Purpose Younger patients with acute myeloid leukemia (AML) harboring NPM1 mutations without FLT3-internal tandem duplications (ITDs; NPM1-positive/ FLT3 -ITD-negative genotype) are classified as better risk; however, it remains uncertain whether this favorable classification can be applied to older patients with AML with this genotype. Therefore, we examined the impact of age on the prognostic significance of NPM1- positive/ FLT3 -ITD-negative status in older patients with AML. Patients and Methods Patients with AML age ≥ 55 years treated with intensive chemotherapy as part of Southwest Oncology Gorup (SWOG) and UK National Cancer Research Institute/Medical Research Council (NCRI/MRC) trials were evaluated. A comprehensive analysis first examined 156 patients treated in SWOG trials. Validation analyses then examined 1,258 patients treated in MRC/NCRI trials. Univariable and multivariable analyses were used to determine the impact of age on the prognostic significance of NPM1 mutations, FLT3-ITDs, and the NPM1-positive/FLT3-ITD-negative genotype. Results Patients with AML age 55 to 65 years with NPM1- positive/ FLT3-ITD-negative genotype treated in SWOG trials had a significantly improved 2-year overall survival (OS) as compared with those without this genotype (70% v 32%; P < .001). Moreover, patients age 55 to 65 years with NPM1-positive/ FLT3 -ITD-negative genotype had a significantly improved 2-year OS as compared with those age > 65 years with this genotype (70% v 27%; P < .001); any potential survival benefit of this genotype in patients age > 65 years was marginal (27% v 16%; P - .33). In multivariable analysis, NPM1-positive/ FLT3 -ITD-negative genotype remained independently associated with an improved OS in patients age 55 to 65 years ( P = .002) but not in those age > 65 years ( P = .82). These results were confirmed in validation analyses examining the NCRI/MRC patients. Conclusion NPM1-positive/FLT3-ITD-negative genotype remains a relatively favorable prognostic factor for patients with AML age 55 to 65 years but not in those age > 65 years.
ASJC Scopus subject areas
- Cancer Research