Medium-term oncological outcomes in a large cohort of men treated with either focal or hemi-ablation using high-intensity focused ultrasonography for primary localized prostate cancer

Abstract

Objective: To report medium-term oncological outcomes in men receiving primary focal treatment with high-intensity focused ultrasonography ( HIFU) for prostate cancer (PCa).

Patients and methods: Consecutive patients with PCa treated with primary focal HIFU at two centres by six treating clinicians were assessed. Patients were submitted to either focal ablation or hemi-ablation using HIFU (Sonablate 500). The primary objective of the study was to assess medium-term oncological outcomes, defined as overall survival, freedom from biopsy failure, freedom from any further treatment and freedom from radical treatment after focal HIFU. The secondary objective was to evaluate the changes in pathological features among patients treated with focal HIFU over time. We also assessed the relationship between year of surgery and 5-year retreatment probability.

Results: A total of 1032 men treated between November 2005 and October 2017 were assessed. The median age was 65 years and median prostate-specific antigen level was 7 ng/mL. The majority of patients had a Gleason score of 3 + 4 or above (80.3%). The median (interquartile range) follow-up was 36 (14-64) months. The overall survival rates at 24, 60 and 96 months were 99%, 97% and 97%, respectively. Freedom from biopsy failure, defined as absence of Gleason 3 + 4 disease, was 84%, 64% and 54% at 24, 60 and 96 months. Freedom from any further treatment was 85%, 59% and 46% at 24, 60 and 96 months, respectively. Approximately 70% of patients who were retreated received a second focal treatment. Freedom from radical treatment was 98%, 91% and 81% at 24, 60 and 96 months. During the study period, we observed an increase in the proportion of patients undergoing focal HIFU with Gleason 3 + 4 disease and with T2 stage disease as defined by multiparametric magnetic resonance imaging. Finally, there was a reduction over time in the proportion of patients undergoing re-treatment within 5 years of first treatment.

Conclusions: Focal HIFU for PCa is a feasible therapeutic strategy, with acceptable survival and oncological results and a reduction in the 5-year retreatment rates over the last decade. Re-do focal treatment is a feasible technique whose functional and oncological outcomes have still to be evaluated.

Keywords: #HIFU; #PCSM; #ProstateCancer; focal therapy; high-intensity focused ultrasonography.