RecruitingPhase 2Radiation therapyRisk Adapted De-Intensification of Radio-Chemotherapy for Oropharyngeal Squamous Cell CarcinomaThis study builds on the results of several prior studies that we have been involved with to test the hypothesis that Risk-Adapted De-Intensification of Radiation Therapy and chemotherapy based on HPV subtype, plasma circulating free HPV DNA (cfHPV DNA) level, and cfHPV DNA clearance rate produces Local-Regional Control rates that are similar to what has been achieved with more aggressive therapy in patients with Favorable Prognosis Oropharyngeal Squamous Cell Carcinoma (OPSCC).