Do perioperative blood transfusions impact oncological outcomes of robot-assisted radical cystectomy with intracorporeal urinary diversion? Results from a large multi-institutional registry

background: blood transfusions (BT) have been associated with adverse oncologic outcomes in multiple malignan-cies including open radical cystectomy (ORC) for urothelial carcinoma of the bladder (UCB). robot-assisted radical cys-tectomy (RARC) with intracorporeal urinary diversion (ICUD) delivers similar oncologic outcomes compared to ORC, yet with lower blood loss and reduced transfusions. however, the impact of BT after robotic cystectomy is still unknown.methods: this is a multicenter study including patients treated for UCB with RARC and ICUD in 15 academic institu-tions, between January 2015 and january 2022. BT were administered during surgery (intraoperative blood transfusions, iBT) or during the first 30 days after surgery (post-operative blood transfusions, pBT). the association of iBT and pBT with recurrence-free survival (RFS), cancer-specific survival (CSS) and overall survival (OS) were evaluated by univari-ate and multivariate regression analysis. results: a total of 635 patients were included in the study. overall, 35/635 patients (5.51%) received iBT while 70/635 (11.0%) received pBT. after a mean follow-up of 23 +/- 18 months, 116 patients (18.3%) had died, including 96 (15.1%) from bladder cancer. recurrence occurred in 146 patients (23%). iBT were associated with decreased RFS, CSS and OS (P<0.001) on univariate cox analysis. after adjusting for clinicopathologic covariates, iBT were associated only with the risk of recurrence (HR: 1.7; 95% CI, 1.0-2.8, P=0.04). pBT were not significantly associated to RFS, CSS or OS on univariate and multivariate cox regression models (P>0.05).conclusions: In the present study, patients treated by RARC with ICUD for UCB have a higher risk of recurrence after iBT, yet no significant association with CSS and OS was found. pBT are not associated with worse oncological prognosis.