According to the co-author of a recent New England Journal of Medicine study, mammograms are largely ineffective in preventing deaths from breast cancer. What the retrospective study by Drs H Gilbert Welch and Dr Archie Bleyer revealed, in essence, was that the mortality benefit of mammography is much smaller, and the harm of overdiagnosis much larger, than previously recognized.
As Dr H. Gilbert Welch wrote in a recent New York Times oped, the effect of three decades of mammogram screening has been the diagnosis of 1.5 million women with early stage breast cancer. While this number might seem impressive, mammography has only reduced the number of women presenting with late-stage (fatal) breast cancer by 0.1 million. What this means, in other words, is that aggressive efforts by public health officials to coerce women to undergo routine mammograms only slightly reduce their risk of dying of breast cancer.
Dr Welch blames the discrepancy on an epidemic of overdiagnosis: his study revealed more than a million women who underwent mammograms were told they had early stage cancer. In most cases this led to unpleasant, invasive and unnecessary treatment (surgery, chemotherapy or radiation) for a non-lethal “cancer.”
In his editorial, Dr Welch laments the misleading statements issued by the Komen Foundation and public health officials that early screening (by mammography) saves lives. The message they should be giving women is that they have a choice. While no one can dismiss the possibility that screening may help a tiny number of women, there’s no doubt that it leads many, many more to be treated unnecessarily for non-lethal cancers. Women have to decide for themselves about the potential benefit and risks. One serious potential risk Dr Welch doesn’t mention is the burden of radiation exposure from a lifetime of unnecessary mammograms.
He recommends instead of screening all women with mammography, health professionals should only target women with a strong family history or genetic predisposition to breast cancer.
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