This is a prospective, observational study to analyze the clinical and dosimetric factors about the radiation oral mucositis caused by radical chemo-radiotherapy for nasopharyngeal carcinoma patients and try to find the indicators for acute radiation oral mucositis.

All patients received 1 - 3 concurrent chemotherapy during the intensity modulated radiotherapy. Before radiotherapy, three types of mouth mucosa are contoured in all treatment plans. Oral mucosa grades are recorded before and during treatment. Dose-volume Histograms are got to analyze the associated factors.

Inclusion Criteria:

1. Histologically conformed Initial nasopharyngeal carcinoma
2. Patients can feed through the mouth.
3. ECOG (Eastern Cooperative Oncology Group) : 0-1.
4. No history of chemo-radiotherapy, immuno-therapy or biotherapy.
5. Normal hemodynamic indices before the recruitment (including white blood cell count>4.0×109/L, neutrophil count>1.5×109/L, platelet count >100×109/L, hemoglobin≥90g/l, normal liver/kidney function).
6. Informed consent signed.

Exclusion Criteria:

1. History of malignant tumors.
2. Any severe complications contraindicated chemotherapy or radiotherapy.
3. Medical history of central nervous system, cognitive or psychological diseases;
4. Pregnant or nursing women.
5. Patients with mental disease cannot complete the questionaire.
6. Patients refused the informed consent.

Histologically conformed Initial nasopharyngeal carcinoma