Do mammograms cause more harm than good? The newest study of breast cancer screening comes down in favor of them. The research, published in the Annals of Internal Medicine, found that the benefits of mammography screenings outweigh the risks -- at least if the tests are done every other year in high-risk women in their 40s.
Women who fit the category had to have at least a two-fold higher risk of developing breast cancer than the average woman. Factors that put women at such risk include having dense breast tissue (about 13 percent of women ages 40 to 49) or having a first-degree relative with the disease (about 9 percent of women ages 40 to 49).
"Benefits" of screening were characterized by increase in life-years and decrease in breast cancer deaths. "Harms" were defined as false positives that can lead to follow-up surgical procedures, pain and anxiety.
Data for the study were taken from three national research groups, including the Breast Cancer Surveillance Consortium (BCSC), Cancer Intervention and Surveillance Modeling Network (CISNET) and the Oregon Evidence-Based Practice Center.
"This research provides important new evidence to support the use of personalized, risk-based breast cancer screening approaches," said Dr. Jean Mandelblatt, lead author of the study and associate director for population sciences at Georgetown Lombardi Comprehensive Cancer Center.
Nevertheless, Mandelblatt said, "I know that women want to know what they should do and the message remains unchanged. They should talk about their risk factors and preferences for the harms of screening with their health care providers to make the best decision for themselves."
Yearly mammograms are currently recommended by the American Cancer Society in women 40 and over, and women should continue their yearly screening as long as they're in good health. These guidelines are different from those of the U.S. Preventive Services Task Force, which currently suggest that women only start receiving mammograms every two years at age 50.
But Dr. Barbara Monsees, professor of women's health and radiology at Washington University School of Medicine in St. Louis, said that most women who develop breast cancer have no known risk factors, and therefore oncologists will miss most cancers if those screenings only happen once every two years.
"Younger women have faster growing tumors and need to be screened yearly, not every other year," she said.
While Dr. Otis Brawley, chief medical officer of the American Cancer Society who wrote an accompanying editorial for the study, does not believe this type of risk-based screening should be implemented just yet, "this is the first of a series of studies that will us to risk-based screening in a few years," he said.
Brawley said he "got in trouble" last year when he questioned whether the health care community puts too much emphasis on mammography. While of course mammograms save lives, he said, the tests are only one factor. They account for about 40 percent of lives saved from the disease.
Another 40 percent comes from women giving themselves examinations by hand -- "women who are getting dressed or in the shower and say, 'What the hell is this?'" Brawley said. The remaining 20 percent of lives saved, Brawley said, can be attributed to improved treatments for breast cancer.
But "by stressing mammography," he said, "I worry that we are not encouraging women as much to have breast awareness. If you find something in your breast, go get it checked out right away."
Self-examination is just as important as mammography, he said.
"In the future, we may be able to identify a population of women in their 40s who definitely should get screened for breast cancer, and others who are in such a low-risk category that they should not get screened as often," Brawley said. "But for the time being, the American Cancer Society will continue to recommend that all women get annual high-quality mammograms."