[Clinical effects of blood transfusion-associated immune modulation on outcome of tumor surgery]

Extended experimental studies revealed different immunological mechanisms which are possibly responsible for blood transfusion-associated immunosuppressive conditions. To expect a clinical impact of these mechanisms on the course of tumor disease, it is necessary to postulate (1) that immunological mechanisms have a significant role in controlling tumor growth and (2) that blood transfusion-induced immunmodulation is long lasting. Both postulates are supported by recent reports and are the rationales of clinical studies indicating that blood transfusion is a risk factor for postoperative infections and tumor recurrence. Since all studies have been retrospective or uncontrolled, we performed a prospective controlled study in randomized groups of patients suffering from colorectal cancer and compared the effects of allogeneic and autologous blood transfusions. The results indicate that patients treated with allogeneic blood transfusion had significantly higher rates of postoperative infectious complications than patients who received autologous blood. Our preliminary follow-up observations found a trend towards higher tumor-free survival in patients treated with autologous blood which is statistically significant in subgroup analysis.