The Effect of Perioperative Blood Transfusion on Long-Term Survival Outcomes After Surgery for Pancreatic Ductal Adenocarcinoma: A Systematic Review.

OBJECTIVE To evaluate survival outcomes associated with perioperative allogeneic red blood cell transfusion (RBCT) in patients with pancreatic ductal adenocarcinoma undergoing surgery. METHODS PubMed, Embase, Cochrane, and Web of Science Core Collection were queried for English-language articles until May 28, 2020. Studies evaluating long-term outcomes of RBCT compared with no transfusion in adults with pancreatic ductal adenocarcinoma undergoing pancreatectomy were included. E-value sensitivity analysis assessed the potential for unmeasured confounders to overcome these findings. RESULTS Of 4379 citations, 5 retrospective cohort studies were included. Three studies reported shorter recurrence-free survival by 1 to 5 months with RBCT. Two studies found shorter disease-specific survival by 5 to 13 months with RBCT. Overall survival was reduced by 5 to 7 months with RBCT in 3 studies. All multivariable findings associated with RBCT could be readily overcome unmeasured confounding on sensitivity analysis. Confounding in baseline characteristics resulted in high risk of bias. CONCLUSIONS Imprecision, unmeasured confounding, small effect sizes, and overall low quality of the available literature result in uncertainty regarding the effect of transfusion on recurrence-free survival, disease-specific survival, and overall survival in patients undergoing surgery for pancreatic cancer. Randomized trials are needed to determine if there is a causal relationship between transfusion and survival after pancreatic resection.