Long-term effectiveness and overdiagnosis in the NHS breast screening programme: a cohort study with up to 33 years of follow-up.

Screening benefits should be assessed long-term. This cohort study evaluates both long-term mortality and overdiagnosis within the UK's NHS breast screening program for over three decades. Patients invited to breast cancer screening had a 28% lower risk of dying from the disease, and those who actually attended had a 33% lower risk, though screening was also linked to a 4% overdiagnosis rate over at least five years of follow-up. The results may bolster policies supporting population health-based breast cancer screening.