So sorry to hear about your husband’s stage 4 prostate cancer. (I was diagnosed with low-grade, localized prostate cancer at 56y; had been getting PSA tests since I was 45y.)
Regarding his difficulty urinating - have they prescribed him either Tamsulosin (Flomax) or Finasteride?
With the PSMA PET scan results, what were the SUVmax scores assigned to each of those suspicious areas? Knowing that, you won’t have to wait 10 days to ask the oncologist what’s going on.
These days there are always treatments available for most any stage of prostate cancer. Use this time to get up-to-speed on his diagnosis, any other tests that might be useful, as well as treatment options.
Prostate cancer diagnoses and treatment is one of self-advocacy and shared decision-making. The more informed you are, the more specific questions you’ll ask, the better treatment options he’ll have as a result, and (hopefully) the outcome will be better.
It’s easy to get overwhelmed; don’t let it happen. Stay focused on the ultimate goal.
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His situation can be a lesson-learned for others, his siblings, as well as for any children (males or females) you and he have:
> being in good shape, working out, and eating well can be helpful at minimizing the occurrence of prostate cancer, but not significantly.
> early PSA screening and early detection is critical. (When did he start getting annual PSA tests?)
> prostate cancer usually has few if any symptoms when detected early, and depending where the lesions are, may not be significant at all. (It’s never a good thing to let new symptoms drive testing. By then, things may have gone too far.)

Good luck.