Perioperative Morbidity of Robotic-Assisted Radical Cystectomy Versus Open Radical Cystectomy in Older Adults and the Role of Frailty as an Effect Modifier.

OBJECTIVES: To examine the role of frailty as a potential effect modifier of the comparative effectiveness of robotic-assisted radical cystectomy (RARC) and open radical cystectomy (ORC) in older adults. Radical cystectomy (RC) is associated with high rates of perioperative morbidity, and frailty may serve as a potentially strong modifier of both perioperative and oncologic outcomes. We therefore emulated a pragmatic clinical trial of RARC versus ORC to examine this question. METHODS: We identified adults 66-89 years with Tis-T4 / N0-N1 / M0 urothelial carcinoma of bladder from 2008 to 2017 treated with RC in SEER-Medicare. Baseline frailty was assessed using the claims-based frailty index (CFI). Associations of RARC and ORC with perioperative and oncologic outcomes were examined in the overall cohort after stabilized inverse probability of treatment re-weighting (sIPW). Baseline frailty was examined as an effect modifier using interaction terms in separate models. RESULTS: A total of 1,750 patients were included in the study cohort, of whom 229 underwent RARC and 1521 underwent ORC. Adjusted rates of perioperative blood transfusion or 90-day ER utilization, hospital readmission, and complications were not statistically significantly different between RARC and ORC. Similarly, there were no statistically significant differences in cancer-specific or all-cause mortality. Notably, there were no statistically significant differences in perioperative morbidity or oncologic outcomes across baseline frailty level. CONCLUSIONS: In observational analyses designed to emulate the iROC trial, RARC was not associated with improved perioperative morbidity or oncologic outcomes in older adults, regardless of baseline frailty level.