Extranodal natural killer (NK)/T-cell lymphoma (ENKTL), nasal type, is a distinct and heterogeneous histopathologic subtype of non-Hodgkin lymphoma (NHL), accounting for 5%~10%. The frequency of ENKTL among NHL patients is significantly higher in Asia than in Western countries, with poor prognosis. Radiotherapy plus chemotherapy has improved the survival for these patients. But the optimal treatment schedule is controversial. The previous protocols usually contained high dose methotrexate, but the application of them is limited for the toxicity.

In mid-2016, we had the final evaluation of the phase 2 study of MESA with sandwiched radiotherapy in newly diagnosed early stage NKTCL (NCT02825147). We obtained the final overall response rate of MESA with sandwiched radiotherapy, while the 2-year progression free survival rate was not available at that timepoint. To make the study design of sample size more accurate, we changed the primary outcome endpoint from 2-year progression free survival rate to overall response rate. The change had been approved by the Ethics Committee in August 10, 2016. At that time, only fourteen patients were enrolled in NCT02631239.

Inclusion Criteria:

• Pathological diagnosis of extranodal NK/T cell lymphoma, nasal type, previously untreated
• Age 14 ~ 70 years old
• ECOG(Eastern Cooperative Oncology Group）performance status 0~2
• Stage I to II
• Life expectancy>6 months
• Informed consented

Exclusion Criteria:

• Chemotherapy before
• Bone marrow transplantation before
• History of malignancy
• Uncontrollable cardio-cerebral vascular, coagulative, autoimmune, serious infectious disease
• LVEF≤50%
• Other uncontrollable medical condition that may that may interfere the participation of the study
• Lab at enrollment ALT or AST >3*ULN, AKP or bilirubin >2.5*ULN Creatinine>1.5*ULN
• Not able to comply to the protocol for mental or other unknown reasons
• Pregnant or lactation
• HIV infection