High Intensity Focused Ultrasound for Radiorecurrent Prostate Cancer: A North American Clinical Trial

Purpose: We determined the safety and efficacy of whole gland high intensity focused ultrasound in men with radiorecurrent prostate cancer. Materials and Methods: A total of 100 men with clinically localized recurrent prostate cancer at least 2 years after external beam radiation therapy underwent whole gland high intensity focused ultrasound in an open label trial from 2009 to 2012. Treatments were performed at 16 sites, including 14 in the United States and 2 in Canada. The primary end point was the combination of a prostate specific antigen nadir of 0.5 ng/ml or less and negative biopsy at 12 months. Validated questionnaires were administered to monitor changes in urinary and sexual function. Results: Of the 100 treated men, in whom mean age was 70 years (range 53 to 83), 78 completed the 12-month biopsy, which was negative in 63 (81%). Mean prostate specific antigen was 4.9 ng/ml (range 0.4 to 14) and the median Gleason score was 7. The 1-year end point of a prostate specific antigen nadir of 0.5 ng/ml or less plus negative biopsy was achieved in 50 men. During post-trial followup mean prostate specific antigen at 2 years was 1.1 ng/ml (range 0.1 to 17) in 33 patients. Adverse events developed in 91 men through 12 months, which were CTCAE grade 1 in 67, grade 2 in 80 and grade 3 in 20. Treatment related grade 3 adverse events included rectal fistulas in 5 men, which required surgery in 3, osteitis pubis in 3 and hematuria requiring intervention in 3. Treatment related grade 3 adverse events developed early in the trial and appeared related to operator experience. There were no life threatening adverse events or treatment related deaths. Conclusions: Whole gland high intensity focused ultrasound appears reasonably safe and effective to treat radiorecurrent prostate cancer. The rate of complications, which are potentially severe, was acceptable, especially considering the advanced, refractory nature of the disease and the limited treatment options.