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

A new analysis of mammography screening suggests the level of overdiagnosis may be far lower than earlier estimates. Researchers re‑examined all eight major randomized screening trials, adjusting for variations in follow‑up duration, screening frequency and the continuation of screening after trial periods ended. By standardising these factors, the team found that the proportion of cancers detected that would not have become clinically relevant appears to be under 5 percent. This contrasts with previous figures that ranged from 30 to 50 percent, which have informed public debate and policy for years. The study does not claim mammograms are without any risk, but it narrows the gap between the benefits of early detection and the potential for unnecessary treatment. Health officials may need to revisit messaging around screening benefits and harms in light of the revised overdiagnosis estimate. What to watch: future guideline updates that incorporate the lower overdiagnosis figure.

Editor's note: The article accurately reflects the source's findings on mammogram overdiagnosis.

This article is AI-generated and fact-gated. Original reporting: ScienceDaily