**8. The principle rationale of tissue preservation is harm reduction and functional preservation**

Adverse events affecting the urinary tract are reported in 2-58% of whole gland HIFU therapy in the literature. Rectal toxicities ranged from 0 to 15%. Erectile dysfunction is reported in 0 to 39% of cases [30]. Toxicity rates are believed to be lower after focal therapy. In our case series, 31 consecutive patients with unilateral organ confined prostate cancer were primarily treated by hemiablation HIFU. Early self-resolving LUTS were the most common complications and no rectal toxicities were reported. The strategy was well tolerated in the genitourinary functional domains: all patients were pad free continent despite a high number of apical lesions (n=12) and only 25% of men in our cohort of relatively elderly patients (average age 71 years) who were potent preoperatively reported having ED post hemiablation. The procedure could possibly be delivered in an ambulatory care setting [19].
