Digital rectal examination in prostate cancer screening at PSA level 3.0-3.9 ng/ml: long-term results from a randomized trial

Abstract

Objective To evaluate digital rectal examination (DRE) as a predictor of prostate cancer (PC) at serum PSA level 3.0–3.9 ng/ml. We compared the PC incidence rates of men with different screening test results in this PSA range and analyzed DRE in comparison with free/total PSA ratio as an additional screening test. Materials and methods Using data from the FinRSPC trial, PC incidence rate ratios (IRR) for groups defined by the secondary screening test results (DRE vs. free/total PSA) were calculated for 17-year follow-up, using adjustment for age, family history of PC and place of residence. Screening test performance was evaluated by calculating sensitivity, specificity, positive and negative predictive value, and likelihood ratio. Results The IRR for men with a positive DRE compared to those with a negative result was 1.40 (95% confidence interval (CI) 1.00–1.96), while the IRR for men with a positive free/total PSA result compared to those with a negative one was 1.62 (95% CI 1.08–2.43). The estimated sensitivity was 0.15 (95% CI 0.11–0.20, 40/270) for DRE and 0.32 (95% CI 0.23–0.41, 36/113) for free/total PSA, and the specificity 0.91 (95% CI 0.88–0.93, 419/461) for DRE and 0.85 (95% CI 0.78–0.90, 134/158) for free/total PSA. Conclusions Our results do not support utility of DRE as a screening test for PC at serum PSA level 3.0–3.9 ng/ml, while the results regarding free/total PSA determination were more encouraging and reconfirm the decision to switch from DRE to free/total PSA.