ABSTRACT
More information is needed about effects of prostate-specific antigen (PSA) screening for informed decision making. The objective of our study is to evaluate the effects of an implemented screening decision on the risk of prostate cancer (PC) diagnosis and PC death. In a randomized trial, 31,867 Finnish men aged 55-67 years were allocated to the screening arm and 48,282 to the control arm during 1996-1999. Two to three screening rounds were offered to the screening arm with a PSA cut-off of 4.0 ng/ml. A counterfactual exclusion method was used to adjust for the effects of screening noncompliance and PSA contamination on risk of PC death and PC incidence by prognostic group at 15 years of follow up. After correcting for noncompliance and contamination, PSA screening led to 32.4 (95% CI 26.4, 38.6) more PC diagnoses per 1,000 men after 15 years and 1.4 (95% CI 0.0, 2.8) fewer PC deaths compared to the control arm. The corresponding results of an intention-to-screen analysis were 16.5 (95% CI 12.3, 20.7) and 0.8 (95% CI 0.5, 2.0), respectively. These results can be used for patient counseling in informed decision making about PC screening. A limitation of the study was the lack of comprehensive data on contamination.