Multicentric Oncologic Outcomes of High-Intensity Focused Ultrasound for Localized Prostate Cancer in 803 Patients

Abstract

Background

High-intensity focused ultrasound (HIFU) is an emerging treatment for select patients with localized prostate cancer (PCa).

Objectives

To report the oncologic outcome of HIFU as a primary care option for localized prostate cancer from a multicenter database.

Design, setting, and participants

Patients with localized PCa treated with curative intent and presenting at least a 2-yr follow-up from February 1993 were considered in this study. Previously irradiated patients were excluded from this analysis. In case of any residual or recurrent PCa, patients were systematically offered a second session. Kaplan-Meier analysis was performed to determine disease-free survival rates (DFSR).

Measurements

Prostate-specific antigen (PSA), clinical stage, and pathologic results were measured pre- and post-HIFU.

Results and limitations

A total of 803 patients from six urologic departments met the inclusion criteria. Stratification according to d’Amico’s risk group was low, intermediate, and high in 40.2%, 46.3%, and 13.5% of patients, respectively. Mean follow-up was 42 ± 33 mo. Mean PSA nadir was 1.0 ± 2.8 ng/ml with 54.3% reaching a nadir of ≤0.3 ng/ml. Control biopsies were negative in 85% of cases. The overall and cancer-specific survival rates at 8 yr were 89% and 99%, respectively. The metastasis-free survival rate at 8 yr was 97%. Initial PSA value and Gleason score value significantly influence the DFSR. The 5- and 7-yr biochemical-free survival rates (Phoenix criteria) were 83–75%, 72–63%, and 68–62% (p = 0.03) and the additional treatment-free survival rates were 84–79%, 68–61%, and 52–54% (p < 0.001) for low-, intermediate-, and high-risk patients, respectively. PSA nadir was a major predictive factor for HIFU success: negative biopsies, stable PSA, and no additional therapy.

Conclusions

Local control and DFSR achieved with HIFU were similar to those expected with conformal external-beam radiation therapy (EBRT). The excellent cancer-specific survival rate is also explained by the possibility to repeat HIFU and use salvage EBRT.

Introduction

In absence of data from large randomized trials, men with clinically localized prostate cancer (PCa) meet a dilemma when selecting treatment. Many treatment options are available and the morbidity associated with radical treatments is significant. The three main strategies are radical surgery, radiation therapy, and active surveillance. Results of a Scandinavian randomized study of radical surgery versus surveillance concluded that radical prostatectomy results in a reduction in distant metastases and disease-specific death among patients with clinically localized PCa not detected by prostate-specific antigen (PSA) screening [1]. The subgroup analyses by age showed that the benefit of radical prostatectomy was limited to men <65 yr. Systematic control biopsies after three-dimensional conformal external-beam radiation therapy (EBRT) demonstrated that local control of the disease was achieved only in 68% of patients, although biochemical-free survival is ≤59% [2]. A well-defined protocol for active surveillance is still lacking and reliable criteria for active treatment are still unknown. High-intensity focused ultrasound (HIFU) is a minimally invasive option for localized PCa [3], [4]. The goal of this study was to report the outcome of 803 consecutive patients who underwent HIFU as primary care option for localized PCa in six institutions and to determine the factors influencing the outcome. The morbidity was not analyzed in this study as it has already been published [5].