['The aim of the study contained herein was to investigate the association between blood transfusion and long-term outcome for patients treated for colorectal cancer, controlling for the effect of other prognostic factors. We also wanted to study whether blood storage time influenced the prognosis.', "Cox's proportional hazards regression analysis was used to analyze data from 336 patients who survived resection with curative intent. Median follow-up was 5.8 (2-16.8) years or until death.", "Local recurrences and distant metastases were significantly more frequent when more than two units of blood had been transfused. In the multivariate Cox's analysis, with backward elimination of nonsignificant factors at the 10 percent level, the following risk factors were significantly related to death by colorectal cancer: tumor stage (T stage and N stage), perforation of tumor, age, and the need for a blood transfusion. Transfusions of more than two units of blood were independently and significantly associated with death from colorectal cancer (relative hazard, 2.7; 95 percent confidence intervals, 1.4-5.2). Time of blood storage had no effect on the prognoses. In patients dying from diseases unrelated to colorectal cancer, age and American Society of Anesthesiologists group were significantly related to death, whereas blood transfusion was not."] Do perioperative blood transfusions reduce long-term survival following surgery for colorectal cancer?