Single-session primary high-intensity focused ultrasonography treatment for localized prostate cancer: biochemical outcomes using third generation-based technology

Study Type – Therapy (case series) Level of Evidence 4 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 (Q₁:0, Q₃:0.37), 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.