The Minimalist Trial-2

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer. Oropharynx SCC (OPSCC) is a common sub-type of HNSCC. Each year, 16,000 new cases of OPSCC are diagnosed in the USA. Most cases of OPSCC (\>90%) are caused by the human papillomavirus (HPV) and are often cured with current therapy. However, patients treated with surgery followed by postoperative adjuvant chemotherapy and radiation therapy (POA(C)RT) still experience substantial morbidity. In this highly curable disease, current clinical research interest is focused on investigation of de-escalated therapy, with the goal to reduce treatment-related adverse events (AEs) while maintaining a low recurrence rate. In this study, patients with HPV-related OPSCC will undergo resection of the primary tumor site and involved/at-risk regional neck nodes. Based on the pathology report, patients will be assigned to: * Arm 1 (de-POACRT-42 Gy) * Arm 2A (de-POART-42 Gy) * Arm 2B (de-POART-37.8 Gy) * Arm 2C (de-POACRT-30 Gy). All patients with high-risk pathology will be assigned to Arm 1 whereas patients with intermediate-risk pathology will be randomized (1:1:1) to Arm 2A, Arm 2B, or Arm 2C. Patients with highest-risk pathology and low-risk pathology will be removed from the trial after surgery and will be advised to pursue standard of care options.