Re: Can't get PSA to zero
It's always a good idea to use the same lab for all your tests. Different test kits have differing sensitivities. As long as you pick one and stick with it, you're OK.
DHT should be suppressed as well. If it isn't, then the cancer is manufacturing DHT from a non-testosterone precursor (androstanedione) and Avodart may block that. Here is a technical reference that you can send to your oncologist. I've found that it often helps to provide such references from reliable sources (but not from random internet sites) and doctors usually appreciate it when I do provide it.
As I said before, Zytiga and Xtandi often continue to work after castrate/Lupron-resistance sets in -- that's why they were developed. They are new and very expensive.
Zytiga (abiraterone) has been available for over a year but was originally only FDA-approved for use after Taxotere (docetaxel) was tried. Just last month, the FDA approved it for use before Taxotere.
Xtandi (enzalutamide) was just FDA-approved 4 months ago, and may be even more effective than Zytiga. Currently it is approved for use after Taxotere. However the chemo pre-treatment requirement may be waived if in the opinion of the doctor or the patient it might be detrimental to his health (I learned this tip from Dr. Scholz, btw). That said, your husband might want to go for a single cycle of Taxotere now anyway, just to get that requirement out of the way. Besides paving the way to get your insurance to pay for Xtandi, it may increase his eligibility for some clinical trials down the road. New drugs are usually tried first on men who are castrate-resistant and have tried Taxotere.