Survival for older patients with acute myeloid leukemia: a population-based study

Abstract

Background: Acute myeloid leukemia is the second most common leukemia among United States adults with a median age of 69 years. We investigated recent clinical practices related to treatments and disease outcomes in older patients with acute myeloid leukemia in the United States.

Design and methods: In this retrospective cohort study, we used Surveillance, Epidemiology, and End Results program data from 2000 through 2007 linked to Medicare enrollment and utilization data in the United States.

Results: Among 5,480 patients with acute myeloid leukemia (median age 78 years, range 65-93), 38.6% received leukemia therapy within three months of diagnosis (treated group). Practice changed with 16.3% of treated patients receiving hypomethylating agents after 2004 when those agents became available. Median survival was two months in the untreated group versus six months in the treated group (P<0.01) with the biggest improvements seen in those aged 65-69 years (10 months vs. 4 months; P<0.01) and 70-74 years (8 months vs. 3 months; P<0.01). In 46 patients receiving allogeneic hematopoietic cell transplantation (0.8%), the median survival from diagnosis was 22 months.

Conclusions: Therapy for leukemia improves overall survival in older acute myeloid leukemia patients. Based on their comorbidities, most patients up to 80 years of age should be considered for treatment. New therapies including hypomethylating agents and allogeneic hematopoietic cell transplantation are promising and must be compared with other chemotherapy regimens.

Figure 1.

Frequency of Charlson comorbidity index (CCI) by age (A) and frequency of leukemia therapy use by age and CCI (B). Although half of all patients had a Charlson comorbidity index (CCI) score of 0, the score progressively worsened with age and there was a strong association of less leukemia therapy and older age with worse CCI.

Figure 2.

Early death rates after AML diagnosis by age and by Charlson comorbidity index (CCI). The treated group was restricted to patients who received leukemia therapy during the same month of AML diagnosis to minimize time to leukemia therapy selection bias.

Figure 3.

Overall survival by leukemia therapy stratified by age (A) Charlson comorbidity index (CCI) (B) previous MDS diagnosis (C) and median income (categorized by quartiles (qrtl)) (D). Median survival was six months longer in patients aged 65-69 (10 vs. 4 mo), five months in age 70-74 (8 mo vs. 3 mo), four months in 75-79 (6 mo vs. 2 mo) and two months in ≥80 (3 mo vs. 1 mo). (A) Patients with CCI of 0 to 1 had improved survival with chemotherapy (7 mo vs. 3 mo and 6 mo vs. 2 mo). However this improvement was less in patients with CCI ≥2 (4 mo vs. 2 mo). (B) Survival was better with therapy, even in patients with previous history of myelodysplastic syndrome (MDS) (5 mo vs. 2 mo); similar to patients with no previous MDS (7 mo vs. 2 mo). (C) With every quartile of some college education at the ZIP code level, improvement in survival observed with therapy (6 mo vs. 2 mo in first, second and fourth quartiles and 7 mo vs. 2 mo in the third quartile).