Gotcha! I agree that skipping further chemo is really no big risk. In RTOG 0521, it only increased 4-year survival from 89% to 93%, which is not a big difference. But I understand your attitude of wanting to eek out every percent improvement you can.
Docetaxel with primary radiation therapy for high risk prostate cancerI think the really big effect is from your combination of HDR brachy and EBRT, which gets the dose to the prostate way higher than anything given in RTOG 0521 (which was only 75.6 Gy):
HDR Brachy Boost and Monotherapy for High-Risk Prostate CancerUnfortunately, that increase in cancer control comes at the cost of increased toxicity, as you, unfortunately, know first hand. I hope they are able to fix it for you quickly.