Head and neck cancer (HNC) is a significant challenge for patients and healthcare providers in Denmark and worldwide. The incidence is rising, and the disease can be difficult to diagnose. Due to significant progress in laboratory technology within the past decades, new possibilities for diagnostic evaluation, treatment, and follow-up are continuously emerging. This may give health professionals new possibilities to diagnose and treat the disease. 

This PhD thesis and its related papers focus on the diagnostic use of new molecular technologies in patients suspected of HNC, mainly analyses of the epigenetic landscape of primary tumors and circulating cell-free DNA in plasma originating from tumors in the oral cavity. The thesis also aims to evaluate patients’ knowledge and acceptance of the use of gene tests and personalized medicine.

Our main hypotheses were that we would be able to discriminate between tumor tissue and healthy tissue based on methylation profiles from biopsies. Furthermore, that we could discriminate between patients with cancer and healthy controls based on methylation profiles from cell-free DNA in plasma and that the alterations found in plasma would match the profiles found in tissue. Lastly, that patients with HNC with no knowledge of such specialized tests and personalized medicine would accept their use for improvement of diagnostic work-up, treatment, and follow-up.