To develop postoperative stratification treatment for patients who have received induction chemotherapy and immunotherapy in locally advanced head and neck cancers. Risk stratification is based on clinical characteristics and pathological responses. In order to achieve no inferior survival rate and a lower treatment-related toxicity rate than the standard treatment.

Induction chemotherapy combined with immunotherapy has shown promising efficacy in the treatment of patients with locally advanced head and neck cancers. However, how to choose a proper postoperative treatment remains unknown. Eligibility patients were assigned to two arms, each divided into three groups: observation, immunotherapy maintenance, and radiotherapy (50 Gy dose) plus immunotherapy maintenance group for low-risk arm; radiotherapy (50 Gy or 60Gy dose) plus immunotherapy maintenance groups, concurrent chemotherapy plus immunotherapy maintenance group for a high-risk arm. Disease-free survival, overall survival, and treatment-related toxicity would be calculated to evaluate the efficacy of treatments.