Shortened Course of Radiation Therapy After Trans-oral Robotic Surgery in Patients With HPV-Mediated Oropharyngeal Squamous Cell Carcinoma.

Eligibility Criteria

• * Participant aged ≥ 18 years.
• * Diagnosis of oropharyngeal squamous cell carcinoma.
• * Eligible to receive transoral robotic surgery.
• * P16 positivity or HPV positivity by in situ hybridization on pathological sampling of lymph node or primary oropharyngeal tumor.
• * Pre-operative TTMV-HPV DNA test collected.
• * Standard of care tests completed within 60 days of registration may be used for screening.
• * Tests results are not required to confirm eligibility for step 1 registration.
• * ECOG Performance Status ≤ 2
• * Able to provide informed consent and willing to sign an approved consent form that conforms to federal and institutional guidelines.
• * History of prior mucosal head and neck cancer treated with radiation therapy
• * Prior or concurrent malignancy whose natural history or treatment has the potential to interfere with the safety or efficacy assessment of this study
• * Participant has smoked cigarettes within 1 month of registration
• * Prior systemic anti-cancer therapy or any investigational therapy ≤ 14 days or within five half-lives prior to starting study treatment, whichever is shorter.
• * Known distant metastatic disease.
• * Current evidence of any condition that would, in the Investigator's judgment, contraindicate the participant's participation in the clinical study due to safety concerns or compliance with clinical study procedures (e.g., infection/inflammation, intestinal obstruction, unable to swallow medication, \[participants may not receive the drug through a feeding tube\], social/ psychological issues, etc.)
• * Medical, psychiatric, cognitive, or other conditions that may compromise the participant's ability to understand the participant information, give informed consent, comply with the study protocol or complete the study.