Adaptive De-intensified Radiotherapy Using Circulating Tumor DNA in HPV- Associated Oropharyngeal Cancer

This study is testing a personalized approach to radiation therapy for HPV-related throat cancer (oropharyngeal cancer). Instead of giving everyone the same radiation dose, doctors will use a blood test that measures tumor DNA to decide whether it is safe to reduce the radiation dose. The goal is to lessen side effects in patients who respond well to treatment. **You may be eligible if:** - You have been diagnosed with squamous cell cancer of the oropharynx (throat, tonsils, base of tongue, or soft palate) - Your cancer tested positive for P16 (a marker linked to HPV-related cancer) - Your cancer is classified as stage T0–T4, N0–N2 without distant spread - You have not yet received treatment for this cancer **You may NOT be eligible if:** - Your cancer has spread to distant organs - Your tumor does not test P16-positive - You have had prior head and neck radiation - You are unable to complete required imaging and blood tests Talk to your doctor to see if this trial is right for you.