Elderly AML: A Five-Year Retrospective Review on Prognostic Features

Background:

Acute Myeloid Leukemia (AML) is a disease of the elderly with a median age of diagnosis of 70 years. Prognosis in this age group is poor, with median overall survival of those undergoing treatment ranging from seven to twelve months. Treatment is difficult for a variety of reasons, including - higher incidence of co-morbid conditions (including frailty and decline in functional status), decreased ability to tolerate infections, socioeconomic considerations, and more aggressive disease phenotype. We present a single-institution retrospective review of acute myeloid leukemia outcomes with respect to these and other variables.

Methods:

A retrospective chart review was performed on all patients with a new diagnosis of AML from November 2013 through October 2017. Descriptive statistics were performed using excel, inferential statistics including Kaplan-Meier with comparison of survival curves by Logrank test and Cox-proportional hazard regression analysis, and correlation coefficients were performed using MEDCALC statistical software package.

Results:

Eighty-four AML patients in total were diagnosed with acute myeloid leukemia within the specified time frame, of these, 45 patients were age 65 or older (elderly) and were included in further analysis. Median age of elderly AML patients in this study was 70 years. Six of these patients were diagnosed with secondary AML (having arisen from MDS (N = 4), or other hematologic malignancy (N=2), and two had therapy-related AML. Eight patients had favorable risk disease, 13 intermediate risk, and 24 adverse risk according to ELN 2017 criteria. The median survival of all elderly patients was 322 days. Median survival of elderly AML according to ELN 2017 risk category criteria (Favorable, Intermediate, or Poor) was not reached (mean 880 days), 390 days, and 117 days, respectively (p = 0.0368 by cox hazard regression). Survival was not affected by type of treatment (induction vs hypomethylating agent (HMA); median 579 and 166 days (p = 0.1378) and mean 1552 and 364 days, respectively. This is likely due to small sample size, although survival does appear to favor intensive induction. Survival was not affected by number of medical co-morbidities (p = 0.66), presence of infectious complications (p=0.152), or unplanned hospitalization (p = 0.144). Overall use of clinical trials (N=3) and transplant (N=2) were low, precluding meaningful statistical analysis. However, both patients undergoing transplant exceeded the median OS (579 and 4745 days). Median OS of patients identified as White/Caucasian was greater than those identified as Hispanic/Latino (166 days vs 66 days, respectively), this did not reach statistical significance.

Conclusion:

Given the limitations of a retrospective review and relatively small sample size, our data shows that the 2017 ELN risk category is the strongest predictor of overall survival. Statistically, those undergoing intensive induction did not have a longer overall survival than those treated with HMAs, highlighting the need for careful selection of induction therapy candidates, and the need for clinical trials investigating other less intense treatment options for patients in this category. Interestingly, number of medical co-morbidities did not influence overall survival, nor did unplanned hospitalizations, presence/absence of significant infections during therapy, or race/ethnicity. Our data suggest an under-utilization of clinical trials and allogeneic hematopoietic stem cell transplant, both of which may serve to improve prognosis.