By Igor Volsky
on Nov 23, 2012
Routine mammograms have caused more than a million U.S. women to receive “unnecessary and invasive cancer treatments over the last 30 years,” a new study finds, detecting tumors that are harmless. The results come after the government’s Preventive Task Force issued recommendations in 2009 advising primary care physicians against recommending mammograms to women under 40 years of age. Those guidelines stirred political outcry on both sides of the aisle and slowed down workon President Obama’s health care law.
But the study shines new doubt “over the effectiveness of an already controversial cancer screening tool that is aimed at detecting tumors before they spread and become more difficult to treat”:
Their analysis showed that, since mammograms became standard in the United States, the number of early-stage breast cancers detected has doubled — in recent years, doctors found tumors in 234 women out of 100,000. But in that same period, the rate of women diagnosed with late-stage breast cancer has dropped just eight percent — from 102 to 94 cases out of 100,000.
“We estimated that breast cancer was overdiagnosed — i.e., tumors were detected on screening that would never have led to clinical symptoms — in 1.3 million US women in the past 30 years,” authors Gilbert Welch of Dartmouth Medical School and Archie Bleyer of the Oregon Health & Science University, wrote in a study published Thursday in the New England Journal of Medicine.
“We estimated that in 2008, breast cancer was overdiagnosed in more than 70,000 women; this accounted for 31% of all breast cancers diagnosed,” they added. These women likely received major medical interventions — including surgery, radiology, hormone therapy and chemotherapy — that ought only to be used when absolutely necessary, the authors stressed.