Biomarker-Driven Radiation Therapy Dose Reduction After Transoral Robotic Surgery for the Treatment of HPV-Positive Oropharyngeal Cancer

PRIMARY OBJECTIVE: I. To evaluate swallow function among post-operative circulating tumor HPV deoxyribonucleic acid (ctHPVDNA)-negative patients treated with reduced intensity adjuvant radiation therapy (RT) doses as compared to historical controls from ECOG 3311. SECONDARY OBJECTIVES: I. Evaluate progression free survival (PFS), overall survival (OS), and locoreginal control (LRC) among post-operative ctHPVDNA-negative patients treated with reduced adjuvant RT doses. II. Evaluate PFS among post-operative ctHPVDNA-positive patients treated with standard of care adjuvant therapy. OUTLINE: Patients who are ctHPVDNA negative after surgery undergo reduced dose radiation therapy for 3 weeks (15 treatments). Patients who are ctHPVDNA positive after surgery undergo standard of care radiation therapy. After completion of study treatment, patients are followed up at 3, 6, 12, 18, and 24 months.