Incidence of and survival after glottic squamous cell carcinoma in Denmark from 1971 to 2011 - A report from the Danish Head and Neck Cancer Group

Aim To describe the incidence, disease-specific mortality (DSM), and overall survival (OS) of patients with glottic squamous cell carcinomas (SCC) in Denmark from 1971-2011 in a national population-based cohort of consecutive patients. Materials and methods All patients diagnosed with glottic SCC stage I-IV between 1971 and 2011 in Denmark were included. Patients were identified from the Danish Head and Neck Cancer database, which has a coverage of approximately 100% of registered glottic cancer in Denmark. Information on vital status and cause of death were updated using patient charts and national registries. Results In total 5132 patients with glottic SCC were included. The yearly number of new cases increased from 107 in the 1970s to 139 in the 2000s. Overall, the incidence increased from 1.9 to 2.6 per 100,000, with a more prominent increase in men (3.5 to 4.7) compared with women (0.4 to 0.6). The 5-year DSM was 16% (15-17%) and the 5-year OS was 63% (61-64). The hazard rate of DSM adjusted for patient characteristics, tumour characteristics and waiting-time was significantly lower in the 2000s (p < 0.01), and the hazard rate of OS was significantly higher (p < 0.01) compared to the earlier decades. Longer waiting-time for treatment (>25 d) significantly increased DSM and reduced OS. Conclusion Despite being highly avoidable with smoking cessation, the incidence of glottic SCC increased in Denmark from 1971-2011. The adjusted hazard rate of DSM and overall death after glottic SCC was significantly lower in the 2000s compared to previous decades. Waiting-time for treatment significantly influenced DSM and OS.