To compare the accuracy of clinical models and Magnetic Resonance Imaging (MRI)-based prostate cancer (PCa) risk calculators in men who have sex with men (MSM) vs heterosexual men (HSM). MSM comprise 3%-6% of US men yet remain underrepresented in validation studies of PCa risk tools. Behavioral and anatomic factors may influence the performance of Prostate-Specific Antigen (PSA), digital rectal examination (DRE), and prostate MRI.

We analyzed 486 men (243 MSM, 243 HSM) undergoing prostate biopsy at a single academic center, matched by age, PSA, race/ethnicity, and MRI status. Sexual orientation, demographics, imaging, laboratory data, DRE findings, and biopsy results were extracted from electronic health records and validated by chart review. MRI-derived prostate volume, PSA density, and Prostate Imaging Reporting and Data System (PI-RADS) scores were included when available. Logistic regression models using PSA, DRE, PSA+DRE, PI-RADS, and PI-RADS+DRE generated predicted probabilities of clinically significant PCa (csPCa; Grade Group ≥2). Predictions from PLUM, UCLA, and My nMRIsk were evaluated using area under the curve (AUC), calibration, decision-curve analysis, and biopsy outcomes at 10% and 30% thresholds.

MSM and HSM were similar in age, PSA, prostate volume, and PI-RADS distribution. Abnormal DRE was more frequent in MSM (12.8% vs 6.6%, P = .02) but was not associated with higher csPCa risk. PI-RADS ≥3 demonstrated higher sensitivity in MSM (94% vs 87%). MRI-based calculators showed higher AUCs in MSM, with best performance for PLUM and UCLA.

MRI-based risk calculators demonstrated higher diagnostic accuracy in MSM, supporting use of current PCa risk tools without recalibration.