Not as Many Lives Saved by Mammogram, Study Finds

A recent study published in the New England Journal of Medicine suggests that frequent mammograms may not be as big of a factor in reducing breast cancer deaths as previously thought. Researchers studied the medical records of more than 40,000 women with breast cancer in Norway and found that mammogram detection of the cancer was responsible for only one-third of the women who survived. According to the U.S. Preventive Services Task Force, annual mammograms for women starting at age 50 are thought to reduce the likelihood of dying from breast cancer by as much as 15 to 23 percent. The new study, however, suggests that overall, regular mammograms reduce the chance of death by only 10 percent. Just the same, some experts remain wary of relying too heavily on a single study, and caution that it should not be used as a justification to lower a standard of preventive care that does save lives.A Flawed Study?The Norwegian study is a new source of fuel in the debate over whether women are being unnecessarily over-screened for breast cancer. In an editorial accompanying the study, Dr. Gilbert Welch, a professor of medicine at Dartmouth Medical School, said that timely care and “the widespread use of adjuvant therapy have probably combined to make screening now less important.”But many critics have pointed to problems in the study’s methodology. Researchers said they used data to follow up with each patient after about two years, even though many experts warn that two years is not enough time to determine whether or not the mammogram helped the patient. According to Dr. Therese Bevers, the director of the cancer prevention clinic at the University of Texas M.D. Anderson Cancer Center, “It takes about seven to 10 years to see the full benefit of mammographic screening,” and that in the new study, “the benefit is just starting to emerge.”Dr. Daniel Kopans, the director of the breast imaging division at Massachusetts General Hospital, agreed, saying “No one presents data on breast cancer with only 2.2 years of follow-up.” Dr. Kopans also pointed to published studies from Sweden and the Netherlands that disagreed with the results of the new study and showed that most of the decrease in breast cancer deaths is due to screening rather than therapy.The Standard of CareWhile the dispute over the efficacy of breast cancer screening in the medical community shows no signs of slowing down, for now, patients in the United States should not see major changes in their preventive routines. Despite the new study, Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, says his organization still gives the same recommendation: annual screening mammograms for women at average risk beginning at age 40. Some doctors are worried that results from the new study could be used to excuse lax preventive care. While the study brings some doubt about the exact numbers of women saved by regular mammograms, there is little doubt that screening saves tens of thousands of lives: even the authors conclude that the “availability of screening mammography [is] associated with a reduction in the rate of death from breast cancer.”Early Detection is KeyLillie Shockney, an associate professor of breast cancer at Johns Hopkins University, says that for most women early stages of breast cancer are more likely to be detected by mammogram, and that when the cancer is found earlier, usually it will be smaller and require less treatment.In fact, because early detection and treatment of diseases like breast cancer is so important, ‘failure to diagnose’ is a well-recognized legal claim frequently brought against doctors who miss cancer during screenings. Doctors who failed to recognize symptoms, failed to order or misread a mammogram, failed to perform a biopsy, or delayed treatment can be responsible for grave consequences to a patient’s health. The fact that doctors can be held financially responsible for failing to order a mammogram shows the importance of the mammogram in preventive care.Given the proven lifesaving results of regular screenings, the troubling questions about the Norwegian study, and the legal standard for responsible cancer detection practices that doctors are routinely held to, the American Medical Association should remain steadfast in continuing its support of the yearly mammogram as a necessary standard of care.