Do you utilize a V80Gy dose constraint for the rectum for definitive dose-escalated RT of the prostate?

I generally treat to 78 Gy in 2 Gy fractions or to 79 Gy in 1.8-2 Gy fractions, so I'm very concerned about hot spots and where they are located. I try hard to keep the rectal Dmax less than 80 Gy. That's not always possible. I will accept max doses up to about 82.5 Gy if the volume is not more than 1-2%, and it doesn't extend to the mucosal surface. I have not seen guidelines addressing doses of 80 Gy and up for prostate EBRT, but we know from the old days looking at point doses to the rectal m...

For many, many years I have treated the prostate (CTV) to a minimum dose of 81 Gy based on MSKCC data that was initially appearing in the late 90's (3DCRT data) and refined/updated later with IMRT data. I'll freely admit I've been a fan of the MSKCC approach/data for a long time. What I'm not so much a fan of is a "constraint" per se in any radiation planning, and I also freely admit a little heresy in that regard. Certainly you don't want to "blow past" known DVH metrics where toxicity is known...