I found the following stats on BRFS (Bioehemical Relapse Free Survival) in "The Prostate Treatment Book" published by Seattle Prostate Institute/Swedish Cancer institute.
As in all studies the data may not be perfect, and combines data from various studies and hospitals. but it's the 1st head to head comparison that I have run across.
Risk Group 5 year BRFS 10 year BRSF
Surgery 3D CRT Seeds Seeds Seeds/ERBT
Low 83-85% 90% 87-94% 87% 84-85%
Intermediate 50-65% 70% 82% 76% 77-90%
High 28-32% 47% 65% -- 46-57%
The low risk group survival rate is pretty much equal for all treatment options and matches everything else I have read. So in treating low risk PC, the side affects are more important than the treatment option when it comes to making a decision.
In the high and intermediate risk groups there is a difference in the BRFS. This makes sense to me as these groups are at higher risk for extra capsular extension, seminal vessel invasion and tumors close to the urethea which are all more difficult to get a clear surgical margin.
If your surgeon or radiologist is quoting higher cure rates than these then he should be able to clearly explain why.