aHR	Adjusted hazard ratio
AJCC	American Joint Committee on Cancer
CCI	Charlson comorbidity index
CCRT	Concurrent chemoradiotherapy
CI	Confidence interval
HNSCC	Head and neck squamous cell carcinoma
HR	Hazard ratio
ICD-9-CM	International Classification of Diseases, Ninth Revision, Clinical Modification
LA-OCSCC	Locally advanced oral cavity squamous cell carcinoma
NCCN	National Comprehensive Cancer Network
OCSCC	Oral cavity squamous cell carcinoma
OS	Overall survival; PS, propensity score
PSM	Propensity score–matched
RCT	Randomized clinical trial
RT	Radiotherapy
TCRD	Taiwan Cancer Registry database
TNM	Tumor, node, metastasis