Prostate cancer mortality in the Finnish randomized screening trial

Abstract

Background: Prostate cancer (PC) screening with prostate-specific antigen (PSA) has been shown to decrease PC mortality by the European Randomized Study of Screening for Prostate Cancer (ERSPC). We evaluated mortality results in the Finnish Prostate Cancer Screening Trial, the largest component of ERSPC. The primary endpoint was PC-specific mortality.

Methods: A total of 80 144 men were identified from the population registry and randomized to either a screening arm (SA) or a control arm (CA). Men in the SA were invited to serum PSA determination up to three times with a 4-year interval between each scan and referred to biopsy if the PSA concentration was greater than or equal to 4.0 ng/mL or 3.0 to 3.99 ng/mL with a free/total PSA ratio less than or equal to 16%. Men in the CA received usual care. The analysis covers follow-up to 12 years from randomization for all men. Hazard ratios (HRs) were estimated for incidence and mortality using Cox proportional hazard model. All statistical tests were two-sided.

Results: PC incidence was 8.8 per 1000 person-years in the SA and 6.6 in the CA (HR = 1.34, 95% confidence interval [CI] = 1.27 to 1.40). The incidence of advanced PC was lower in the SA vs CA arm (1.2 vs 1.6, respectively; HR = 0.73, 95% CI = 0.64 to 0.82; P < .001). For PC mortality, no statistically significant difference was observed between the SA and CA (HR = 0.85, 95% CI = 0.69 to 1.04) (with intention-to-screen analysis). To avoid one PC death, we needed to invite 1199 men to screening and to detect 25 PCs. We observed no difference in all-cause mortality between trial arms.

Conclusions: At 12 years, a relatively conservative screening protocol produced a small, non-statistically significant PC-specific mortality reduction in the Finnish trial, at the cost of moderate overdiagnosis.