Up to now, IMRT has largely improved the local control of locally advanced nasopharyngeal carcinoma (NPC), leaves the distant metastasis as the main treatment failure modality of patients with bulky lymph nodes (especially N3 stage). Although concurrent chemoradiotherapy (CCRT) continues to stand as the standard treatment of these patients, the role of adjuvant chemotherapy remains controversial due to its relatively severe toxicities and inferior compliance. However, our retrospective study of 2D-RT and IMRT era had proved adjuvant chemotherapy played key role in N3 NPC patients in terms of reducing distant metastasis and improving overall survival. Maintenance chemotherapy of gemicitabine single drug is promising with adequate efficacy and moderate toxicities. So we aim to conduct "A Phase III Randomized Trial of Maintenance Chemotherapy in High-metastatic Risk Nasopharyngeal Carcinoma Patients of N3 Stage" to evaluate the effectiveness and compliance of gemicitabine as maintenance chemotherapy in N3 nasopharyngeal carcinoma.

We aim to conduct "A Phase III Randomized Trial of Maintenance Chemotherapy in High-metastatic Risk Nasopharyngeal Carcinoma Patients of N3 Stage" to evaluate the effectiveness and compliance of gemicitabine as maintenance chemotherapy in N3 nasopharyngeal carcinoma.

Inclusion Criteria:

• AJCC/UICC 8th edition N3 nasopharyngeal carcinoma
• Pathology: WHO II/II
• No prior anti-tumor treatment
• Age 18-60
• KPS≥70
• Adequate blood supply
• Informed consent obtained

Exclusion Criteria:

• Pathology: WHO I
• Pregnant
• Combined with other malignant tumor