Blood transfusion and recurrence of colorectal cancer.

Because perioperative blood transfusions have been shown to have an impaired effect on survival in patients with colorectal cancer, we examined retrospectively the records of 882 patients who had undergone curative operations: 170 patients had distant metastases at the time of operation. Of the 499 patients with colonic cancer 332 (67%) had received perioperative blood transfusions. The corresponding figure for the 213 patients with rectal cancer was 190 (89%). Colonic tumors recurred in 45% of the patients who received blood transfusions and in 39% of those who did not. Corresponding figures for tumors in the rectum were 54% and 55%. When dividing the patients with colonic cancer into different subgroups according to Dukes' grade we found differences in survival rates. The poorer survival for transfused patients was, however, only significant for those with Dukes' A tumors (p less than 0.05). This difference disappeared when the influence of age was eliminated. The estimated risk ratio of recurrence and death was 1.23 with the 95% confidence interval (0.99, 1.53) when taking Dukes' grade, current age and localization into account. Blood transfusion should be avoided if possible until adequate prospective studies have been carried out.