The Role of Induction Chemotherapy for High-risk Locally Advanced Nasopharyngeal Carcinoma in the Era of IMRT

Inclusion Criteria: * biopsy-proved NPC * N3 or T4N2 or multiple lymphnodes involved with at least one mass 4 cm or more in maximal diameter according to 7th UICC Staging * provide written informed consent * Kps\>70 * no dostant metastasis * Life expectancy≥6 months * Adequate renal function, defined as follows: Serum creatinine \< 2 x institutional upper limitof normal(ULN) within 2 weeks prior to registration or; creatinine clearance rate (CCr) ≥ 50 ml/min within 2 weeks prior to registration determined by 24- hour collection or estimated by Cockcroft-Gault formula: CCr male = \[(140 - age) x (wt in kg)\] \[(Serum Cr mg/dl) x (72)\] CCr female = 0.85 x (CCrmale) * The following assessments are required within 2 weeks prior to the start of registration: Na, K, Cl, glucose, Ca, Mg, and albumin. Exclusion Criteria: * Prior invasive malignancy (except non-melanomatous skin cancer) unless disease free for a minimum of 3 years; noninvasive cancers (For example, carcinoma in situ of the breast, oral cavity, or cervix are all permissible) are permitted even if diagnosed and treated \< 3 years ago * Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields * Severe, active co-morbidity