Perioperative blood transfusion and solid tumor recurrence--a review.

Evidence regarding the association of blood transfusions with recurrence of solid tumors is largely conflicting. This is perhaps not surprising given the retrospective nature of the studies, the complexity of the disease and its treatment, and variations in local transfusion practices. Nonetheless, data demonstrating that transfusions of whole blood are associated with earlier cancer recurrence are most readily explained by a cause and effect relationship. There is a growing literature documenting previously unforeseen immunologic consequences of homologous blood transfusion. These possible clinical consequences may include earlier cancer recurrence, and increased susceptibility to infection with bacteria and viruses. The questions raised in this review will likely be answered by further studies. For the present, the prudent clinician will select red blood cells rather than whole blood for transfusion, and recognize that blood transfusion is a therapy with considerable benefits, but also considerable risks.