologist, Director of Research at the CNRS, holder of the Health Chair at Sciences Po, and researcher at the Centre Sociologie des Organisations (CNRS and Sciences Po)). We know that this President is not very inclined to oppose the alcohol or pesticide lobbies. Health, particularly public health and the ecological transition, is a long-term task. It is not easy to prove oneself in five years..."

Let's hope that these far-sighted scientists are heard...


Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


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When marketing, finance, lobbying, and advertising invite themselves into the health care sector

Commercial determinants of cancer control policy (Eurohealth)

https://eurohealthobservatory.who.int/publications/i/commercial-determinants-of-cancer-control-policy-(eurohealth)
European Observatory on Health Systems and Policies (downloadable)

27 April 2022, Journal article
Summary by Dr. Cécile Bour - 30 April 2022

In this Eurohealth report, the authors focus on the negative influence of private interests on prevention, screening, and healthcare policies.

Cancer control, as defined by WHO and also often referred to as "cancer prevention and care," consists of a continuum from prevention, early detection (i.e., screening and early/rapid diagnosis of symptomatic patients), diagnosis, and treatment, to palliative/supportive care and survivorship

A definition of "the commercial determinants of health" was presented to the United Nations (UN) General Assembly 2017: "The commercial determinants of health are those conditions, actions, and omissions that affect health. Commercial determinants arise in the context of the provision of goods or services for payment and include commercial activities, as well as the environment in which commerce takes place.
Generally, private sector activities that impact population health."
This issue of the commercial determinants of cancer, referred to as the "dark side of health," has not yet been thoroughly explored.

According to the World Health Organization (WHO), 30-50% of all cancer cases are preventable, with tobacco use being the leading preventable cause of cancer in Europe. Other important risk factors are alcohol consumption, overweight and obesity, poor diet, and insufficient physical activity.
Added to this are sources of radiation and other chemical carcinogens, including from the cosmetics industry. These sources also increase the risk of developing various forms of cancer.

Europe is one of the largest markets for alcohol sales and is also the region with the highest proportion of alcohol-related diseases and premature mortality.
Europe has the highest average current tobacco use among adolescents. The evidence for a causal link to cancer is indisputable.
Of course, various behavioral and environmental factors account for the increased incidence of cancer. Many are preventable, but corporate interests and actions undermine public health efforts to combat them.

The response to industry criticism takes many forms. It ranges from threats of legal action for infringement of the industry's commercial rights, including intellectual property and economic freedom, to concerns that constraints on the industry will have a disproportionate impact on the economy and employment.
Other examples of industry tactics include enhancing corporate reputation (the concept of corporate social responsibility (CSR)*), denying the impact of their products or diverting attention from the harms caused by their products, and attempts to build an "evidence" base and then divide the public health community.
The bottom line is that the impact of tobacco and alcohol industry players on the cancer continuum includes a range of effective tactics that undermine public health, including recent direct marketing** to consumers.

* Companies consider environmental, social, economic, and ethical issues in their activities.

** Direct marketing is a communication and sales technique that consists in broadcasting a personalized and inciting message to directly reach a target of individuals to obtain an immediate and tangible reaction.

Deceptive drifts

A-Innovation as a panacea

It is striking that most of the articles reviewed in this report raise a particular concern, namely a blind and deceptive faith in "innovation."

Innovation has great appeal to policymakers, clinicians, the public, and donors, but all authors caution against launching new preventive, diagnostic, or therapeutic innovations without a rigorous evaluation of their basic safety and benefit to the population and call for an adequate evidence base to demonstrate their effectiveness and cost-effectiveness.
They also remind us of the rapid growth in pharmaceutical revenues generated by the sale of cancer drugs, despite a lack of return in terms of survival or cure during the same growth period.

B- Screening

The Council of the European Union still recommends screening for cervical, breast, and colorectal cancers, but with more nuanced information, and has published a guide to the proper use of systematic screening.

Since then, research continues to evaluate the advantages and disadvantages of screening, particularly for other types of cancers (lung is under study).

Despite an evidence base that does not support such practices, much "opportunistic" (i.e., off-recommendation, requested by a public demanding more medical care) screening occurs across Europe.
Managers and sales representatives play an essential role in promoting systematic testing practices that can do more harm than good (see the massive sponsorship at Pink October).
Commercial drivers can work through financial incentives, creating a "culture" that promotes rapid adoption of new technologies, lobbying, and marketing to clinicians and consumers.

The report says that many people may be included in irrelevant screenings, and resources may be diverted from those most in need of medical attention and treatment.
Overdiagnosis, in particular, is currently a specific problem. Since, at the individual level, it is not possible to determine whether cancer will progress or not, healthy people may be subjected to potentially unnecessary diagnostic procedures and treatment, with a consequent risk of adverse effects.

For example, thyroid screening has no benefit for the population but provides considerable evidence of massive overdiagnosis and unnecessary therapeutic procedures.

The first wave of cancer screening tests was developed mainly in the public sector and promoted by charities and professional bodies. There is a new wave of innovation in cancer screening, and much of this innovation comes from the private sector, often supported by professionals.

Diagnostic companies have become essential players in promoting new screening technologies, private laboratories and clinics may seek to expand the market for screening services by offering new technologies (such as 3D mammography) or expanding into disease areas not covered by national programs, which could increase public demand and intensify political pressure for their adoption within public health systems.

There has been a lot of commercial enthusiasm for cancer screening (such as predictive software, see for example here and here), industry analysts predicting the potential for "drug-like blockbuster revenues."

Companies developing new cancer screening technologies based on liquid biopsy have attracted huge billions of dollars in private investment. The technology has been very disappointing in screening, clinical studies that lack the rigor to assess the harms and benefits of this technology fully and accurately have been published to great media hype, and a phenomenon of "capture" of key opinion leaders has been added, through research collaboration with industry.

There is evidence, according to the report, that the new generation of molecular testing is being marketed using strategies that come directly from the pharmaceutical industry: recruitment of key opinion leaders, direct-to-consumer advertising, direct-to-physician advertising, and funding of NGOs, including patient organizations, to engage in ostensibly independent lobbying for government adoption of new technologies.
The commercial drive to generate revenue leads to distorted messages that present a partial view of the scientific evidence, biased towards claimed health benefits but obscuring potential harms, resulting in unnecessary public expenditure.
Carefully crafted public relations strategies can ensure media coverage that reinforces this unbalanced image, such as liquid biopsy molecular tests, 3D mammography, and artificial intelligence-based detection, which are heavily geared toward declaring tremendous benefits to populations and generally fail to report conflicts of interest.

C-Hyper-technology

Da Vinci Robot: this device is put forward in the report as the archetype of NPT (non-pharmaceutical technology).

Few technologies better represent the commercialization of the so-called NPT than the Da Vinci Robotic Surgical System.
This device, which allows surgeons to perform surgery remotely, sitting at a console to operate remote-controlled arms for micro-invasive surgery, was first approved by the U.S. Food and Drug Administration (FDA) in 2000.
Despite the lack of clear evidence of its superiority over open and laparoscopic techniques and its enormous costs, the method has been widely adopted throughout Europe, even in countries with lower living standards. Its inherent benefits, including improved visualization of the surgical field, greater range of motion of the robotic arms, and improved ergonomics for the surgeon, were expected to translate into improved patient outcomes. However, in the case of prostate and rectal cancer, no improvement in functional or oncologic outcomes was observed.

This is even though guidelines have been created to improve the rigor of evidence collection, particularly for medical devices.
Regulatory approval of a new medical device or technology requires clinical data and a demonstration of its safety before bringing the device to market.
In comparison, systemic therapies must go through a more complex process of demonstrating efficacy beyond current standards of care. This partly explains the lack of randomized controlled trials for medical devices.

However, the recent Cumberledge review highlighted the devastating impact of integrating drugs and devices without rigorous and thorough evaluation of the implications for patients, especially in terms of safety and health benefits. Unfortunately, the design of studies used to evaluate new technologies often lacks rigor. However, it can form the basis for clinical implementation, with less reliable single-center retrospective series still dominating the literature.

D-Lack of balanced media coverage

This drift can influence public perceptions and those who make decisions about funding biomedical research and clinical care, exacerbating general support.

We refer here to the enormous enthusiasm for innovation and, in particular, the idea of personalized or precision medicine, rooted in the long-standing belief that genomics will revolutionize the practice of medicine, a view now reinforced by faith in the transformative potential of digital technologies, including artificial intelligence

Public policymakers are prone to this form of buy-in, which can have two potential adverse effects on public health, including:

- a willingness to adopt new technologies because they are believed to represent the future of health care, without solid evidence that they improve clinical outcomes;

- misallocation of research resources, as funding goes to the discovery and development of new technologies, at the expense of simpler incremental improvements in care delivery, such as improved rapid clinical diagnosis for patients with actual potential symptoms of cancer

This can be a waste of resources, but in countries that lack qualified technicians in areas such as imaging or endoscopy, it exacerbates these shortages and delays in diagnosis for symptomatic individuals. It also exacerbates growing inequalities in access to medical care.

The landscape of commercial screening offerings is being transformed by innovation in diagnostic technologies and the broader development of the Internet as a new mechanism for consuming health care. In recent years, various consumer biological testing services sold over the Internet have been the subject of regulatory action.

In conclusion, and as Ioannides noted, medicine and health care waste society's resources because "we" as clinicians have allowed evidence-based medicine in cancer to be diverted by using technologies with marginal effectiveness but maximum cost.

The commercial determinants of cancer remind us that both governmental and whole-of-government approaches (combining vertical and horizontal management while partnering with organizations outside of government) are essential to meeting the challenge facing our society and that health decisions remain a political choice.

Range of ways in which private interests influence public health

1. Financial incentives affect all areas of health

- Economic incentives are misaligned with the promotion of overall quality of life.

- There is a misrepresentation of clinical information and public health data. (For example, in breast cancer, read here and here)

Economic incentives drive the development of new drugs with increasing applications, leading to trials over weak comparators (e.g., non-inferiority studies) and approvals based on modest effects in new settings.
In discussing the development of new screening technologies, diagnostic tools using molecular biomarkers, new precision therapies, or targeted drugs, all authors of the WHO report raised concerns about whether a drug or device efficacy measures were validated correctly.
Measures of benefits may or may not track in parallel outcomes that matter to patients, such as data on reduction in overall (all-cause) mortality or parameters such as quality of life; several of the report's authors expressed concern about how social factors and economic incentives have shaped clinical care, advertising, and investments in ways that do not promote the health and well-being of patients overall.

2° Lobbying

On behalf of the industry, and with the complicity of physicians and opinion leaders, the promotion of cancer screening research and technology development has led to an overemphasis on the benefits of these tools and technologies. It underestimates the harms of false positives or overdiagnosis.

3. Advertising

Many authors have drawn attention to the misleading nature of advertising and media communication about cancer risks and treatments.

They have raised concerns about the overselling of cancer drugs and new and unproven technologies.

4° Economic factors

Economic factors influence the rising costs of care, which disproportionately affect the most disadvantaged. For example, the uncritical press for new drugs and "technomania" has contributed to the increasing costs of new drugs and screening technologies, making access to care even more difficult for many patients, particularly those in developing countries.

Regulatory tools could encourage investment in actual prevention measures (alcohol, tobacco, obesity, physical inactivity), better palliative care, and more integrative care.

There is also a need for improved medical education on the roles of commercial interests in shaping cancer care, which may already mitigate tendencies toward "technomania" among physicians so that medical students have a better appreciation of the costs and benefits of new treatments and technologies, as well as the importance of palliative and end-of-life care with better patient integration.

How can we do better?

In summary, there are ethical and justice issues everywhere, and these issues have to do with respect for patient autonomy, equity, and beneficence.
Autonomy, with strong patient support and transparent communication about the benefit-risk balances of health devices.
Equity and justice about risk identification and prevention, early detection, alternative solutions, therapeutic solutions, and palliative care appropriate to the patient's real need.

Regulatory tools need to be developed to improve medical education, emphasizing transparency. Public administrations, national governments, and international agencies can do, and civil society can demand to mitigate the harms associated with conflicts of interest.

The authors also note a clear need for high standards, both at the level of the European Medicines Agency and through more robust health technology assessment mechanisms, with more sophisticated pricing and reimbursement systems at the national level.

The inadequate quality of research and regulatory standards and the critical lack of correlation between economic incentives and what is sought in terms of overall patient quality of life is a critical issue.



Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Cancer Screening—The Good, the Bad, and the Ugly

JAMA Surg. Published online April 6, 2022. doi:10.1001/jamasurg.2022.0669
https://jamanetwork.com/journals/jamasurgery/article-abstract/2790973

H. GilbertWelch,MD, MPH-Center for Surgery and Public Health, Brigham and Women’s Hospital, Boston, Massachusetts.

In clinical practice to say that a person has cancer gives as little information about the possible course of his disease as to say that he has an infection. There are dangerous infections that may be fatal and there are harmless infections that are self-limited or may disappear. The same is true of cancers. Cancer is not a single entity. It is a broad spectrum of diseases related to each other only in name. George Crile,MD, cancer surgeon 1 (p128)

Dr Crile’s recognition of the heterogeneity of cancer growth

Dr Crile's recognition of the heterogeneity of cancer growth in a 1955 issue of LIFE magazine presaged why early cancer detection might defy simple intuition. It is tempting to think that cancer screening can only help individuals and that all survivors of cancer detected by screening provide powerful evidence that it saves lives. However, cancer screening is counterintuitive. It turns out that the harms are more certain than the benefits; the survivors are less likely to be evidence of its benefit and more likely to be evidence of its harms.

Dr Criles uses an analogy of a barnyard pen :

The bird is a very fast cancer (missed by screening). The bear is a slow cancer, caught by the screening but which, not screened, would have manifested itself just a little later by a clinical symptom without loss of chance. The turtle and the snail represent very slow and stagnant cancers, for which screening is useless, because they would never have manifested. The patient dies with her cancer but not because of it.
The birds have already escaped the barnyard: they are the fastest growing and most aggressive cancers, those that have already spread by the time they are detectable. Screening cannot help with the birds.

Editor's note, another representation:

Limited (or Uncertain) Benefit

The goal of cancer screening is to reduce cancer mortality. Screening tends to miss the fastest growing cancers (the birds) because these cancers have such a short time window during which they are detectable by screening, but they are not clinically evident. Furthermore, effective screening requires not only earlier detection, but also treatment initiated earlier is reliably better than treatment initiated later.
Now we can notice that as cancer treatment improves, the benefit of screening decays. If clinically detected cancer can be routinely treated successfully, the utility of cancer screening naturally falls to zero.

Poorly Recognized (or Hidden) Harms

From an individual’s perspective, overdiagnosis is the most consequential harm of screening.
Overdiagnosis is so rarely confirmed in an individual (ie, a patient with a cancer that is detected by screening but is not treated, never develops symptoms, and dies of some other cause), so there was considerable debate about whether the problem really existed.
However, overdiagnosis can be easily confirmed at the population level. Thus, debates about the existence of overdiagnosis are now largely settled and have rightly moved to the question about its frequency— and how much it matters. In the case of breast, prostate, skin, and thyroid cancer screening, patients are more likely to experience the harm of overdiagnosis than they are the benefit of screening—avoiding a cancer death.

Problem is: many individuals must be screened to potentially benefit a very few. Roughly 1000 people must be screened to avert 1 cancer death in 10years.2 Thus, questions about what happens to the other 999 individuals become relevant.

Another issue apart from overdiagnosis: false alarms affect many: there are as many as 600false-positive results in a 10-year course of mammography.3 However, the bigger problem is that many people with false-positive test results are not told that the test was wrong, but rather that something is wrong with them.

Misleading Feedback, Financial Incentives, and Distraction

These harms might be acceptable were they accompanied by substantial and certain benefit. Unfortunately, screening itself provides misleading feedback that always suggests it is more beneficial than it really is.

As shown in the example in panel B of the Figure, the proportion of late-stage cancers detected falls from 50% to 25%, despite no change in late-stage incidence. Over time, 5-year survival rises owing to the combined association of lead time and overdiagnosis bias, even if the age of death is unchanged. Survivor stories are particularly pernicious: the more overdiagnosis from screening, the more people there are who believe that they owe their life to the test—and the more popular screening becomes.4 (click on the picture below)

Editor's note: In fact, if overdiagnosis could be completely eliminated, the proportion of advanced cancers would appear to be greater in the total number of cancers minus overdiagnosis, which usually amplifies the total number of cancers. The proportion of advanced cancers is diluted in the total cancer count when the proportion of overdiagnoses is added to this total. See the screening paradox:

Pr Welsch's conclusion

Dr Crile believed that medical care should be driven by patient needs, not surgeon needs (or now, system needs). He recognized there was a price to be paid for getting ahead of symptoms. Although cancer screening may make sense in selected high-risk individuals, I believe general population screening, as currently practiced in the US, has become a huge distraction to our core work.  It distracts the system away from acutely ill and injured patients: as physician performance is measured in terms of how frequently they test the well and not how well they care for the sick. General population screening distracts patients and policymakers away from the genuine determinants of human health. The tremendous resources involved in screening—in terms of money, people, and effort— would be better directed elsewhere.

References

1. Crile G Jr. A plea against blind fear of cancer. Life. 1955;128-142.

2. Welch HG. Evidence on cancer screening efficacy in randomized trials & effectiveness in US practice. Accessed March 2, 2022.
https://csph.brighamandwomens.org/wp-content/uploads/2021/12/Evidence-on-Cancer-Screening-Efficacy-in-Randomized-Trials-Effectiveness-in-United-States-Practice.pdf

3. Hubbard RA, Kerlikowske K, Flowers CI, Yankaskas BC, ZhuW, Miglioretti DL. Cumulative probability of false-positive recall or biopsy recommendation after 10 years of screening mammography: a cohort study. Ann Intern Med. 2011;155(8):481-492. doi:10.7326/0003-4819-155-8- 201110180-00004

4. Raffle AE, Gray JM. Screening: Evidence and Practice. 2nd ed. Oxford University Press; 2019.

Read more: https://cancer-rose.fr/en/2020/12/17/are-small-breast-cancers-good-because-they-are-small-or-small-because-they-are-good/

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

False-positive results in screening: tomosynthesis not effective enough

Summary Dr. C.Bour, March 28, 2022

Tomosynthesis and annual screening: half of the women experience a false alarm

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2790521?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=032522

A study conducted by UC Davis Health* found that half of all women screened annually with tomosynthesis** experience at least one false-positive mammogram over a decade of screening.

Reminder: A false positive occurs when a mammogram is indicated as abnormal, but there is no cancer in the breast; this is after verification by other examinations (ultrasound, MRI, sometimes breast biopsy) and after a waiting period for the results between a few days and a few weeks.

Also, to be reminded, false positives in this screening are common. While approximately 12% of 2D screening mammograms are recalled for further investigation because of a false alarm, only 4.4% of these recalls, or 0.5% overall, result in a cancer diagnosis. Thus, women are most commonly alerted and recalled for nothing, resulting in significant moral harm.

* UC Davis Medical Center is part of a major academic health center located in Sacramento, California.

** Tomosynthesis (TDS): Tomosynthesis (or 3-D mammography) is an X-ray imaging technique that decreases the effect of breast tissue overlay by reconstructing a three-dimensional image of the breast from multiple low-dose X-rays acquired at different projection angles.

The objective of the study

This study aims to answer the following question: Is there a difference between screening with digital breast tomosynthesis (3D) vs. digital mammography (2D) in the probability of false-positive results after 10 years of screening?

Method

This is a comparative effectiveness study of 903 495 individuals undergoing 2 969 055 screening examinations.

Results:

The study found that repeated breast cancer screening with 3D mammography only modestly decreased the risk of having a false-positive result compared with standard 2D digital mammography.

The 10-year cumulative probability of at least 1 false-positive result was 6.7% lower for tomosynthesis vs. digital mammography with annual screening and 2.4% lower for tomosynthesis vs. digital mammography with biennial screening.
Therefore, the risk of false positives is lower when screening is performed every two years instead of every year, but also in the case of non-dense breasts and for older women.
However, as can be seen, the difference is modest, and the reduction in false positives with 3D mammography is only 2.4% compared to standard mammography.

Conclusion.

"Screening technology did not have a very large impact on reducing false positives," said Michael Bissell, an epidemiologist in the UC Davis Department of Public Health Sciences and co-leader of the study, on interview.

The first author notes, "We were surprised that the new 3D technology in breast cancer screening did not significantly reduce the risk of having a false-positive result after 10 years of screening; however, the risks of false-positive results are much lower with biennial screening compared with annual screening."

Contribution of this study

An earlier study was published in JAMA Oncol in 2018 and suggested that screening with the 3D technique was associated with better specificity (i.e., fewer false positives) and an increased proportion of breast cancers with a better prognosis (smaller and node-free) across all age and breast density groups. As the false positive rate was lowered, this resulted in a decrease in the number of repeat examinations.

We had analyzed this study here (only in French) and highlighted several limitations of this study, starting with the too-small size of the sample.
The over-detection problem remained unresolved since the claimed improvement in recalling rates was made at the cost of a significant over-diagnosis.

An article in the BMJ in July 2019 by Jeanne Lenzer, a science journalist, questioned the value of adding tomosynthesis to digital mammography, which she said was unproven. According to this author, the information given to women undergoing this technique, which is on the rise in the United States, is more of a marketing argument than neutral and scientific information.

3D technology has not been integrated into the French screening program due to the uncertainties highlighted by the French High Authority for Health.

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Respect patient preferences

Summary by Sophie, patient et C.Bour, MD

March 28, 2022

Patient Preferences for Outcomes Following DCIS Management Strategies: A Discrete Choice Experiment*

Chapman BM, Yang JC, Gonzalez JM, Havrilesky L, Reed SD, Hwang ES.

JCO Oncol Pract. 2021 Nov;17(11):e1639-e1648. doi: 10.1200/OP.20.00614. Epub 2021 Mar 12. PMID: 33710917.
https://ascopubs.org/doi/10.1200/OP.20.00614

*The Discrete Choice Method (DCM) analyzes consumer choices. Under specific behavioral hypotheses, it makes it possible to explain the trade-offs individuals make between the various attributes of a good or service.

Summary:

Ductal carcinoma in situ (DCIS) is more frequent as it is routinely screened; estimates indicate that 80% of DCIS are of good prognosis and do not threaten women's health. They thus contribute significantly to the overdiagnosis of breast cancer, i.e., needless diagnoses of lesions that, if they had not been found, would not have impacted either the health or the life of women.
But almost all DCIS are treated aggressively by surgery, often combined with radiotherapy and/or hormonal therapy, depending on the management guidelines in each country. In some countries, active surveillance is proposed; in others, like France, DCIS are treated with the same aggressiveness as "true" invasive cancers.

However, there are few studies on patients' preferences for treatment options.

Here the question asked is: What trade-offs are women willing to make between side effects of treatment for ductal carcinoma in situ (DCIS) and future risk of invasive cancer?

Main result: A majority of women (71%) were willing to accept a small increase in future risk of invasive cancer for treatment scenarios that offered a reduction in treatment-related side effects.

The results of this study underscore the importance of shared decision making, weighing risks and benefits, between the patient and the caregiver managing a low-risk condition.

Background

The term "overtreatment" has been used to characterize treatment for conditions that look like early cancer but are not destined to cause symptoms during a patient's lifetime or to be a cause of death. It has been estimated that as many as one in four patients with breast cancer detected by screening may be subject to overdiagnosis and overtreatment.
Much of this burden relates to treating ductal carcinoma in situ (DCIS or preinvasive breast cancer).
In fact, almost all CCIS are treated aggressively with surgery, radiotherapy, and/or endocrine therapy, especially in France.

The 10-year breast cancer–specific survival among women treated for DCIS is 98%-99%, implying that either current therapy is almost completely effective in eradicating breast cancer mortality or many women with DCIS would not have progressed to invasive breast cancer and thus were overtreated.

The exceptionally high breast cancer–specific survival across alternative treatment options has raised concern that in patients who have an indolent form of DCIS, treatment imposes harm without offering significant benefit.

An alternative to standard guidelines that has been proposed is the active surveillance (AS) approach, as is currently offered for many men with early prostate cancer and for women with other conditions considered high risk for breast cancer, such as atypical ductal hyperplasia, lobular carcinoma in situ, or a hereditary deleterious mutation. An AS strategy would entail close monitoring, with the aim of intervening only upon evidence of disease progression.

At the international level, four active prospective clinical trials are testing the safety and benefits of this approach: the LORD trial, which still includes patients.

(Read here: https://clinicaltrials.gov/ct2/show/NCT02492607
-Since February 2019, are also accepted CIS grade II, in addition to grade I
-Since July 2020, the randomized trial has been transformed into a patient preference trial: women have the choice of the trial arm (either surveillance or conventional treatment)
-Estrogen receptor and HER2 testing has been added before patients are enrolled in the trial to rule out high-grade lesions, to make the trials even safer
-There are now 28 sites open in the Netherlands, 6 in Belgium, including a francophone site opened in Brussels : https://www.chu-brugmann.be/fr/research/trials/trial.asp?num=82
15 sites will open in other countries, including France, to come!)

As awaiting the results of these trials, it is important to discern whether AS might be an acceptable option to some women if they were offered the opportunity to evaluate the benefits and harms of alternative management options.

In other words, would women accept other options such as AS instead of standard treatments if the benefit/risk balance was well explained to them?
To test this hypothesis, this study elicited patient preferences to quantify how women are willing to accept trade-offs among the possible management options for CCIS, including AS.

Discrete choice experiments, as in this case, are survey-based instruments used to obtain information about preferences for different aspects of goods and services of interest.
In a discrete choice experiment, participants are asked to choose between two or more experimentally designed scenarios that require trade-offs across the features (termed "attributes") of a good or a service; here, the management of DCIS; by analyzing participants' choices across questions, it is possible to estimate the relative importance of features on choices and how this orients the choices that persons then make.
In oncology scenarios, this may include trade-offs among the additional survival afforded by a proposed cancer treatment and the side effects, inconveniences, or costs associated with that treatment.

Methods

To better understand patient preferences, using a "discrete choice experiment," Hwang and coauthors recruited 194 healthy women in a screening mammography clinic.

Participants were provided with informational videos about the diagnosis and clinical significance of CCIS.
Then the women were asked to imagine that they had been diagnosed with CCIS and then choose between several management scenarios that included the option of aggressive treatments, less aggressive treatments, which also included the estimated risk of cancer and the side effects of treatments.
Different criteria were defined, such as breast appearance, severity of infection in the first year, chronic pain, hot flashes, and risk of developing or dying from breast cancer within 10 years, to create clinical pictures or "health profiles" for the different scenarios, for a more concrete representation for women depending on the choice they would make.

Results:

Not surprisingly, future risk of breast cancer and its attendant risk of mortality were the most important factors when women evaluated hypothetical management options.
However, the study found that over two-thirds of participants were willing to accept some increase in future breast cancer risk to reduce the extent of surgery or the severity and/or duration of treatment-related side effects.

In other words, a majority of women were willing to accept a small increase in a possible future risk of invasive cancer for treatment scenarios that offered reduced treatment side effects.

Conclusion and implication in real life :

This indicates that there is likely a subset of women who, when diagnosed with DCIS, would prioritize a reduction in side effect burden or extent of surgery over future breast cancer risk in certain contexts,  researchers concluded.

Most women were willing to make trade-offs between treatment-related effects and risk of invasive cancer, underscoring the need for shared decision making between patients and providers regarding treatment strategies for carcinoma in situ.

Although many discussions of management options for CCIS focus almost exclusively on future breast cancer risk and risk reduction, the results of this study confirm that women benefit if they are presented with detailed information about risks and treatment outcomes, allowing them to make a fully informed, personalized health decision.

The study confirms that treatment choice decisions for CCIS are highly sensitive to personal preferences, and that no a priori assumptions can be made about the trade-offs patients would be willing to consider when weighing the risks and side effects of treatment.

These complex considerations are fundamental to efforts to de-escalate treatments for low-risk conditions such as CCIS.

Advice for Oncologists, interview with principal author:

https://www.medpagetoday.com/reading-room/asco/breast-cancer/97547
By Jeff Minerd, MedPage Editor March 8, 2022

In an interview, the principal author provides advice to oncologists on how to discuss CCIS treatment options with patients in a thorough and balanced manner.
Shelley Hwang, MD, on Helping Patients Make DCIS Management Decisions/Excerpts

Ductal carcinoma in situ (DCIS) is common in the United States, but there are few studies of patient preferences for treatment options. Authors :
"Estimates indicate that only 30% of DCIS may progress to invasive cancer. Nevertheless, almost all DCIS is aggressively treated with surgery, often combined with radiation and/or endocrine therapy, according to guideline-concordant care."

To better understand patient preferences, using a "discrete choice experiment, "Hwang and co-authors recruited 194 women without breast cancer from a screening mammography clinic. The women were asked to imagine they had been diagnosed with DCIS and then asked to choose among several scenarios that included aggressive and less-aggressive forms of treatment, estimation of cancer risk, and side effects.
Not surprisingly, future risk of breast cancer and mortality were the most important factors when the women evaluated hypothetical management options. However, the study found that more than two-thirds of the participants were willing to accept some increase in future breast cancer risk to reduce the extent of surgery or the severity and/or duration of treatment-related side effects.

This indicates that there is likely a subset of women who, when diagnosed with DCIS, would prioritize a reduction in side effect burden or extent of surgery over future breast cancer risk in certain contexts," the researchers concluded.

In the following interview, Hwang elaborates on the details of the study and how to discuss treatment options with patients.

Do you have any advice for how oncologists can discuss treatment options for DCIS with patients in a thorough and balanced way?

Hwang: One key step is eliciting how much knowledge a patient has about her diagnosis and its implications. I think a surgical oncologist would tend to jump right in and say, it's a cancer, we need to remove it, these are the surgical options. That's always the easiest thing for us to do, but we sometimes neglect to spend time with the patient upfront talking about the diagnosis itself and what the clinical implications are.
And when you're dealing with a disease that has no immediate clinical or life-threatening implications, and specifically for DCIS when we don't even know if it will turn into cancer even if we don't intervene surgically, I think framing the diagnosis first and making sure the patient understands the implications of the diagnosis is important.

Your study used discrete choice experiments, which were first developed for market research. Can you briefly describe how these work?

Hwang: Discrete choice experiments have been used a lot in areas such as health economics to see how people make decisions and weigh pros and cons of all the different aspects of making that decision. So say you're about to buy a house, not only do you have to consider cost but also location, how many bedrooms it has --there are many different components that go into that decision.
It's never just one driver that makes an individual decide which house to buy. There are some very emotional aspects to that too. So a discrete choice experiment tries to come up with a set of attributes that are important for making a certain kind of decision.

In this case it was a diagnosis of DCIS and the decision about how to manage it. We tried to include attributes we thought would be meaningful for patients. So postoperative pain, for instance -- that's something people wonder about and are concerned about. We included different levels of pain in the experiment. Cosmesis and side effects of treatment are also important considerations. We created different scenarios where we mixed and matched these different attributes. We presented them to patients and asked them to choose which scenario most matched their preferences. That gave us an idea of what values patients considered most important when trying to make a decision about DCIS.

I think this is something that's becoming more and more relevant. Cancer screening detects precancers such as DCIS that have no immediate clinical implications. There are no symptoms, there are no mortality implications, there's just this concern, that we're trying to prevent cancers from occurring. And I think the better we are at screening, the more we're going to find ourselves in this position, not only with cancer but also with cardiac disease and metabolic diseases, where we diagnose a condition before the patient has any symptoms.

So I think balancing the pros and cons is a lot more relevant when you're not dealing with immediate life-threatening illnesses, and learning how to talk to patients about these scenarios will be an increasingly important skill.

Your study included women without an actual diagnosis of DCIS. Do you think this limits the generalizability of your results to the general DCIS population?

Hwang:That's a really good point. We didn't feel we could do this study with women who were diagnosed with DCIS, because we didn't know what information they would come in with already. If someone somewhere along the way said to them you have cancer and it needs to come out, that could certainly affect how they viewed their choices.
To do this discrete choice experiment, we needed a group of patients that didn't have a lot of other sources of information about the disease already.
...........

On the other hand, women in the study were coming in and presenting with an abnormality, or they were coming for a breast cancer screening, so they were  already thinking about what would happen if they did have a diagnosis. So we felt like it wasn't a stretch to use this population.

We as surgeons are taught to focus on cancer outcomes and mortality, and we should focus on those things. However, sometimes our training hasn't incorporated how to balance other things that patients care about and helping them apply these values to a treatment decision that's comfortable or preferable to them.

I've found that sometimes surgical oncologists, and oncologists in general, treat the cancer, but what we really need to do is holistically treat the patient along with the cancer. That's the take-home message of this study, underscoring how important it is to treat each person as a unique individual and someone who may not necessarily share the treating provider's belief system.

There is room in medicine to accommodate many differing views of risk and health.

For more information:

Surtraitement du CCIS du cancer du sein de stade 0

Perspective : Les risques de surdiagnostic - Nature

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

A Modeling Study on Overdiagnosis

By the Cancer Rose Collective, March 12, 2022

https://www.acpjournals.org/doi/10.7326/M21-3577

According to a modeling study based on data from Breast Cancer Surveillance Consortium (BCSC), about one in six to seven screened breast cancer cases is overdiagnosed.

This study first highlights that overdiagnosis in breast cancer screening is real.

Results of study

An average of 15.4% (95% CI: 9.4%-26.5%) of screened cancer cases were estimated to be overdiagnosed, reports lead author Marc D. Ryser* of Duke University in Durham, North Carolina, and colleagues.

* Ryser: Marc Daniel Ryser, Assistant Professor of Population Health Sciences. Dr. Marc Ryser is an expert in mathematical and statistical modeling. His research uses biological, clinical, and population-level data to inform and guide the early detection and prevention of cancer.

Below are the results by age group and type of cancer detected (Figure 3 and Table 3).

Beyond the average values, we can observe (Fig 3) that for all age groups, the rate of overdiagnosis can reach maximum values higher than 20%, and according to Table 3, the rate of overdiagnosis at the first screening reaches a maximum value of 28%, at 58 years 21.1%, at 66 years 25.4% and at 74 years 31.9%

In this model study, an interesting finding is that the rate of overdiagnosis increased with age and almost doubled depending on the age range analyzed: 11.5% (95% CI, 3.8%-28.3%) at the first screening at age 50 to 23.6% (95% CI, 17.7%-31.9%) at the last test at age 74.

Comparison with previous data

The authors note, "comparison of our estimates against those from other studies is not straightforward because of differences in overdiagnosis definitions and screening practices."

They conclude that their results regarding overdiagnosis are both higher than previous modeling studies (ranging from 1% to 12%, depending on the studies cited in the article) because of differences in screening practices, diagnostic practices, and modeling assumptions, but lower than other studies that have shown rates much higher than the average in this study.
For example, the Canadian screening trial estimated an overdiagnosis rate of 30% (Baines CJ, To T, Miller AB. Revised estimates of overdiagnosis from the Canadian National Breast Screening Study. Prev Med. 2016;90:66-71. [PMID: 27374944] doi:10.1016/j.ypmed.2016.06.033 ) for cancers detected by screening.
In a population-based study, Bleyer and Welch (Bleyer A, Welch HG. Effect of three decades of screening mammography on breast-cancer incidence. N Engl J Med. 2012;367:1998- 2005. [PMID: 23171096] doi:10.1056/NEJMoa1206809 ) estimated that 31% of all diagnosed breast cancer cases were overdiagnosed.

The authors conclude with the hope that their findings will join a consensus and facilitate decision-making regarding mammography screening.

Conclusions of the Editorial "Reducing the Burden of Overdiagnosis in Breast Cancer Screening and Beyond

The editorial published in conjunction with the study emphasizes the importance of informing women about what this overdiagnosis represents.
(Marcondes FO, Armstrong K. Reducing the Burden of Overdiagnosis in Breast Cancer Screening and Beyond. Ann Intern Med. 2022 March 1. doi: 10.7326/M22-0483. Epub ahead of print. PMID: 35226534.)

Authors underline: « Women who are considering having mammography screening should be counseled about the risk for unnecessary cancer treatment using this information."
Estimating that about 60% of the 280,000 cases of breast cancer diagnosed each year in the United States are discovered through mammography screening, eliminating overdiagnosis could save 25,000 women the cost and complications of unnecessary treatment.

"Substantial advances" in critical areas need to be made, according to the authors, including:
- Develop a better predictive capability to accurately identify tumors that will not progress
- Improve the accuracy of screening technologies to reduce the risk of overdiagnosis and improve the ability to detect breast cancer that has not been detected by mammography
-Implement prevention strategies to reduce the overall rate of breast cancer diagnosis, such as providing counseling on lifestyle changes and screening for genetic risk.

The authors of the editorial conclude: « Screening tests, whether for cancer or other conditions, can provide great benefit by detecting disease when it is more easily treatable. However, the risk of labeling millions of persons as having a disease without improving their outcomes is very real. For now, the key to navigating these tradeoffs remains open and effective physician–patient communication, rigorous evaluation of all proposed screening strategies, and continued investment in early detection research. We look forward to the day when making an early diagnosis always helps our patients achieve better outcomes. »

And the findings go beyond breast cancer screening.
"As screening and diagnostic testing continues to grow in clinical practice, the issue of overdiagnosis is being felt far beyond cancer screening. For some conditions, changing definitions have led patients to be labeled with a predisease state on the basis of a test result that was previously considered in the normal range. Although there are strong arguments in favor of early treatment to prevent long-term complications in many conditions, the reality is that, just as with cancer screening, there is little doubt that some patients diagnosed through a screening test would never have progressed and are likely to be receiving unnecessary treatment."

Comments and criticisms, opinion of Dr. V.Robert, statistician

1-A modeling study

The study remains a modeling study, which means that the results of a model depend on a chosen model and conditions of validity, at best unverifiable and at worst questionable. For example, the authors are obliged to consider that a breast cancer is either definitively non-evolving or inexorably evolving, with no possibility that the evolutionary status of cancer changes over time. It is not clear that things are that simple.

Another example is that the authors are obliged to build their model by considering that all progressive breast cancers evolve at the same rate and that this rate remains constant throughout the evolutionary period. In practice, there are most likely different distributions of progression rates for each type of breast cancer, and it is not clear that progression rates cannot vary over time.

2- The data on mortality from causes other than breast cancer used by the study do not seem well adapted.

On the one hand, after checking reference 25 of the study, which corresponds to the source of these data (Contribution of Breast Cancer to Overall Mortality for US Women): for a population of women aged 50 to 80 years, these data are not derived from direct measurements of mortality but from data estimated from projections (in other words, from models).

On the other hand, the data correspond to a cohort of women born in 1971. Since the median age of the women included in the study is 56 years, the cohort born in 1971 is adapted for the mortality of women included in 1971 + 56 = 2027. Or, if you prefer, the cohort adapted to have the mortality of women aged 56 in 2000-2018 should be born between 1944 and 1962. Whatever the reasoning, it is clear that the cohort considered to obtain the mortality data is too recent by at least a decade. This is not neutral since the tables in Reference 25 show a non-negligible decline in mortality over time.

3-The definition of screen-detected cancers is questionable.

Screen-detected cancers are considered to be those that meet the following two conditions: screening mammograms BI-RADS 3 to 5 + diagnosis of cancer within the next 12 months.
With criteria such as these, interval cancers are likely to be classified as screen-detected cancers (BI-RADS 3 + negative complementary examinations = screening showing no cancer; if a cancer occurs 11 months after the screening mammogram, it is an interval cancer, and yet it will be classified as a screened cancer). Even if these cases are not very frequent, they are part of the data used to adjust the parameters, and adjusting on "garbage in, garbage out" data can only give garbage results.

4- It is wrong to pretend that the study found that the overdiagnosis rate is 15%.

The reality is that the study shows that the overdiagnosis rate is somewhere between 9% and 27% (and any value within that range is possible, no more 15% than 9% or 27%).

Figure 3 from the study:

Depending on the age range, the percentage of overdiagnosis can vary up to 25% or even 32%.

Unfortunately, it is a very common mistake to take the result of a study (estimated rate from a sample) for the reality (real and unknown, rate in the population). And it is an even more common mistake to believe that the estimated rate is more likely to be close to the real rate than any other value in the confidence interval.

Conclusion

Based on such a study, we cannot arbitrarily consider that the debate on the frequency of overdiagnosis is closed, with a definitive frequency of 15%, as the study's authors would like.

On the other hand, the model may be interesting for answering questions about the evolution of the frequency of overdiagnosis as a function of the age of the women screened or about the evolution of the frequency of overdiagnosis as a function of the interval between two screening mammograms.    

Professor Alexandra Barrat of the University of Sydney, interviewed by Amanda Sheppeard, associate editor and reporter for Oncology Republic and The Medical Republic, said there are different methods for estimating the potential rate of overdiagnosis through breast cancer screening.
She said the study demonstrated the inevitability of overdiagnosis in screening for a number of cancers. "I think there is a need in the professional community for greater acceptance of what the evidence shows about breast cancer screening."
"We just need to recognize that this is inherent in a cancer screening program."

As a result, and beyond the evidence, according to A.Barrat, the study helped to underscore the importance of informed consent in breast cancer screening.

Conflicts of interests

Dr Ruth Etzioni - Individual investor and stock in Seno Medical  https://senomedical.com/clinical/product-applications

Seno’s first clinical product targets the diagnosis of breast cancer and will be used in addition to screening mammography, integrating opto-acoustics and ultrasound.

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Preventing Overdiagnosis Conference 2022

FEBRUARY 22, 2022 BY CANCER ROSE

Click on the image to access Preventing Overdiagnosis website

We are invited to Preventing Overdiagnosis Conference in Calgary (9 - 12 June) as speakers for the theme: Promotional messaging vs neutral messaging – impact on individual breast screening decisions when information is suppressed.
Dr. Cécile Bour's presentation is scheduled for June 11 at noon.

Keynote speakers: https://www.preventingoverdiagnosis.net/?page_id=2354

We will expose French censorship of information due to women on the issue of breast cancer screening.

To access the program, click here :




Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Anatomopathology, possible uncertainties

Summary by Dr. C.Bour, 18 December 2021

Observation:

This case involves a 65-year-old woman who began mammograms at age 40 due to a family history of breast cancer (mother at age 80). She has already had biopsies, which revealed that she had a simple mastosis (benign condition of the breast, characterized by tension and pain in the breasts, as well as a "granular" consistency when palpating the breasts, in areas where the mammary gland is more present and dense).

A mammogram revealed two small foci of microcalcifications in one breast. A preliminary macrobiopsy was carried out, but it was unsuccessful due to difficulties in locating them. A few months later, a second macrobiopsy was performed.

The two biopsied sites revealed a carcinoma in situ (ductal carcinoma) and an "atypical hyperplasia" lesion. Due to the presence of two concomitant lesions, a complete mastectomy (complete removal) of the breast was recommended based on the pathology report.

Anatomopathology is not infallible

Breast biopsy samples can be difficult to analyze.

In a 2016 study published in the BMJ, American researchers assessed the effectiveness of 12 different strategies in reducing interpretation errors (second opinion requested for all samples, second opinion only in the case of atypia, or only in the case of the wish of the first pathologist or for first readers with less experience in breast pathology, etc...).

115 pathologists examined 240 breast biopsy specimens, one slide per case, and compared their observations to an expert consensus diagnosis.

This study revealed that pathologists who took part in the study disagreed with the expert panel's consensus about 25% of the time. Most of the disagreements were with specimens from difficult-to-interpret conditions, such as atypia, which occurs when cells appear abnormal but are not cancerous, and ductal carcinoma in situ (DCIS)

The conclusion of the study: except for invasive cancer cases where the second opinion rarely differs from the initial interpretation, ALL strategies requiring a second opinion improve diagnostic concordance and reduce misclassification rates of breast specimens from 24.7% to 18.1%, showing that variability in diagnosis is still only incompletely eliminated, especially for breast specimens with atypia.

A second opinion is thus recommended because it can mean the difference between a diagnosis of benign hyperplasia or carcinoma in situ, influencing surgical sanctions, the need for re-intervention, radiotherapy, and/or chemotherapy.

As a result, a second opinion can help patients make a therapeutic choice.

Why not propose a more systematic second reading of the biopsy?

In the case of a positive biopsy, the start of the disease is defined by this single examination of the tissue taken under the microscope (i.e., except for invasive cancer, where uncertainty is rarer) (histological diagnosis).

And it is astounding to note how, on the one hand, DCIS is considered a “stage 0” breast cancer with a very good prognosis, and how, on the other hand, the therapeutic sanctions for this DCIS and a fortiori for pre-cancerous lesions can be extremely aggressive, as aggressive as for a "true" invasive cancer.

The patient does not know the name of the person who read her biopsy; worse, she does not have the choice of the reader of her biopsy, the anatomopathologist, contrary to the choice she has for the general practitioner, the gynecologist, and even a surgeon if necessary.

This pathological anatomy report is never communicated to the patient, although it is strictly necessary and mandatory for treatment to begin. It determines the course of treatment and the therapeutic options available.

On the other hand, the pathology report is part of the patient's file and can thus be requested by the patient.

Recommendations for patients if carcinoma in situ or a borderline or atypical lesion is found.

First and foremost, don't panic; take your time. You have the following options:

1- Request that the biopsy results be sent to you physician.

2- In the event of a failure, request a complete copy of the medical file (mandatory within 8 days)

3- If you are unsuccessful, request that the Medical Council intervene to obtain it for you. You are the owner of the medical file.

4- With the result, it is legitimate to ask for a revision of the anatomopathology slides. You can even have the file re-examined by an expert (your general practitioner just has to ask for it).

5-It is also possible to ask for a second opinion from another surgeon, possibly located in another region.

The therapeutic choice can be discussed: a less aggressive intervention or even simply "careful monitoring," knowing that unfortunately in France, for the moment, very few practitioners are adept at this wait-and-see approach which is being studied in several large European trials, including the LORD trial which is still including patients.

Read here: https://www.dcisprecision.org/clinical-trials/lord/https://www.dcisprecision.org/clinical-trials/lord/

(-Since February 2019 are also accepted CIS grade II, in addition to grade I

-Since July 2020, the randomized trial has been transformed into a patient preference trial: women have the choice of the trial arm (either surveillance or conventional treatment)

Estrogen receptor and HER2 testing has been added before patients are enrolled in the trial to rule out high-grade lesions, to provide even greater safety in the trial

-There are now 28 sites open in the Netherlands, 6 in Belgium, and 15 sites will open in other countries (France, to come!)

Conclusion

An anatomopathological diagnosis should be reviewed and discussed by caregivers, rather than being accepted as a "gold standard" because it may trigger a series of aggressive treatments, the usefulness of which should be discussed with the patient.

Read more :

https://newsroom.uw.edu/story/second-opinions-notably-reduce-breast-biopsy-misdiagnoses

Website DCIS

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.


Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Explanation of the Cancer Rose Decision Support Tool

By Cancer Rose, November 27, 2021

The decision aid describes the number of cancers, the number of deaths from cancer, and the number of false alarms estimated in 2 cohorts of 2,000 women starting at age 50:

- One cohort participates in organized screening until age 59 and has 5 screening mammograms (at age 50, 52, 54, 56, and 58)

- The other cohort does not participate (0 screening mammograms).

The calculations are based on:

- French epidemiological data available (in October 2021) on the Santé Publique France website 1,2

- An assumption of 65% of the women concerned getting screened (50% through organized screening + 15% through screening on individual initiative). This hypothesis is consistent with the figures announced by INCa 3

- A hypothesis of overdiagnosis representing 20% of cancers detected in a population of screened women. This hypothesis is in the middle of the range of published values and is compatible with the range of values accepted by INCa (1 to 20%) 4

- An assumption of a 15% reduction in mortality through screening. This assumption is in the middle of the range of published values and is consistent with the range of values accepted by the INCa (15 to 21%)4

1-Estimation of the number of cancers

The epidemiological data used are presented in the table below extracted from reference 1.

click on image

The incidences shown above are expressed as the number of breast cancers per 100,000 women.

For 2.000 women, we have :

- for women aged 50-54:

285.1*2000/100000 = 5.702 cancers / 2.000 women

- for women aged 55-59:

273.1*2000/100000 = 5.462 cancers / 2,000 women

In a cohort of 2,000 women, we would observe:

5.702 cancers when the cohort is 50 years old

5.702 cancers when the cohort is 51 years old

5.702 cancers when the cohort is 52 years old

5.702 cancers when the cohort is 53 years old

5.702 cancers when the cohort is 54 years old

5.462 cancers when the cohort is 55 years old

5.462 cancers when the cohort is 56 years old

5.462 cancers when the cohort is 57 years old

5.462 cancers when the cohort is 58 years old

5.462 cancers when the cohort is 59 years old

This means a total of 55.82 cancers (rounded to 56)

This incidence, cumulated over 10 years, of 56 cancers per 2,000 women corresponds to a cohort representative of the French population. This population comprises screened women and women who are not getting screened.

In other words, the 56 cancers are the sum of cancers that affect women who get screened + cancers that affect women who do not get screened.

This can be expressed as 56 = PD*CD + PN*CN

where CD  = cumulative incidence of cancer in women who are screened

        C = cumulative incidence of cancers in women who are not screened

       PD  = proportion of women who are screened

       PN = proportion of women who are not screened

With our assumption of 65% of women being screened: PD  = 0.65 and  PN = 0.35.

We therefore have: 56 = 0,65*C+ 0,35*CN  (equation 1)

With our hypothesis of 20% overdiagnosis of cancer among women who are screened, we have: overdiagnosis = CD - C= 0,2*C       d'où   CN = 0,8*CD   (equation 2)

Combining equations 2 and 1, we obtain: 56 = 0,65*CD + 0,35*0,8*C  soit : 56 = 0,65*CD + 0,28*CD  

hence : 56 = 0,93*CD      hence :  CD = 56/0,93 = 60,22     and : CN = 0,8*CD = 0,8*60,22 = 48,18

In summary:

- the number of expected cancers in the screened cohort can be estimated at 60

- the number of expected cancers in the non-screened cohort can be estimated at 48

- the number of overdiagnoses in the screenedcohort can be estimated at 12.

2- Estimating the number of deaths

The epidemiological data used are presented in the table below taken from reference 2.

click on image

The data for women aged 50 and 60 allows us to draw Graph 1 below.

This graph suggests that survival tends to stabilize at around 70% over time. Therefore, the lethality associated with breast cancer can be estimated at approximately 30% (by lethality, we mean the proportion of women with breast cancer who will die).

To have at least 20 years of hindsight in 2018, the data come from cancers diagnosed before 1998, therefore, before the organized screening. We can therefore consider that this 30% lethality concerns unscreened women.

The number of deaths in the unscreened cohort can be estimated by applying this 30% case fatality rate to the 48 breast cancers expected in this cohort.

Thus: number of deaths among women not screened = 48*0.3 = 14.4 (rounded to 14)

Assuming a 15% reduction in mortality in the screening cohort, the number of deaths in this cohort equals 85% of the number of deaths in the unscreened cohort.

Thus: number of deaths in the screening cohort = 14.4*0.85 = 12.24 (rounded to 12)

In summary:

- The expected number of breast cancer deaths in the unscreened cohort can be estimated at 14

- the number of breast cancer deaths expected in the screening cohort can be estimated at 12

- the number of breast cancer deaths prevented by screening can be estimated at 2.

3- Sensitivity analysis

The assumption of 65% of women being screened is questionable. A sensitivity analysis, using a proportion of women being screened ranging from 50% to 90%, in 10% increments, gives the following results.

Click on image

There is slight variation in the results, particularly in overdiagnosis estimates and avoided deaths.

The assumption of a 30% case fatality in women not being screened is also questionable. A sensitivity analysis, re-running the calculation with a case fatality ranging from 10% to 50% in 5% increments, gives the results below.

click on image

The estimate of deaths is sensitive to the value chosen for the case fatality. In particular, with the problem of rounding, an underestimation of the case fatality, even a modest one (30% rather than 35%), could lead to underestimating the deaths prevented.

However, this underestimation is unlikely because the epidemiological data correspond to cancers diagnosed more than 20 years ago. The therapeutic progress made since then suggests that our estimate of 30% is more likely to be overestimated than underestimated.

4-Two other decision aids

The hypotheses used for the frequency of overdiagnosis (20%) and the reduction in mortality (15%) correspond to median hypotheses and are compatible with the ranges accepted by the INCa. However, it is interesting to look at the outcome of the decision aid based on other assumptions.

Decision aid with assumptions favorable to screening: overdiagnosis = 10% - reduction in mortality = 25%.

click on image

Decision-aid with unfavorable assumptions for screening: overdiagnosis = 40% - mortality reduction = 5%.

Click on image

Références

  1. Defossez G, Le Guyader‑Peyrou S, Uhry Z, Grosclaude P, Colonna M, Dantony E, et al. Estimations
    nationales de l’incidence et de la mortalité par cancer en France métropolitaine entre 1990 et 2018. Volume 1 – Tumeurs solides
    . Saint‑Maurice (Fra) : Santé publique France, 2019. 372p.
    https://www.santepubliquefrance.fr/maladies-et-traumatismes/cancers/cancer-du-sein/documents/enquetes-etudes/survie-des-personnes-atteintes-de-cancer-en-france-metropolitaine-1989-2018-sein
  2. Molinié F, Trétarre B, Arveux P, Woronoff A-S, Lecoffre C, Lafay L et al. Survie des personnes atteintes de cancer en France métropolitaine 1989-2018 – Sein. Boulogne-Billancourt : Institut national du cancer, septembre 2020, 12 p.
    https://www.santepubliquefrance.fr/maladies-et-traumatismes/cancers/cancer-du-sein/documents/enquetes-etudes/survie-des-personnes-atteintes-de-cancer-en-france-metropolitaine-1989-2018-sein
  3. https://www.e-cancer.fr/Professionnels-de-sante/Depistage-et-detection-precoce/Depistage-du-cancer-du-sein/Le-programme-de-depistage-organise
  4. https://www.e-cancer.fr/Professionnels-de-sante/Depistage-et-detection-precoce/Depistage-du-cancer-du-sein/Les-reponses-a-vos-questions

5-Number of positive screenings

Source: "Indicateurs nationaux de performance du programme de dépistage du cancer du sein sur la période 2017-2018. Updated July 12, 2021. Open access on the Santé Publique France website - https://psite.santepubliquefrance.fr/ Last access on September 17, 2021.

https://www.santepubliquefrance.fr/maladies-et-traumatismes/cancers/cancer-du-sein/articles/indicateurs-nationaux-de-performance-du-programme-de-depistage-du-cancer-du-sein-sur-la-periode-2017-2018

During 2017-2018:

- among women aged 50 to 54, 1,131,008 screenings were performed (N01)

- In women aged 55-59, 1,043,554 screenings were performed (N01)

Calculation of what happens to 2000 women aged 50 who start screening without having had any mammograms before and who continue for 10 years, i.e. 5 screening cycles

Number of positive screenings (N05)

A cohort of 2,000 women aged 50 years and exposed to screening for 10 years:

"number of positive L1 or L2 screens before the assessment"

(N05) / number of women screened (N01) x 2,000

50 years old, Initial screening 50-54

23,310 / 150,107 x 2000 = 311 positive tests.

Remaining 2000 - 311 = 1689 women without a positive test.

52 years old, subsequent screening 50-54 years

42,351 / 526,619 x 1689 = 136 positive tests.

Remaining 1689 - 136 = 1553 women without positive test results

54 years old, subsequent screening 50-54 range

42,351 / 526,619 x 1553 = 125 positive tests.

Remain 1553 - 125 = 1428 women without positive test results

56 years old, subsequent screening 55-59

68 566 / 943 696 x 1428 = 104 positive tests

Remain 1428 - 104 = 1324 women without positive test results

58 years old, subsequent screening 55-59

68,566 / 943,696 x 1324 = 96 positive tests.

Remain 1324 - 96 = 1228 women without positive test results

Number of women with at least one positive test after 5 cycles (10 years): 2000 - 1228 = 772

This number was rounded to 770 to avoid giving a false impression of accuracy and precision.

6-Number of interval cancers

Source : Exbrayat C. et coll. "Sensibilité et spécificité du programme de dépistage organisé du cancer du sein à partir des données de cinq départements français, 2002-2006" BEH 2012 ; (35-36-37) : 404-406.

As of November 2011, there is no more comprehensive or recent French data to our knowledge.

In this study of 5 French departments from 2002 to 2006, there were:

414,432 mammograms resulting in 3082 screened cancers plus 638 interval cancers.

The percentage of interval cancers among all breast cancers is therefore :

638 / (3082 + 638) = 638 / 3720 = 17,15 %

Out of 60 cancers, we have 60 x 17.5/100 = 10.29 interval cancers, rounded to 10.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

7-Number of true positives

Since there are 60 breast cancers, of which 10 are interval cancers, the number of true positive cancers detected by mammography is 60 - 10 = 50.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

8-Number of non-overdiagnosed cancers detected

Since there are 12 overdiagnosed cancers (20% of 60), the number of true positive non-overdiagnosed cancers detected by mammography is 50 - 12 = 38.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

9-Number of false positives

Since there are 770 positive screenings, of which 50 are true positives, there are 770 - 50 = 720 false positives.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

10-Number of women who had at least one biopsy

Source:

https://www.santepubliquefrance.fr/maladies-et-traumatismes/cancers/cancer-du-sein/articles/indicateurs-nationaux-de-performance-du-programme-de-depistage-du-cancer-du-sein-sur-la-periode-2017-2018

File: "tableaux de l'ensemble des indicateurs nationaux pour les années 2017 et 2018 cumulées, déclinés par rang published on July 12, 2021. Last access on November 27, 2021.

"Number of surgical biopsies or tumor resection performed (N10)

+ Number of micro or macro biopsies performed (N11)

(N10+N11) / number of women screened (N01) x 2,000

50 years old, initial screening 50-54

N10 + N11 = 1863 + 3711 = 5574

5574 / 150 107 x 2000 = 74 biopsies

Remaining 2000 - 74 = 1926 women without biopsy

52 years old, subsequent screening 50-54 years

N10 + N11 = 3335 + 6330 = 9665

9665 / 526 619 x 1926 = 35 biopsies

Remaining 1926 - 35 = 1891 women without biopsy

54 years old, subsequent screening 50-54

N10 + N11 = 3335 + 6330 = 9665

9665 / 526 619 x 1891 = 35 biopsies

Remaining 1891 - 35 = 1856 women without biopsy

56 years old, subsequent screening 55-59

N10 + N11 = 6438 + 10659 = 17097

17097 / 943 696 x 1856 = 34 biopsies

Remaining 1856 - 34 = 1822 women without biopsy

58 years old, subsequent screening 55-59

N10 + N11 = 6438 + 10659 = 17097

17097 / 943 696 x 1822 = 33 biopsies

Remaining 1822 - 33 = 1789 women without biopsy

Number of women with at least one biopsy after 5 cycles (10 years):

2000 - 1789 = 211 rounded to 210. Of these 210 biopsies, 50 resulted in cancer diagnoses, and therefore there are 210 - 50 = 160 biopsies for women who had a false positive.

Estimation of deaths due to overdiagnosis - Dr. V. Robert

Overdiagnosis is treated in the same way as progressive breast cancer. They, therefore, generate unnecessary treatments (= overtreatments). Like all treatments, overtreatment leads to side effects, some of which can be fatal. This is particularly true of radiotherapy, which can cause lung cancer or heart complications.

It is therefore indisputable that overdiagnosis and its treatment cause deaths. However, it is impossible to quantify these deaths precisely in the absence of reliable epidemiological data.

All clinical trials concluded that there is no significant difference in overall mortality (all causes) between women who are screened and those who are not screened.

This finding can be interpreted in 3 ways:

  • either there is no difference in overall mortality. In this case, the breast cancer deaths prevented by screening have to be compensated by an equivalent excess of deaths from other causes. Applied to our cohort of 2,000 screened women, this means that the 2 breast cancer deaths prevented are compensated by an excess of 2 deaths from other causes due to the 12 overdiagnoses.
  • or there is a decrease in overall mortality among screened women, which does not appear statistically significant due to a lack of power in the clinical trials. At most, this decrease in overall mortality could be equal to the decrease in breast cancer mortality. This assumes that there are no excess deaths from other causes. Applied to our cohort of 2,000 screened women, this means that there are 2 breast cancer deaths avoided and 0 deaths due to overdiagnosis.
  • or there is an increase in overall mortality in screened women, which does not appear to be statistically significant because of a lack of power in clinical trials. In this case, deaths due to overdiagnosis must outnumber breast cancer deaths prevented by screening. Applied to our cohort of 2,000 screened women, this means that the 12 overdiagnoses should account for more than 2 deaths. More than 2 deaths per 12 overdiagnoses means that overdiagnosis would cause death in more than 17% of cases. Due solely to side effects, such high case fatality seems unlikely. We do not support this hypothesis.

In summary: It is not possible to quantify precisely the deaths due to the 12 overdiagnoses, but it is likely that these deaths are between 0 and 2.

Deaths from screening and overdiagnosis - Dr. J. Doubovetzky

Randomized controlled trials have not shown a statistically significant decrease in the number of deaths due to screening. Neither have epidemiological studies (historical or geographic comparisons).

Since the introduction of screening, there has been an overall decrease in breast cancer mortality, but this is mainly attributed to improved treatment and reduction of certain risks (e.g., "preventive" hormonal treatments for menopausal disorders).

As long as it is not demonstrated that screening decreases mortality, it is normal to include the lack of mortality decrease in the assumptions.

Plausible explanatory hypotheses support this view.

There are many potentially fatal adverse effects of screening mammography and overdiagnosis. Unfortunately, these adverse events have never been thoroughly evaluated, so their mortality is not quantifiable.

These potentially fatal adverse effects include:

- The direct effects of ionizing radiation from mammography. To estimate them, we rely on indirect data such as the data from Hiroshima, the impact of the former X-ray monitoring of tuberculosis patients, or even the historical treatment of dermatological diseases by radiation. Linear mathematical models are used, which are known to be wrong.

- Suicides, cardiovascular deaths, and road accidents following the announcement of a cancer diagnosis. Their existence is demonstrated for the first two but not quantified. It is probable for the third. As far as we know, this risk is all the higher when cancer in question is perceived as serious (which is what the pro-screening campaigns contribute to). But we don't have precise figures.

- Anesthetic and infectious complications of biopsies and surgical treatments (known, poorly quantified)

- Cardiac and cancerous complications of over-treatment with radiotherapy.

- Adverse effects of treatments. For example, the undesirable effects of heart failure treatments due to overdiagnosis of radiotherapy. Or the undesirable effects of psychiatric treatments linked to anxiety and depression secondary to overdiagnosis (for example, rhythm disorders secondary to antidepressants by prolongation of the QT interval, or falls or accidents linked to benzodiazepines, partially overlapping with the previous item). These effects have been demonstrated but not quantified. They also depend on prescribing habits, which vary from country to country...

While each of these numbers may seem small, no one can assess the total impact of these adverse events. Any assessment of "I think it is a lot" or "I think it is not a lot" is purely subjective. The only true expression of this risk is "between zero and equivalent to the benefit." Or even more. Some authors have made calculations and projections that the mortality due to the adverse effects of screening and overtreatment would be greater than the gain in mortality made possible by mammography.

For example, Professor Baum estimated that for every life saved by screening, between 1 and 3 lives would be shortened by the adverse effects of overdiagnosis ([1]).

Therefore, the range we have chosen (0 to 2 deaths due to adverse effects of screening and overdiagnosis) is reasonable.


[1]Baum M "Harms from breast cancer screening outweigh benefit if death caused by treatment is included" Br Med J 2013; 346: f385. Doi: 10.1136/BMJ.f385

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