The optimal first-line treatment for extra-nodal NK/T-cell lymphoma (ENKTL) has not been well-defined. This phase II study aimed to evaluate the efficacy and safety of pegaspargase, cyclophosphamide, vincristine, etoposide and prednisone (COEPL) regimen combined with radiotherapy for patients with newly diagnosed ENKTL.

Inclusion Criteria:

• patients with confirmed pathological diagnosis of ENKTL as defined by WHO criteria
• age 14-80 years
• no prior chemotherapy or radiotherapy
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2
• at least one measurable lesion
• adequate bone marrow function (i.e. hemoglobin ≥80 g/l, absolute neutrophil count ≥ 1.0 × 10^9/L, platelets ≥ 100 ×10^9/L), adequate renal function (i.e. serum creatinine ≤177 μmol/L), adequate hepatic function (e.g. total bilirubin ≤ two times the upper limit of normal, and ALT /AST ≤2.5 times the upper limit of normal)
• expected survival of more than three months

Exclusion Criteria:

• invasion of lymphoma to central nervous system
• pre-existing coagulation disorder
• other concomitant neoplasms
• severe infection
• positive HIV antibody
• HBV DNA titer higher than 10^4 copies /ml in HBsAg-positive patients post antiviral therapy
• pregnant or lactating women
• women of childbearing age unwilling to take contraceptive measures during the study period