Radiation therapy and the role of red blood cell transfusion

Based on a survey of fifty radiation therapy departments in this country revealing that a majority transfuse anemic cancer patients to a predetermined hemoglobin level prior to and during radiotherapy, a review of the literature was undertaken to assess whether the potential benefits of such a practice outweigh the very real risks (especially non-A, non-B hepatitis) associated with transfusions. Although the intent of transfusion is to increase tumor oxygenation and thereby reduce the number of radioresistant hypoxic cells, studies in laboratory animals do not support a relationship between the hemoglobin level and the percentage of hypoxic tumor cells in normovolemic anemia, both acute and chronic. Several large studies of carcinoma of the cervix agree that anemia is a poor prognostic feature at presentation and correlates with shorter survival and poorer control of local disease in those patients treated solely with radiation. These findings have been interpreted by many to reflect impairment of tumor oxygenation directly attributable to anemia in the poor responders and has been used to support the recommendation of blood transfusion. An alternative explanation for which considerable supporting data exist is that carcinoma of the cervix associated with anemia is, by nature, a biologically more aggressive subtype and portends a poorer prognosis for reasons other than anemia-related tumor hypoxia. It is concluded that the practice of routinely transfusing all chronically anemic cancer patients prior to radiation therapy is not justified.