Oral squamous cell carcinoma (OSCC): An overview.

Oral cavity cancer comprises malignancies arising from anatomical sites within the oral cavity, including the gingiva, buccal mucosa, anterior two-thirds of the tongue (oral or mobile tongue), hard palate, floor of the mouth, retromolar area, and mucosal surface of the lip. More than 90% of oral cavity cancers are histologically squamous cell carcinomas (oral squamous cell carcinoma, OSCC). Combined with mucosal lip cancer, oral cavity cancer ranks as the 19th most common cancer globally, with approximately 390000 new cases and 190000 deaths annually. However, the burden of OSCC varies geographically, with Melanesia and South-Central Asia showing a much higher disease incidence. Despite advances in diagnostic and therapeutic approaches over recent decades, OSCC mortality has remained largely unchanged, with only approximately 55-60% of patients surviving 5 years after diagnosis. Tobacco use (both smoking and smokeless forms) and alcohol consumption are among the most important risk factors for OSCC. This book chapter aims to provide a general introduction to OSCC, including its epidemiology, associated etiological factors, a proposed model of molecular pathogenesis, the diagnostic pathway, common treatment modalities, and prognostic factors.