A Multicenter, Phase 3, Randomized Trial of Sequencial Chemoradiotherapy with or Without Toripalimab (PD-1 Antibody) in Newly Diagnosed Early-Stage Extranodal Natural Killer/T Cell Lymphoma, Nasal Type (ENKTL)

Inclusion Criteria: * biopsy proved extranodal natural killer/T-cell lymphoma, nasal type; * newly diagnosed stage I/II patients; * at least one evaluable lesion； * ECOG PS 0-2; * 18-75 years; without other malignancy; * proper functioning of the major organs. Exclusion Criteria: * hemophagocytic syndrome or aggressive NK cell leukemia; * involvement of central nervous system; * previously received treatment of chemotherapy, radiotherapy, immunotherapy or biotherapy for lymphoma；