Association between head and neck cancer and sexually transmitted diseases: a Danish nationwide, case-control study.

Background: An association between sexually transmitted diseases (STDs) and occurrence of head and neck cancer (HNC) is proposed.Aims/objectives: We aimed to determine the association between selected STDs (syphilis, gonorrhoea, HIV) and HNC.Materials and methods: Patients diagnosed with HNC in Denmark between 1978 and 2014 identified through the Danish Cancer Registry were included. Patients were age- and sex-matched in a 1:10 ratio with general population controls. Uni- and multivariate analyses were performed using the Cox regression model to assess the correlation between STD and HNC.Results: A total of 39,405 HNC patients (63% men; 63.0 years at HNC diagnosis) and 393,238 controls were included. STD in HNC patients was 0.27%, vs. 0.11% in controls. Patients with cancer of the upper airways had a significantly higher prevalence of an STD prior to the HNC compared to controls. Most HNC patients with a prior STD (64.1%) developed the HNC within five years after the STD diagnosis.Conclusions: Although the studied STDs are rare, patients with cancer of the upper aerodigestive tract more commonly had a previous diagnosis of STD compared to controls. The study promotes the hypothesis that a causal link exists between STD and HNC.