Impact of the Modified Frailty Index-5 on Treatment Selection and Prognosis in Octogenarians with Bladder Cancer Eligible for Radical Cystectomy: A Single-center, Retrospective Study

Background Developing treatment strategies for bladder cancer in octogenarians remains challenging owing to concerns regarding surgical invasiveness and the risk of undertreatment. We aimed to evaluate the effect of the modified Frailty Index-5 score on treatment selection and prognosis in this population. Methods We retrospectively analyzed 44 patients with bladder cancer aged ≥ 80 years who were candidates for radical cystectomy. The patients were stratified into three groups: robot-assisted radical cystectomy (n = 10), non-surgical treatment (n = 24), and observation (n = 10). Results Multivariate analysis revealed that compared with chronological age or sex, surgical selection was strongly influenced by the modified Frailty Index-5 status (odds ratio 0.31), suggesting that frailty assessment plays a crucial role in clinical decision making. Overall survival did not differ significantly among the groups (p = 0.11); however, the robot-assisted radical cystectomy group showed a trend toward improved survival compared with the non-surgical treatment (hazard ratio [HR] 4.93; p = 0.054) and observation (HR 2.43; p = 0.38) groups. Conclusions Robot-assisted radical cystectomy appears to be a safe and feasible treatment option for carefully selected octogenarian patients. The modified Frailty Index-5 may serve as a practical and objective tool to support treatment decision making, helping avoid undue risk aversion based solely on chronological age.