Blood transfusions and prognosis in colorectal cancer.

Background: Blood transfusions may adversely affect the prognosis of patients treated surgically for cancer, although definite proof of this adverse effect has not been reported.

Methods: We carried out a randomized trial to investigate whether the prognosis in patients with colorectal cancer would be improved by a program of autologous blood transfusion as compared with the current practice of allogeneic transfusion. Patients in the autologous-transfusion group were required to donate two units of blood before surgery.

Results: A total of 475 patients were evaluated. We found no significant difference in prognosis between the allogeneic-transfusion group (236 patients) and the autologous-transfusion group (239 patients); colorectal cancer-specific survival rates at four years were 67 percent and 62 percent, respectively (P = 0.39). Among the 423 patients who underwent curative surgery, 66 percent of those in the allogeneic-transfusion group and 63 percent of those in the autologous-transfusion group had no recurrence of colorectal cancer at four years (P = 0.93). We also found that the risk of recurrence was significantly increased in patients who received blood transfusions, either allogeneic or autologous, as compared with patients who did not require transfusions; the relative rates of recurrence were 2.1 (P = 0.01) and 1.8 (P = 0.04), respectively; these rates did not differ significantly from each other.

Conclusions: The use of autologous blood as compared with allogeneic blood for transfusion does not improve the prognosis in patients with colorectal cancer. Regardless of their type, transfusions are associated with poor prognosis, probably because of the circumstances that necessitate them.