Camrelizumab, Pegaspargase and Apatinib With Radiation Therapy for Stage IE/IIE ENKTL

Inclusion Criteria: * Patients who meet the WHO 2016 diagnostic criteria for NK/T-cell lymphoma by biopsy histopathology, immunohistochemistry and EBER. * The primary site is in the nasal cavity or upper gastrointestinal tract. The de novo diagnosed patient has at least one objective and evaluable lesion. * Stage IE / IIE disease according to Lugano 2014 lymphoma staging system. * ECOG score 0-3. * The laboratory examination within 1 week before entering the group meets the following conditions: 1. Blood routine test: neutrophil count≥1.0 × 10\^9/L, Hemoglobin≥80g/L, Platelet≥50 × 10\^9/L. 2. Coagulation routine: plasma fibrinogen ≥ 1.0g / L. 3. Liver function: Alanine aminotransferase, aspartate aminotransferase and total bilirubin ≤ 2 times the upper limit of normal value. 4. Renal function: Creatinine is normal. 5. Refers to oxygen saturation\> 93%. 6. Cardiac function: Left ventricular ejection fraction ≥50%, electrocardiogram does not suggest any acute myocardial infarction, arrhythmia or atrioventricular block above 1 degree * Signed informed consent. * Voluntarily follow the research protocol, follow-up plan, laboratory and auxiliary examinations. Exclusion Criteria: * accompanied with HCV or HIV infection, HBV-infected patients who also receive antiviral treatment are not excluded. * Severe infection requires ICU treatment. * Serious complications such as hemophagocytic syndrome, DIC, etc. * Impairment of important organ functions: such as respiratory failure, chronic congestive heart failure with NYHA grade ≥3, decompensated liver or kidney dysfunction, hypertension and diabetes that cannot be controlled despite active treatment. * Have a history of autoimmune diseases, have disease activity in the last 6 months, and are still taking oral immunosuppressive therapy within the past three months, with a daily dose of oral prednisone greater than 10 mg. * Pregnant and lactating women. * Those who are known to be allergic to drugs in the CAPA regimen. * Patients with other tumors who need surgery or chemotherapy within 6 months. * Other experimental drugs are being used. * The investigators believe that other clinical conditions (including medical history or the presence of comorbidities) of the patient will significantly increase the risk of the subject when using the study treatment drugs.