Hi Mahalo and welcome. I have observed that most of the guys on this site have elected surgery and you will get plenty of advice from them. My stats were not far from yours and I looked at all options, narrowed them down to da vinci and brachy, and ultimately chose bracytherapy. My procedure was recent (3 weeks ago) and, if you are interested, you can check my thread "Tudpock's Brachaytherapy Journey" on this site to see my thought process re my choice -- plus you'll see my post-op situation which is remarkably good, i.e. my life is normal and all equipment is functioning great.
Having said that, I wouldn't necessarily recommend seeds for you, I just know it was right for me. I'm sure you have examined both options carefully and know the stats and SE's backward and forwards so I won't go into those except to say that, with your cancer stats as I read them, the cure rate for both options is basically the same. There are a few other things to consider, however, that may not necessarily be in all of the books, so I'll throw them in for whatever help they can be:
1. There is a personal psychological issue that only you can answer. That is, how important is "getting it out" to you? You'll read a lot of posts on this site from men for whom that was a really big deal. They wanted the cancer out of their bodies, wanted to see an immediate pathology report and that was that. For me, that wasn't a big deal at all...the important thing was to do lots of research and make an informed decision as to the right cure and the quality of life issues, then move on. There are no sure things with either choice...
2. The other issue many men bring up is that "surgery after radiation" is not really a good option but that "radiation after surgery" is possible. That is true (though some docs do surgery after radiation but it is a very difficult procedure). There are other options after seeds that are available but you should probably assume that surgery is not among them. If this issue is important to you, then brachy may not be your best choice.
3. The immediate side effects from surgery are well known...and you can read them in spades on this site. Re brachy, the immediate urinary side effects are generally frequency and urgency and may last a couple of months. However, IF you don't have much of an issue with this pre-procedure, you probably won't post-procedure. My urologist gave me a test (can't remember what it is called) that scored me on such things as number of times I had to go urgently now, number of times I get up in the night, weak stream, etc. My score was low (that's good), meaning that I did not have issues on those functions pre-procedure. My radiation oncologist and my urologist both predicted that my post-procedure issues would be minor or non-existant with Flomax treatment and, so far, they have been correct. Now, remember I'm only 3 weeks out, so I may yet have some of these issues but, so far - so good.
4. ED issues occur in brachy patients at a slightly lower rate than in surgery patients -- but there are varying reports on this. However, the ED with surgery occurs immediately after the surgery and generally gets better (with pills) over time. The ED with brachy occurs later, i.e. 2 years++. And, as in the case of urinary effects, if your equipment is working well before the procedure, the chances are better that it will work after the procedure. Also, if ED does occur, the same little pills that surgery patients take work with brachy patients. For me, sex started 2 weeks after the seeding, and junior responded well with no pill assistance needed. I'm looking forward to 2 good years and then, if we need a little help, I'll pop the pills at that time.
5. There are a small % of brachy patients who have bowel issues...but it's a larger % than surgery patients. Experience of your radiation oncologist is key here as the issues seem to vary with seed placement and dosage.
I hope this helps a bit. It's a BIG decision and I wish you the best. Please come back and let us know what you decide.
Happy New Year!