Study finds benefits of mammograms for women in their 40s, sparking disagreement

Oct 1 2010

The New York Times: "Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s. But their results were greeted with skepticism by some experts who say they may have overestimated the benefit. The study's authors include Dr. Stephen Duffy, an epidemiologist at the University of London, and Dr. Laszlo Tabar, professor of radiology at the University of Uppsala School of Medicine in Sweden, who have long been advocates of mammography screening. Their paper is published online in the journal Cancer." The study looked at women in Sweden, where some counties offer mammograms to women in their 40s and others do not. Researchers compared death rates from those counties (Kolata, 9/29).

The Associated Press: The study's benefits are larger than earlier studies, which "a year ago led an influential panel of U.S. science advisers to recommend against routine screening before age 50. The panel said the benefits were so small and potential problems from screening so great that the decision should be left to each woman and her doctor. ... And just last week, another study in Norway found that the benefit of mammograms even for women 50 and older is less than has been believed. … The new study has major limitations, and cannot account for possibly big differences in the groups of women it compares. Nor does it consider the harm -- such as unnecessary stress, unwarranted biopsies and overtreatment -- of screening women in their 40s" (Marchione, 9/29).

ABC News/MedPage Today: "Jonsson pointed out, though, that the body of research upon which the [U.S. science advisers] based its recommendations included eight largely older randomized trials, most of which ended more than 20 years ago. By contrast, his study included 600,000 women in Sweden age 40 to 49 and took place since national guidelines were implemented in 1986 in Sweden calling for screening mammography -- making it the largest epidemiological study of mammography in this age group. The varying benefits seen in different studies and lack of consensus on timing of screening mammography has made some clinicians hesitant to alter their practice" (Phend and Malajian, 9/29).

Reuters reports on another study: "Sixty years ago, a woman had just a 25 percent chance of living 10 years if she got a breast cancer diagnosis. Now the survival rate is more than 75 percent, U.S. doctors reported on Wednesday. The study of women treated at the University of Texas M.D. Anderson Cancer Center [since 1944] demonstrates how improvements in treatment and screening have transformed the disease from a virtual death sentence, experts said." The study will be presented "at a meeting in Washington of breast cancer specialists sponsored by the American Society of Clinical Oncology later this week" (Fox, 9/29).

Related, earlier KHN story: Mammogram Controversy: 'Politics Is Always Intruding Into The World Of Breast Cancer' (Girshman, 11/20/09).