Diana J. Mason, PhD, RN, AJN editor-in-chief emeritus
Exactly what is the evidence supporting annual mammography screening and breast self-examination for women over the age of 40?
The U. S. Preventive Services Task Force (USPSTF) conducted a systematic review of this issue and concluded that the evidence for mammography screening of women before the age of 50 years is equivocal and the evidence for breast self-examination is inconclusive. The report notes that the Task Force reached a different conclusion about the quality of the studies on mammography than did a Cochrane Collaboration review done in 2001, with the Cochrane review having much less confidence in the quality of the available research
In April 2001 and January 2004, AJN published two controversial commentaries on the topic by Maryann Napoli, a member of the AJN editorial board and deputy director of the Center for Medical Consumers. Napoli pointed out that the available evidence from large international studies didn’t support the belief that early detection of breast cancer actually resulted in lower mortality rates and that the high number of false positive tests resulted in unnecessary anxiety and treatment. At the time, there was even some evidence that premenopausal women who are diagnosed with breast cancer through mammography may actually die earlier than women who are not screened. More recently Napoli has been updating her thoughts on mammography screening in response to new research (but not yet the USPSTF guidelines) at her center’s Web site.
Breast cancer is a leading cause of death among women, but we can’t assume that early screening will save lives. As we discovered with prostate cancer, some cancers simply won’t be eliminated by any treatments we have available, and we need a more critical examination of the potential adverse effects of all those biopsies.
Maybe the new emphasis on the importance of comparative effectiveness research for measuring quality and controlling costs might help us to design studies that will provide stronger evidence for the proper place of mammography and breast self-examination for reducing the number of deaths from breast cancer.