Single-session primary high-intensity focused ultrasonography treatment for localized prostate cancer: biochemical outcomes using third generation-based technology
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UNLABELLED: What's known on the subject? and What does the study add? The experience with HIFU as a minimally invasive treatment for localized prostate cancer is relatively new and most reports are from European centres. Our study is unique in five regards: 1. Data was collected prospectively. 2. All patients were treated with contemporary technology. 3. Outcomes are reported after a single HIFU session using two definitions of biochemical failure that have the ability to predict longer-term clinical failure after primary ablative therapies for prostate cancer (Stuttgart definition for HIFU and Horwitz definition for radiation). 4. All patients were treated in a single centre. 5. No patients underwent peri-HIFU TURP. The present study represents the largest North American prospective cohort of primary HIFU for prostate cancer with mid-term oncological outcome data. OBJECTIVE: To assess 4-year biochemical failure (BCF) rates in patients after high-intensity focused ultrasonography (HIFU) treatment using the Horwitz and Stuttgart definitions. PATIENTS AND METHODS: A total of 447 consecutive patients were treated with a single session of HIFU between May 2005 and December 2010. Follow-up included prostate-specific antigen (PSA) measurement every 3 months during the first year and every 6 months thereafter. Patients who had previously received radiation, androgen deprivation or HIFU therapy, and patients with <2 consecutive PSA measurements were excluded. BCF was reported using the Stuttgart (PSA nadir + 1.2 ng/mL rising) and the Horwitz (two consecutive increases of at least 0.5 ng/mL) definitions. RESULTS: In all, 402 patients met the inclusion criteria and the median (range) follow-up was 24 (6-48) months. Of these patients, 183 (45.5%) had low and 219 (54.5%) had intermediate D'Amico's risk stratification disease. Mean and median absolute PSA nadir levels were 0.36 ± 0.69 and 0.1 ng/mL (Q(1):0, Q(3):0.37), respectively and these were achieved in median time of 3 months. Overall 4-year mean (range) BCF-free rates were 68 (61-75)% and 72 (68-77)% according to the Stuttgart and Horwitz definitions at 4 years, respectively. Mean (range) BCF-free rates were significantly higher for a PSA nadir ≤0.5 ng/mL and prostate volume ≤30 mL for both definitions at 4-year follow-up [Stuttgart: 79 (72-86)% vs. 25 (13-38)%; Horwitz: 82 (77-87)% vs. 33 (21-44)%] and [Stuttgart: 72 (64-79)% vs. 56 (42-69)%; Horwitz: 75 (69-80)% vs. 63 (53-74)%], respectively. Pre-treatment PSA and PSA nadir of >0.5 ng/mL were the predictors of BCF using both definitions. CONCLUSIONS: Primary HIFU appears to result in promising 4-year BCF-free rates in individuals with low- and intermediate-risk prostate cancer who achieve PSA nadir <0.5 ng/mL. A prostate volume <30 mL is associated with PSA nadir levels of <0.5 ng/mL suggesting a potential role for pretreatment volume reduction (medically or surgically) in larger prostates.