Predictive factors of biochemical recurrence after robot-assisted radical prostatectomy: Results from a monocentric cohort.

e17128 Background: Robot-assisted radical prostatectomy is a modern surgical approach for the treatment of localized prostate cancer. Despite technological advances, biochemical recurrence (BCR) remains a frequent event, warranting the identification of reliable predictive factors. Early identification of such predictors is essential to refine risk stratification, personalize postoperative monitoring, and guide additional therapeutic decisions. Methods: The PROROB study is a retrospective, single-center analysis including 75 consecutive patients treated with robot-assisted radical prostatectomy in the urology department of Sens Hospital between Febrary 2023 and Febrary 2025. Concordance between preoperative and postoperative ISUP grades was assessed using the Kappa coefficient. The association between a preoperative PI-RADS 5 score and a high postoperative ISUP grade (4 or 5) was tested using a Chi-square test. Biochemical recurrence-free survival was estimated using the Kaplan-Meier method and compared using the log-rank test. A multivariable Cox regression model was used to identify independent predictors of recurrence. Results: The median age was 71 years (52–79), with a median PSA of 7.7 ng/mL (2.5–26) and a median delay between diagnosis and surgery of 2 months (1–38). Clinically, 48% were staged T1c on digital rectal examination. MRI showed a PI-RADS score of 4 or 5 in 76% of cases. Capsular invasion was reported in 5.3%. Most tumors were ISUP 1 or 2 at biopsy (83%). Postoperative complications occurred in 9 patients (12%) with 4 cases of hemorrhage (5.3%). Positive surgical margins were observed in 26.7% of cases, and pelvic lymph node dissection was performed in 66.7%. Postoperative urinary incontinence was reported in 21% of patients. Median follow-up was 13 months. Biochemical recurrence occurred in 11 patients (14.7%). A significant association was found between a PI-RADS 5 MRI score and a postoperative ISUP grade of 4 or 5 (p < 0.001). Concordance between pre- and postoperative ISUP scores was moderate (Kappa = 0.395). The 24-month biochemical recurrence-free survival rate was estimated at 82.2% (95% CI: 72.8%–92.8%). Positive surgical margins and postoperative urinary incontinence were significantly associated with BCR. In multivariate analysis, only positive margins remained an independent predictor of BCR (HR = 4.14; 95% CI: 1.14–15.09; p = 0.031). Conclusions: In this cohort, positive surgical margins and a PI-RADS 5 score were the main factors associated with BCR. The moderate concordance between biopsy and surgical ISUP grades highlights the limitations of biopsy alone for tumor risk stratification. These findings support the relevance of comprehensive preoperative imaging and reinforced postoperative follow-up in high-risk patients, particularly in the presence of positive margins or elevated MRI scores.