This is a randomized, phase III, prospective, multi-center trial in newly diagnosed nasopharyngeal carcinoma (NPC) patients without distant metastasis. This study will evaluate whether omitting Level Va irradiation in patients without these risk features does not compromise regional control or survival, with the goal of providing robust evidence to guide further personalization of NPC radiotherapy.

Inclusion Criteria:

1. Pathologic diagnosis (pathologically confirmed by nasopharyngeal biopsy) was nasopharyngeal carcinoma;
2. No distant metastatic;
3. Eastern Cooperative Oncology Group (ECOG) score of 0 or 1;
4. Signing informed consent;
5. Follow up regularly and comply with test requirements.

Exclusion Criteria:

1. Ipsilateral Level IIb involvement;
2. Ipsilateral Level III nodes involvement;
3. Ipsilateral positive lymph nodes below the cricoid cartilage (Level IV or Vb-c);
4. Disease progression during IMRT;
5. Previous malignancy or other concomitant malignant diseases;
6. The evaluation information of tumor efficacy can not be obtained;
7. Receive blind treatment in other clinical research;
8. Have or are suffering from other malignant tumors within 5 years (except non- melanoma skin cancer or pre-invasive cervical cancer);
9. Serious complications, such as uncontrolled hypertension, coronary heart disease, diabetes, heart failure, etc;
10. Active systemic infection;
11. No or limited capacity for civil conduct;
12. The patient has a physical or mental disorder, and the researcher considers that the patient is unable to fully or fully understand the possible complications of this study;
13. Pregnancy or lactation period;