Content	Grade I recommendations	Grade II recommendations	Grade III recommendations
Technique to obtain tissue or cytology analysis	Mass biopsy via nasopharyngoscopy: using forceps or puncture technique.	Cervical lymph node puncture or biopsy (patients whose biopsy cannot be obtained from the nasopharynx); Puncture or biopsy of suspected distant metastasis (such as soft tissue masses).
Pathological diagnosis	Nasopharyngeal tumors are diagnosed as NPC according to histopathological morphology. It can be divided into three subtypes: nasopharyngeal keratinizing squamous cell carcinoma, non‐keratinizing carcinoma (differentiated and undifferentiated), and basal‐like squamous cell carcinoma. The types of cervical mass puncture pathological diagnosis include metastatic non‐keratinizing carcinoma or metastatic undifferentiated carcinoma.
Molecular diagnosis	Immunohistochemical/in situ hybridization detection: for cases of NPC whose pathological morphology cannot be accurately diagnosed, immunohistochemical (such as pan‐cytokeratin) or in situ hybridization (such as EBER) detection should be performed to assist the pathological diagnosis. Peripheral blood EBV antibody and EBV DNA: serum EBV antibody and plasma EBV DNA copy number may assist in the diagnosis of NPC.		Plasma EBV DNA copy number can help in the diagnosis of distant metastasis or the recurrence of NPC after initial treatment. Its diagnostic accuracy in distant metastasis is higher than that of recurrence.

Abbreviations: NPC, nasopharyngeal carcinoma; EBER, Epstein‐Barr encoding region; EBV, Epstein‐Barr virus.