Evaluating the Prostate Cancer Prevention Trial High Grade prostate cancer risk calculator in 10 international biopsy cohorts: Results from the prostate biopsy collaborative group

Objectives: To assess the applicability of the Prostate Cancer Prevention Trial High Grade (Gleason grade ≥ 7) Risk Calculator (PCPTHG) in ten international cohorts, representing a range of populations. Methods: A total of 25,512 biopsies from 10 cohorts (6 European, 1 UK and 3 US) were included; 4 implemented 6-core biopsies, and the remaining had 10 or higher schemes; 8 were screening cohorts, and 2 were clinical. PCPTHG risks were calculated using prostate-specific antigen, digital rectal examination, age, African origin and history of prior biopsy and evaluated in terms of calibration plots, areas underneath the receiver operating characteristic curve (AUC) and net benefit curves. Results: The median AUC of the PCPTHG for high-grade disease detection in the 10- and higher-core cohorts was 73.5 % (range, 63.9-76.7 %) compared with a median of 78.1 % (range, 72.0-87.6 %) among the four 6-core cohorts. Only the 10-core Cleveland Clinic cohort showed clear evidence of under-prediction by the PCPTHG, and this was restricted to risk ranges less than 15 %. The PCPTHG demonstrated higher clinical net benefit in higher-core compared with 6-core biopsy cohorts, and among the former, there were no notable differences observed between clinical and screening cohorts, nor between European and US cohorts. Conclusions: The PCPTHG requires minimal patient information and can be applied across a range of populations. PCPTHG risk thresholds ranging from 5 to 20 %, depending on patient risk averseness, are recommended for clinical prostate biopsy decision-making.