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 19^th 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.