Feasibility and patient tolerance of a novel transrectal ultrasound hyperthermia system for treatment of prostate cancer

This report describes patient tolerance and toxicity of a transrectal ultra sound hyperthermia system used with external beam radiation therapy in trea tment of locally advanced prostate cancer. Nine patients with clinical T2B- T3B (4(th) edition AJCC criteria) disease received external beam radiation therapy, with two hyperthermia treatments scheduled at least 1 week apart d uring the first 4 weeks of radiation. Five patients also received hormonal therapy. Interstitial and anterior rectal wall thermometry were performed. Median temperature for each treatment (T-50) was 40.8 degreesC and mean CEM T-90=43 degreesC was 3.4 min. Rectal wall temperature was maintained at le ss than or equal to 40 degreesC. Treatment duration was limited in three of 17 sessions due to positional discomfort which was alleviated with light I V sedation and use of a 'New Life' mattress (Comfortex, Inc. Winoba, MN, US A). Acute toxicity was limited to NCl common toxicity criteria grade 1 and no excess toxicity was noted with full course radiation therapy +/- hormona l therapy. These findings are consistent with those reported in a previous phase I trial assessing this device. Given the favourable toxicity profile demonstrated to date, modification of treatment parameters for this ongoing phase II study have been instituted that should further the efficacy of tr ansrectal ultrasound hyperthermia for treatment of prostate cancer.