It might be interesting to ask some questions that most docs have not heard or not prepared (already) to answer to, just to see what words you might hear and encounter, it could give you a good clue for many reasons. Do not be afraid to use your streets smarts, intuitive mindset, gut impression (etc.) and those entangibles that was given to you.
Ideas for off the wall questions: what do you think of surveilance or non-treatment at this juncture (listen closely is my suggestion), do you think I should get different opinions (and if no, why not???), do you follow up with your patients long term (years down the road, even if not coming to your office????). Don't I actually (most patients here now) have reasonable time to make my decision and consider all methods??? (the response is what you are looking for). What are the negative side effects that could happen, even if you normally have not had such in your experience??? (listen to what may be missing...especially if you do your homework on side effects)
Have you ever had problems with any patient(s) in doing this proceedure and what was the worst or it or their outcome??? (they don't hear that one often) What if your treatment fails me in a short period of time, what then is next??? What would you say is your cure rate in your clinical experience (or what do my chances seem to be)??? (write down or tape record the answer, perhaps)
These are just suggestions, what you might like to look for is either sales tactics, overstatements, bias, pressure to commit asap. , perhaps agendas, perhaps out right lying (it is possible, I have witnessed such)*-(glass 1/2 empty?)- (no this is part of the PCa Jungle) 
*(ok-now full glass and cheerio) 
Also look for truthfulness, sincerity, frankness, unbiased verbage, caring, compassion, interest, non-pressure and confidence-especially when confronted with you looking/getting second opinions. (this is the better side of the Jungle..has edible fruit...LOL) 
Hey if you are going to in effect interview mutliple docs and get your opinion(s), you need to compare and weigh everything you heard, good-bad-ugly. Then make your best decision based upon not only what docs tell you, but all sources lead you to...use books, internet, other patients, PCa support groups, and such. A complete understanding of PCa is your best heads up as to what you have to put yourself through in treating this thing. Suggest that you try to be unemotional (very difficult) and analyze all possible considerations, before diving into your possible one way decision (you cannot take it all back come monday morning-quarterbacking). 
Hey if this rocks your world good!