Risk of Clinically Significant Prostate Cancer after a Nonsuspicious Prostate MRI-A Comparison with the General Population.

ABSTRACT

BACKGROUND: We compare the risk of clinically significant (csPCa; ISUP Grade Group ≥ 2) and insignificant prostate cancer (isPCa; ISUP Grade Group 1) in men with a nonsuspicious prostate MRI (nMRI; PI-RADS ≤ 2) with the general population, and assess the value of PSA density (PSAD) in stratification. METHODS: In this retrospective population-based cohort study we identified 1,682 50-79-year-old men, who underwent nMRI at HUS (2016-2019). We compared their age-standardized incidence rates (IR) of csPCa and the odds of isPCa to a local age- and sex-matched general population (n = 230,458) during a six-year follow-up. Comparisons were performed by calculating incidence rate ratios (IRR) and ORs with 95% confidence intervals (CI). We repeated the comparison for the 920 men with nMRI and PSAD < 0.15 ng/mL/cm3. RESULTS: Compared with the general population, the IR of csPCa was significantly higher after nMRI [1,852 vs. 552 per 100,000 person-years; IRR 3.4 (95% CI, 2.8-4.1)]. However, the IR was substantially lower if PSAD was low [778 per 100,000 person-years; IRR 1.4 (95% CI, 0.9-2.0)]. ORs for isPCa were 2.4 (95% CI, 1.7-3.5) for all men with nMRI and 5.0 (95% CI, 2.8-9.1) if PSAD was low. CONCLUSIONS: Compared with the general population, the risk of csPCa is not negligible after nMRI. However, men with nMRI and PSAD <0.15 ng/mL/cm3 have worse harm-benefit balance than men in the general population. IMPACT Prostate biopsies for men with nMRI should be reserved for cases indicated by additional risk stratification. See related In the Spotlight, p. 641.