[Minimally invasive therapy of benign prostatic hyperplasia with focussed ultrasound].

To determine the morphologic impact and safety of high-intensity focused ultrasound (HIFU) administered transrectally for tissue ablation, a total of 22 prostates were treated in vivo with transrectal HIFU prior to surgical removal. Location and size of the tissue lesions correlated well with the predefined target area and revealed sharply delineated coagulative necrosis in all cases. In a subsequent phase II clinical trial the clinical effectiveness of transrectal HIFU as a minimally invasive treatment modality for patients with symptomatic benign prostatic hyperplasia (BPH; n = 50) was studied. The maximum urinary flow rate (Qmax, ml/s) increased from 8.9 +/- 0.6 (n = 50; mean +/- SEM) to 12.8 +/- 0.9 (3 months, n = 46), 11.9 +/- 0.9 (6 months, n = 44) and 12.2 +/- 1.0 (12 months, n = 32). Within the same time period, the post-voiding residual volume (ml) decreased from 113 +/- 17 (mean +/- SEM) to 47 +/- 6, 57 +/- 7, and 49 +/- 6. These data demonstrate that transrectal HIFU can induce intraprostatic coagulative necrosis. The phase-II clinical data presented in this paper reveal that transrectal HIFU is an effective and safe minimally invasive treatment option for BPH. Nevertheless, a randomised phase-III trial comparing HIFU and TURP is mandatory to define the definitive role of transrectal HIFU in BPH, and is presently planned.