The recent controversy surrounding mammography may die down somewhat with the release, in the July 2011 issue of Radiology, of a three-decade-long study in Sweden demonstrating that death from breast cancer is prevented in every 414 to 519 women who undergo the procedure. Previous studies had pegged this figure at 1,000 to 1,500 women.
“What this tells us is that, in the long term, screening for breast cancer is a very good investment,” says epidemiologist Robert A. Smith, PhD.
Dr. Smith is director of cancer screening at the American Cancer Society and a co-author of the study. “There is little question that there is some over-diagnosis, but the number we have identified is really quite small," he says. "We have estimated it is less than half the number of lives saved—really pretty low.”
Still, questions remain. Notably, the study does not address the portion of the controversy that focuses on the value of mammography for women in their forties, as the results did not stratify women by age. It also does not take into account the hotly debated question of how frequently women should submit to mammographic screening.
Moreover, H. Gilbert Welch of the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, N.H.—who continues to assert that women are being over-screened for breast cancer, says the study does not take into account the significant advances in breast cancer therapy occurring over the past two decades. He notes that as the treatments have improved, the vast majority of patients have “done well”, regardless of how early their tumors were diagnosed.
Read the study abstract.—Julie Ritzer Ross