Risk-adapted Therapy in HPV+ Oropharyngeal Cancer Using Circulating Tumor (ct)HPV DNA Profile - The ReACT Study

This research is being conducted to understand if treatment can be tailored for participants with HPV-related oropharynx cancers using both clinical features (stage of the tumor, smoking status) combined with an investigational HPV blood test. The names of the test and treatments involved in this study are: * NavDx® HPV ctDNA testing (HPV blood test) * Radiation therapy * Chemotherapy: Cisplatin, or Carboplatin and Paclitaxel (not all participants receive any or all of these agents)