This is a single-arm Phase II non-inferiority study of adjuvant radiation for locally-advanced HPV-Associated oropharyngeal squamous cell carcinoma. Patients with pT0-T3, N0-N1, M0 disease (per AJCC 8th Edition), detectable pre-operative and undetectable postoperative ctHPVDNA will be eligible. Patients will have undergone TORS primary site resection and neck dissection. Patients will undergo adjuvant RT +/- guideline-indicated chemotherapy. The neck and the primary site will be considered separately.
The primary objective of the study will be to determine the 2-year locoregional control (LRC) rate. Secondary objectives include measures of toxicity (as measured by CTCAE, version 5.0), patient-reported QOL (as measured by the MDASI and MDADI questionnaire), progression-free survival, metastasis-free survival, and overall survival. Differences between patients treated with IMRT and proton therapy in terms of toxicity and QOL will serve as another secondary objective.