Carbon Ion Re-Radiotherapy in Patients With Recurrent or Progressive Locally Advanced Head-and-Neck Cancer

This study is testing carbon ion re-irradiation — a specialized, highly targeted form of radiation — for patients with head and neck cancer that has come back after initial radiation therapy. Carbon ions can deliver high doses more precisely than conventional radiation, which may help when re-treating previously irradiated areas. **You may be eligible if...** - You have head and neck cancer that has returned or progressed after prior radiation - You have had surgery to remove as much tumor as possible (with some microscopic or visible cancer remaining) - You are in reasonable health (Karnofsky performance score 60 or above) - You are 18 or older and can give written consent **You may NOT be eligible if...** - You have not had a prior course of radiation to the head/neck (this trial is specifically for re-irradiation) - You have distant metastases (cancer that has spread to other organs) - You have not yet healed from surgery - You have severe neurological or psychiatric conditions Talk to your doctor to see if this trial is right for you.