Knowing this…you need to know specifically how surgery, radiation, or any other treatment will affect your erections. With this information, the specifics of your cancer, the level of importance you attach to sexual function, chance of cure and incontinence…you can smartly go about honing in on your decision.
The diagram shows the nerves responsible for erections very near the prostate…so you can cut it, burn it, freeze it, radiate it, HIFU it-it doesn’t matter they will be affected to some degree. Is that important to you?
Let us be clever and cut a little rather than fall and bruise to death. Shakespeare (Or something like that.)