Adult Aged Aged, 80 and over Carcinoma, Squamous Cell--pathology Carcinoma, Verrucous--pathology Female Head and Neck Neoplasms--pathology Humans Leukoplakia, Oral--pathology Male Middle Aged Neoplasm Recurrence, Local Neoplasm Staging Neoplasms, Multiple Primary--pathology Neoplasms, Second Primary--pathology Retrospective Studies