You may want to read this:
For very high-risk patients, EBRT + BT is superior to surgery or EBRT onlyIf you're talking about
focal cryo, it is not used for GS9 except within a clinical trial. Very doubtful, imho.
If you meant proton, it would most likely be given as a boost, although some are using it as a monotherapy for high risk. It's not bad, just a lot of expensive treatments, with results (oncological control and toxicity) no better than photon.
Even small amount of GS 9s can become metastatic. I hope you've had a bone scan and CT to check for that.