ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the outcomes of childhood acute monocytic leukemia (AML-M5) and explore the indications of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for children with AML-M5.</p><p><b>METHOD</b>Seventy-five AML-M5 patients and 201 non-AML-M5 AML patients were enrolled in this retrospective analysis. Event-free survival (EFS) and overall survival (OS) rates were estimated by Kaplan-Meier method and prognostic factors were evaluated by COX regression with SPSS.</p><p><b>RESULT</b>(1) Twelve patients gave up treatment after confirmed diagnosis. Two patients died on the second day after chemotherapy. Of the 61 patients, 73.8% (45/61) achieved complete remission (CR) after two courses of chemotherapy. The 5-year EFS rate was 34.5% ± 6.8%. But of the 117 non-AML-M5/M3 AML patients, the 5-year EFS rate was 51.0% ± 4.9%. (2) Multivariate analysis showed that age ≥ 10 y, the proportion of bone marrow blast cell counts ≥ 15% after the first induction therapy, not CR after two courses of chemotherapy were risk factors for the long-term prognosis. (3) Of the 20 patients whose bone marrow blast cell counts ≥ 15% after the first induction therapy, 5 patients who choose allo-HSCT had a better OS than the other 15 patients who choose chemotherapy only (60.0% ± 21.9% vs. 7.3% ± 7.1%, P = 0.024).</p><p><b>CONCLUSION</b>Children with AML-M5 had a poorer prognosis than the other AML patients; patients whose bone marrow blast cell counts ≥ 15% after the first induction therapy chose allo-HSCT had a better prognosis. At present, there is no enough evidence to support that patients whose bone marrow blast cell counts < 15% after the first induction therapy should choose unrelated donor for allo-HSCT.</p>