Head and neck squamous cell carcinoma in young patients.

Epidemiologic analyses have shown disproportional increases of head and neck squamous cell carcinoma (HNSCC) incidence in a younger age group (younger than 45 years old), compared to patients above 45 years old. Although this group is small (5%), it includes a significant subset of the HNSCC patient population, and is characterized by a distinct clinical and etiological phenotype. HNSCC in young patients often presents without significant exposure to alcohol and tobacco and primarily affects the oropharynx and oral cavity. Exposure to human papilloma virus (HPV) has been identified as a major contributor to the pathogenesis of oropharyngeal carcinomas, and explains part of the observed incidence variation. Specific hereditary influences, including genetic predispositions accounting for an increased mutagen sensibility and inherited syndromes like Fanconi Anemia and Bloom's syndrome, have been identified as causative factors in a subgroup of young-onset HNSCC, but their cumulative influence remains at present likely underestimated. Circumstantial evidence suggests that young-onset HNSCC patients have a clinically different phenotype compared to older patients, however, the true impact of young age on HNSCC clinical behavior will remain difficult to determine unless multi-institutional databases will be combined. The rising incidence of young-onset HNSCC mandates intensification of research endeavors into its etiology, clinical phenotype and optimal management.