Acute myeloid leukemia in the older patient.

Acute myeloid leukemia (AML) is an extremely heterogeneous disorder. The biology of AML is incompletely understood, but much data indicates that older patients have a more biologically diverse and chemotherapy resistant form of AML that is quite different from that seen in the younger patients. Approximately 60% of AML cases are in patients greater than 60 years of age, so the predominant burden is in older patients. This problem will be magnified in the future, because the US population is both growing and aging. When one examines the treatment outcomes of older AML patients over the last three decades, there is little progress in long-term survival. Nine major published randomized placebo controlled trials of myeloid growth factors given during induction for AML have been conducted. All of these trials with one exception demonstrated no significant impact on the clinical outcomes of complete response (CR) rate, disease-free, and overall survival. However, the duration of neutropenia was consistently and uniformly reduced by the use of growth factor in all nine of these trials. Because of the favorable impact of the colony-stimulating factors (CSFs) on resource use, antibiotic days, hospital days, etc., it can be more economical and beneficial to use CSFs in AML than to withhold use. The overall dismal outlook for the older AML patient can only be altered by clinical trials with new therapeutic agents. New cellular and molecularly targeted agents are entering clinical trials and bring hope for progress to this area of cancer therapy.