Endemic nasopharyngeal carcinoma (NPC) is invariably associated with Epstein-barr virus (EBV) infection. Plasma EBV DAN detected by polymerase chain reaction (PCR)-based assays can provide important informations of disease screening, disease relapse, and risks classification. In this study, the investigators will explore the impact of serial plasma EBV DNA during chemotherapy and radiotherapy on initial tumor response and long-term survival in patients with non-metastatic nasopharyngeal carcinoma

Inclusion Criteria:

1. Patients with newly histologically confirmed non-keratinizing carcinoma (according to WHO histological type)
2. No evidence of distant metastasis (M0)
3. Receive standard radical treatment
4. Not exhibiting overt psychopathology, and willing to participate and written informed consent was obtained

Exclusion Criteria:

1. WHO type keratinizing squamous cell carcinoma or basaloid squamous cell carcinoma.
2. Treatment with palliative intent
3. Previous chemotherapy or radiotherapy (except non-melanomatous skin cancers outside the intended RT treatment volume)
4. Severe intercurrent disease

Patients with histologically confirmed, non-metastatic, previously untreated nasopharyngeal carcinoma (NPC) will be invited to join this study.

not to share individual participant data (IPD) available to other researchers unless reasonably required, and only the PI has the whole access to the complete data