Long-Term Observed Risk of Clinically Significant Prostate Cancer After Negative mpMRI and Systematic Biopsy in Biopsy-Naïve Men: A MULTIPROS Subanalysis.

BACKGROUND: mpMRI is now widely used before prostate biopsy and has improved the detection of clinically significant prostate cancer (csPCa). However, the subsequent risk of csPCa among men with both negative mpMRI and negative systematic biopsy (SBx) remains uncertain. PURPOSE: To evaluate the observed medium-term risk of csPCa in biopsy-naïve men with initially negative mpMRI and negative SBx. METHODS: This post hoc longitudinal follow-up subanalysis included biopsy-naïve men from the prospective multicenter MULTIPROS trial who had negative baseline mpMRI (PI-RADS ≤ 2) and negative SBx. Of the 582 enrolled men, 169 had negative mpMRI; 138 underwent baseline SBx, of whom 8 had csPCa, and 31 had < 12 months of follow-up, leaving 99 men for analysis. Follow-up was PSA-based, with repeat mpMRI and biopsy performed when clinically indicated. Kaplan-Meier analysis estimated csPCa-free survival. RESULTS: During a mean follow-up of 61.8 ± 22.1 months, four patients were diagnosed with csPCa (4/99; 4.0%). The mean time from initial negative mpMRI to csPCa diagnosis was 68.3 ± 22.4 months. Repeat biopsy was performed in 16 patients. csPCa-free survival was 100% at 24 months and 97.3% at 60 months (95% CI: 93.7%-100%). CONCLUSION: In this selected cohort of biopsy-naïve men with both negative mpMRI and negative SBx, the observed incidence of csPCa during medium-term follow-up was low but based on only four events. Because repeat imaging and biopsy were selectively triggered rather than systematically performed, the true incidence of csPCa may be underestimated. Continued PSA-based monitoring, with repeat mpMRI and biopsy when clinically indicated, remains important.