The effect of erythropoietin on tumor oxygenation in normal and anemic rats.

Abstract

Anemia associated with malignancy is a common clinical problem. Its etiology is varied and includes nutritional causes, hemorrhage, hemolysis, bone marrow metastasis and hypoplasia, paraneoplastic syndromes, and chemotherapy1, with many patients presenting with anemia even before they receive cytotoxic therapy and even if their bone marrow is not invaded by tumor cells2. The response of tumors to standard radiotherapy and oxygen-dependent chemotherapy in these patients is often less satisfactory than in subjects with normal hemoglobin levels3. This is presumed to be due to the worsening of tumor oxygenation as a result of the decreased oxygen-carrying capacity of the blood in these anemic tumor patients. Blood transfusions for anemic patients undergoing radiotherapy have not been universally accepted on the ground of infection risks and non-specific immunosuppression, although beneficial effects of transfusions on radiotherapy in anemic patients have been reported4. As a result, interest has recently focused on the possible use of erythropoietin - a glycoprotein hormone regulating the differentiation and maturation of red blood cells - in the correction of malignancy-associated anemia. The aim of this study was to investigate the effects of recombinant human erythropoietin (rhEPO) on red blood cell-related parameters, tumor blood flow and tumor oxygenation, in anemic and non-anemic rats, in order to ascertain whether this more “physiological” approach could have implications for improving tumor oxygenation and subsequently radiotherapy outcome in anemic tumor patients.KeywordsAnemic PatientRecombinant Human ErythropoietinTumor Blood FlowTumor OxygenationBone Marrow MetastasisThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.