All patients will have the volume treated and radiation dose delivered to the regional lymphatics decreased according to the characteristics of the primary site and involved lymph nodes. The high risk neck will receive 50 Gy instead of 60 Gy, and the treated volume of the contralateral low risk neck will be reduced and receive only 45 Gy.

• Treatment of the primary tumor bed will be omitted in appropriate patients, as per the initial TORS de-intensification protocol. In those patients requiring treatment of the primary site, reduced dose (50 Gy) will be delivered.
• Receipt of concurrent chemotherapy per current guidelines. Chemotherapy may be omitted in patients with focal or microscopic ENE (defined as ≤ 1 mm ENE), at the discretion of the treating Medical Oncologist.
• Blood samples will be obtained at time of enrollment, and at two time points during RT, to quantify circulating HPV DNA and perform immune profiling.

Number of patients with 2-year locoregional control, defined as control at the primary site and in the neck, in patients undergoing de-intensified radiation to the primary site and regional lymphatics after Transoral Robotic Surgery (TORS) and neck dissection for p16+ oropharyngeal squamous cell carcinoma (OPSCC)

Number of participants with treatment-related toxicity as gauged by Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. the CTCAE v.5 utilizes a five point scale to report Adverse Events (AEs), defined as any unfavorable and unintended sign, symptom, or disease temporally associated with the use of medical treatment or procedure that may or may not be considered related to the medical treatment or procedure (cancer.gov)