Pathological and biochemical outcomes after radical prostatectomy in men with low-risk prostate cancer meeting the Prostate Cancer International: Active Surveillance criteria.

UNLABELLED WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Active surveillance has been widely accepted as a treatment tool for low-risk prostate cancer, and use of the Prostate Cancer Research International: Active Surveillance (PRIAS) criteria can select smaller and less aggressive tumours in low-risk disease. The study shows the pathological outcomes of radical prostatectomy for patients with low-risk disease who met the PRIAS criteria. It found that ~20% had unfavourable pathological features and only 30% satisfied insignificant cancer criteria with pT2 stage, a Gleason score ≤6 and tumour volume <2.5 mL. It concludes that close follow-up including repeat biopsy or MRI is necessary to minimize unexpected progression of disease. OBJECTIVE To assess the effectiveness of the Prostate Cancer Research International Active Surveillance (PRIAS) criteria in identifying indolent cancer. PATIENTS AND METHODS Data from 1268 patients undergoing radical prostatectomy without neoadjuvant therapy were retrospectively reviewed. Within this cohort, patients with low-risk disease (n = 211) were classified according to whether they met (Group A, n = 87) or did not meet (Group B, n = 124) the PRIAS criteria. Pathological upstaging, upgrading, tumour volume and 5-year prostate-specific antigen (PSA) recurrence-free survival were compared between the two groups, and factors that predicted upstaging, upgrading and PSA recurrence were analysed by univariate and multivariate methods. RESULTS Pathological T3 stage was present in 10.3% of patients in Group A and in 18.5% of patients in Group B (P = 0.08). Gleason score upgrading to 4+3 or greater was seen in 19.5% of Group A and in 29.9% of Group B (P = 0.01). The mean (range) tumour volume was 0.81 (0.03-5.09) mL in Group A and 1.40 (0.04-8.21) mL in Group B (P < 0.01). The rates of insignificant cancer with total tumour volume <2.5 mL, Gleason score ≤6 and stage pT2 were 30.6% in Group A and 15.4% in Group B (P = 0.07). With a median follow-up of 44 months, the 5-year PSA recurrence-free survival rates were 91.2% in Group A and 86.4% in Group B (P = 0.47). In multivariate analysis, PSA density and the PRIAS criteria were independent factors that predicted upstaging. CONCLUSIONS Although use of the PRIAS criteria could select more favourable tumours even in low-risk prostate cancer, about one in five men had unfavourable pathological outcomes and only three in ten had insignificant cancer. Close and careful follow-up is necessary to avoid misclassification or progression of disease, especially during the first few years of active surveillance.