Science

A major risk of breast cancer screening may have been overestimated for decades

A new analysis suggests mammograms may lead to far less breast cancer overdiagnosis than some earlier studies indicated. Researchers reexamined all eight major randomized screening trials and accounted for differences in follow-up time, screening frequency, and screening after trials ended. Their results were consistent with an overdiagnosis rate below 5%, rather than estimates approaching 30% to 50%.