Is nephrology more at ease than oncology with erythropoiesis-stimulating agents? Treatment guidelines and an update on benefits and risks.

Erythropoiesis-stimulating agents (ESAs), which promote RBC production, have been extensively used to reduce transfusion requirements and improve quality of life (QoL) in both cancer patients and those with chronic kidney disease (CKD). However, the likelihood of response and duration of treatment differ in the two settings. In renal anemia, ESAs act straightforwardly as hormone-replacement therapy. The anemia of cancer, however, relates not to a lack of endogenous erythropoietin production but to diverse aspects of the disease (including a relevant inflammatory component) and chemotherapy. Response to ESAs is slower and less certain than in nephrology. In both settings, early studies showed that reversal of severe anemia was accompanied by substantial improvement in QoL. However, again in both settings, subsequent studies indicated that efforts to normalize hemoglobin might worsen outcome. In the context of cancer, this concern was reinforced by the suggestion that malignant cells had erythropoietin receptors and that its administration might therefore accelerate tumor growth, and moreover that cancer patients are more susceptible to venous thrombosis. The absence of these concerns for nephrologists, and their greater experience in managing ESAs and patients' iron status, may make them more at ease with ESAs than their counterparts in oncology. However, both groups of specialists have had to deal with reversals in recommended thresholds for intervention and restrictions imposed by regulatory authorities. In both specialties, the broad consensus now emerging is that the optimum balance of benefits and risks lies in using ESAs aimed at a hemoglobin level in the range of 11-12 g/dl, although for CKD patients there is still room for an individualized approach.