A new analysis from Massachusetts General Hospital researchers suggests that mammograms prevent breast cancer deaths in women in their 40s by detecting some cancers in an earlier, more curable stage than cancers in women who don’t get screened. At first blush, the findings published online in the journal Cancer seem to make a strong case in favor of mammography screening for younger women. (For those over age 50, annual screening has been shown to reduce the risk of dying from breast cancer by 30 percent.) But there are some limitations in the study design that cast doubt on the findings.
The researchers analyzed 609 breast cancer deaths that occurred at hospitals in the Partners HealthCare system between 1990 and 1999 and found that more than 70 percent of the deaths occurred in the 20 percent of the women who weren’t getting regular mammograms. The average age of the women who died was 49, leading the researchers to conclude that screening these women in their 40s might have caught the cancers early enough to have prevented some deaths.
Dr. Gil Welch, a professor of medicine at the Dartmouth Institute for Health Policy & Clinical Practice who wasn’t involved in the research, said the study tells “half the story” because it examined only women diagnosed with breast cancer, rather than sampling a general population in their 40s.