Head and neck neoplasms Article 6 Humans 6 human 6 Female 5 female 5 priority journal 5 Head and Neck Neoplasms 4 Male 4 Middle Aged 4 adult 4 aged 4 head and neck tumor 4 male 4 middle aged 4 Aged 3 Retrospective Studies 3 controlled study 3 follow up 3 major clinical study 3 retrospective study 3 squamous cell carcinoma 3 Mouth Neoplasms 2 Radiotherapy 2 Risk Factors 2 cancer patient 2 cancer radiotherapy 2 head and neck cancer 2 mouth cancer 2 mouth tumor 2