Increasing incidence and survival in oral cancer: a nationwide Danish study from 1980 to 2014.

BACKGROUND: Oral carcinomas (OCs) make up a significant proportion of head and neck carcinomas (HNCs) and are an important cause of morbidity and mortality globally. The purpose of this population-based study was to determine trends in incidence and survival in OC in the Danish population from 1980 to 2014. MATERIAL AND METHODS: This study covered all patients registered in the nationwide Danish cancer registry (DCR) in the period 1980-2014. Age-adjusted incidence rate (AAIR) per 100,000 and annual percentage change (APC) were evaluated. Also, 5-year overall survival (OS) was calculated with Cox regression analysis in relation to location, gender, age, and calendar year at diagnosis. RESULTS: Altogether, 8299 patients with oral cancer were identified, 5062 (61%) of whom were males and 3237 (39%) were females. The median age at diagnosis was 63 years. The AAIR of patients with OC increased from 1.9 per 100,000 in 1980 to 3.5 per 100,000 in 2014, and we observed a significant increase in 5-year OS of 12% points (a relative increase of 38%) from the period 1980-1984 to 2005-2009. Women were found to have a better prognosis than men. CONCLUSIONS: We found an unexpected increase in the age-standardized incidence of OC during the last 30 years in Denmark, and also an improvement in survival. The 5-year OS was significantly better in recent years even when we adjusted the analysis for relevant covariates.