Iron Metabolism and Iron Supplementation in Anemia of Cancer

Iron is an essential trace element important for hematopoiesis, oxygen transport and delivery, and other biologic functions. Iron uptake and utilization are strictly regulated but severely altered in anemia of chronic disease. In this condition, availability of iron for erythropoiesis is insufficient and a limiting factor for red blood cell production, in spite of normal or increased storage iron. Although concomitant oral iron supplementation is recommended in guidelines for treatment of cancer-associated anemia with erythropoietic agents, its efficacy is not documented. Recent studies evaluated the impact of parenteral iron supplementation in comparison with oral iron therapy and with control in anemic cancer patients treated with epoetin alfa or beta, or with darbepoetin. Concomitant treatment with parenteral iron proved superior to oral iron or no treatment. Hematologic response rates were higher, time to increase of hemoglobin was shorter, the need for red blood cell transfusions lower, and the quality of life better than in patients treated with oral or no iron at all. Severe side effects were rare and tolerance was remarkably good in most patients. However, information on long-term safety is not available as yet. Taken together, parenteral iron administration seems likely to evolve as an important adjunct to treatment with erythropoietic agents in patients with treatment-induced or chronic anemia of cancer.