There is never going to be a certainty of a successful outcome regardless of which treatment you have. Also, outcomes of various individual cases may not be typical. Much will depend on whether the cancer is well confined within the Prostate. If so, the chances of cure by surgery is probably as good as present experience shows to be the case. (My second opinion was of the opinion that surgery was the 'Gold Standard' notwithstanding the fact that he was an expert on radiotherapy, and on a committee that advised the UK Government on forms of radiotherapy, so perhaps a surprising view for a different therapy).
The surgeon who headed the MDT told me that he would remove my Prostate if I wished but advised against it because he doubted he could remove all the cancer. So he recommended the RT with HT which I had. For just over a couple of years or so thereafter, regular MRI scans and PSA results tended to indicate I had been lucky and had had a good result without incontinence (my biggest concern), although gradually worsening ED. However, my PSA continued to increase slowly but at a faster pace. My consultant at the Marsden felt there was some new cancer in the Prostate and subsequent MRI's showed this was the case. There followed HIFU which dealt the cancer a blow but again it seems that increasing PSA and scans have raised suspicion that there is some cancer within my Prostate. I do wonder whether had I had the Prostate removed when I had the chance, perhaps followed by HT/RT, whether this would have been more successful even if it meant being more adversely affected by side effects. A friend who followed this route with a very similar diagnosis to mine is doing very well some 10 years on.
For me, eradicating or knocking back the cancer has been the objective almost regardless of adverse side effects (maybe a view reinforced by the fact that these have for me been relatively minor) but for some, side effects play a much more significant part in the decision making process.