Do you dose escalate a patient with high risk prostate cancer who refuses ADT due to potential side effects?

I would treat the elective pelvis to around 50 Gy with a simultaneous boost to the LN to as high as tolerable based on proximity to the bowel. The prostate should be taken to normal dose-escalated levels depending on your fractionation, and you can add a microboost to a DIL. I generally do not add a brachy boost in node-positive cases (as the failure pattern is more likely to be regional/distant rather than local), although some practitioners do use brachy boosts in node positive cases.

I would ...

I would treat with standard options of definitive EBRT to prostate and gross node, as feasible based on location and OAR tolerance, along with elective dosing to pelvic nodal basins up to likely the aortic bifurcation.

I would not escalate further than normal EBRT doses. Consideration could be given for FLAME-style boosting of the primary while keeping treatment isotoxic.

In the setting of a radiographically positive lymph node, I would specifically recommend against brachytherapy boost.

First, I'd get a PSMA PET scan to check for bony mets, and assuming it was negative, would try again to convince the patient to take at least a short course of androgen ablation.

Assuming he continued to refuse androgen ablation, I'd take the prostate and involved nodes to 70 @ 2.5/d, with the clinical nodal field running at 170/d for 28 (4760 cGy).