Incidence and Survival for Head and Neck Cancers in Estonia, 1996-2016: A Population-Based Study.

Background: Changing patterns of alcohol and tobacco consumption and human papillomavirus (HPV) infection have affected the epidemiology of head and neck cancers. The aim of this study was to examine 20-year trends in the incidence and survival of head and neck cancers in Estonia by site, sex, morphology, and stage.

Methods: Data on all adult cases of invasive head and neck cancers diagnosed in Estonia in 1996-2016 were obtained from a population-based cancer registry. TNM stage was available for 2010-2016. Incidence trends were modeled with join-point regression, and five-year relative survival ratios (RSRs) were calculated.

Results: A total of 6,769 cases were included, 64% men. We observed declining incidence of lip and laryngeal cancer and substantial increases in the incidence of hypopharyngeal and oropharyngeal cancers. Over 60% of mouth and pharyngeal cancers were diagnosed at stage IV. Age-standardized 5-year RSR for mouth and pharyngeal cancer increased substantially over the study period, from 21% (95% CI 16%-25%) in 1996-2002 to 33% (29%-38%) in 2010-2016. The largest survival increases were seen for cancers of the oral cavity (reaching 44% in 2010-2016), tongue (41%), and larynx (63%), while modest changes were seen for the oropharynx (24%) and hypopharynx (17%). The latest 5-year RSR was 90% for thyroid cancers (99% for papillary carcinoma). Large female survival advantage was seen for most sites.

Conclusion: The observed trends suggest an emerging role of HPV infection in combination with traditional risk factors in the development of head and neck cancers in Estonia. Efforts targeting health behavior, HPV vaccination, and earlier diagnosis are crucial for reducing mortality from these cancers.