Hi Sober1, and welcome to the club nobody wants to join.
I don't think that is unheard of - it implies that there is cancer throughout most of your prostate.
I would recommend you send your biopsy slides to Johns Hopkins for a second reading - they are the best in the world at this. It may or may not be covered by your insurance, but it always makes sense to have the experts take a look. Your pathologist probably reads biopsy slides from all kinds of cancers, Dr. Epstein at Johns Hopkins specialized in reading prostate cancer slides. Gleason scores can go up or down on a second reading - but either direction will affect your treatment decisions.
Here's a link for a second opinion at JHU: pathology.jhu.edu/department/services/secondopinion.cfm
Best of luck
5/2017 PSA 34.2 age 53
6/2017 Dx by biopsy - 9 of 14 positive; Gleason 7 (4+3) 5% to 90% cancer
8/24/2017 RARP, Dr. Canes - Lahey Burlington (MA)
4/8 lymph nodes positive
Positive margin 5 MM
Seminal vesicle invasion
pT3b; pN1; M0
10/24/17 PSA 0.13
12/11/17 Started 18 months of Lupron
1/18 PSA <0.1; T=31
SRT 3/14 - 5/7/18 - 39 fractions