What are the documented risks relating to hifu treatment of the prostate cancer confined to the prostate capsule

The short version: HIFU is not a gentle option. The documented harms are real and common, and the cancer-control evidence is weak.

The clearest complication numbers come from a 74-patient series: impotence in about 90% [1], positive biopsy after treatment in about 15.5% [1], and one case of a rectovesical fistula, the hole between bladder and rectum that is the feared HIFU injury [1]. A separate 250-patient series reported recto-urethral fistula in 6%, severe incontinence in 7%, and bladder neck stenosis in 17% [2]. Fistula is rare but devastating, needing reconstructive surgery. Impotence is not rare. It is the norm in that series.

The efficacy side is thin. The 2011 systematic review concluded the evidence is low quality and insufficient to support widespread use over standard treatments [3]. The 74-patient series saw biochemical failure in about 27% at a mean 30 months, worse in higher-risk disease [1]. Thirty months is short. Prostate cancer takes a decade or more to recur, so these studies cannot tell you whether HIFU cures you or just delays a recurrence.

Note also that the 250-patient series mixes patients treated for local relapse after radiotherapy [2], which is not the same population as a man with newly diagnosed cancer confined to the capsule. The clean case, low or intermediate risk, first treatment, capsule-confined disease, is where the risk numbers above are least well characterized.

My call: if you are choosing between HIFU and surgery or radiation for capsule-confined disease, the harms are documented and the cure data is not. Confidence: moderate on complications, low on long-term cancer control.