That's really not an accurate statement, Dave. Surgery and HT+RT have very different side-effects, but neither is a "gold standard". They have almost identical long-term success rates, and which is better depends very much on the individual circumstances; every instance of prostate cancer is different. There are cases where a patient will be offered both, and other cases where the MDT will recommend one in preference to the other. In my own case, for example, they gave a strong recommendation that RT was to be preferred to surgery because there was a high risk of surgery not getting a negative surgical margin.
Chris