Changes in levels of serum erythropoietin, serum iron and unsaturated iron binding capacity during chemotherapy for lung cancer

Background: The serum erythropoietin level increases markedly during chemotherapy for leukemia. A number of hypotheses have been built for the mechanism, none of them satisfactory. Difficulty in evaluating bone marrow activity hampers the elucidation. Therefore, we focused on patients who had non-hematological cancer and no evidence of bone marrow suppression. Methods: Twelve patients, who had lung cancer (four with small cell cancer and eight with non-small cell cancer) and who had not undergone any chemotherapy, were studied. During chemotherapy, we measured serum erythropoietin, serum iron, unsaturated iron binding capacity and hemoglobin concentration in these patients. Results: The serum erythropoietin level before chemotherapy (10.8 +/- 7.4 mU/ml) was within the normal range but the peak values after the first treatment (73.4 +/- 90.4 mU/ml) increased in all patients. In the patients with small cell cancer, a transient but marked increase in erythropoietin value (204.6 +/- 167.3 mU/ml) was observed after each session of chemotherapy while hemoglobin concentration decreased gradually. Throughout treatments, elevation of the serum iron concentration and concomitant reduction of unsaturated iron binding capacity were observed after each session of chemotherapy. They regained their original values whilst the serum erythropoietin level decreased after each chemotherapy session was completed. Conclusions: It is suggested that the suppression of erythroid marrow by chemotherapeutic agents causes the changes in serum erythropoietin level during chemotherapy in patients with lung cancer.