Reducing Target Volumes in NPC Treated With Induction Chemotherapy Followed by Concurrent Chemoradiotherapy

Inclusion Criteria: * histologic confirmation of nonkeratinizing nasopharyngeal carcinoma; no previous treatment for cancer; nondistant metastatic, newly diagnosed stage III to IVa disease that was staged according to the American Joint Committee on Cancer-Union for International Cancer Control 8th edition stage-classification system; a Karnofsky performance-status score of at least 70 (on a scale from 0 to 100, with lower scores indicating greater disability); planned to receive 3 cycles of Induction Chemotherapy (regimens included docetaxel and cisplatin; docetaxel, cisplatin, and fluorouracil; and gemcitabine and cisplatin); and adequate hematologic, renal, and hepatic function. Exclusion Criteria: * younger than 18 years or elder than 70 years; receipt of treatment with palliative intent; a history of cancer; receipt of previous treatment (radiotherapy, chemotherapy, or surgery \[except diagnostic procedures\]) to the nasopharynx or neck; lactation or pregnancy; or severe coexisting illness; had disease progress after IC