Allogeneic blood transfusion is associated with a poorer prognosis in cancer patients, but the independent effect of the transfusion has been the subject of controversy. The mechanisms giving rise to the reported cancer-promoting effects of blood transfusion have not been elucidated.
The authors used two syngeneic tumour models in Fischer 344 rats: the MADB106 mammary adenocarcinoma and the CRNK-16 leukaemia. Outcomes included host ability to clear circulating cancer cells, and host survival rates. The independent impact of blood transfusion was assessed, and potential harmful characteristics of the transfusion were studied, including blood storage duration; the role of erythrocytes, leukocytes and soluble factors; and the kinetics of the effects.
Blood transfusion was found to be an independent and significant risk factor for cancer progression in both models, causing up to a four-fold increase in lung tumour retention and doubling mortality rates. Blood storage time was the critical determinant of these adverse effects, regardless of whether the transfused blood was allogeneic or autogenic. Aged erythrocytes (9 days and older), rather than leukocytes or soluble factors, mediated the effects, which occurred in both operated and non-operated animals. The effects of erythrocyte transfusion in the MADB106 model appeared immediately and dissipated within 24 hours.
The authors conclude that, in rats, transfusion of fresh blood is less damaging than transfusion of stored blood in the context of progressing malignancies. They state that further studies are needed to elucidate the mechanisms through which the storage duration of erythrocytes can affect the rate of complications while treating malignant diseases.
|Anesthesiology 2008; 109: 989-97|