Whole-gland ablation of localized prostate cancer with high-intensity focused ultrasound: oncologic outcomes and morbidity in 1002 patients

Abstract

Background: High-intensity focused ultrasound (HIFU) is a nonsurgical therapy for selected patients with localized prostate cancer (PCa).

Objective: The long-term oncologic and morbidity outcomes of primary HIFU therapy for localized PCa were evaluated in a prospective, single-arm, single-institution cohort study.

Design, setting, and participants: Participants were patients treated with HIFU for localized PCa from 1997 to 2009. Excluded were patients with local recurrence following radiotherapy. A second HIFU session was systematically performed in patients with biopsy-proven local recurrence.

Intervention: Whole-gland prostate ablation with transrectal HIFU.

Outcome measurements and statistical analysis: Incontinence was assessed using the Ingelman-Sundberg score, and potency was assessed using the five-item version of the International Index of Erectile Function (IIEF-5) scores. Primary outcomes were survival rates (biochemical-free, cancer-specific, metastasis-free, and overall survival). Secondary outcomes were morbidity rates. Median follow-up was 6.4 yr (range: 0.2-13.9). The Kaplan-Meier method was used to determine survival estimates, and multivariate analysis was used to determine predictive factors of biochemical progression.

Results and limitations: A total of 1002 patients were included. The median nadir prostate-specific antigen (PSA) was 0.14 ng/ml, with 63% of patients reaching a nadir PSA ≤0.3 ng/ml. Sixty percent of patients received one HIFU session, 38% received two sessions, and 2% received three sessions. The 8-yr biochemical-free survival rates (Phoenix definition) were 76%, 63%, and 57% for low-, intermediate-, and high-risk patients, respectively (p < 0.001). At 10 yr, the PCa-specific survival rate and metastasis-free survival rate (MFSR) were 97% and 94%, respectively. Salvage therapies included external-beam radiation therapy (EBRT) (13.8%), EBRT plus androgen-deprivation therapy (ADT) (9.7%), and ADT alone (12.1%). Severe incontinence and bladder outlet obstruction decreased with refinement in the technology, from 6.4% and 34.9% to 3.1% and 5.9%, respectively. Limitations included the fact that the study was a single-arm study without a comparison group, technological improvements, changes in surgical protocol during the study, and the use of ADT to downsize the prostate in 39% of patients.

Conclusions: HIFU is a potentially effective treatment of localized PCa, with a low PCa-specific mortality rate and a high MFSR at 10 yr as well as acceptable morbidity.

Keywords: Disease-free survival; High-intensity focused ultrasound ablation; Localized prostate cancer; Survival rate.