This is an interesting thread but, your post on another thread about cognitive dissonance should make you realize that most of us will rationalize our treatment decisions including the relative importance of post surgical radiation as a backup plan for surgery patients...
Having said that, I'll still weign in on this with my commentary. My primary point is that psychological reasons can be a powerful motivator in making a treatment choice. I do not believe, as you postulate, that having the radiation option available after surgery is invalid reasoning. However, I do believe that the relative weighting of that can be vastly different in different men.
Let's take an example. Say we have a 60 year old man with early stage cancer. PSA is 5, nothing found on DRE, Gleason 3 +3, normal sized prostate and a couple of core samples with 25% or so cancerous. That man has pretty much the full range of treatment options available. So, what factors does he consider when making his choice?
1. Cure rate of treatment.
2. Short and long term urinary issues.
3. Short and long term ED issues.
4. Invasiveness of procedure.
5. Potential bowel issues.
6. Need to have a "backup plan" if primary treatment doesn't work.
7. Need to "get it out" of his body (the cancer that is).
8. Need to see pathology immediately after procedure.
I think both rad and surgery guys would agree that "cure rate" is number one with all of us. After that the similarities diverge based on the psyche of the particular individual. Now I will generalize a bit…the surgery guys seem to place a high degree of importance on items like “getting it out”, seeing the pathology and having a backup plan. The radiation guys appear to weigh low invasiveness and fewer immediate side effects as higher motivators than backup plan or the other surgery motivators. For me personally, I felt that there was a very high likelihood of cure so I didn’t worry too much about backup plans. I figure that, if I had either surgery or seeds and either didn’t work, I would probably end up on HT eventually anyway, so I didn’t weight the loss of the option of having post-surgery radiation as very important.
I guess my point is that, while I do believe that the surgery guys’ point about an extra backup plan is valid, it’s not that important to me (and I’m guessing not to you) because of the weighting I personally give to some of the other factors listed above.
I’m sure I didn’t solve anything here, but this hopefully adds another perspective to this thread.