To evaluate the efficacy and safety of first-line gemcitabine, oxaliplatin, and asparaginase (GELOX) with concurrent involved-field radiation therapy for patients in newly diagnosed stage IE/IIE ENKTL.

1. Patients

   • All patients should sign a written informed consent form before enrollment, and the study should be approved by the Sun Yat-sen University Cancer Center Ethics Board.
   • Baseline of patients: Computed tomography (CT) scans of the chest, abdomen, and pelvis, magnetic resonance imaging studies of the head and neck, and bilateral bone marrow aspiration or biopsy. Positron emission tomography-CT scans (optional). Epstein-Barr virus (E B V) DNA blood levels, titer of EBV antibody (EA-IgA, VCA-IgA), β2-micro globulin (β2-MG) and soluble CD 25 (sCD 25) in the serum.
   • Recheck before and after every course: Epstein-Barr virus (EBV) DNA blood levels, titer of EBV antibody (EA-IgA, VCA-IgA), β2-micro globulin (β2-MG) and soluble CD 25 (sCD25) in the serum.
   • Recheck every two course: Computed tomography (CT) scans of the chest, abdomen, and pelvis, magnetic resonance imaging studies of the head and neck, and bilateral bone marrow aspiration or biopsy. Positron emission tomography-CT scans (optional)

2. Treatment Protocol - The GELOX regimen consist of the following drugs: gemcitabine ：1250 mg/ m2 on days 1,ivdrip oxaliplatin ：85 mg/m2 on day 1, ivdrip pegaspargase : 2500 IU/m 2 daily on day 1,intramuscular The treatment cycle was repeated every 14 days.

   • IFRT was delivered using 6-MeV linear accelerator using 3-dimensional conformable treatment planning. The IFRT dose was 56 grays (Gy) in 28 fractions, we define the clinical target volume of limited stage IE disease as the bilateral nasal cavity, bilateral ethmoid sinuses, and ipsilateral maxillary sinus; and the clinical target volume would extend to involved tissues for patients who had extensive stage IE disease. For patients who had stage IIE disease, the clinical target volume also, included the bilateral cervical lymph node area.

     • Disease Progression during the treatment should be treated with second-line therapy.

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