Oral Herpesviruses and Oral Mucositis in Patients Receiving Head and Neck Radiotherapy

Oral mucositis is a frequent and clinically significant side effect of radiotherapy for head and neck cancer. While mucosal injury is primarily related to radiation exposure, additional biological factors may influence the onset and severity of this condition. Reactivation of viruses from the Herpesviridae family has been suggested as a potential contributing factor, but existing evidence is limited and inconsistent. There is currently no standard preventive antiviral strategy for oral mucositis in this population.

This study is designed to characterize the presence and changes of herpesviruses in the oral cavity of adults undergoing radiotherapy for head and neck cancer and to evaluate whether prophylactic antiviral treatment affects viral detection and clinical outcomes related to oral mucositis. The trial uses a randomized, double-blind, placebo-controlled design to reduce bias and allow for an objective assessment of antiviral prophylaxis.

Participants receive either oral valacyclovir or matching placebo during the course of radiotherapy. Oral and saliva samples are collected at predefined time points before the start of radiotherapy, during treatment, and after completion of radiotherapy. These samples are analyzed to detect and quantify human herpesviruses using molecular methods. Clinical assessments of the oral cavity are performed regularly to evaluate the presence and severity of oral mucositis, and patient-reported pain is monitored throughout treatment.

The study aims to describe the pattern of herpesvirus detection in the oral cavity over time and to explore associations between viral presence, mucositis severity, and pain. In addition, the study evaluates whether antiviral prophylaxis influences these outcomes when compared with placebo.

By improving the understanding of the relationship between herpesvirus activity and oral mucositis, this study may inform future preventive or supportive care strategies for patients receiving radiotherapy for head and neck cancer.

Inclusion criteria

• Adults aged 18 years or older.
• Diagnosis of head and neck cancer.
• Planned to receive curative or definitive radiotherapy to the head and neck region.
• Ability to swallow oral medication.
• Adequate clinical condition to participate in study procedures.
• Ability to provide written informed consent.

Exclusion criteria

• Known hypersensitivity or contraindication to valacyclovir or related antiviral agents.
• Current or recent use of systemic antiviral therapy.
• Severe renal impairment requiring dose adjustment or contraindicating valacyclovir use.
• Active oral infection requiring systemic antimicrobial treatment at baseline.
• Pregnant or breastfeeding individuals.
• Participation in another interventional clinical trial that may interfere with study outcomes.