Abstract: Because of the lymphatic drainage of the neck area level-Ⅰb of nasopharyngeal carcinoma is particular, and “skip” metastasis in the cervical lymph node is rare, the involved region of level-I b lymph node metastasis rate is low in nasopharyngeal carcinoma. In the three-dimensional radiotherapy era of precision radiotherapy,  there is no consensus on whether level-Ⅰb need to be prophylactic irradiated in the clinic.

Key words: Nasopharyngeal neoplasm, Radiotherapy, Level-Ⅰb lymph node