Carcinoma of the tonsillar region: potential for use of proton beam therapy.

An investigation of treatment results in tonsillar region carcinomas was conducted, with particular attention to local control and morbidity from current therapy. The purpose of the investigation was to identify problems that might be resolvable with a superior treatment modality. A search was made of the National Library of Medicine's MEDLINE database, covering local control, survival, and morbidity from current therapies; dose-response relationships; and prognostic indicators. Three-dimensional radiotherapy plans were developed for representative cases, comparing photon-beam plans with proton-beam plans. Locoregional control is a major problem, and morbidity from standard therapy is high. Comparative treatment plans reveal that proton beams can deliver higher doses to the tumor volume, with significantly reduced radiation to salivary glands and mandible, than can photon-beam irradiation. The absorption and distribution characteristics of protons provide the radiation oncologist with a superior tool for treating patients with tonsillar region carcinomas. The therapeutic advantage accrues from these superior characteristics, not from an inherent biologic advantage.