Impacts of anemia and transfusion on oncologic outcomes in patients undergoing surgery for colorectal cancer

Purpose This study aimed to evaluate the prevalence of preoperative anemia and impacts of anemia and transfusion on survival in patients undergoing surgery for colorectal cancer. Methods This study included patients who underwent surgery for primary colorectal cancer between 2011 and 2012. The influence of preoperative anemia and postoperative transfusion on recurrence-free survival and overall survival were retrospectively investigated. Anemia was defined as hemoglobin level < 13 g/dL in males and < 12 g/dL in females. The primary outcome was the prevalence of preoperative anemia in patients with colorectal cancer. Secondary outcomes included preoperative anemia management, postoperative 30-day mortality and morbidity, tumor recurrence, and overall survival. Results Among a total of 1899 patients, 823 patients (43.3%) were anemic preoperatively, and 264 patients (13.9%) received postoperative transfusions. Postoperative transfusion was associated with 30-day postoperative complications (OR = 1.514, 95% CI = 1.020 ~ 2.247) but not preoperative anemia (OR = 1.143, 95% CI, 0.811 ~ 1.611). Preoperative anemia (HR = 1.459, 95% CI = 1.104 ~ 1.929) and postoperative transfusion (HR = 1.566, 95% CI = 1.089 ~ 2.252) were significantly associated with worse recurrence-free survival in multivariable analysis. Preoperative anemia (HR = 1.572, 95% CI = 1.274 ~ 1.940) and postoperative transfusion (HR = 1.381, 95% CI = 1.076 ~ 1.773) were significant independent risk factors for worse overall survival. Conclusions Preoperative anemia and postoperative transfusion were associated with worse survival in patients undergoing surgery for colorectal cancer. An alternative therapy to treat anemia and reduce transfusions should be introduced to improve oncologic outcomes.