 The first Part: recruiting untreated ENKL patients with extensive stage I or limited stage II disease only referring to patients with the invasion of Waldeyers ring and cervical lymph nodes . Patients are randomly divided into two arms, IPGDP regimen chemotherapy followed by radiotherapy or radiotherapy followed by IPGDP regimen chemotherapy. IPGDP regimen for both arms are 3 cycles. And the chemotherapy is repeated every 3 weeks.. 