Positive surgical margins after robot-assisted radical prostatectomy Long-term oncologic consequences.

INTRODUCTION: We aimed to evaluate the prognostic significance of positive surgical margins (PSM) and associated clinicopathologic factors on long-term oncologic outcomes following robot-assisted radical prostatectomy (RARP). METHODS: We analyzed a prospectively maintained registry of patients undergoing RARP between 2003 and 2022, stratified by surgical margin status (positive vs. negative [NSM]). Primary outcomes were overall survival (OS) and biochemical recurrence-free survival (BCRFS). Multivariable Cox regression adjusted for age, prostate-specific antigen (PSA), Gleason grade group (GGG), pathologic stage, nodal status, and adjuvant therapy. A prognostic nomogram for OS was developed in the PSM cohort. RESULTS: Among 3969 patients, 459 (11.4%) had PSM, which was more common in the presence of adverse pathologic features. On unadjusted analysis, PSM was associated with worse OS (hazard ratio [HR] 1.39, 95% confidence interval [CI] 1.02-1.90, p=0.036) and BCRFS (HR 2.20, 95% CI 1.62-2.97, p<0.001). After adjustment, PSM was not independently associated with OS (adjusted [a]HR 1.16, p=0.377) or BCRFS (aHR 0.86, p=0.343). In the PSM cohort, ≥pT3a disease, node-positive status, and advanced pathologic stage were strong predictors of mortality (HRs 3.91, 3.86, and 3.62, respectively), while adjuvant radiation therapy was associated with improved survival (HR 0.46, p=0.025). The PSM-specific nomogram demonstrated time-dependent area under the curve (AUC) of 0.737 (3 years), 0.713 (5 years), 0.774 (10 years), and 0.932 (20 years). CONCLUSIONS: PSMs are associated with worse unadjusted outcomes, largely driven by their association with high-risk pathologic features, but are not independently prognostic after accounting for tumor biology and disease stage. A PSM-specific nomogram may support individualized postoperative risk stratification and shared decision-making, pending external validation.