The causes and prognostic significance of low hemoglobin levels in tumor patients.

BACKGROUND: While the production and degradation of erythrocytes are carefully balanced in healthy persons several processes can lead to an imbalance in tumor patients resulting in anemia. PATHOGENESIS: Processes caused by the tumor itself can lead to a typical "anemia of chronic disease" which is normochromic, normocytic, accompanied by both a reduced number of reticulocytes and reduced iron-binding capacity. In many cases, the erythropoietin response to anemia is insufficient. Cytokines such as interleukin-1, interleukin-6, and tumor necrosis factor seem to be involved in suppressing erythropoiesis by acting on the bone marrow and on erythropoietin production. Anemia can also be the result of cancer therapy, as is particularly prominent in patients with lung cancer receiving chemotherapy (incidence of anemia 20 to 50%). PROGNOSTIC FACTOR: Several studies have demonstrated that anemia is not only linked to an impaired quality of life but to prognosis as well. Albain et al. [2] identified a hemoglobin level of below 11 g/dl as a significant independent prognostic factor associated with shorter survival of chemotherapeutically treated non-small cell lung cancer (NSCLC) patients. The same applies to a hemoglobin level below 12.7 g/dl for radiotherapeutically treated NSCLC patients according to a study by Ohlhauser et al. (Oncology 1997;20:1689-92). Several studies have confirmed this prognostic importance of hemoglobin level for other solid tumors. TREATMENT: To correct anemia, clinicians have several options. Given the risks associated with transfusions, especially for tumor patients, recombinant erythropoietin holds promise for raising hemoglobin levels and thereby improving therapeutic efficacy and survival.