Pathophysiology of anemia in cancer

Anemia is a frequent complication of cancer, and there are numerous causes that could have produced the anemia. In a considerable number of cases, however, there are no bone marrow infiltration, no signs of blood loss, hemolysis, renal, hepatic or endocrine disorders or nutritional deficiencies that could explain the anemia. This type of anemia, which can be called cancer-related anemia (CRA), is exclusively a consequence of the presence of the malignant disease itself. It has many hematological and biochemical similarities with anemias that occur in chronic inflammatory diseases, such as rheumatoid arthritis, and chronic infectious diseases, such as tuberculosis, systemic fungal infections and acquired immunodeficiency syndrome (Cartwright 1966; Lee 1983; Zucker 1985; Kreuzer et al. 1997). This type of anemia, referred to as the anemia of chronic disease (ACD), accounts for 52% of anemias in patients without blood loss, hemolysis or hematologic malignancies. Cancer is the cause of anemia in 19% of cases of ACD (Cash and Sears 1989). CRA is often associated with advanced stages of disease, and usually worsens during chemotherapy or radiotherapy, leading to a high proportion of patients requiring red blood cell (RBC) transfusions (Skillings et al. 1993, 1995; Abels et al. 1991). Chemotherapy and radiotherapy themselves can also produce anemia (Skillings et al. 1993, 1995; Groopman et al. 1999; Barrett-Lee et al. 2000; Coiffier et al. 2001; Ludwig et al. 2004 and in this book).