High-intensity focused ultrasound success in prostate cancer improves with technological advances

San Francisco-High-intensity focused ultrasound (HIFU) is emerging as a viable treatment for localized prostate cancer. Among studies on the technology presented at the AUA annual meeting in San Francisco, two showed encouraging biochemical disease-free survival rates for primary treatment as well as salvage therapy.

"HIFU is a promising treatment, especially for patients in the low- and intermediate-risk groups," said Toyoaki Uchida, MD, of Tokai University Hachioji Hospital, Hachioji, Japan, first author of one of the studies. "With 11 years of experience, we have seen that newer-generation devices are delivering better outcomes."

Dr. Uchida presented 10 years of survival data that span four generations of HIFU devices. The Sonablate 200 ([S200] Focus Surgery, Inc., Indianapolis) was used from 1999 to 2001, the Sonablate 500 (S500) from 2001 to 2005, the Sonablate 500 version 4 (V4) from 2005 to 2008, and the Sonablate 500 TCM (TCM) from 2007 to the present. The study followed 657 men who were treated for localized prostate cancer and followed for at least 2 years after HIFU.

The mean patient age declined slightly over the course of the study, from 71 years to 67 years, Dr. Uchida noted. The mean PSA also declined, from 15.2 ng/mL for the S200 group to 12.1 ng/mL for the S500 group and 10.0 ng/mL for the V4/TCM groups. The mean Gleason score increased slightly from 5.7 in the S200 group to 6.6 in the TCM group. The mean operating time decreased substantially, from 189 minutes for the S200 to 127 minutes for the S500, 78 minutes for the V4, and 69 minutes for the TCM. The mean follow-up time fell from 50 months to 40 months, 31 months, and 24 months in the four device groups.

The biochemical disease-free survival rate for all patients was 59% at 8 years, but there were large variations among devices. Biochemical disease-free survival rates at 8 years were 55% for the S200 and 56% for the S500. Biochemical disease-free survival at 4 years was 72% for the V4 and 84% at 2 years for the TCM.

Biochemical disease-free survival in low-, intermediate-, and high-risk groups was 75%, 54%, and 43% in the S200/500 groups and 93%, 72%, and 58% in the V4/TCM groups. The negative biopsy rate following HIFU was 97% in the S200 group, 79% in the S500 group, 94% in the V4 group, and 100% in the TCM group.

Grade I complications included urethral stricture (16.7%), epididymis (5.2%), and incontinence (1.5%). Erectile dysfunction was reported in 48% of patients at 6 months, 37% at 12 months, and 22% at 24 months.

Potential as salvage therapy

In a separate study, results using HIFU as salvage therapy following failed radiation therapy were encouraging, said first author John F. Ward, MD, assistant professor of urology at the University of Texas M.D. Anderson Cancer Center, Houston. A retrospective study of salvage HIFU in patients with radiorecurrent, localized prostate cancer from the Ablatherm Treatment-Registry ([@-Registry] EDAP TMS, Lyon, France) found 56% of patients remained biochemically disease free 4 years after HIFU and 73.8% showed no evidence of local recurrence on follow-up biopsy.

"Patients who have low-risk disease have progression-free survival up to 85%," Dr. Ward said. "Oncologic success is dependent on patient selection. Salvage HIFU seems to be comparable to other salvage therapies. With lower morbidity, patients with radiorecurrent prostate cancer may be offered definitive local therapy earlier and avoid metastases associated with recurrence after radiotherapy and the adverse effects of hormone therapy."

Funding for the @-Registry study was provided by EDAP TMS.