Connection between the length of the heating antenna and volume of the prostate in transurethral thermotherapy for benign prostatic hyperplasia.

From June 1990 to June 1991, 79 poor surgical risk patients with benign prostatic hyperplasia (BPH) were treated with transurethral hyperthermia. The patients were divided into 2 treatment groups. In group I, 40 patients were treated by two 2-hour sessions at 44.5 degrees C and a heating antenna of 1 cm long. In group II, 39 patients received one 3-hour treatment session at a temperature of 46 degrees C and a 2-cm-long heating antenna. The mean follow-up period was 7.9 months for group I and 8.4 months for group II patients. In group I, 22 of 40 patients (55%) showed subjective and objective improvement. In group-II patients a major improvement was noted in 25 of 39 patients (64%). The patients in both groups were subdivided into those with prostates smaller or larger than 50 ml. Significantly better treatment results were obtained in patients with prostates smaller than 50 ml in group-I and group-II patients. The mean Madsen-Iversen score, residual urine and maximum flow rate improved significantly in 47% of groups-I patients with larger prostates and 62% of those with prostates < 50 ml (p < 0.05), and in 50% of group-II patients with prostates > 50 ml and 82% of those with prostates < 50 ml (p < 0.01). A temperature of 46 degrees C with a 2-cm-long heating antenna in patients with prostates < 50 ml gave the best treatment results (82%).