Comparison of risk calculators from the Prostate Cancer Prevention Trial and the European Randomized Study of Screening for Prostate Cancer in a contemporary Canadian cohort

OBJECTIVE To compare the Prostate Cancer Prevention Trial Risk Calculator (PCPT-RC) and European Randomized Study of Screening for Prostate Cancer Risk Calculator (ERSPC-RC) in a single-institution Canadian cohort. PATIENTS AND METHODS At Princess Margaret Hospital, 982 consecutive patients with PCPT-RC and ERSPC-RC covariables were prospectively catalogued before prostate biopsy for suspicion of prostate cancer (PCa). Receiver-operating characteristic (ROC) curves were generated for each calculator and prostate-specific antigen (PSA). Comparisons by area under the curve (AUC) and calibration plots were performed. Predictors of PCa were identified by univariable and multivariable logistic regression. RESULTS PCa was detected in 46% and high-grade (HG) PCa (Gleason >= 4) in 23% of subjects with a median PSA level of 6.02 ng/mL. Multivariable analysis identified transrectal ultrasonography nodule, prostate volume and PSA as the most important predictors of PCa and HG PCa. ROC curve analysis showed that the ERSPC-RC (AUC = 0.71) outperformed the PCPT-RC (AUC = 0.63) and PSA (AUC = 0.55), for PCa prediction, P < 0.001. The PCPT-RC was better calibrated in the higher prediction range (40-100%) than the ERSPC-RC, whereas the ERSPC-RC had better calibration and avoided more biopsies in the lower risk range (0-30%). Discrimination of the ERSPC-RC continued to be superior to the PCPT-RC when the cohort was stratified by different clinical variables. CONCLUSIONS The ERSPC-RC had better discrimination for predicting PCa compared to the PCPT-RC in this Canadian cohort. Calibration would need to be improved to allow routine use of the ERSPC-RC in Canadian practice.