Management of iron deficiency anemia and the role of intravenous iron supplementation in patients undergoing cancer chemotherapy: a real-world retrospective study in Japan.

backgroundAnemia is one of the common complications in patients with cancer, particularly among those undergoing systemic chemotherapy. Current guidelines for chemotherapy-induced anemia (CIA) recommend anemia evaluation and treatment, including assessing iron deficiency. However, actual pre- and post- chemotherapy clinical practices in Japan remain unclear. This retrospective observational study investigated real-world CIA management.

methodsIn this descriptive study, we included patients with solid tumors who underwent antineoplastic therapy between January 2015 and March 2025. Baseline and follow-up hemoglobin (Hb) levels, transferrin saturation (TSAT), and serum ferritin levels were assessed. We also evaluated the anemia treatment status before and after chemotherapy, and changes in Hb levels following iron supplementation before chemotherapy.

resultsIn total, 75,603 patients were included. At baseline, 55.1% of patients had Hb levels below the lower limit of normal, and 11% presented with moderate-to-severe anemia (Hb < 10 g/dL). Iron parameters were measured in < 10% of patients. Among them, functional iron deficiency (TSAT < 50% with ferritin ≥ 30 and ≤ 500 ng/mL) was the predominant finding, increasing from 54.8% to 61.6% after chemotherapy initiation. Nevertheless, intravenous iron therapy was prescribed in < 3% of patients. An increase in Hb levels was observed in certain patients who prescribed intravenous iron 4-8 weeks prior to chemotherapy, including those with initially low Hb levels.

conclusionThis study demonstrated that anemia is highly prevalent in patients with cancer and worsens following chemotherapy. Additionally, iron parameters were rarely measured, and functional iron deficiency was frequently observed among the tested subgroup.