The prognostic impact of FLT3-ITD and NPM1 mutation in adult AML is age-dependent in the population-based setting

In acute myeloid leukemia (AML) FLT3 internal tandem duplication (ITD) and nucleophosmin 1 (NPM1) mutations provide prognostic information with clinical relevance through choice of treatment, but the effect of age and sex on these molecular markers has not been evaluated. The Swedish AML Registry contains data on FLT3-ITD and NPM1 mutations dating to 2007, and 1570 adult patients younger than 75 years, excluding acute promyelocytic leukemia, had molecular results reported. Females more often had FLT3(ITD) and/or NPM1(mut) (FLT3(ITD) : female, 29%; male, 22% [P - .00151; NPM1(mut) : female, 36%; male, 27% [P < .0001]), and more males were double negative (female, 53%; male, 64%; P < .0001). Patients with FLT3(ITD) were younger than those without (59 vs 62 years; P = .023), in contrast to patients with NPM1(mut) (62 vs 60 years; P = .059). Interestingly, their prognostic effect had a strong dependence on age: FLT3(ITD) indicated poor survival in younger patients (<60 years; P = .00003), but had no effect in older patients (60-74 years; P = .5), whereas NPM1(mut) indicated better survival in older patients (P = .00002), but not in younger patients (P = .95). In FLT3(ITD)/NPM1(mut) patients, the survival was less dependent on age than in the other molecular subsets. These findings are likely to have clinical relevance for risk grouping, study design, and choice of therapy.