Fewer mammograms means more breast cancer deaths

Our Review Summary

This broadcast describes data from two recent government reports showing that fewer women are undergoing mammograms and fewer mammography centers are in business today than a few years ago. It quotes one expert who says this means that more women will therefore die of breast cancer. Few would argue that all women should have access to mammography. However, the broadcast provides no evidence to support the dire conclusion of the expert that more deaths will ensue. It also fails to balance this view with information about the potential harms of mammography. And it neglects to note that the GAO report says that current capacity is “likely adequate.”  What is the quality of evidence on this complex topic? There is no way to tell from the broadcast whether the scientific evidence supports the view that fewer mammograms will categorically result in more cancer deaths, nor any attempt to weigh this against the evidence that mammography may produce harms as well as benefits.  Most experts believe that mammography in women aged 50 to 69 saves lives; its benefit in those younger and older is controversial. But like other cancer screens, improved survival among women who undergo mammography may be deceiving. It is possible, for example, that screened patients do not actually live longer than unscreened patients do, but simply appear to live longer because they receive a diagnosis earlier.  It is also possible that mammography will actually cause harm. Exposure to radiation during mammography could itself cause breast cancer 10 or 20 years down the road. (Br J Cancer 2005;93:590-6. Lancet 2000;355:1757-70) In addition, mammograms increase the diagnosis of lesions. Left untreated, some of these will become cancers, but many will not. The discovery of a lesion leads not only to fear and anxiety, but also to invasive diagnostic tests and invasive treatments (including mastectomy or lumpectomy) that inflict additional emotional and physical harm. “For every woman who has her life extended by screening,” writes the Cochrane Center’s Peter Gotzsche in Denmark, “there are at least five women who will be diagnosed with, and treated for, cancer unnecessarily.” (Lancet 2005;366;1519-20) One learns nothing about these potential harms in the ABC News broadcast.  Because medicine does not yet have perfect estimates of the harms of mammography, some would say there is no simple “right” recommendation for every patient. The only possible blanket recommendation might be for clinicians–and the news media–to explain the potential benefits and harms, and thus help women to evaluate their own individual tolerance for risk and preferences so that they can choose the course of action that best suits them.  News organizations that choose to cover medicine should explain the quality of the evidence and the pros and cons surrounding any medical procedure well enough for patients to understand what is known and what remains unknown. Unfortunately, instead of an even-handed analysis, this broadcast promotes fear.