High-energy proton beam radiation therapy for gynecologic malignancies. Potential of proton beam as an alternative to brachytherapy.

Fifteen patients with advanced gynecologic malignancies were treated with high-energy proton beam radiation therapy (RT) at the Particle Radiation Medical Science Center (PARMS), Tsukuba University, Japan, from 1983 to 1987. The potential of proton beam RT as an alternative to conventional brachytherapy was evaluated. Except for one local recurrence, 14 of 15 patients were locoregionally controlled for 15 to 57 months. Two-year local control rate and 2-year survival rate were 92.3% and 93.3%, respectively. Two cases of transient, radiation-induced proctitis (neither of which required surgical treatment) were the only complications despite a target dose that exceeded 8000 cGy in most cases. The results suggest that sharply localized, high-dose proton beam RT can produce an antitumor effect equivalent to that of conventional brachytherapy.