Impact of frailty on perioperative and oncologic outcomes after robotic radical prostatectomy: a multicenter study with competing risk analysis

Frailty is increasingly recognized as a key determinant of surgical risk in patients undergoing robotic-assisted radical prostatectomy (RARP), particularly among elderly and comorbid populations. However, its impact on oncologic outcomes remains incompletely understood, especially in the presence of competing mortality risks. To evaluate the association between frailty and perioperative, oncologic, and survival outcomes following RARP, and to assess the performance of frailty-informed predictive models. We conducted a retrospective multicenter study including 587 patients aged 70-80 years who underwent RARP between 2017 and 2023. Frailty was assessed using the Geriatric 8 (G8) score and categorized into mild, moderate, and severe frailty. Primary outcome was major postoperative complications (Clavien-Dindo ≥ 3). Secondary outcomes included biochemical recurrence (BCR) and other-cause mortality. Kaplan-Meier and Cox regression analyses were performed, alongside competing risk analysis using cumulative incidence functions. Multivariable logistic regression, receiver operating characteristic analysis, calibration assessment, and decision curve analysis were used to evaluate predictive performance. The overall rate of major complications was 14.8%. Increasing frailty was independently associated with higher odds of major complications (severe vs. mild: OR 2.66, 95% CI 1.37-5.16, p = 0.004). While frailty was not significantly associated with BCR on Cox regression, competing risk analysis demonstrated substantially higher rates of other-cause mortality among frail patients, attenuating observed recurrence rates. Predictive modeling demonstrated limited discrimination (AUC 0.50-0.55) but acceptable calibration and modest clinical utility within intermediate risk thresholds. Non-linear modeling identified a frailty threshold (G8 ≈ 10-11) below which complication risk increased sharply. On cause-specific analysis, cancer-specific mortality did not differ significantly across frailty strata (p = 0.34), confirming that competing non-cancer mortality drives the observed outcome differences. Frailty is a major determinant of perioperative morbidity following RARP and significantly influences the interpretation of oncologic outcomes through competing mortality risks. Incorporating frailty assessment into preoperative evaluation may help contextualize perioperative vulnerability and competing mortality risks in elderly patients undergoing RARP.