TISSUE ABLATION IN BENIGN PROSTATIC HYPERPLASIA WITH HIGH-INTENSITY FOCUSED ULTRASOUND

In a phase I clinical trial the morphological impact and safety of hig h intensity focused ultrasound administered transrectally for tissue a blation in prostates from 22 patients undergoing subsequent prostatect omy were evaluated. Location and size of the tissue lesions correlated well with the predefined target area and revealed sharply delineated coagulative necrosis in all cases. Intervening tissues, such as the re ctal wall and posterior prostate capsule, were invariably intact. In a subsequent phase II clinical trial the effectiveness of transrectal h igh intensity focused ultrasound as a novel minimally invasive treatme nt modality for 50 patients with symptomatic benign prostatic hyperpla sia was determined. The maximum urinary flow rate (mi. per second) inc reased from 8.9 +/- 4.1 to 12.7 +/- 6.4 at 3 months in 44 patients, 12 .4 +/- 5.6 at 6 months in 33 and 13.1 +/- 6.5 at 12 months in 20. Duri ng the same period the post-void residual volume (mi.) decreased from 131 +/- 120 to 48 +/- 41, 59 +/- 42 and 35 +/- 30, respectively, and t he American Urological Association symptom score (points) decreased fr om 24.5 +/- 4.7 to 13.3 +/- 4.4, 13.4 +/- 4.7 and 10.8 +/- 2.5, respec tively. These data demonstrate that transrectal high intensity focused ultrasound is capable of inducing coagulative necrosis in the human p rostate via a transrectal approach while preserving intervening and ad jacent tissue. A 47% (+4.2 mi. per second) improvement in uroflowmetry and a 53% (-13.7 points) decrease in the American Urological Associat ion symptom score 1 year after treatment clearly prove that transrecta l high intensity focused ultrasound is a novel and safe minimally inva sive treatment option for benign prostatic hyperplasia.