Objective: To conduct a systematic review of whether blood transfusions may be associated with worse outcomes for patients with bladder cancer treated with radical cystectomy (RC), as there has been a recent increase in studies addressing this clinically relevant topic. Methods: PubMed, Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE), Google Scholar, and the ClinicalTrials.gov databases were searched with
pre-specified search terms for studies published between January 2010 and May 2020. The systemic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 17 studies with 19 627 patients were included after 183 records were screened for eligibility. In all, 10 studies proposed perioperative blood transfusion to be associated with impaired prognosis regarding overall survival, nine studies regarding cancer-specific and four studies regarding recurrence-free survival. The timing of blood transfusion might affect patient outcomes. Notably, several studies did not find a significant correlation between blood transfusions and prognosis. As all studies to date are of retrospective design, the grade of evidence is still limited. Conclusions: Despite the lack of prospective trials, perioperative blood transfusion may lead to worse oncological outcomes. These results, as well as known non-oncological side-effects and associated costs, are important arguments to carefully consider the indication for blood transfusion. Abbreviations BCa: bladder cancer; CSS: cancer-specific survival; HR: hazard ratio; (N)MIBC: (non-) muscle-invasive BCa; OS: overall survival; PBT, perioperative blood transfusion; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; RC: radical cystectomy; RFS: recurrence-free survival.