PURPOSE: The objective of this study was to evaluate whether morphological (linear measurements) and functional (ADC value) assessments of periprostatic fat can predict the aggressiveness of prostate cancer (PCa) over a 5-year follow-up period. MATERIAL AND METHODS: This retrospective study included patients with histologically proven PCa who underwent 3.0T MRI between July 2016 and June 2018. Clinical and demographic data collected included PSA, PSA density (dPSA), ISUP grade, clinical and pathological staging, and treatment details. MRI-derived parameters were assessed by an experienced radiologist, who measured subcutaneous and periprostatic fat thickness, and calculated ADC values from ROI plots in periprostatic fat. Clinical and MRI parameters were analyzed for associations with biochemical recurrence, systemic metastasis, and PCa-related mortality. RESULTS: After applying exclusion criteria, 109 patients were included. Using the Cox model, dPSA (p<
0.01), systemic disease at diagnosis (p<
0.01), and mean ADC (p<
0.02) were independent predictors of overall survival (OS). For progression-free survival (PFS), only dPSA (p<
0.01) and systemic disease at diagnosis (p<
0.01) were significant predictors. In the Poisson Model for systemic recurrence risk, dPSA had a relative risk (RR) of 1.04 (95%CI 1.0-1.07, p=0.03), systemic disease at diagnosis had an RR of 63.3 (95%CI 3.7-86.4, p<
0.01), and average ADC had an RR of 3.42 (95%CI 1.52-7.69, p<
0.01). CONCLUSIONS: The ADC value of periprostatic fat may serve as an additional tool for PCa risk stratification, correlating with poorer outcomes such as systemic recurrence and overall survival. If validated by external, prospective, multicenter studies, these findings could impact future therapeutic decisions.