Nasopharyngeal Malignancies in Denmark Diagnosed from 1980 to 2014

Objectives: Nasopharyngeal malignancies are reported having decreasing incidence and reduced mortality. This study provides a nationwide update of the incidence and survival in Denmark. Materials and methods: The Danish Cancer Registry (DCR) and Central Population Register (CPR) were used to identify all patients registered with nasopharyngeal malignancies between 1980 and 2014 in Denmark. We evaluated the age-adjusted incidence rate (AAIR), average annual percent change (AAPC) and relative survival (RS) and also constructed age-population-cohort (APC) models. Results: 911 patients were identified with a male:female ratio of 2.2:1, a median age of 57.7 years (range 2.8-98.3 years) and an overall median follow-up time of 2.7 years (range 0-37 years). The AAIR was 0.39 cases per 100 000 in 1980 and 0.28 cases per 100 000 in 2014 with an AAPC of -3.2 (95% CI:-7.5; 1.2, p = 0.1). The overall 1-year and 5-year RS rates were 76.3% and 42.1%, respectively. We found a significant age effect in the APC model for the incidence of nasopharyngeal malignancies, but no significant cohort or period effects. Conclusion: The incidence of nasopharyngeal carcinomas has slightly decreased over the last four decades, however insignificantly. Meanwhile, the relative survival has increased significantly in Denmark since 1980. The cause of improved relative survival might be attributed to altered treatment practices.