Increasing incidence of base of tongue cancers from 2000 to 2010 due to HPV: the largest demographic study of 210 Danish patients

BACKGROUND: We assessed the development in the number of new base of tongue squamous-cell carcinoma (BSCC) cases per year in eastern Denmark from 2000 to 2010 and whether HPV may explain any observable increased incidence. METHODS: We performed HPV DNA PCR and p16 immunohistochemistry analysis for all (n=210) BSCCs registered in the Danish Head and Neck Cancer Group (DAHANCA) and the Danish Pathology Data Bank, and genotyped all HPV-positive specimens with amplicon-based next-generation sequencing. RESULTS: The overall crude incidence of BSCCs increased significantly (5.4% per year) during the study period. This was explained by a significant increase in the number of HPV-positive BSCCs (8.1% per year), whereas the number of HPV-negative BSCCs did not increase significantly. The overall HPV prevalence was 51%, with HPV16 as the predominant HPV type. CONCLUSIONS: The increased number of HPV-positive BSCCs may explain the increasing incidence of BSCCs in eastern Denmark, 2000–2010.