Role of Multi-Parametric Magnetic Resonance Image and PIRADS Score in Patients with Prostate Cancer Eligible for Active Surveillance According PRIAS Criteria.

OBJECTIVE: To evaluate the prognostic role of multiparametric-MRI (mp-MRI) in patients with clinically localized prostate cancer (PCa) eligible for active surveillance (AS) according to Prostate Cancer Research International: Active Surveillance (PRIAS) criteria.

PATIENTS AND METHODS: We analyzed prospectively 73 patients with PCa and PRIAS criteria for low-risk disease. All patients fitted criteria for AS but optioned surgery treatment. The mp-MRI was performed to define the likelihood of malignancy according to the Prostate Imaging Reporting and Data System (PIRADS) score (1-5). Patients were divided in 2 groups: non-visible cancer lesion on MRI (PIRADS 2-3) and visible cancer (PIRADS 4-5). Preoperative clinical data (age, body mass index, prostate specific antigen (PSA) level, positive core biopsy, PSA density (PSAD)) and definitive pathological findings (staging, upgrading, unfavorable disease) were compared between groups. PIRADS score was correlated with pathological data to evaluate the prognostic role of mp-MRI; and preoperative variables and definitive pathology (upgrading, upstaging and unfavorable disease) were also assessed.

RESULTS: PSAD (p = 0.04) and pathological stage (p = 0.03) were significantly associated with the presence of visible disease. Visible disease was significantly associated with upstaging (p = 0.03). Correlation between PIRADS 5 and unfavorable disease was statistically significant (p = 0.02). The mp-MRI had adequate sensibility in detecting upstaging (92%), intermediate for upgrading (76%) and unfavorable disease (76%). Negative predictive value was higher for upstaging than for upgrading or unfavorable disease (96 vs. 68% and 64%). Multivariate logistic regression revealed that PIRADS 5 was a significant predictor of upstaging (p = 0.05, OR 16.12) and unfavorable disease (p = 0.01, OR 6.53).

CONCLUSION: A visible lesion on mp-MRI strongly predicts significant PCa in patients eligible for AS according to PRIAS criteria, based on upstaging and unfavorable disease. We believe that mp-MRI is an important tool and should be added to clinical selection criteria for AS.