Allogeneic Hematopoietic Stem Cell Transplantation Overcomes the Poor Prognosis in MLL-Rearranged Solid Tumor Therapy Related-Acute Myeloid Leukemia

BACKGROUND: MLL rearrangement is very common in solid tumor therapy-related acute myeloid leukemia (t-AML). This study investigated the prognosis of MLL t-AML.

METHODS: Patients with solid tumor t-AML and MLL de novo AML were enrolled in this retrospective study. The patients were divided into 3 groups: non-MLL t-AML(n=41), MLL t-AML(n=18) and MLL de novo AML(n=98).

RESULTS: Of the 157 patients enrolled, 150 patients underwent anti-leukemia therapy. The complete remission (CR) rate was 83.3%, 85.5% and 86.2%(P=0.251), respectively, in MLL t-AML, non-MLL t-AML and MLL AML groups. The 3-years overall survival (OS) was 37.5%, 21.5% and 20.4% (P=0.046). The 3-years leukemia-free survival (LFS) was 28.0%, 32.2% and 22.7% (P=0.031), and the incidence of relapse was 30.0%, 50.4% and 53.5% (P=0.382), respectively, in the three groups. Multivariate analysis revealed that MLL t-AML was a risk factor while allo-HSCT a protective factor for relapse, LFS, and OS (P=0.005, P<0.001 and P<0.001) (P<0.001, P<0.001 and P=0.002, respectively). The 3-years OS was 0%, 17.9% and 0%( P=0.038), LFS was 0%, 23.1% and 0%( P=0.017), and relapse was 100%, 53.1% and 74.4% (P=0.001), respectively among three groups in patients undergoing chemotherapy alone, while OS was 64.3%, 52.7% and 40.7% (P=0.713), LFS was 60.0%, 48.8% and 37.0% (P=0.934), and relapse was 25.0%, 47.4% and 47.5% (P=0.872), respectively, among these group in the patients undergoing allo-HSCT. Intriguingly, MLL t-AML was no longer risk factor for relapse and LFS (P=0.882 and P=0.484, respectively), while it became a favorable factor for OS (P=0.011) in the patients undergoing allo-HSCT

CONCLUSIONS: MLL t-AML had poor prognosis compared with non-MLL t-AML and MLL de novo AML,, but allo-HSCT might overcome the poor prognosis of MLL t-AML.