Sir, Most people could be forgiven for believing that one of the vital weapons in the war against breast cancer is early detection — even before there are any symptoms of breast cancer present. This belief has generated a Europe-wide consensus that screening healthy women for breast cancer will save lives. In the vanguard of this campaign, the NHS screening programme for breast cancer (NHS BSP) by mammography has been lauded as a triumph and has laid claim to the responsibility for the dramatic decline in breast cancer mortality since its initiation 20 years ago. An alternative view is that such success might equally well be attributed to improvements in treatment that anteceded the launch of the NHS BSP.

However, there are harms associated with early detection of breast cancer by screening that are not widely acknowledged. For example, there is evidence to show that up to half of all cancers and their precursor lesions that are found by screening, if left to their own devices, might not do any harm to the woman during her natural lifespan. Yet, if found at screening, they potentially label the woman as a cancer patient: she may then be subjected to the unnecessary traumas of surgery, radiotherapy and perhaps chemotherapy, as well as suffer the potential for serious social and psychological problems. The stigma may continue to the next generation as her daughters can face higher health-insurance premiums when their mother’s overdiagnosis is misinterpreted as high risk. We believe that women should be clearly informed of these harms in order to make their own choice about whether to attend for screening.

The subject has now come to a head with the publication in the next issue of the British Medical Journal of Breast screening: the facts — or maybe not by Peter C. Gøtzsche and his colleagues from the independent Nordic Cochrane Centre. They describe a synthesis of published papers that quantify the benefits and harms of screening using absolute rather than relative numbers that make it easier to comprehend. They conclude as follows: if 2,000 women are screened regularly for ten years, one will benefit from the screening, as she will avoid dying from breast cancer. At the same time, ten healthy women will, as a consequence, become “cancer patients” and will be treated unnecessarily. While there is debate about exactly what these numbers are (some data shows more women benefit and fewer healthy women treated unnecessarily) the overall picture is clear.

The most disturbing statistic is that none of the invitations for screening comes close to telling the truth. As a result, women are being manipulated, albeit unintentionally, into attending. It is therefore imperative that the NHS BSP rewrites the information leaflets, for example by using the template provided by the Nordic Cochrane Centre, and leave it to the properly informed woman to accept the invitation or not.

Professor Michael Baum

Emeritus Professor of Surgery, UCL

Dr Margaret Mccartney

GP and medical writer, Glasgow

Hazel Thornton

Independent Lay Advocate for Quality in Research and Healthcare

Dr Susan Bewley

Consultant Obstetrician/ Maternal Fetal Medicine Guy’s & St Thomas’ NHS Foundation Trust, London

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