This study focuses on the longitudinal monitoring of HPV infection in patients with head and neck cancers, particularly oropharyngeal carcinoma (OPC), using a new electrochemical detection method. This method has already been successfully developed and validated for cervical cancer. The aim of the project is to monitor the dynamics of HPV viral load before the start of treatment and during conservative radiation therapy or concurrent chemoradiation therapy. HPV will be analyzed from oral swabs, oral cavity washings, and plasma as part of a small prospective study. The results of the new method will be correlated with standard techniques, particularly qPCR. Longitudinal monitoring may contribute to the individualization and potential de-escalation of treatment in selected patients.