Colony-stimulating factors in the treatment of older patients with acute myelogenous leukaemia.

The treatment of acute myelogenous leukaemia (AML) in the elderly is a difficult and increasing problem. The elderly are generally less able to tolerate the intensive chemotherapy required to achieve a sustained remission, and there is an increased incidence of resistant disease in this age group. Granulocyte- and granulocyte-macrophage colony-stimulating factors have been demonstrated to shorten the duration of severe neutropenia following chemotherapy for solid tumours and after bone marrow/peripheral blood stem cell transplantation, and the effect of these growth factors in the treatment of AML has been investigated in a number of trials using 2 distinct strategies. Growth factors may be administered following chemotherapy in an attempt to accelerate neutrophil recovery, and they may be given before and during chemotherapy with the aim to increase the number of leukaemic blast cells in cell cycle and enhance their responsiveness to chemotherapy. Both of these approaches have proved safe despite initial theoretical concerns regarding the expression of receptors for these growth factors on leukaemic cells. The results of trials using these growth factors in the treatment of AML in the elderly generally show a significant reduction in the duration of neutropenia following induction chemotherapy. However, consistent benefits with respect to morbidity and early mortality together with improvements in long term disease outcome have not been observed. The 'priming' approach using growth factors before and during induction chemotherapy has proved equally disappointing in failing to improve response rates or survival. The routine use of these growth factors in the treatment of AML in the elderly population as a whole would, therefore, not seem to be cost effective.