Cancer-related anemia is common and multifactorial in origin. Functional iron deficiency (FID) is now recognized as a cause of iron-restricted erythropoiesis and may be one of the major reasons for lack of response to treatment with Erythropoietic Stimulating Agents (ESAs). Numerous studies have shown that intravenous (IV), but not oral, iron therapy effectively provides sufficient iron for optimal erythropoiesis in anemic patients with chronic renal disease receiving ESA therapy. The use of IV iron has also been suggested in the cancer setting. Six recent studies have tested this assumption and are summarized in this review. Four formulations of IV iron are available in Europe, with different pharmacokinetics, iron bioavailability, and risk of acute adverse drug reactions.
Conclusion: Limited iron stores and FID are common causes of response failure during ESA treatment in cancer patients and should be diagnosed. There is now substantial scientific support for the use of IV iron supplementation to improve response and this has been acknowledged in international and national guidelines. Prospective long-term data on the safety of IV iron in this setting are still awaited. Recommendations concerning the optimal formulation, doses, and schedule of iron supplementation to ESA treatment in cancer-related anemia are provisional awaiting data from prospective, randomized trials.