Randomized controlled trial for early ONS treatment vs standard nutrition treatment in patients with nasopharyngeal carcinoma undergoing concurrent chemoradiotherapy

INTERVENTION: experimental group:early ONS;control group:normal nutrition treatment; CONDITION: nasopharyngeal carcinoma PRIMARY OUTCOME: percentage of weight loss at the end of radiotherapy; SECONDARY OUTCOME: The changes of weight at the end of 4th week and the last day of radiotherapy;PGS‐GA at the end of the 2nd week, 4th week, the last day of radiotherapy and 1 month after radiotherapy;Incidence of radiation induced grade 3‐4 mucositis (CTCAE 4.03) at the end of 4th week and the last day of radiotherapy;Incidence of any grade 3‐4 side‐effect (CTCAE 4.03);Incidence of prolonged radiation treatment time caused by side‐effects;Days prolonged more than planed treatment time caused by side‐effects;Incidence of unplanned hospitalization in 3 months after radiation.;The changes of QOL‐C30, EORTC QLQ‐H&N35 at the end of radiation, the 1st and the 3rd month after radiation as compared with the beginning of radiation; INCLUSION CRITERIA: 1. Pathologically confirmed nasopharyngeal carcinoma (NPC); 2. The clinical stage of NPC is TxN1‐3M0 (AJCC 7th edition); 3. Planned to receive concurrent chemoradiotherapy with intensity‐modulated radiation therapy (IMRT). 4. Aged 18 to 75 years; 5. Performance status (PS) score 0‐1; 6. NRS2002<3; 7. Blood regular test should be satisfied the following conditions: white blood cell count =3.5×10^9/L Neutrophil count =1.5×10^9/Lplatelet count =100×10^9/Lhemoglobin =10g/L; 8. Liver and kidney functions test should be satisfied the following conditions: AST and ALT < 2.5 times the upper limit of normal value, bilirubin < 1.2 times the upper limit of normal value, creatinine < 1.2 times the upper limit of normal value, and alkaline phosphatase < 5 times the upper limit of normal value; 9. Could complete required oral nutrition, questionnaire survey and follow‐up; 10. Signed informed consent voluntarily.