Decreased Erythropoietin Response in Patients with the Anemia of Cancer

Patients with solid tumors are often anemic even before they undergo cytotoxic therapy. Since the cause of the anemia of cancer is unknown, we examined the possible role of erythropoietin. Using a sensitive radioimmunoassay, we determined serum immunoreactive erythropoietin levels in 81 anemic patients with solid tumors. For any given degree of anemia, the serum concentration of immunoreactive erythropoietin was lower in this group of patients than in a group of control patients with iron-deficiency anemia (P = 0.0001). Furthermore, the expected inverse linear relation between serum levels of immunoreactive erythropoietin and of hemoglobin was absent in the group with cancer. The erythropoietin response was further decreased in patients receiving chemotherapy; it was not influenced by the presence or absence of cisplatin in the treatment regimen. The inability of the patients with cancer to produce erythropoietin was not absolute; if they had hypoxemia, adequate erythropoietin production was restored. We conclude that erythropoietin levels are inappropriately low in anemia associated with cancer, and that erythropoietin deficiency may contribute to the development of this form of anemia. Treatment of the anemia of cancer with erythropoietin may be of value. (N Engl J Med 1990; 322:1689–92.) THERE can be many causes of anemia in patients with cancer. However, such patients are often anemic even before they receive cytotoxic therapy and even if their bone marrow is not involved by tumor. 1 The anemia of cancer is normochromic and normocytic, with an inappropriately low reticulocyte count. Although this anemia is usually mild (hemoglobin level >5.6 mmol per liter [9 g per deciliter]), hemoglobin values as low as 4.3 mmol per liter (7 g per deciliter) are not rare. 1 2 3 4 5 Serum iron concentrations and iron-binding capacity are low, and morphologic examination of the bone marrow reveals erythroid precursors with a . . .