Fast neutron teletherapy for advanced carcinoma of hypopharynx and supraglottic larynx.

The results of a Phase I clinical trial using fast neutron teletherapy for advanced squamous cell carcinoma of the hypopharynx and supraglottic larynx are reported. Ten patients with hypopharyngeal tumors were treated for cure using neutrons alone and 6 patients with hypopharyngeal tumors were treated for cure using a combination of neutrons and photons as part of a mixed beam fraction scheme. In the neutron-only group, the initial complete remission rate was 4/10 (40%). The mean survival of this group of patients with initial complete remission was only 5.75 months (range 2--10) but all patients died without evidence of recurrent tumor at the primary site. In the mixed beam group, the initial complete remission rate was 5/6 (83%) but the local control rate dropped rapidly to 41 per cent when displayed on an actuarial plot. Six patients with advanced tumors of the supraglottic larynx were treated for cure, 5 with neutrons alone and one with a mixed beam regime. The initial complete remission rate was 3/6 (50%) but 2 of these patients rapidly recurred, which reduced the local control rate on an actuarial plot to 16 per cent. The relative adverse effects of the neutron-only treatment regime appear to be substantially greater than those of the mixed beam treatment regime.