Risk of overdiagnosis doesn’t deter women from breast cancer screening, study finds
BMJ 2013; 346 doi: https://doi.org/10.1136/bmj.f2621 (Published 23 April 2013) Cite this as: BMJ 2013;346:f2621All rapid responses
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The battle between proponents and opponents of breast screening has reached a well entrenched stalemate. (1). A new randomised trial which could confirm or refute breast screening benefits is not realistically feasible.
The women's views in this study offers an elegant way forward. (2). We need to untangle the issue of over- treatment from over- diagnosis. Rather than concentrating on over- diagnosis, the option of active surveillance for low grade lesions needs to be explored.
The use of PSA screening in men coupled with active surveillance for low risk prostate cancer suggests that this approach is clinically feasible. (3). Non- prostate clinicians should note that active surveillance is different from wait &watch policy. Active surveillance implies close clinical observation followed by active curative treatment when there is progression of lesions (low grade cancer or DCIS) whereas a wait &watch policy implies symptom directed, often palliative, management of cancer.
A feasibility study followed by a large scale randomised study of active surveillance for 'low- risk' screen detected lesions (DCIS or cancer) is urgently needed. Cancer Research UK should use its considerable resources to kick start an active surveillance trial for women.
References
1. Independent UK Panel on Breast Cancer Screening, The benefits and harms of breast cancer screening: an independent review. Lancet 2012;380:1778-86
2. Waller J, Douglas E, Whitaker KL, Wardle J. Women’s responses to information about overdiagnosis in the UK breast screening programme: a qualitive study. BMJ Open 22 Apr 2013, doi:10.1136/bmjopen-2013-002703.
3. NICE clinical guideline 58. Prostate cancer: diagnosis and treatment. 2008. http://www.nice.org.uk/CG058 (accessed 29 April 2013).
Competing interests: No competing interests
Seems strange to me that women could be shocked about over-diagnosis, and about consequent over-treatment yet still have faith in screening. Indeed why was the headline 'Risk of over-diagnosis doesn't deter women from breast cancer screening' rather than 'women shocked about over-treatment'? The way in which information was presented might have created bias towards screening and the terminology employed to decribe low-grade DCIS is of particular concern. It demonstrates also why we need careful scrutiny of the new breast cancer screening information leaflet and desperately need good and speedy recruitment to the forthcoming Low Risk DCIS trial (LORIS)see Fallowfield LJ, Francis A, Catt S, Mackenzie M, Jenkins V. Time for a low-risk DCIS trial: harnessing public and patient involvement, 2012. doi:10.1016/S1470-2045(12)70503-X
Competing interests: No competing interests
Forty women informed by researchers about overdiagnosis still thought they would rather attend screening than miss a treatable cancer. Therefore we may deduce that the researchers didn’t get the message across.
Breast screening has not been shown to save life by finding treatable cancers that would otherwise be missed.
The researchers gave limited selective information using estimates showing ‘lives saved’ and which are inherently uncertain. There is no reason to favour these estimates over others and to omit to mention that other studies find no contribution to mortality reduction from screening and that some women die sooner. Had these women been fully informed, and had time to assimilate the bigger picture, they would have been able to see that accepting screening for a chance of benefit is a triumph of hope over evidence.
These women still think that the important decision is not about screening, but treatment. To be labouring under that misapprehension after receiving information shows the inadequacy of the information, not that they have made a considered evaluation of screening.
They think that after a screening ‘diagnosis’ it will be possible to distinguish life-threatening from other cancers and treat them differently. These women needed to know that by screening they embark on a cascade of interventions outside their control. They needed to know that whether their diagnosis is of invasive or noninvasive cancer no-one can predict its future course yet there is no evidence that anyone lives longer after what is in effect precautionary treatment and if anyone does they will never know. For any individual, it is highly unlikely that they have been helped by screening. The majority, or all, receive cancer treatment for nothing, or cancer treatment early to no avail.
The very existence of the programme in the face of these facts is enough to confuse and appears to confuse even the professionals involved. Practitioners continue daily to screen women who still have no access to fair information, apparently without troubled consciences.
If the message wasn’t got across to forty women in a focus group, then it is blindingly obvious that an information leaflet of whatever quality is not enough to inform about the serious risks of accepting screening. Equally, if this team thought it acceptable to inform selectively when investigating how information affects decisions, there is little hope that the revised information leaflets, if they ever appear, will do better.
That the women in this study got as far as they did in understanding the pointlessness of breast screening on the limited information they were given is testament to the fact that the only reason any women still want screening is because other people want them to want it for their own dark reasons. “CRUK continues to recommend that women go for breast screening when invited.”
Healthy women will go on being made cancer patients, with the permanent distress and damage that goes with it, until screeners can absorb the information themselves, and they seem to be a lot slower than women.
Competing interests: Diagnosed through screening
Re: Risk of overdiagnosis doesn’t deter women from breast cancer screening, study finds
Prof Fallowfield is so right to say the headline should have been “Women shocked about overtreatment.” They would be. If they knew.
I am worried about the DCIS trial she mentions. How can it be ethical? The distinction between DCIS and invasive cancer is not material to the outcome of screening. Nobody ever was shown to benefit from treatment following a screening diagnosis whether of invasive or noninvasive cancer compared with the nonscreened. Screening has not been shown to prolong anyone’s life, whatever their diagnosis. We already know that.
Therefore to randomize women to treatment or monitoring means consigning half the subjects to treatment it is already known will not improve their chance of survival while inflicting needless harm. The other half will be assigned to monitoring it is already known will not reduce their chance of survival while sparing them futile harm.
Moreover, monitoring raises the chance of overdiagnosis. What change would warrant intervention? Since diagnosing nonsymptomatic breast cancer has not been shown to improve survival, these women too will be at raised risk of overdiagnosis without evidence of a chance of living longer than they would have without monitoring.
It is unethical to carry out a trial without securing informed consent. This means women must consent to a chance of being randomized to treatment. Treatment is either a totally futile harm or a pointlessly early harm with added years of suffering but not survival, with the additional harm that they can never know which it is. Who in their right mind would consent to that?
It would follow that any who agree to participate in the trial have not understood its implications. The reactions encountered in the feasibility study mentioned by Professor Fallowfield show the difficulty of ensuring that participants would not bitterly regret their decision as they experienced the realities which they had only (briefly, on dubious information) considered in the abstract before consenting.
Would the researchers be participants? If so, it could only be because they believe that screening saves lives thus creating a difference between trial groups. But this belief is unwarranted by the existing evidence. It cannot be right to endanger people by conducting research without taking account of existing evidence.
Can it be ethical to capitalize on the unethical practice of screening for the purpose of research? To recruit women into a trial after they have received a diagnosis for which they had not been adequately prepared? When they might (surely would) not have been screened had they known? To yield what knowledge, that we do not already have?
Overdiagnosis involves both invasive cancers and DCIS. The distinction is a red herring because some invasive cancers do not progress while some noninvasive cancers do. Therefore, shouldn’t any trial randomize both DCIS and invasive cancers to treatment or monitoring? But since we already know that the screen-diagnosed do not live longer than the nonscreened, that would be unethical for the same reasons. People get hurt.
Competing interests: Diagnosed through screening