Oncologic Outcomes after Localized Prostate Cancer Treatment: Associations with Pre-treatment Prostate MRI Findings.

PURPOSE To investigate whether T2-weighted magnetic resonance imaging (MRI) findings could improve upon established prognostic indicators of metastatic disease and cancer-specific survival. MATERIALS AND METHODS For a cohort of 3,406 consecutive men who underwent prostate MRI before definitive prostatectomy (n=2,160) or radiotherapy (n=1,246) between 2001 and 2006, T2-weighted MRI exams were retrospectively interpreted and categorized as (I) No focal suspicious lesion; (II) organ-confined focal lesion; (III) focal lesion with extraprostatic extension; or (IV) focal lesion with seminal vesicle invasion. Clinical risk was recorded based on European Association of Urology (EAU) guidelines and the Cancer of the Prostate Risk Assessment (CAPRA) scoring system. Survival probabilities and c-indices were estimated using Cox models and inverse probability censoring weights, respectively. RESULTS The median follow-up was 10.8 years (IQR: 8.6-13.0 years). Higher MRI categories were associated with a higher likelihood of developing metastases (hazard ratios: 3.5-18.1, p <0.001 for all MRI categories) and prostate cancer death (hazard ratios: 3.1-29.7, p <0.001-0.025); these associations were statistically independent of EAU risk categories, CAPRA scores, and treatment type (surgery vs. radiation). Combining EAU risk or CAPRA scores with MRI categories significantly improved prognostication of metastases (c-indices: EAU: 0.798, EAU+MRI: 0.872; CAPRA: 0.808, CAPRA+MRI: 0.877) and prostate cancer death (c-indices: EAU: 0.813, EAU+MRI: 0.889; CAPRA: 0.814, CAPRA+MRI: 0.892) (p <0.001 for all). CONCLUSION MRI findings of localized prostate cancer are associated with clinically relevant long-term oncologic outcomes. Combining MRI and clinicopathologic data results in more accurate prognostication, which could facilitate individualized patient management.