Study of De_Intensified Postoperative Radiation Therapy for HPV Associated Oropharyngeal Squamous Cell Carcinoma

This study is exploring whether the radiation dose given after surgery for HPV-related throat cancer (tonsil or base of tongue cancer) can be safely reduced. Because HPV-positive throat cancers respond very well to treatment, researchers want to test if a lower, gentler radiation dose is just as effective while producing fewer side effects. **You may be eligible if...** - You have been diagnosed with squamous cell cancer of the tonsil or base of tongue that is HPV-positive (confirmed by p16 staining or other tests) - Your surgery was performed at Brigham and Women's Hospital - Your surgeon expects to remove the tumor completely with clear margins - You are 18 or older in good general health **You may NOT be eligible if...** - Your tumor is HPV-negative - You have had prior radiation to the head or neck - You are pregnant - Your organ function does not meet required thresholds - You have serious medical conditions making surgery or radiation unsafe Talk to your doctor to see if this trial is right for you.