Definition of clinical efficacy
The sites of treatment failure were assessed based on the patients’ medical records. The Response Evaluation Criteria in Solid Tumors (RECIST version 1.1) was used to define response assessment after IC treatment. In our study, both laryngoscopy and CT or MRI scans of the neck were used to evaluate the efficacy of the primary tumor. The patients were grouped based on the overall assessment of IC efficacy: IC responders were defined as the patients with CR or PR, and IC non-responders were defined as the patients with stable disease (SD) or progressive disease (PD). OS, progression-free survival (PFS), distant metastasis-free survival (DMFS) and locoregional progression-free survival (LRPFS) were conducted to depict the survival of the patients, all of which were calculated from the start of therapy and adopted the varied endpoints.