Breast cancer overdiagnosis under 5%: new analysis — SkimNews
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- University of Southern Denmark researchers led a meta-analysis of all eight major randomized mammography trials, concluding that overdiagnosis rates are likely below 5% when accounting for timing and screening exposure differences.
- Elsebeth Lynge, professor emerita at University of Copenhagen, explains that initial spikes in cancer diagnoses after screening starts are often mistaken for overdiagnosis, but reflect earlier detection rather than unnecessary findings.
- Matejka Rebolj, senior epidemiologist at Queen Mary University of London, states that prior high estimates failed to account for full temporal patterns and post-trial screening, leading to inflated harm assessments.
- Sisse Helle Njor, professor at University of Southern Denmark and Lillebælt Hospital, emphasizes that the benefits of early detection now clearly outweigh the small risk of unnecessary treatment for most women.
- The study compared trial data with real-world patterns in Denmark, where staggered rollout of screening programs allowed precise tracking of diagnosis trends over time, reinforcing low overdiagnosis estimates.
Why it matters: For decades, the perceived risk of overdiagnosis—cited as high as 50%—has fueled hesitancy in screening programs and influenced guidelines. With robust evidence now pointing to under 5%, public health messaging can shift toward greater confidence in mammography’s net benefit, potentially increasing participation and reducing preventable deaths.
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