A national story published in November reported that the American Cancer Society (ACS), one of the staunchest defenders of cancer testing, was planning to scale back its support of mass breast and prostate cancer screenings. Otis Brawley, the group’s chief medical officer, said that “American medicine has overpromised” and that “the advantages to screening have been exaggerated.”
One impetus for Brawley’s statements — which also ignited a furor and forced the ACS to quickly reiterate its support of mammography beginning at 40 — was an analysis published Oct. 21 in the Journal of the American Medical Association.
Researchers from the University of California, San Francisco (UCSF), and the University of Texas Health Science Center in San Antonio reported that 20 years of screening for breast and prostate cancer, which account for more than 25 percent of cancers diagnosed annually in the United States, have not significantly reduced the death rate from either.
Instead, the authors wrote, widespread screening has increased the detection and treatment of small, slow-growing tumors that may never cause harm — and in some cases may even disappear — while failing to detect aggressive tumors sometimes known as "interval" cancers because they arise between screenings and grow swiftly.
For every breast cancer death averted in women ages 50 to 70, 838 women must undergo screening for six years, “generating thousands of screens, hundreds of biopsies and many cancers treated as if they were life threatening when they are not,” wrote the team headed by breast cancer specialist Laura Esserman, a professor of surgery and radiology at UCSF.
Baltimore area internist Mary Newman says she thinks many patients are not aware of the potential harms of screening: the small risk posed by repeated radiation, the stress caused by a false positive and the risk of overtreating a small, slow-growing cancer that may never cause problems.
So what advice do cancer experts offer Americans over 50 wrestling with the question of when — or whether — to be screened? How risky is it for those without risk factors — such as a family history of breast or prostate cancer — to forgo annual screening?