Salvage hifu (Sat) for radiorecurrent prostate cancer: factors influencing the outcome

Introduction & Objectives:

To evaluate the efficacy of a salvage therapy with transrectal High Intensity Focused Ultrasound (HIFU) for local relapse after external beam radiation therapy (EBRT).

Material & Methods:

All patients were treated with the Ablatherm^®-HIFU device (EDAP SA, France) under general or spinal anaesthesia. Specific shot parameters were adapted during the study period in order to avoid any rectal damage. Patient follow-up included control biopsies and serial PSA measurements. Progression was defined as the date of salvage androgen deprivation (SAD) introduction.

Results:

118 patients, mean age 68.9±6.01 years, were included in this study. Overall mean PSA level was 7.87±8.52 ng/ml. All patients had positive prostate biopsies with a pre-HIFU Gleason score ≤6 in 38 patients (32%), 7 in 28 patients (24%) and ≥8 in the remaining 52 patients (44%). Mean follow-up was 16.4 months. After HIFU treatment 84% of the patients had negative control biopsies and 62% demonstrated a nadir PSA level <0.5 ng/ml within 4 months following HIFU. The survival free rates without SAD were 58%, 44%, and 14% for patients with pre-HIFU Gleason score ≤6, equal to 7, and ≥8, respectively (log rank test, p<0.05). Progression free rate significantly decreased with the increase of the pre-HIFU initial risk level (D'Amico et al, 1998) with 78%, 49.5% and 14% for low (18pts), intermediate (37pts), and high (63pts) risk groups, respectively (log rank test, p<0.005). Adverse events related to HIFU included recto-urethral fistula in 3%, grade II or III incontinence in 28%, and bladder neck strictures in 10%. With the modified shot parameters we found no more rectal injury.

Conclusions:

HIFU appeared as a promising treatment option with a curative intent for patients with local recurrence after EBRT. The HIFU provided a high local control of the tumour. The disease control was highly correlated with the initial risk level.