Sequence 1: Includes prednisolone, cyclophosphamide, doxorubicin, methotrexate, Vincristine. ⁽¹⁾

Sequence 2: Includes cytarabine and etoposide. ⁽¹⁾

Positive FDG-PET/CT: Residual lesion is Deauville score more than 3. ⁽²⁾

Negative FDG-PET/CT: Residual lesion is Deauville score < 3. ⁽²⁾

Risk group definitions ⁽¹⁾

Group A

· Completely resected stage I

or

· Completely resected abdominal stage II

Group B (Low risk)

· Unresected stage I and non-abdominal stage II

or

·  stage III with low LDH (≤2 times [ULN])

Group B (High risk)

· Stage III with high LDH (>2 times ULN),

or

· All non-CNS stage IV with bone marrow involvement (<25% lymphoma cells)

· Achieving more than 20% regression after COP

Group C

· Any CNS involvement and/or Bone marrow involvement (≥25% lymphoma cells)

· Achieving less than 20% regression after COP

International Paediatric NHL Response criteria ⁽³⁾:

CR

·  Disappearance of all disease

·  CT or MRI reveals no residual and no new lesions

·  Residual mass pathologically negative for disease BM and CS free of disease pathologically

CRb

· Residual mass with no pathologic evidence of disease from limited or core biopsy; no new lesions by imaging examination

·  BM and CSF free of disease pathologically

·  No new and/or progressive disease elsewhere

CRu

· Residual mass negative by FDG-PET; no new lesions by imaging examination

· BM and CS free of disease pathologically

·  No new and/or progressive disease elsewhere

PR

· At least 50% decrease in SPD on CT or MRI; FDG-PET may be positive (Deauville score 4 or 5 with reduced lesional uptake compared to baseline)

· May have evidence of disease in BM or CSF if present at diagnosis but should have 50% reduction in percentage of lymphoma cells.

· No new and/or progressive disease

MR

· Decrease in SPD >25%, but <50% on CT or MRI

·  May have evidence of disease in BM or CS if present at diagnosis, but should have 25% to 50% reduction in percentage of lymphoma cells

·  No new and/or progressive disease

NR

· Not meeting CR, PR, MR, or PD criteria

PD

· >25% increase in SPD on CT or MRI; Deauville score 4 or 5 on FDG-PET with increase in lesional uptake from baseline; or new morphologic disease in BM or CSF