Effect of implementing population-based prostate-specific antigen screening on testing rates and prostate cancer overdiagnosis in England: a statistical modelling study.

Objective: To determine the potential effect of implementing population-based prostate-specific antigen (PSA) screening in England on overdiagnosis and testing rates compared with the current opportunistic testing policy. Design: Statistical modeling study. English data on rates of prostate cancer by stage, symptomatic and asymptomatic PSA testing, and life expectancy were merged with epidemiological assumptions on lead time to evaluate plausible overdiagnosis and PSA testing rates from an organized population-based program, in comparison with the current opportunistic policy. In the base-case scenario, organized screening increased the rate of asymptomatic PSA testing (screening) in men aged 50 - 69 year and decreased PSA testing in older men. An alternative modeling approach estimated change in overdiagnosis using data from the CAP trial, and current asymptomatic cancer detection rates. Setting: England, 2018/19. Participants: Adult men. Main outcome measures: Rates of PSA testing, early-stage prostate cancer incidence, and overdiagnosis (prostate cancer that would not be diagnosed in a man's lifetime but for the PSA test). Results: In the base scenario, introduction of population-based screening led to an approximate 25% reduction in both PSA testing and overdiagnosis rates in the target population compared with the current policy. This was due to the anticipated decrease in PSA testing and overdiagnosis in men aged 70+ years being larger than the projected increase in PSA testing and overdiagnosis in men 50-69 years. The overall incidence of early-stage cancer prostate cancer was similar. Population-based screening was found to detect more early-stage cancers that were not overdiagnosed, and therefore likely to have a greater impact on prostate-cancer morbidity and mortality than current policy. Findings were robust in sensitivity analyses including an entirely separate modeling approach. Conclusion: Opportunistic screening policies in England have led to high rates of overdiagnosis and PSA testing. In comparison with current policy, a risk-adapted, population-based prostate cancer screening program would likely reduce the number of PSA tests and overdiagnoses, and increase benefits of PSA testing from reduced prostate-cancer mortality Population health in England could be improved by either adopting an organized program or by prohibiting PSA testing of asymptomatic men in primary care.