Acute Myeloid Leukemia Relapse Before And After The Change Of Molecular Marker

ObjectiveTo investigate the change of oncogene FLT3-ITD/TKD mutations for patients with acute myeloid leukemia (AML) relapse and the impact on the prognosis.Methods23patients in our hospital from August2007to May2011with acute myeloid leukemia received FLT3-ITD/TKD gene tests in the first visit and after relapse. In the first visit,12patients resulted positive in FLT3-ITD/TKD gene tests (FLT3+group), and11resulted negative(FLT3-group). The cases were followed up until Dec31st2011. The basic clinical characters, the incidence of FLT3mutation after relapse, secondary complete remission (CR2) rate, disease free survival (DFS) rate, overall survival (OS) rate of2groups of patients were analyzed. The correlation between the prognosis and white blood cell (WBC) count in the disease onset, FLT3phenotype, karyotype, and disease classification of2groups of subjects were discussed. The SPSS13.0software was used for statistics.Results1. The incidence of FLT3mutation:In the FLT3+group, after relapse, the mutation rate was91.7%(11/12); in the FLT3-group, the mutation rate was27.3%(3/11). Two out of3patients with FLT3mutation, failed to show remission after chemotherapy, and passed away after2months. The rest1patient achieved CR2after chemotherapy and matained DFS till the last follow up.2. The CR2rate in the2groups:In the FLT3+group, only1patient achieved complete remission after relapse, the CR2rate was8.3%(1/12); the patient was a FLT3/TKD+subject in the first visit, and survived after chemotherapy till now. In the FLT3-group,3patients achieved complete remission after remission after relapse, the CR2rate was27.2%(3/11). There was a trend of higher CR2in the FLT3-group as compared to the FLT3+group, but there was no stastistically significant difference (P=0.261) between the2groups.3. The DFS in the2groups:The median DFS was5(2-34) months in the FLT3+group, and5(3-19) months in the FLT3-group. There was no statistically significant difference between the2groups (P=0.857). Further classification of the FLT3+group demonstrated that:The average DFS was5.8months in the group of patients with FLT3/ITD+in the first visit, and19.7months in the group of patients with FLT3/TDK+in the first visit. The group of patients with FLT3/ITD+in the first visit showed a shorter DFS. However, there was no statistically analysis between the2groups, due to the relatively small number of sample size.4. The OS in the2groups:The median OS was12.5(7-35) months in the FLT3+group, and15(6-40) months in the FLT3-group. There was no statistically significant difference between the2groups (P=0.434). The average OS was12.4months in the group of patients with FLT3/ITD+in the first visit, and25.7months in the group of patients with FLT3/TDK+in the first visit. The latter group showed a trend of higher OS. However, there was no statistically analysis between the2groups (P=0.359), due to the relatively small number of sample size.5. In the2groups of patients:most showed a normal karyotype, and could be categorized Into the AML-M5b type. However, there was no significant correlation to the DFS and OS of AML patients.ConclusionAfter the relapse, most AML patients with FLT3+in the first visit demonstrated a FLT3mutation, while only some of patients with FLT3-in the first visit demonstrated a FLT3mutation. Therefore the FLT3mutation was unstable. The AML patients with FLT3mutation showed a remarkably high relapse rate, and the first therapeutic choice should be hematopoietic stem cell transplantation after complete remission.