FLT3-ITD As a Prognostic Factor for Chinese Patients with Acute Myeloid Leukemia

Internal tandem duplication of the FLT3 gene (FLT3-ITD) is one of most common genetic mutations found in patients with acute myeloid leukemia (AML). Although FLT3-ITD has been widely studied and used as an important prognostic indicator of AML in the western world, its association with disease features and prognosis in Chinese AML patients to date has rarely been investigated.In this study, 177 Chinese patients with AML were enrolled including a FLT3-ITD mutation positive group (n = 83) and a FLT3-ITD mutation negative group (n = 94).In FLT3-ITD-positive AML patients, the number of patients whose peripheral blood leucocyte count (≥ 100 × 10⁹/L) before treatment was significantly higher than in FLT3-ITD negative patients (32.1% vs 7.6%), but comparing to FLT3-ITD mutation negative patients, 1 year and 2 year event free survival rates (EFSR) of FLT3-ITD-positive AML patients was lower ((37.0% vs 56.0%) and (14.8% vs 38.4%)), and also their 1 year and 2 year OS rates were significantly lower ( (50% vs 100%) and (18.0% vs 36.5%)). However, it was found that the rate of induced remissions in FLT3-ITD-positive AML patients was much lower than in negative patients (39.4% vs 56.0%). The median survival time of the FLT3-ITD+/NPM1- group (n = 39) was superior to the FLT3-ITD+/NPM1+ group (n = 27) (16.1 months vs 5.8 months). Lastly, after comparing chemotherapy regimes, we found that the allogeneic hematopoietic stem cell transplantation treatment method significantly improved the survival rate of FLT-ITD positive AML patients (not reached vs 14.5 months). Therefore, for FLT3-ITD-positive Chinese patients with AML, the relative rate of complication with leucocyte was increased; both the event free and overall survival rates were lower, these characteristics are the same as the FLT3-ITD-positive patients in western countries. The lower induced remission rate and shorter survival time suggested FLT3-ITD+/NPM1+ mutation is inferior to FLT3-ITD+/NPM1- mutation, which is not consistant with most reports. In addition, allogeneic hematopoietic stem cell transplantation was clearly an effective treatment for patients with FLT-ITD positive AML in China.