The main known side effects of the HIFU procedure (for a whole-gland ablation) are the narrowing of the prostatic urethra (stenosis) that may occur in the months following treatment, as well as stress urinary incontinence or erectile dysfunction.
The first results of focal ablation show excellent preservation of quality of life with minimal impact on urinary and sexual functions.[1; 2]
 A Abreu, et al. (2020). High Intensity Focused Ultrasound Hemigland Ablation for Prostate Cancer: Initial Outcomes of a United States Series. Journal of Urology, 204(4), 741-747. https://doi.org/10.1097/JU.0000000000001126
 B Nahar, et al. (2020). Prospective Evaluation of Focal High Intensity Focused Ultrasound for Localized Prostate Cancer. Journal of Urology. 204(3). 483-489. https://doi.org/10.1097/JU.0000000000001015