Inclusion Criteria:  Age ≥18 years old, no gender limitation; Histopathologically or cytologically proved to be phase III-IVb of head and neck squamous cell carcinomas (including oral cancer, oropharynx cancer, hypopharynx cancer, larynx cancer, but except for nasopharyngeal carcinoma). Patients who received chemoradiotherapy combined with or without nimotuzumab from January 2015 to December 2018; Patients in the study group received nimotuzumab, while patients in the control group did not receive nimotuzumab. And patients in the control group were collected 3 times as many cases as the study group in each center. If the number of patients in the control group were less than 3 times of the study group, all cases were collected.  Exclusion Criteria:  Complicated with primary malignancies other than head and neck tumors (except cured basal cell carcinoma of the skin and carcinoma in situ of the cervix); Patients received other targeted therapy, immunotherapy, or Traditional Chinese medicine with anti-tumor effect, along with the application of nimotuzumab; Lack of critical evaluation information.