Hematuria from prostate and urethra: How do I stop the bleeding?

The unfortunate thing is that you had radiation “first” without having the prostatectomy “first.” Your prostate is now a scarred piece of walnut sized “concrete” (my urologist’s descriptive). The problem with radiation is that it passes right through the target tissue, in this case sounding like your entire prostate. Therefore…your non-cancerous bladder and urethra were also irradiated. Perhaps they are scarred or the tissue is altered enough that it is causing bleeding.
We all know that when we re-injure cut or have bleeding of a scar elsewhere on our bodies, that even with normally healing, that scar tissue more easily bleeds, and more profusely. Your scarred urethra and/ir bladder/bladder-neck may be the source of the bleeding.
I offer all of this without knowing about your entire case, but I would venture that your scarred, previously treated prostate, bladder, and urethra are the source.
One person commented on the possibility of kidney stones. That usually causes occult (unseen) microscopic bleeding. If you have visible, overt bleeding from a kidney stone, then you KNOW you have a kidney stone. That stone is moving causing you severe pain to often include overt, visible blood coming from the kidney or ureter.
I am very interested in this…your progress, and I wish you well. Keep us posted with reminder/recall summaries before giving us the latest info. Good luck to you.