Based on the radiobiological findings that accelerated tumor repopulation in nasopharyngeal carcinoma occurs in the late-course of radiation therapy, the investigators hypothesize that intensity-modulated radiation therapy(IMRT) with concomitant boost schedule by increasing daily dose starting at the fifth week after initiation of IMRT might improve tumor control and decrease treatment toxicities for locoregionally advanced nasopharyngeal carcinoma. The study is designed to test if late-course accelerated hyperfractionated IMRT can improve the outcomes as compared with conventionally fractionated IMRT in newly diagnosed patients with locoregionally advanced nasopharyngeal carcinoma.

Inclusion Criteria:

• Histologically proven non-keratinizing or undifferentiated type nasopharyngeal carcinoma for primary treatment with curative intent
• According to AJCC 2002 Staging System, clinical stage must be Ⅱb-Ⅳb
• Age between 18-70
• Karnofsky performance status ≥70
• WBC ≥4,000/mm3, PLT ≥ 100,000/mm3,serum creatinine ≤ 1.6 mg/dl
• Without radiotherapy or chemotherapy
• Signed study-specific consent form prior to study entry

Exclusion Criteria:

• Patients with distant metastasis
• Pregnant or lactating women
• The presence of uncontrolled life-threatening illness
• Patients who received radiotherapy or chemotherapy previously