Iron deficiency in cancer patients.

Anemia is a frequent complication in cancer patients, both at diagnosis and during treatment, with a multifactorial etiology in most cases. Iron deficiency is among the most common causes of anemia in this setting and can develop in nearly half of patients with solid tumors and hematologic malignancies. Surprisingly, this fact is usually neglected by the attending physician in a way that proper and prompt investigation of the iron status is either not performed or postponed. In cancer patients, functional iron deficiency is the predominant mechanism, in which iron availability is reduced due to disease or the therapy-related inflammatory process. Hence, serum ferritin is not reliable in detecting iron deficiency in this setting, whereas transferrin saturation seems more appropriate for this purpose. Besides, lack of bioavailable iron can be further worsened by the use of erythropoiesis stimulating agents that increase iron utilization in the bone marrow. Iron deficiency can cause anemia or worsen pre-existing anemia, leading to a decline in performance status and adherence to treatment, with possible implications in clinical outcome. Due to its frequency and importance, treatment of this condition is already recommended in many specialty guidelines and should be performed preferably with intravenous iron. The evidences regarding the efficacy of this treatment are solid, with response gain when combined with erythropoiesis stimulating agents and significant increments in hemoglobin as monotherapy. Among intravenous iron formulations, slow release preparations present more favorable pharmacological characteristics and efficacy in cancer patients.