The role of myelopoietic growth factors in managing cancer in the elderly

More than 50% of all malignancies are diagnosed in patients aged >65 years and most cancer-related deaths occur in this population. Misconceptions about prognosis and treatment contribute to the undertreatment of elderly cancer patients and consequent poor outcomes. Although older patients have been excluded from cancer treatment trials in the past, response rates to chemotherapy in a variety of common cancers in otherwise healthy elderly patients are comparable to those attained in younger patients. Lower functional reserve in many organ systems alters the pharmacokinetics of chemotherapeutic drugs as well as the patient's response to treatment-induced toxicity. Except for myelosuppression and mucositis, otherwise fit elderly cancer patients are not at significantly enhanced risk of toxicity to chemotherapy. Severe neutropenia and related infection are encountered much more frequently during the treatment of elderly as compared with younger cancer patients. These lead to treatment delays, dose reductions and higher hospitalisation rates. Myelopoietic growth factor support reduces myelosuppression and the associated risk of severe infection, thereby allowing delivery of chemotherapy at full dose intensity. Beneficial responses to granulocyte colony-stimulating factor (G-CSF; filgrastim) in elderly patients have been found in aggressive non-Hodgkin's lymphoma with standard cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) therapy and acute myeloid leukaemia (AML) during induction and consolidation chemotherapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF; sargramostim) has been found to reduce myelosuppression in elderly AML patients receiving induction but not consolidation chemotherapy. These prophylactic treatments produce significant cost benefits because of the reduced hospitalisation and antibiotic use associated with neutropenia. To maximise positive outcomes, elderly patients should be included in clinical trials of new cancer agents. Since myelosuppression is the main risk factor for elderly patients undergoing chemotherapy, optimisation of growth factor support and the development of more effective and safer myelopoietic agents may improve success rates and reduce adverse events. Such information will lead to better management of cancer in older patients.