Blood transfusion and recurrence of cancer of the colon and rectum.

Clinical and experimental studies indicate that transfusion of allogeneic blood has immunomodulating properties, and that the behaviour of some tumours may be influenced by the immune system of the host. Eighty-seven patients who had undergone 'curative' resection of cancer of the colon or rectum were studied retrospectively to determine whether blood transfusion adversely affected the rate of cancer recurrence. Fifty-three patients (61 per cent) were transfused and 34 were not. The transfused and non-transfused groups were comparable in terms of age, sex, duration of follow-up, mode of presentation, stage of disease and haemoglobin level at discharge from hospital, and differed in admission haemoglobin and distribution of tumour locations (right- or left-sided colonic or rectal tumours). Recurrent malignancy was detected in 36 per cent of transfused patients and 26 per cent of non-transfused patients (P greater than 0.1). There was no association between the number of transfusions and recurrence for any tumour site or stage. The incidence of recurrence was significantly higher in those patients who received transfusions during surgery than in those who received transfusion either before or after surgery (chi 2 = 7.01, d.f. = 1, P less than 0.01) or no transfusions (chi 2 = 4.23, d.f. = 1, P less than 0.05). The study indicates that factors influencing the need for blood transfusion during operation had a greater bearing on prognosis than receipt of a blood transfusion per se and that future prospective studies investigating the association between transfusion and cancer recurrence need to determine accurately the indications for transfusion.