Ian. You and I share the same boat. See my profile. As soon as salvage failed, they put me on Casodex. When that failed, they put me on hormones. Ive been on them nearly two years and they are failing too. My radical prostatectomy was, like yours, in 2010. I would ask what trials are available and take views from the professionals on the options open to you of which there are many.
Good luck brother.
Bazza