Epidemiology and management of oral cavity squamous cell carcinoma in Ireland

Introduction: The epidemiology and management of oral cavity cancer have changed considerably in recent decades. This study examines epidemiological and management trends in oral cavity squamous cell carcinoma (OCSCC). Methods: A retrospective cohort study of data from the National Cancer Registry of Ireland between 1994 and 2014. Results: A total of 2725 patients were identified. The most common subsites were the tongue (34 %, n =1025), lip (19 %, n = 575), floor of mouth (FOM) (18 %, n = 550), and retromolar trigone (RMT) (6 %, n = 189). The incidence of OCSCC remained largely unchanged (3.14 cases/100000/year) during the study period. 5-year disease-specific survival (DSS) was 58.6 % overall, varying between subsites (lip 85 %, RMT 62.9 %, tongue 54.7 %, and FOM 47.3 %). DSS improved over the study period (p = 0.03), in particular for tongue primaries (p = 0.007). Primary surgery significantly improved DSS versus radiotherapy (HR 0.28, p < 0.0001). Survival of T4 disease managed surgically was superior to that of T1 disease managed with radiotherapy. In node positive patients, chemotherapy improved overall survival (HR 0.8 p = 0.038) but not DSS (HR 0.87 p = 0.215). Conclusion: Primary surgery remains the standard of care in the management of OCSCC. Prognosis has improved in line with an increase in the use of primary surgery in the same time frame, though the incidence remains unchanged.