Reducing High Risk Primary Tumor Clinical Target Volumes (CTVp1) in Non-metastatic Nasopharyngeal Carcinoma

This study is testing whether it is safe to use a smaller radiation treatment zone for people with nasopharyngeal carcinoma (a cancer at the back of the nasal cavity). Reducing the radiation area could lower side effects while still effectively treating the cancer. **You may be eligible if...** - You have a confirmed diagnosis of nasopharyngeal carcinoma (a specific type) - Your cancer is newly diagnosed and has not been treated before - Your tumor is contained on one side of the nasopharynx and does not cross the midline - Your cancer is Stage I through IVa **You may NOT be eligible if...** - Your tumor crosses to both sides of the nasopharynx - You have previously received treatment for this cancer - Your cancer is a different type or stage not covered by the study Talk to your doctor to see if this trial is right for you.