The breast screening controversy

Abstract

of screening, it could be argued that one in three of these deaths could be prevented. In other words, about 0.3% of women invited for screening over a decade would be saved from a premature death. Against this benefit has to be balanced the undoubted harm of the anxieties that are generated, the false alarms, the unnecessary biopsies and the diagnosis of borderline pathology [2]. This area is most problematical. Post mortem studies of women dying from unrelated causes have suggested that perhaps only one in four or one in five cases of in situ carcinoma would progress to invasive disease in that woman’s lifetime [3]. The other women with the label “duct carcinoma in situ” carry the stigma of breast cancer for the rest of their lives, they have a disease where there is great uncertainty about its treatment so there is every chance she could be overtreated, and she may be denied life insurance, health insurance, or a mortgage. Furthermore, even those women diagnosed with invasive breast cancer only benefit in a minority of cases. The others will merely extend their period of observation and this has been estimated as a lead time of say 2 years. Putting it another way, some of these women will be predetermined to die in any case and others would have been cured if their disease had presented clinically. All they gain is an additional 2 years’ knowledge that they have breast cancer without anything to show for it (it is arguable though that many of these women might enjoy conservative surgery rather than a mastectomy). It is often stated that if nothing else, screening offers reassurance, yet one must ask, who generated the anxiety in the first place? Surely the marketing initiative for the screening programme must carry some of that blame. Just how much reassurance does a woman get with a normal screen. In the 3 year period betwen one screen and another, six per thousand women would normally develop breast cancer. A negative screen can provide false reassurance, and, with the current interval cancer rate (i.e. the cancers that become palpable lumps between one negative screen and the next scheduled screen), we might expect approximately three per thousand women to develop breast cancer in the interval after a negative mammogram [4]. In other words, the additional reassurance that a normal mammogram provides is 0.3%. It might be that the individual woman faced with these statistics would accept the invitation to screen out of a sense