Mammography back and forth

The role screening mammography should play has been debated for years—a debate that reached fever pitch following the shift in U.S. Preventive Services Task Force (USPSTF) guidelines in 2009—and the first half of 2014 has been no different.

One of the stronger statements came in April from two members of the Swiss Medical Board, who wrote an editorial for The New England Journal of Medicine that called for the elimination of aggressive mammography screening efforts and for balanced information about the benefits and harms of screening to be passed to women.

A couple weeks ago, at the American Society for Clinical Oncology annual meeting in Chicago, results of a survey presented to women in their 40s, who mostly lived in rural areas, revealed that many women indeed don’t have the most up-to-date information. About two-thirds of the women had undergone screening mammography in the past year, despite the 2009 USPSTF guidelines recommending against mammograms for women that young in most circumstances. Less than 1 percent of the women knew of the recommendations, despite 70 percent saying they thought they understood current guidelines.

But another top headline from the past month was considerably more optimistic about mammography, as a study from the University of Michigan Comprehensive Cancer Center in Ann Arbor found a drop in late-stage breast cancer incidence since mammography was popularized more than 30 years ago. The study, published in Cancer, demonstrated a 37 percent drop in late-stage breast cancer when comparing rates from 1977-1979 with those from 2007-2009.

To account for changes in breast cancer incidence independent of detection efforts—based on changing diets and environmental factors, among others—the Michigan study used observed trends in breast cancer incidence dating back to the 1940s to calculate an expected annual percentage change. The estimated increase in breast cancer incidence over the study period was 1.3 percent per year, though other estimates pegging the annual percentage change anywhere from 0.5 percent to 2 percent all would have resulted in a decrease of observed late-stage disease compared with projections.

But the impact of false positives is another factor not addressed in the findings and, of course, a major factor in the debate over breast cancer screening. We’re far from hearing the last on this debate.

-Evan Godt
Editor – Health Imaging