Treatment Study for Children and Adolescents With Acute Promyelocytic Leukemia

To evaluate the rate of hematological Complete Remission (CR) (defined as bone marrow regenerating normal hematopoietic cells and containing < 5% blast cells by morphology, with ANC in peripheral blood > 1.0 x 10^9/L and platelet count > 100 x 10^9/L) and Complete Remission with incomplete hematologic recovery (CRi) (defined as CR except that peripheral blood neutrophils and/or platelets do not meet the criteria as defined above) after induction therapy.

To evaluate the rate of molecular CR/CRi (defined as the absence of PML/RARα fusion transcript in bone marrow assessed by RQ-PCR, with an assay sensitivity of at least 10^-4).

To evaluate the rate of early death during induction (defined as any death occurring within 14 days from diagnosis from any cause).

To evaluate the rate of overall survival

To evaluate the cumulative incidence of hematological relapse (defined as reappearance of promyeloblasts/abnormal promyelocytes > 5% in the bone marrow) and molecular relapse (defined as reappearance of PML/RARα fusion transcript in two successive samples taken at least 2 weeks apart in patients previously in molecular remission).

Incidence of treatment-related hematological and non-hematological toxicity assessed by CTCAE v4.0

To evaluate the rate of molecular remission (defined as the absence of PML/RARα fusion transcript in bone marrow assessed by RQ-PCR, with an assay sensitivity of at least 10^-4) after 3 consolidation cycles.

To evaluate the reduction of PML/RARα fusion transcript in bone marrow by means of RQ-PCR during treatment.

Pediatric Quality of life assessed by PedsQoL questionnaire, in the questionnaire there is a list of things that might be a problem for the child. The minimum value is 0 (never a problem) - maximum value 4 (almost always problem)

Number of total hospitalization days during the treatment.