Results of intensive chemotherapy in 998 patients age 65 years or older with acute myeloid leukemia or high-risk myelodysplastic syndrome: predictive prognostic models for outcome.

BACKGROUND: Elderly patients (age > or = 65 years) with acute myeloid leukemia (AML) generally have a poor prognosis. AML-type therapy results are often derived from studies in younger patients and may not apply to elderly AML. Many investigators and oncologists advocate, at times, only supportive care or frontline single agents, Phase I-II studies, low-intensity regimens, or 'targeted' therapies. However, baseline expectations for outcomes of elderly AML with 'standard' AML-type therapy are not well defined. The aim was to develop prognostic models for complete response (CR), induction (8-week) mortality, and survival rates in elderly AML, which would be used to advise oncologists and patients of expectations with standard AML type therapy, and to establish baseline therapy results against which novel strategies would be evaluated.

METHODS: A total of 998 patients age > or = 65 years with AML or high-risk myelodysplastic syndrome (> 10% blasts) treated with intensive chemotherapy between 1980 and 2004 were analyzed. Univariate and multivariate analyses of prognostic factors associated with CR, induction (8-week) mortality, and survival used standard methods.

RESULTS: The overall CR rate was 45% and induction mortality 29%. Multivariate analysis of prognostic factors identified consistent independent poor prognostic factors for CR, 8-week mortality, and survival. These included age > or = 75 years, unfavorable karyotypes (often complex), poor performance (3-4 ECOG [Eastern Cooperative Oncology Group]), longer duration of antecedent hematologic disorder, treatment outside the laminar airflow room, and abnormal organ functions. Patients could be divided into: 1) a favorable group (about 20% of patients) with expected CR rates above 60%, induction mortality rates of 10%, and 1-year survival rates above 50%; 2) an intermediate group (about 50-55% of patients) with expected CR rates of 50%, induction mortality rates of 30%, and 1-year survival rates of 30%; and 3) an unfavorable risk group (about 25-30% of patients) with expected CR rates of less than 20%, induction mortality rates above 50%, and 1-year survival rates of less than 10%.

CONCLUSIONS: Prognostic models, based on standard readily available baseline characteristics, were developed for elderly patients with AML, which may assist in therapeutic and investigational decisions. These predictive models, based on a retrospective analysis, will require validation in independent study groups.