2.1 Patients and treatment
A total of 176 pediatric patients with Ph-negative BCP-ALL were enrolled in the current study. They were diagnosed at our hospital from December 2008 to January 2016, received at least 1 course of chemotherapy and received chemotherapy only as post-remission treatment. The median age at diagnosis was 4 (range, 0-16) years. A total of 94 (53.4%) patients were male. The diagnosis was based on bone marrow morphology, immunophenotyping, karyotyping and molecular testing. The cutoff date for follow-up was December 2019.
As we reported previously,19,20 all the patients received treatments according to an improved ALL-Berlin-Frankfurt-Munster (BFM) protocol or the Chinese Children’s Protocol for ALL 2008 (CCLG-ALL-2008). Briefly, the CODPL (cyclophosphamide and prednisone or dexamethasone, vincristine, and daunorubicin or idarubicin and L-asparaginase) regimen was used during induction therapy; 15 courses of high-dose methotrexate with or without pegaspargase, 3 courses of high-dose cytarabine, and a round of ifosfamide were used during consolidation therapy. Re-induction therapy was administered at half-year intervals during consolidation therapy. The cumulative doses of L-asparaginase and daunorubicin (or idarubicin) were 300,000 units/m2 and 400(or 100) mg/m2, respectively. 6-mercaptopurine and methotrexate were used for maintenance therapy. Besides, 23-25 doses of intrathecal methotrexate, cytarabine, and dexamethasone administration was used for central nervous system leukemia (CNSL) prevention. The whole treatment course lasted 3-3.5 years.
The study was approved by the Ethics Committee of Peking University People’s Hospital, and all of the patients’ parents/guardians provided written informed consent to participate in the study in accordance with the Declaration of Helsinki.