Lymphoscintigraphy Directed Elective Neck Radiation for p16+ Favorable Risk Oropharynx Cancer

This is a prospective, phase II, stratified single arm investigation for favorable prognosis in p16+ oropharynx cancer patients with either node negative or malignant neck adenopathy with lymphoscintigraphy mapping confined to the ipsilateral neck. Patients positive for p16 status will be approached for consent during the pre-treatment intake process. Contralateral neck progression will be measured by PET (positron emission tomography)/CT scans. Xerostomia will be measured by the EORTC QLQ (European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire) H\&N35 at 6, 12, and 24 months. Patients will remain on study treatment for 6-7 weeks or until unacceptable toxicity or withdrawal of consent. Disease free survival (DFS) and overall survival (OS) will be assessed until 24 months after completion of study treatment