The Pathophysiologic Basis of Anaemia in Patients with Malignant Diseases

Cancer patients frequently present with anaemia that may result from the direct or indirect effects of the tumor or its treatment. Anaemia is an independent adverse prognostic factor that exerts negative influence on quality of life and survival of cancer patients. Anaemia in malignant disorders often arises from an interplay of multiple aetiological and pathophysiologic mechanisms. Understanding these mechanisms will help the oncologist identify and treat specific causes of the anaemia thereby minimizing the use of blood transfusion, which is associated with many adverse effects. This paper reviewed the various aetiological and pathophysiologic mechanisms of anaemia in cancer patients including direct and indirect tumour effects that lead to reduced red cell production or increased red cell destruction via a myriad of mechanisms ranging from marrow infiltration and cancer-associated acute myelonecrosis to chronic inflammation, blood loss, iron, folate, vitamin B12 and other nutrients deficiencies, malignancy related renal injury, pure red cell aplasia, hypersplenism, haemophagocytic syndrome, red cell autoantibody production, non-immune red cell fragmentation and cytotoxic therapy-induced erythroid cell apoptosis and eryptosis. Hence anaemia in cancer patients is attributable to a wide spectrum of aetiological factors with multiple and sometimes overlapping pathophysiologic mechanisms. It is therefore necessary for the oncologists to thoroughly investigate all cases of anaemia with the aim of identifying the actual causative factors in order to offer more sustainable cause-specific treatment modalities that will minimize the use of blood transfusion with its attendant adverse effects.