Iron deficiency is a frequent complication associated with cancer. In a single-centre study of 1,528 patients, more than 40% had iron deficiency, defined as a transferrin saturation [TSAT] level of <20%. Of these patients, 82% had functional iron deficiency (TSAT <20%, ferritin ≥30 ng/mL) and 18% had absolute iron deficiency (TSAT <20%, ferritin <30 ng/mL).1 Patients with pancreatic cancer, colorectal cancer and lung cancer showed the highest rates of iron deficiency.1
Multiple factors contribute to the development of iron deficiency in cancer patients, depending on the type of cancer and the treatment that the patient receives. These factors include:
- Reduced intake of dietary iron: Patients with gastrointestinal or colorectal cancer may not be able to eat a diet high in iron or in general, due to disease or treatment-related anorexia.2
- Chronic bleeding: Gastrointestinal or colorectal cancer can cause internal bleeding,2 and some gynaecological cancers such as ovarian or cervical cancer, can also lead to greater than normal blood loss.
- Chronic inflammation: Chronic inflammation is a major cause of iron deficiency in patients with cancer.2 Inflammatory cytokines stimulate the release of hepcidin that inhibits the release of iron from iron stores, which can result in functional iron deficiency in the short term. Absorption of iron from the intestine is also blocked by hepcidin, preventing iron stores from being replenished and leading to absolute iron deficiency over the longer term.3
- Anti-cancer therapy, including chemotherapy: Anti-cancer therapy, including chemotherapy and radiotherapy, is likely to contribute to the pathogenesis of iron deficiency. The incidence of iron deficiency has been shown to be higher in patients who have recently received anti-cancer treatment (i.e. within 12 weeks) compared with those whose last treatment was more than 12 weeks ago (48 vs 36%; p<0.001).1
- Increased iron requirements during ESA therapy: Patients undergoing myelosuppressive chemotherapy may be given erythropoiesis-stimulating agents (ESAs).4 ESAs reduce the pool of circulating iron by increasing erythropoiesis, and iron supplementation may be required concomitantly.5
Studies in cancer patients with iron deficiency anaemia have found a direct correlation between quality of life and haemoglobin levels in cancer patients receiving chemotherapy.6 Evidence also suggests that treatment of chemotherapy-related iron deficiency anaemia with intravenous iron and ESA therapy significantly increases haemoglobin levels, with resulting increases in energy, activity, and overall quality of life.7,8