Effects of Allogeneic Red Blood Cell Transfusions on Clinical Outcomes in Patients Undergoing Colorectal Cancer Surgery A Systematic Review and Meta-Analysis

Objective: To determine the effect of allogeneic blood transfusion (ABT) on clinical outcomes in patients with colorectal cancer undergoing surgery. Background: Perioperative ABTs may be associated with adverse clinical outcomes. Methods: Systematic review of the literature with odds ratio (OR) and incidence rate ratio (IRR) meta-analyses of predefined clinical outcomes based on a MEDLINE search. Results: In total, 20,795 colorectal cancer (CRC) patients observed for more than 59.2 +/- 26.1 months (108,838 patient years) were included, of which 58.8% were transfused. ABT was associated with increased all-cause mortality OR = 1.72 (95% confidence interval [CI] 1.55 - 1.91, P < 0.001); I-2 = 23.3% (0 - 51.1) and IRR = 1.31 (1.23 - 1.39, P < 0.001), I-2 = 0.0% (0 - 37.0). ABT was also associated with increased ORs (95% CI, P) for cancer-related mortality of 1.71 (1.43 - 2.05, P < 0.001), combined recurrence-metastasis-death 1.66 (1.41 - 1.97, P < 0.001), postoperative infection 3.27 (2.05 - 5.20, P < 0.001), and surgical reintervention 4.08 (2.18 - 7.62, < 0.001). IRR (95% CI, P) was 1.45 (1.26 - 1.66, < 0.001) for cancer-related mortality and 1.32 (1.19 - 1.46, < 0.001) for recurrence-metastasis-death. Mean length of hospital stay was significantly longer in transfused compared with nontransfused patients (17.8 +/- 4.8 vs 13.9 +/- 4.7 days, P = 0.005). Conclusions: In patients with colorectal cancer (CRC) undergoing surgery, ABTs are associated with adverse clinical outcomes, including increased mortality. Measures aimed at limiting the use of ABTs should be investigated further.