The treatment regimen included CCRT ( involved field radiotherapy 50GY, concurrent 2 cycles of pegaspargase treatment ) followed by 4 cycles of pegaspargase. Chemotherapy and RT were performed simultaneously within one week after enrollment. The administration regimen was as follows : day1, deep intramuscular injection of 2500 unit/m2 pegaspargase at three different sites, and repeated once every 3 weeks. 3D conformal radiotherapy was performed using 4 or 6 MV photons generated by a linear accelerator. The radiation dose was 50 Gy, 2.0 Gy / time, 1 time / d, for 5 weeks. The clinical target volume ( CTV ) of limited stage IE patients was defined as bilateral nasal cavity, bilateral ethmoid sinus and ipsilateral maxillary sinus. The CTV of extensive stage IE patients was extended to the affected tissues. The CTV of stage IIE lesions also included the involved cervical lymph node area.
