Shown at the bottom of this post are the John Hopkins "requirements" for patients in their active surveillance program. This is per John T's reference. Based on the info you provided, you would probably not be a candidate for this based on their criteria.
Frankly, I can understand your concern about bad side effects. Every time I read a post here about severe incontinence or injecting the penis to get an erection, I find it disconcerting.
Having said that, there are treatments with fewer side effects than surgery and clearly you are exploring them. I would also suggest you check out realziggy's posts re TFT...I don't know if you would be a candidate but at least you might explore the option.
Best of luck and let us know how your brachy consult goes.
Hopkins Criteria for Active Surveillance
1. Age 60+.
2. T1C, i.e. nothing felt on DRE.
3. PSA density of .1 or less (this is PSA divided by size of prostate, e.g. PSA of 3 divided by prostate size of 35cc equals PSA density of .086 which is less than the .1 threshhold.
4. Gleason 6 or less.
5. 2 or fewer cores of cancer.
6. No core with more than 50% cancer involvment.