Fast neutron teletherapy for advanced carcinomas of the oral cavity and soft palate

A retrospective study was performed to determine the efficacy of using fast neutron radiation for treating advanced squamous cell carcinomas of the oral cavity and soft palate. The majority of patients were judged to have less than a 10% 5-year survival with conventional medical treatment. Fifteen patients with oral cavity tumors were treated for cure with neutrons alone and six were treated with a combination of neutrons and photons as part of a mixed beam fractionation scheme. In the neutron-only group, the complete regression rate was 33% in the mixed beam group, the rate was 50%. Five patients who had squamous cell carcinomas of the soft palate were treated for cure, one with neutrons alone and four with a mixed beam regimen. The complete regression rate was 100%. The two-year NED results are comparable with literature results for more selected groups of patients with oral cavity and soft palate tumors treated by conventional photon therapy. The acute treatment morbidity was perhaps somewhat greater in the subgroup of patients treated with neutrons alone, and this subgroup later developed a more pronounced subcutaneous fibrosis. Morbidity associated with the mixed beam treatment regimen was comparable to that associated with conventional radiotherapy.