No need to screen out the risks

SCREENING FOR breast cancer is now well established in the Republic. Cervical cancer screening also takes place here and there are plans for colorectal cancer screening to begin soon. Meanwhile, Britain has published a report into the first 20 years of breast cancer screening there. But not everyone is happy with the report as an article in the current issue of the Journal of the Royal Society of Medicine (JRSM) makes clear.

The ultimate justification for screening must be a reduction in deaths from breast cancer. However, according to the authors of the JRSM piece, Karsten Jorgensen and Peter Gotzsche, the NHS Breast Cancer Screening Programme report fails to demonstrate the expected mortality reduction.

In a provocative conclusion, the authors from the Nordic Cochrane Centre in Copenhagen, state: “There is no convincing evidence that has saved lives. In fact, the effect of 20 years of screening in the UK is not visible in the mortality statistics. In contrast, there is solid evidence of serious and common harms, and the screening programme is very costly.”

They are also critical of a lack of comparison of potential benefits with possible harms, claiming this would allow readers (of the report) judge for themselves whether the programme has been worth the cost. And in a full-frontal assault, they declare: “The review exaggerates the benefit, omits the harms, and looks like propaganda aimed at persuasion.” Ouch.

Apart from outright disagreement that screening saves lives, the Cochrane reviewers argue the process results in the overdiagnosis and overtreatment of healthy women. To the lay person, the notion of “overdiagnosis” may seem ludicrous. If a disease is present then surely it needs to be diagnosed? But there are some subtleties at play here: what if screening picks up cases of the disease that otherwise would not have manifested themselves during the person’s lifetime?

Using this argument, for every woman who has her life prolonged, five healthy women, who would not have received a breast cancer diagnosis if there had not been screening, will be converted into cancer patients. Is it too high a price to pay?

Dr Iona Heath, a prominent GP in the UK, wrote about her decision to decline a breast cancer screening appointment, in the British Medical Journal last year. She is concerned about the “overdiagnosis” issue, pointing out that the percentage of women surviving for 10 years if they are not screened is 90.2 per cent; as against 90.25 per cent if they undertake regular breast screening. “Why . . . are autonomous adult women not being fully informed about the scientific debate concerning ‘overdiagnosis’ and the uncertainties about the natural history of ductal carcinoma in situ [cancer that has not spread within the breast]?” she asks.

How does Breastcheck, the Republic’s breast cancer screening programme which began on a pilot basis in 1998, compare? The numbers, the length of time the programme has been running and the age groups screened differ markedly between here and Britain, making direct comparisons difficult.

The latest report to hand is from 2007. It cannot be accused of propaganda; a sober publication, it is full of statistical information. Some 66,527 women were screened in 2007; 396 breast cancers were detected, 72 of which were carcinoma in situ. Of those undergoing their first screening, 7.2 per cent were recalled for further assessment and 42 women underwent open breast biopsies that were benign, a rate of 2.7 per 1,000 women screened.

So, information on potential harms, such as false positives, is in the report. But it is not mentioned outside the statistical tables nor in Breast- check’s Women’s Charter. Why not? For women to make an informed choice, they deserve to read about the risks as well as the benefits in the annual report. And while I’d encourage women to say yes, we might think again about labelling them as “wrong” if they choose to say no.