Competing risks analysis of the association between perioperative blood transfusion and long‐term outcomes after resection of colorectal cancer

AIM: Despite numerous reports over three decades, the association between perioperative blood transfusion and long-term outcomes after resection of colorectal cancer remains controversial. This cohort study used competing risks statistical methods to examine the association between transfusion and recurrence and colorectal cancer-specific death after potentially curative and noncurative resection. METHOD: A hospital database provided prospectively recorded clinical, operative and follow-up information. All surviving patients were followed for at least 5 years. Data were analysed by multivariable competing risks regression. RESULTS: From 2575 patients in the period 1995-2010 inclusive, after exclusions, 2334 remained for analysis. Among 1941 who had a potentially curative resection and 393 who had a noncurative resection the transfusion rates were 24.9% and 33.6%, respectively. After potentially curative resection there was no significant bivariate association between transfusion and recurrence (HR 0.93, CI 0.74-1.16, P = 0.499) or between transfusion and colorectal cancer-specific death (HR 1.04, CI 0.82-1.33, P = 0.753). After noncurative resection there was no significant association between transfusion and cancer-specific death (HR 0.93, CI 0.73-1.19, P = 0.560). Multivariable models showed no material effect of potential confounder variables on these results. CONCLUSION: The competing risks findings in this study showed no significant association between perioperative transfusion and recurrence or colorectal cancer-specific death.