You can have radiation only once in certain region - you can not do it twice. So the idea is that if cancer cells survive radiation in a prostate gland, you will not be able to repeat radiation to that region. Once you radiate a prostate it becomes one thick mess that is almost impassible to remove. Yes, there are one or 2 surgeons in the USA that are able to perform that task , but not everybody has a means to travel nor pay for that.