Published online ahead of

Background: Little is known about the outcome of radical prostatectomy (RP) in men initially followed on active surveillance (AS) for low-risk prostate cancer (PCa). Objective: Evaluate pathology findings after RP in our prospective AS cohort. Design, setting, and participants: All men participated in the Prostate Cancer Research International: Active Surveillance (PRIAS) study. Eligible men were initially diagnosed with low-risk PCa (clinical stage T2, prostate-specific antigen [PSA] 10 ng/ml, PSA tions led to deferred RP in 143men (75.7%); 24men (12.7%) switched because of anxiety, and 22 (11.6%) had other reasons. Pathology results showed 134 (80.8%) organ-confined cases and 32 (19.2%) cases with extracapsular extension. Gleason scores 6, 3 + 4, 4 + 3, and 8 were found in 79 (47.3%), 64 (38.3%), 21 (12.6%), and 3 (1.8%) cases, respectively. Unfavourable RP results (pT3–4 and/or Gleason score 4 + 3) were found in 49 patients (29%), of whom 33 (67%) had a biopsy-related reason for deferred RP. Conclusions: RP results inmen initially followed onAS showorgan-confined disease and favourable Gleason grading in a majority of cases. Most men in our cohort had a protocol-based reason to switch to deferred RP. A main focus for AS protocols should be to improve the selection of patients at the time of inclusion to minimise reclassifica-tion of risk and preserve the chance for curative treatment, if indicated