Postremission therapy of acute myeloid leukemia in older adults

Acute myeloid leukemia (AML) in people over age 60 is characterized by adverse cytogenetic characteristics, prior myelodysplasia, and phenotypic features predictive of poor response to induction chemotherapy and brief leukemia-free survival. Because increased treatment-related toxicity complicates both induction and consolidation chemotherapy, most studies of AML in the elderly focus on induction regimens designed to reduce toxicity. Consolidation usually consists of a repeat cycle of conventional-dose induction chemotherapy. Older patients who achieve complete remission may represent a select population, clinically distinct from patients receiving induction therapy. Regardless of the consolidation regimen, the duration of complete remission is 3 months to 11 months, with long-term leukemia-free survival rates of 10 percent to 28 percent. In the UCLA experience, patients over age 60 who received consolidation, chemotherapy and pretreatment characteristics similar to elderly patients undergoing induction. Postremission treatment varied from standard-dose ara-C to high-dose ara-C consolidation followed by autologous stem-cell transplantation. Leukemia-free survival appears to be longer with high-dose ara-C and autologous stem-cell transplantation. Further randomized studies should be conducted to determine the feasibility of and response to postremission treatment.