You have quite a few cores positive and with some some Gleason 4, even at only 5%, I would seek the exact treatment you mentioned, SBRT. You should also look at getting a Decipher score as well. If you were unlucky on that with a high score as I was (0.81) with my 3+4 case, you might even need some ADT. But most likely ADT will not be needed. See my bio for more details.