Changes in incidence and prevalence of human papillomavirus in tonsillar and base of tongue cancer during 2000-2016 in the Stockholm region and Sweden

Background Tonsillar and base of tongue squamous cell carcinoma (TSCC/BOTSCC) has increased. In Stockholm, the proportion of human papillomavirus (HPV)-positive cases and the incidence of TSCC rose between 1970 and 2006 then stabilized. Here, HPV-prevalence, and TSCC/BOTSCC incidence 2000-2016, in Stockholm and Sweden were followed. Methods Incidence data for 2000-2016 were obtained from the Swedish Cancer Registry. TSCC/BOTSCC biopsies, 2013-2016 from Stockholm, were examined for HPV DNA and p16(INK4a), or data obtained from medical reports. For cases 2000-2012, data were available from previous studies. Results The incidence of TSCC/BOTSCC has continued to rise in Stockholm and Sweden 2000-2016, especially after 2008. HPV DNA and p16(INK4a) analysis was determined for 795 Stockholm cases from 2000 to 2016, with 72% being HPV DNA and p16(INK4a) positive 2013-2016, and 70% positive 2000-2016. Conclusion During 2000-2016, especially after 2008, the incidence of TSCC/BOTSCC has continued to increase in Stockholm and Sweden, with an HPV-prevalence of approximately 70% in Stockholm.