I’m talking about long-term incontinence which is what people are most concerned about. You probably are reading about short-term incontinence. If you are having a radical prostatectomy done, you probably are hoping to live at least ten more years or even longer, so you’re basically saying you want short-term pain (surgery, pain, incontinence, etc) for long-term peace of mind (no metastases).

1 in 10 is the usual order of magnitude for side effects labelled "common", so this doesn't disagree with the 90% number at all.