24 August 2020 by Cancer Rose
We have previously reported on a publication by Stephen Duffy and al. about the final results of the UK Age Trial on breast cancer screening by mammography [1].
This is the "nth" publication by this author, which attempts to show the benefits of screening mammography for women, even at an early age, in this case from the age of 40.
We explained that, contrary to the result that Prof. Duffy is victoriously brandishing, the most important statement of his study was :
"After more than 10 years of follow-up, no significant difference in breast cancer mortality was observed in the intervention group compared with the control group, with 126 deaths versus 255 deaths occurring in this period (0-98 [0-79-1-22]; p=0-86). Overall, there was no significant reduction in breast cancer mortality in the intervention group compared with the control group, with 209 deaths in the intervention group versus 474 deaths in the control group by the end of follow-up (0-88 [0-74-1-03]; p=0-13). »
Therefore, no benefit can be expected from screening.
But what does the international scientific community think of this study?
1) Position paper by Professor Anthony MILLER [2], professor at the University of Toronto [3].
Professor Miller is a leading expert in breast cancer screening since many years, as evidenced by his publications. [4] [5]
For this scientist, the absence of a control group without screening in the study is critical for drawing any conclusions about the interest and possible benefit of screening.
This point is essential, because the omission of a control group without any screening is a major shortcoming that we highlighted in another ongoing trial on screening, namely the MyPeBS study [6], a European trial that aims to compare a personalized screening strategy to the standard screening in 4 European countries and Israel.
Again, the use of a control group "without any screening" was carefully omitted, which was the only way to know whether or not screening would be beneficial compared to women who had never been screened.
While no conclusions can be drawn from a medical intervention without a control group which is not affected by the process being tested, Duffy and al. nevertheless assert :
"There was a substantial and significant reduction in breast cancer mortality, of the order of 25%, associated with the invitation to yearly mammography between age 40 and 49 years in the first 10 years."
It should also be noted that the 25% reduction (Relative Reduction) put forward by the authors is far from being "substantial", since the absolute reduction is actually only 0.04% [7].
Anthony Miller also contests, with references [8], the minimization of over-diagnosis, which Professor Duffy persistently tries to minimize in his demonstration: "Results with respect to breast cancer incidence suggest at worst modest overdiagnosis in this age group, and that any overdiagnosed cancers would otherwise be diagnosed at NHSBSP screening from age 50 years onwards. Therefore, screening in the age group of 40-49 years does not appear to add to overdiagnosed cases from screening at age 50 years and older. There might have been some overdiagnosis in the intervention group and during the intervention period, which was balanced when the control group received screening in the NHSBSP. However, we cannot directly observe or estimate overdiagnosis in a trial in which the control group also receives screening, albeit later than the intervention group. »
Studies on over-diagnosis are numerous and attest to this phenomenon in all age groups [10].
However, authors Duffy et al. concede: “we cannot directly observe or estimate overdiagnosis in a trial in which the control group also receives screening, albeit later than the intervention group”.
We therefore again come back to the fundamental obstacle: without a group free of any screening, no reliable conclusion can be drawn either on the benefits in terms of mortality or on the evaluation of over-diagnosis.
2) Other scientists
Journalist Jacqui Wise [11] published an analysis of this study in the British Medical Journal, including remarks made by other scientists about the study.
A-Reaction by K-J.Jorgensen [12]
Karsten Juhl Jørgensen, acting director of the Nordic Cochrane Centre in Copenhagen, told the BMJ : “Since the trial was initiated, breast cancer mortality in the UK in the included age range has been cut by half due to major improvements in treatment, including centralisation and specialisation of care, as well as better systemic treatment.
“…we can be reasonably sure that any benefit in absolute terms will be less today, as there are simply substantially fewer lives to be saved ».
The trial was originally planned to include 195,000 participants, but the number was revised due to slow recruitment. Jørgensen said, Jørgensen said, “As the 160 000 women enrolled in this study was not enough to show any difference in overall mortality, the study really cannot be used to conclude that ‘lives were saved.’
“The study tells us very clearly that any benefit of breast screening in this young age group is very small in absolute terms, as you would expect due to the inherently low risk of breast cancer death before age 40 years.”
In other words, it is impossible, in a population with a very low incidence of breast cancer (young women) [13], to conclude that a reduction in deaths can be obtained through screening. This is another factor that the author of the study has not taken into account.
Jorgensen also pointed out the number of false alarms experienced by women in the test group, i.e. 18% of the women during the trial period.
B-Reaction of V. Prasad [14]
For Vinay Prasad, Associate Professor at the University of California, San Francisco : “It is disappointing to see the authors of this study continue to promote misleading rhetoric ».
”Saves lives” said V. Prasad “means that women, as a result of doing this, live longer than those who do not do it. That did not occur in this dataset. Quite the opposite.” He added “The authors note a very small reduction in death from breast cancer which is tiny, and so small it does not impact dying for any reason.” [15].
D-Reaction from scientists of Sydney University in the Lancet.
https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(20)30528-3/fulltext
"An earlier report on the trial (Moss SM Effect of mammographic screening from age 40 years on breast cancer mortality at 10 years' follow-up: a randomised controlled trial.Lancet. 2006; 368: 2053-2060), where mean follow-up was 10·7 years, did not find a significant difference in breast cancer mortality between groups, and there was no breast cancer mortality benefit in the trial overall (after a median follow up 22·8 years). "
E- Two additional responses, from eminent scientists, were made to Wise's article in the BMJ [16]
First of all, the opinion of Professor Michael Baum, Professor Emeritus of Surgery and Invited Professor of Medical Humanities at University College London.
For Professor Baum there are only two significant outcome measures in the practice of medicine for the patients we follow: length and quality of life. All other outcome measures should be considered, in his view, as surrogates.
M Baum comments :
« This trial claims that screening woman under the age of 50 for breast cancer, will save lives without having a detrimental impact on Qof (Editor note : quality of life). Starting with the first claim let us look at the raw numbers without any modelling or “mathemagic”, and here I acknowledge the help of Dr Vinay Prasad. The percent of deaths from breast cancer in the intervention and control arms were, 0.39 v 0.44, whilst deaths from all causes were, 6.5 v 6.5. Little evidence for screening as a “life saver”.
“As there was no formal assessment of QoL then we have to make the assumption that over-diagnosis or false positive results might impact on the woman’s psychological wellbeing to which can be added the toxicity of any surgery, radiotherapy or systemic therapy as the consequence of over-diagnosis”.
M. Baum estimates, based on available data, that 35% of women experience false alarms and over-diagnosis during the intervention period, with the consequent impact on their quality of life. According to Michael Baum, the authors' conclusions are unfortunately mainly driven by an ideological attitude that is not worthy of scientists.
Next, the opinion of Hazel Thornton, Honorary Visiting Research Fellow in the Department of Health Sciences at the University of Leicester who also comments.
« Recruitment of the 160,921 women in this study took place from 1990 to 1997. We learn that women in the intervention group were unaware of the study. In other words, they were denied their right to consider whether they wished to participate in the study. Screening by mammography is not without potential for harm: properly informed consent should have been sought from these asymptomatic citizens. The fundamental principle of the Declaration of Helsinki, of respect for the individual and the right to make informed decisions, was ignored.[17]
For H. Thornton, the problem with organized screening is that it focuses on the women who benefit from it, while neglecting the hundreds of women who go through this public health process and suffer harm, in some cases even psychological harm.
H. Thornton also refers to the current pandemic and its economic stakes.
« They (Editor note, those who talk about saving lifes) seem unable to see the wasteful disproportionateness of their stance at a time when currently, in the UK, for example, 1.85 million people are waiting for treatments put on hold in this time of pandemic. Only Covid-19 seems to have had the power to put a stop to breast screening when evidence, reason and clamours for distributive justice have not. »
In conclusion
We therefore see that many international scientific personalities are questioning Professor Duffy's conclusions.
This study and the sound analyses show once again, and this against the conclusions of the author, that breast cancer screening by mammography does not bring any benefit.
We remind that all published studies, and even the Duffy ‘s study presented here as "positive", demonstrate year after year, the ineffectiveness of screening in reducing mortality from breast cancer.
More and more voices are being raised calling for an end to this ineffective screening that has adverse effects on women.
It is quite disturbing to note that the scientific controversy, now almost swept away by ever-increasing evidence of the ineffectiveness of the program, is once again being renewed by the beliefs and ideology of scientists, as raised by Mr. Baum, and that these beliefs and ideology are leading these scientists to engage in manipulations of figures in order to erase the bitter failure of the results of an old trial, which was very well conducted, and whose conclusions on the failure of screening are nevertheless implacable.
Moreover, as Jorgensen and Thornton point out, all of these screenings have a cost that would certainly be better used elsewhere, especially in this epidemic period. Not to mention the cost of false alarms, both financial and psychological, that women have to face.
In addition, as Thornton points out, there is a lack of informed consent, as well as manipulative information which are often used with women.
In the next two articles, we will refer to this crucial issue of informing women about screening, and we will relate how screening promoters deliberately manipulate the information they give to women, when they give it….
References
[1] https://cancer-rose.fr/en/2020/11/30/absence-of-benefit-from-mammograms-in-women-aged-40-50-years-confirmed-by-final-results-of-uk-age-trial/
[2] https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(20)30428-9/fulltext?rss=yes
[3] https://www.dlsph.utoronto.ca/faculty-profile/miller-anthony-b/
[4] https://pubmed.ncbi.nlm.nih.gov/24519768/
[5] https://cancer-rose.fr/en/2020/12/30/impact-of-screening-mammography-on-breast-cancer-mortality/
[6] Read : https://cancer-rose.fr/en/2020/11/30/letter-of-4-collectives-on-the-subject-of-mypebs-study/
[7] https://cancer-rose.fr/en/2020/11/30/absence-of-benefit-from-mammograms-in-women-aged-40-50-years-confirmed-by-final-results-of-uk-age-trial/
[8] references quoted by A. Miller :
Forrest APM Aitken RJ,Mammography screening for breast cancer. Annu Rev Med. 1990; 41: 117-132
Marmot MG Altman DG Cameron DA Dewar JA Thompson SG Wilcox M-The benefits and harms of breast cancer screening: an independent review. Br J Cancer. 2013; 108: 2205-2240
Miller AB To T Baines CJ Wall C-The Canadian National Breast Screening Study-1: breast cancer mortality after 11 to 16 years of follow-up. A randomized screening trial of mammography in women age 40 to 49 years. Ann Intern Med. 2002; 137: 305-312
Miller AB Wall C Baines CJ Sun P To T Narod SA-Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial. BMJ. 2014; 348: g366
Baines CJ To T Miller AB-Revised estimates of overdiagnosis from the Canadian National Breast Screening Study. Prev Med. 2016; 90: 66-71
[9] National Health Service Breast Cancer Screening,
[10] See part "overdiagnosis" in this article: https://cancer-rose.fr/en/2020/12/17/mammography-screening-a-major-issue-in-medicine/
[11] https://www.bmj.com/content/370/bmj.m3191
[12] https://www.bmj.com/content/370/bmj.m3191
[13] Hill C. Screening of breast cancer. Presse med. 2014 mai;43(5):501–9