A phase 2 study was conducted of "sandwich" protocols, with earlier RT after an initial 2 of P-CHOP (Pegaspargase, cyclophosphamide,vincristine, doxorubicin and dexamethasone ), followed by further two "consolidation" cycles,to explore the appropriate mode of combined modality therapy (CMT) in early stage ENKTL.

The extranodal natural killer/T-cell lymphoma (ENKTL) shows high local or systemic failure rates when radiotherapy (RT) is taken as the primary treatment, suggesting a role for chemotherapy (CT) added to RT for this disease. However, the appropriate mode of combined modality therapy (CMT) has not been fully defined.We conducted a prospective phase II study of "Sandwich" Pegaspargase, cyclophosphamide,vincristine, doxorubicin and dexamethasone (P-CHOP) regimen in combination with radiotherapy.The "sandwich" protocols, refer to earlier RT after an initial 2 cycles of P-CHOP followed by further two "consolidation" cycles.

Inclusion Criteria:

• newly diagnosed ENKTL
• age:18-69years
• Ann Arbor stage IE,or stage IIE with cervical lymph node involvement
• at lease one measurable lesion
• receive no chemotherapy or radiotherapy before
• Eastern CooperativeOncology Group performance status of 0 to 2.
• Adequate hematologic function (eg, white blood cell ≥ 3×10e9/l,neutrophils count ≥1.5×10e9/L, and platelet count≥ 100×10e9/L),renal function (eg, serum creatinine≤1.5 mg/dL and creatinine clearance ≥50 mL minute), and hepatic function (e.g, total bilirubin≤ 2 times the upper limit of normal and aspartate and alanine transaminase levels ≤ 3 times the upper limit of normal)

Exclusion Criteria:

• mismatch the inclusion criteria
• systematic central nervous system involvement
• previous or concomitant malignancies and any coexisting medical problems that could cause poor compliance with the study protocol.
• primary lesion not from the upper respiratory