The NHS breast screening programme needs independent reviewBMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d6894 (Published 25 October 2011) Cite this as: BMJ 2011;343:d6894
- Susan Bewley, professor of complex obstetrics, Division of Women’s Health, King’s College London
Personal reasons propelled me into the debate on breast cancer screening. As a house officer (in the early 1980s) working for two surgeons—one still performing “frozen section, query proceed to radical (Halsted) mastectomy” and the other promulgating the perceived heretical practice of breast conservation by lumpectomy—we dealt with what seemed an inevitably fatal disease. After my sister’s discovery in 2006 of a malignant lump when in her mid-40s I was impressed by the intervening improvements in diagnosis, treatment, care, and prognosis, which were based on a continuing programme of research evidence.
Approaching 50, with a family history of the cancer (grandmother, aunt, and sister) and risk factors (late childbearing, low parity, obesity), I had to consider screening mammography for myself. It is natural to fear cancer and its treatments and understandable to think “better safe than sorry”—that the promise of early detection could offer me a much better chance of life and health.
I declined screening when it was offered, as the NHS breast screening programme was not telling the whole truth. As a non-expert in the subject, I found myself examining the evidence for breast screening with increasing doubts. I compared the NHS and Nordic Cochrane Centre leaflets1 and found that the NHS leaflets exaggerated benefits and did not spell out the risks.2 Journals showed a reputable and growing body of international opinion acknowledging that breast cancer screening was not as good as used to be thought. The distress of overdiagnosis and decision making when finding lesions that might (or might not) be cancer that might (or might not) require mutilating surgery is increasingly being exposed.3 The oft repeated statement that “1400 lives a year are saved” has not been subjected to proper scrutiny.4 Even cancer charities use lower estimates.5 I expressed my misgivings to you “behind the scenes” as a work colleague. You replied in a personal email “that the large majority of experts in this country disagrees with the methodology used in the Cochrane Centre reviews of breast screening.”
It is extraordinary to be told that methodology is contentious so many years into the national programme. Many people believe that “evidence based medicine” has rightly succeeded “eminence based medicine,” so it was disappointing that such a senior, successful, and respected medical professional apparently disagreed with the open, highly defensible, peer reviewed Cochrane methodology without suggesting something better. That more people support one side of an argument does not make it right. Large groups of well educated, well intentioned, and kind people can be wrong. The fact that British experts see it one way holds no sway, as many do indeed support the Cochrane Centre’s viewpoint.6 Experts simply disagreeing with the Nordic methodology is not enough: it is necessary to know what their expertise is, what their vested interests are (financial, academic, reputation, and so on), how they came to their conclusions, and why they disagreed. Your argument—that our (British) experts are better than their (Nordic) experts—is inadequate and unpersuasive.
There is a science behind the numbers and a duty to debate the facts, question the assumptions, and agree—or at least explain systematically—where the areas of dispute and uncertainty lie. How information is delivered must be explicit so that the ethical imperative for women to come to a free and fully informed decision is supported. The usefulness of screening diminishes with development of better treatments. In recent decades, breast cancer treatments improved unambiguously, so the risk:benefit ratio of screening inevitably changed as the “window of opportunity” narrowed. Evidence questioning the purported size of the benefits of screening continues to accumulate. 7 8 9 10 11 12 It seems that the biology of breast cancer is not fully understood.13 14 15 Predictions of its behaviour from microscopic examination remain elusive. Earlier is not necessarily better: the increasing literature concerning overdiagnosis suggests that many “cancers” detected through screening have been revealed “too early” in their unpredictable lives. Surgery may even accelerate cancer.16 Fixed thinking also means that research opportunities and discoveries arising from new understandings will be delayed.
Women should be reassured that the NHS treats breast cancer more successfully now, but screening is only of marginal benefit, at best. The medical profession needs to find ways to cope with the complex issues. Trust is at stake if the public is not told the full story. In the past few years British women have not been told about the genuine doubts. Those millions of women passing through the breast screening treadmill have been unaware of the problems, criticism, and real numerical risks they face. The new leaflet17 is still not good enough and contrasts with the excellent NHS screening information for men regarding prostate specific antigen testing.18 Whether for historical reasons, the NHS breast screening programme reports to you as cancer director. Accountability to the UK National Screening Committee might merit more professional confidence. It’s uncomfortable to change set beliefs in the face of changing evidence but unforgivable not to. I am not convinced that you have challenged your experts competently and mercilessly, rather than hidden behind them.19 Thus I support the calls for an independent review of the evidence20 21—a real, unbiased review that will not be kicked into the long grass, whose findings will be widely and properly disseminated, and that will adjust screening policy appropriately and will lead to proper pursuit of the research implications.
Cite this as: BMJ 2011;343:d6894