Clinical Characteristics and Outcomes of 82 Patients with Mixed-Phenotype Acute Leukemia

Objectives: Mixed-phenotype acute leukemia(MPAL) is a rare disease and comprises 2% to 5% of all acute leukemia. Outcomes for MPAL are worse than both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML).The complex phenotype exhibited by this type of leukemia resulted in a myriad of treatment approaches.In our study, we retrospective analysis 82 patients in clinical trail, treatment strategy and prognosis.

Method: eighty-two patients diagnosed with MPAL at Nan fang hospital from 2006 to 2017 using either EGIL or 2008 WHO criteria were analyzed. Comparison the treatment effect and outcomes between different therapy types.

Result: eighty-two patients, including 60 males and 22 females with a median age of 29 years (range, 2 months-72 years), were studied. 61 patients (77%) were older than 18years, 73patients met the criteria for MPAL via EGIL, 68via WHO2008, and 59of these were reported to satisfy both definitions. fifty one of these cases (62.2%) had a B/myeloid phenotype, Twenty four of these cases (29.3%) had a T/myeloid phenotype. The other cases (8.5%) showed immunophenotypic evidence of a B, T, and myeloid lineage in one blast population. Among the 82 cases, 57 cases with successful cytogenetic studies, 20(35.1%) had normal karyotypes and 37patients(64.9%) had abnormal karyotypes. Twelve patients (21.05%) translocation between chromosomes 9 and 22, five (8.8%) patients had 11q23/MLL translocations. Twelve patients (21.05%) had a complex karyotype and eight patients (14%) had other karyotype. The rarity of this disease and the fact that patients with MPAL are excluded from most AML and ALL clinical trials further complicates guidance about therapy. Of the 82 cases, 75 patients underwent the complete first course of treatment and complete remission rate was 49.8%. treatment approaches utilizing therapy for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and so-called "hybrid" therapy mixing elements of both are 51.9%, 16.7% and 66.7% respectively (P=0.003).OS and EFS with hybrid induction therapy and ALL like induction were not significantly different than those with AML induction by either definition (P>0.05). A total of 60 patients received consolidation treatment, 21 patients received the chemotherapy while 39 patients received stem cell transplant (HSC). The total Median EFS was 21months, in Chemotherapy group and HSC group, the Median EFS was 6 months and 40 months respectively, The 3-year EFS was 26.1% and 55.6% respectively (P=0.038). The total Median OS was 21 months, Median OS showed a significant survival benefit for starting with chemotherapy as compared to HSC( 12 months and 43 months respectively (P=0.001)), The 3-year OS was 19.1% and 57.7% respectively.

Conclusion: In this study, ALL like induction therapy or "hybrid" therapy was associated with a more than three-fold greater CR rate than AML therapy. SCT therapy showed a trend for an association with higher OS and EFS for MPAL .

Key words: MPAL, Immunophenotype,Treatment strategy

Funding

Key Sci-Tech Research Projects of Guangdong Province (2014A02021102).