Visually Directed Transrectal High Intensity Focused Ultrasound for the Treatment of Prostate Cancer: A Preliminary Report on the Italian Experience

Abstract

High intensity focused ultrasound is a minimally invasive treatment option for prostate cancer. Data from the literature show promising early oncological outcomes and a favorable side effect profile. This study is a preliminary report of the Italian experience (Perugia and Turin) of patients treated with the Sonablate(R)500 high intensity focused ultrasound device. Between 2004 and 2007, 163 consecutive men with T1-T3 N0M0 prostate cancer underwent high intensity focused ultrasound with the Sonablate 500. Followup included prostate specific antigen tests at 1 month and then every 3 months after treatment, and a random prostate biopsy at 6 months. Failure was defined according to prostate specific antigen nadir, positive findings on followup biopsy and biochemical failure according to Phoenix criteria. Median patient age was 72 years old, median baseline prostate specific antigen was 7.3 ng/ml, and disease stage was T1 in 44.1%, T2 in 42.5% and T3a in 13.4% of patients. Median followup was 23.8 months. After high intensity focused ultrasound treatment prostate specific antigen decreased to a median nadir of 0.15 ng/ml. Median prostate specific antigen at 3 and 6 months was 0.30 and 0.54 ng/ml, respectively. At 6 months the negative biopsy rate was 66.1%. There was no biochemical evidence of disease in 71.9% overall. On multivariate analysis prostate specific antigen nadir became the only independent predictor of no biochemical evidence of disease and positive biopsy at a cutoff of 0.40 ng/ml. A favorable outcome of high intensity focused ultrasound is associated with lower baseline prostate specific antigen, lower prostate specific antigen nadir, lower Gleason score and lower tumor stage. As with any novel technology long-term data will be required before this technique gains widespread clinical acceptance.