Outcomes in Obese and Overweight Acute Myeloid Leukemia (AML) Patients Receiving Chemotherapy Dosed According to Actual Body Weight

Cytotoxic chemotherapy (CT) dosages are traditionally calculated according to body surface area (BSA). There are no recommendations for the dosing of CT in obese (OB) and overweight (OV) patients (pts) with AML. In solid tumor malignancies, use of actual body weight to calculate CT dosages in OB pts did not result in increased toxicities. Due to the lack of data in leukemia pts, we investigated efficacy and safety outcomes between underweight and normal weight (NW), OV, and OB pts when CT was dosed according to BSA based on actual body weight.

We identified AML pts treated with anthracycline and cytarabine-based remission induction CT dosed according to actual body weight from 2002 to 2009 at Cleveland Clinic. Pts were divided into three groups according to body mass index (BMI): NW (BMI < 24.9), OV (BMI 25.0–29.9), and OB (BMI > 30.0). Cytogenetics were categorized according to CALGB. Complete remission (CR) rates, overall survival (OS), and safety outcomes were compared between groups. Means, percentages, and median survival time were compared among groups using ANOVA, chi-square tests, survival analysis with log-rank tests and Cox regressions, as appropriate.

Of the 247 AML pts included, 81 were NW, 81 were OV, and 85 were OB. Baseline characteristics were not different between groups; within the entire study population, the mean age was 55.6 years (SD 14.3), 49.0% were female, and 69.2% had de novo AML. Favorable, intermediate, and unfavorable cytogenetics were not significantly different in NW (6.2%, 55.6%, and 30.9%), OV (18.5%, 38.3%, and 29.5%), and OB pts (15.3%, 42.4%, and 27.1%; p=0.107), respectively. Among NW, OV, and OB pts, CR rates were similar (69.1%, 79.0%, and 76.5%, respectively; p=0.321), as was median OS (10.7, 16.7, and 14.2 months, respectively, p=0.352) and early mortality within 30 days of induction CT (3.7%, 2.5%, and 7.1%, respectively, p=0.331). There was no difference in days to neutrophil recovery (34.4, 31.9, and 32.7, respectively, p=0.134) or days to platelet recovery (34.2, 31.7, and 31.2, respectively, p=0.490). Days spent in the hospital during initial induction CT (p=0.095) and incidence of documented bacteremia (p=0.288) also did not differ among groups. Post-therapy left ventricular ejection fraction < 40% or symptomatic heart failure was documented in 12.3% of NW, 3.7% OV, and 4.7% OB pts (p=0.058). After adjustment for confounders (age, cytogenetic risk, and etiology), the OS was significantly shorter for NW compared to OB (p=0.016), but was not different between NW and OV (p=0.104).

CR rates and CT-associated adverse events were not significantly different among NW, OV, and OB AML pts when standard induction CT was dosed according to actual body weight. This demonstrates that standard induction CT can be safely dosed using actual body weight in these pts. Although not significant, NW patients had the lowest CR rate and shortest median OS. Low BMI could be a marker of worse performance status.

No relevant conflicts of interest to declare.