Why do we value screening so much?

24/08/2024

Dr. René Wittmer is a family physician in Quebec, and Assistant Clinical Professor at the Université de Montréal.
He is also President of the Choisir avec soin Québec campaign, an organization actively committed to shared decision-making with the patient, and a researcher with the Canadian Network for Appropriate Medication Use and Deprescription.
https://lactualite.com/sante-et-science/pourquoi-aimons-nous-tant-le-depistage

According to Dr. Wittmer, “the question of the relevance of cancer screening is a very complex one, and many misconceptions or poorly nuanced ideas pollute the debate.” Indeed, what the general public is often largely unaware of is that ALL screening involves risks, and the issue is whether the balance between the inherent risks of screening and the potential benefits to the population is, without a doubt, really in favor of the promised benefits.

This balance varies considerably depending on the type of screening. It is clearly negative for prostate cancer screening, which is no longer recommended.
The potential harms associated with this screening are sufficiently worrying, which is why, to date, no population-based prostate cancer screening program has been implemented in Europe.
Breast cancer screening, unfortunately, is the subject of commercial campaigns, which confiscate the debate every October and often beyond. Despite scientific questioning, breast screening is heavily promoted with slogans, “testimonials” and simplistic, misleading messages. In this pink concert, it’s almost impossible to make the voice of reason heard…

The problem is the biased presentation of the facts. Yes, women’s mortality from breast cancer has declined since the 90s, and we can only rejoice. But, as René Wittmer explains, “a complete analysis of the scientific data suggests that these advances in women’s health are mainly the result of improved treatments. In Western countries, the reduction in breast cancer mortality observed is more or less the same in countries that screen a lot and those that screen less. What’s more, breast cancer mortality declines markedly even in age groups where screening is not offered.
The good news is that all women benefit from these advances, whether they choose screening or not.”

We love these deceptively reassuring screenings, when we should be more informed, and demand information on all aspects of these health devices, for the following reasons.

Risk underestimation

To quote Dr. Wittmer again: “It’s human nature for survivors to sincerely believe that without screening, their survival would have been compromised. This is true for some, but not for others. It’s hard to accept that the cancer you found might never have become symptomatic, and so you might have received treatment unnecessarily.”

“Conversely, tragic accounts of breast cancer deaths are often accompanied by incentives to screen, implying that screening could have prevented this situation. Unfortunately, even with systematic screening, some women still die of breast cancer (1 or 2 women out of 1,000 in the 50 to 59 age group, and 2 or 3 women out of 1,000 in the 60 to 69 age group).”
Why is this so? Because some cancers are intrinsically lethal by their very nature, and will kill their host no matter what we do.

The amplification of a benefit effect – which, all in all, is rather meagre, as can be seen above – glosses over the undesirable effects of screening, which are immediate and very real, and which represent an accounting reality that is very little explained by the health authorities, in France certainly.
These are false alarms and, above all, overdiagnosis, notions that are extensively developed on our website.

Our French National Cancer Institute sends out an information booklet to women when they are first called for screening at the age of 50; the quality of this booklet is not optimal in terms of side effects, which are largely downplayed, but it has been updated in 2022, which we analyzed here. While overdiagnosis is mentioned, its extent is given in its lowest range.
This low estimate is not erroneous; however, it is dishonest, because what is reprehensible is that no mention is made of the highest range, which is suggested by studies that are much more recent than the estimates given by INCa, and just as solid.
A second criticism of the communication issued by our national institute is that the consequences of overdiagnosis are not detailed, yet for a woman, an unnecessary diagnosis leads to unnecessary treatment, which is far from trivial; it involves unnecessary mastectomies, radiotherapy and chemotherapy, also unnecessary, with all the side effects that this implies.
The third criticism is that, while this insufficient INCa booklet is sent to women at the time of their first screening appointment, it is not sent at all at subsequent invitations, when only a flyer is sent to women, with NO mention of the harms of screening.
INCa therefore merely paid lip service to the requests of the 2016 citizens’ consultation to inform women about overdiagnosis (given at its lowest range), and then found a way to subtract this information from subsequent mailings, scandalously depriving women of the information to which they are entitled.
Finally, the fourth criticism that can be levelled at INCa’s communication is the presentation of information in percentages, thus embellishing the data, instead of providing this information in absolute figures.

Misrepresentation of data, amplification of benefits

This is what René Wittmer points out: “… a survey of American women shows that they attribute far greater virtues to screening than are actually the case. Some 65% of respondents overestimated the benefits by 40 to 50 times…”.
“It can, however, inspire a sense of vulnerability or fear, induce an exaggerated perception of risk (or of the benefits associated with a test or treatment) and create a social imperative that undermines people’s free choice. As patients, we should demand more transparent communication, where risks and benefits are presented in an understandable way. We should no longer be content with hearing that “screening saves lives”.

Communication is the key to enabling women to make their own choices.

Decision-support tools are designed to provide honest information that reflects reality.
The Canadian Task Force on Preventive Health Care (CTFPHC), which published this twitt, was created by the Public Health Agency of Canada (PHAC) to develop guidelines for clinical practice. The group recently published its new recommendations on age-specific breast cancer screening.

In many countries, these tools, presenting very simple visuals to help understand the data, are offered to women, which is also what the French citizen concertation asked for.
As the French health authorities are still not responding to women’s requests, we have reproduced on our website some decision-making tools, which are available to women in a simple and free way.
You’ll find them here: https://cancer-rose.fr/en/category/essential-our-tools/, including the Cancer Rose tool based on French data. You’ll also find help in our “supports”, including a summary poster that healthcare professionals can print out and display in their waiting rooms.

In France, the recommendations are issued by the Haute Autorité de Santé.

The recommendations are important in helping practitioners to find their way through the procedures they will be proposing to these patients. Generally speaking, however, these recommendations need to be reliable and established independently, on the basis of well-conducted studies…

Guidelines correctly established

The guidelines, or recommendations, issued by health authorities can, however, also be subject to controversy and various influences…

A case in point is the recent debate following U.S. recommendations to lower the age of breast cancer screening, supposedly to erase racial differences, as black women suffer more from breast cancer in terms of mortality. Unfortunately, the causes are not to be found in insufficient screening, but rather in flagrant inequality of access to care for black populations.
Not only will the aim of lowering the age of screening not be achieved, but the adverse effects will be much greater for all categories of women if screening begins at the age of 40 – an aberration that has been amply denounced by independent researchers and scientists.
We discussed it here and here.

It’s dismaying to note that these official U.S. recommendations, promoted by the media and opinion leaders, were in no way based on new evidence of the proven efficacy of earlier screening, but on … discussions and rather hazardous modeling.

A Canadian team, with René Wittmer, (again, bravo to these providential and dynamic Canadian friends!), a team that campaigns for the judicious use of healthcare resources, has proposed a detailed table of 10 recommendations, a table of 10 commandments as it were, aimed “in particular at continuing professional development managers, lecturers, teachers, medical school managers, guideline managers and other system players.”

Ten (10) recommendations from Choisir avec soin Québec for the judicious use of resources in guidelines, knowledge transfer tools and scientific presentations

As this article states, “Studies have shown that the majority of expert panels propose broadening diagnostic criteria, and that most of their members have financial conflicts of interest with industry.”
Pharmaceutical companies can also influence expert opinions. Dr. Wittmer and his colleagues advise against using this type of information without considering the potential effect of conflicts of interest.”
“The recommendations of his group (Choisir Avec Soins Québec, Editor’s note) could help to restore order to the various tests and treatments. “Given the explosion in the number of tests and treatments, it’s more important than ever to train doctors who can assess and propose the right tests to the right patient at the right time.

But general practitioners are also concerned: “We invite healthcare professionals to start insisting on transparency in the information they read or listen to. They are probably the most important lever for change. Applying these principles would represent a step forward towards judicious use of our healthcare resources, and should begin as soon as possible.”

We’d like to see this kind of awareness in France, and an end to promotional campaigns around screening, in favor of a shared, informed decision with the patient.
Because, when it comes to healthcare, anything we achieve in excess for targeted populations has repercussions in terms of care deficits for others.

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