The Guangdong work group of childhood acute lymphoblastic leukemia (ALL) therapy was set up in October 2002. The investigators treated the childhood ALL with a GZ2002 protocol since the year 2002, and the protocol was mainly derived from the ALLIC-BFM 2002 protocol. After summarizing the last six years' experience, our group revised the GZ2002 ALL protocol in the year 2008, which is named GD-2008 ALL protocol. The diagnosis and classified criteria is according to the ALLIC-BFM 2002 protocol, and the chemotherapy protocol consists all the therapeutic phases as the ALLIC-BFM 2002 protocol prescribed.

The modification includes:

1. In the induction phase, the agent of dexamethasone 6 mg/m2 is used instead of prednisone after prednisone prophase.
2. The phase "CAM" is 2 weeks for SR patients and 4 weeks for IR and HR patients,respectively.
3. Both the SR and IR treatments involve the protocol mM /M (8 weeks) in the phase of consolidation. However, the folinic acid rescue starts at 36 hours instead of 42 hours. The type of HR enters the block treatment the same with the BFM protocol.
4. There is not randomized study in delayed intensification. The GD-2008 ALL protocol uses the same protocol II with the BFM study.
5. The randomized study focus on the phase of maintenance. The maintenance A is the same with the BFM protocol, while the maintenance B consists of 6mp/MTX and VCR/ dexamethasone. The cycle is 8 weeks: VCR at d1, Dexamethasone at d2 to d7, 6mp from d8 to d56, and MTX at d9,d16, d23, d30, d37,d44,d51.
6. The GD-2008 ALL protocol for HR patients use the re-blocks and protocol II phases.

Inclusion Criteria:

• Cytologically proven acute lymphoblastic leukemia (ALL)

• No relapse of a previously unrecognized ALL

• Patients must meet one of the following risk criteria:

• Standard-risk (SR) group meeting all of the following criteria:

• Blasts < 1,000/μL in peripheral blood (PB) on day 8

• Aged 1 to < 6 years

• Initial WBC < 20,000/μL

• M1 (5%) or M2 (≥ 5% to < 25%) blasts in bone marrow on day 15;

• M1 marrow on day 33.

• Intermediate-risk (IR) group meeting all of the following criteria:

  • Aged < 1 or ≥ 6 years and/or WBC ≥ 20,000/μL
  • Blasts < 1,000/μL in PB on day 8
  • M1 or M2 marrow on day 15
  • M3 (≥ 25%) marrow on day 15 OR meets SR criteria but M3 marrow on day 15 and *M1 marrow on day 33.

• High-risk (HR) group meeting ≥ 1 of the following criteria:

  • Meets IR criteria and M3 marrow on day 15 (not SR and M3 on day 15)
  • Blasts ≥ 1,000/μL in PB on day 8
  • M2 or M3 marrow on day 33
  • Translocation t(9;22) [BCR/ABL+] (Philadelphia chromosome-positive) or t(4;11) [MLL/AF4+].

Exclusion Criteria:

• No Down syndrome
• No other major disease that prohibits study treatment (e.g., severe congenital heart disease)
• Not requiring significant therapy modification owing to study therapy associated complications
• No complications due to other interventions
• No one with missing data that are needed for the differential diagnosis, or for selection of the proper therapy arm