EBV Positive Nasopharyngeal Carcinoma Treated With Concurrent Chemo-radiotherapy With or Without Anti-Viral Drug

Inclusion Criteria: * Confirmed histopathologic diagnosis of nasopharyngeal squamous cell carcinoma, types WHO II-III. * Stage II-IVB * Requiring primary concomitant Radiotherapy and Chemotherapy. * No head and neck surgery of the primary tumor or lymph nodes except for incisional or excisional biopsies. * Positive PCR-DNA EBV * ≥ 18 years of age * ECOG performance status 0-1 * WBC ≥ 4,000/µl, platelets ≥ 100,000/µl; serum creatinine ≤ 1.6 mg/dl or 24 hr. calculated creatinine clearance ≥ 60 ml/min (see Section 3.1.6). * Pre-treatment evaluation of tumor extent and tumor measurement. * Nutritional and general physical condition must be considered compatible with the proposed radio-therapeutic treatment. * Signed study-specific consent form prior to study entry Assessment. Exclusion Criteria: * Prior radiotherapy to the head and neck or any prior chemotherapy ≤ 6 months prior to study entry. * Other malignancy except non-melanoma skin cancer or a carcinoma not of head and neck origin ≤ 5 years * Evidence of distant metastasis. * on any experimental therapeutic cancer treatment. * major medical or psychiatric illness. * pregnant females. * Age ≤ 18 years old