Treatment of benign prostatic hyperplasia with high intensity focused ultrasound: an initial clinical trial in Japan with magnetic resonance imaging of the treated area.

BACKGROUND

High intensity focused ultrasound (HIFU) is a method of delivering acoustic energy to a focal point and is expected to induce tissue thermal ablation. Transrectal HIFU was applied to symptomatic benign prostatic hyperplasia (BPH) for relief of intravesical obstruction without injury to surrounding tissue. The clinical effectiveness and safety of transrectal HIFU were investigated.

METHODS

Thirty-seven Japanese men with symptomatic BPH were treated with HIFU. The treatment was minimally invasive; operating time was less than 40 minutes, and a posttreatment indwelling catheter was left in place for 3-4 days.

RESULTS

The maximum urinary flow rate (ml. per second) increased from 7.6 +/- 0.6 to 9.3 +/- 0.6 at three months in 37 patients (P < 0.05). During the same period the International Prostatic Symptom Score and Quality of Life score (points) decreased from 23.6 +/- 1.4 to 10.5 +/- 0.3, 5.2 +/- 0.3 to 2.6 +/- 0.1 (P < 0.001), respectively. Overall response estimated by these three individual parameters were as follows; excellent 18.9%, good 48.6%, fair 10.8% and poor 21.6% at three months. Magnetic resonance imaging using an endorectal coil showed coagulative necrosis defined in the therapy zone at one month after treatment. Side effects were transient urinary retention in six patients (16.2%), gross hematuria in four patients (10.8%) and hematospermia in four patients (10.8%). There was almost no intraoperative blood loss.

CONCLUSIONS

Transrectal HIFU treatment of symptomatic BPH is safe, reduces symptoms significantly, and leads to a slight increase in uroflow.