A risk-benefit assessment of epoetin in the management of anaemia associated with cancer

Abstract

Many patients with solid tumours or haematological malignancies develop anaemia, and the use of chemotherapy aggravates this condition. Red blood cell transfusions are often necessary but are associated with many risks, including immunosuppressive effects that may increase the risk of tumour recurrence. Many clinical studies have shown that epoetin (recombinant human erythropoietin) therapy can ameliorate, or even prevent, the anaemia associated with chemotherapy and cancer (including solid tumours as well as multiple myeloma or lymphoma). Response, defined as a significant (>50%) reduction in the rate of transfusions and/or a significant (>2 g/dl) elevation of haemoglobin levels, is usually observed in about 60% of the patients, irrespective of the type of standard chemotherapy given. The decrease in transfusion requirements is the major objective of epoetin therapy, because they are costly, inconvenient and are associated with potential adverse effects. Epoetin therapy also brings about substantial improvements in various indices of quality of life that are proportional to changes in haemoglobin level. However, large dosages of epoetin are generally required and about 40% of patients do not respond even to very high dosages. A number of adverse effects of epoetin therapy have been observed in patients with renal failure. The most prominent include hypertension, headaches, seizures and thrombotic events. These complications can also occur in patients with renal failure who are not receiving epoetin. Their exact incidence has been assessed in placebo-controlled studies, which have demonstrated that there is no increased risk of thrombosis or seizure with epoetin. However, it is now generally accepted that 10 to 20% of haemodialysis patients will experience an elevation of blood pressure because of epoetin and there is no doubt that a rapid elevation of blood pressure may cause generalised seizures. In other settings, including anaemia associated with cancer, very few adverse effects have been attributed to epoetin. However, close monitoring of blood pressure should be implemented in patients with hypertension. There is no evidence that epoetin stimulates tumour growth. With the dosages of epoetin currently used, there is no evidence of stem cell competition, resulting in thrombocytopenia or neutropenia, or of stem cell exhaustion, producing secondary anaemia when treatment is stopped. Epoetin is a remarkably well tolerated drug that offers significant benefits in patients with cancer.