Here is a response from my MO when I asked him about intermittent vs continuous ADT.
You are right for patients with only biochemical (PSA) progression of disease, continuous did not show evidence of superiority over intermittent treatment.
For widespread metastatic disease in the bone, intermittent treatment is not feasible, because the disease progresses rapidly when we take a break from treatment.
For oligometastatic disease, I think that intermittent schedule may be practical for a minority of patients whose prostate cancer is exquisitely sensitive to ADT and who can therefore afford to take a break from treatment, because they will respond to everything and tend to do well anyway.
If you do not feel comfortable with an ADT "drug holiday", you should not do it.
According to our current understanding and from the research I am aware of, those patients who have done the best tend to respond well to standard treatments in which we treat differentiateded cancer cells (that express AR, depend on androgens, and produce PSA) and also take something else that controls the CRPCa cells (the most important of which probably comprise cancer stem cells that do not express AR, do not depend on androgens, and do not produce PSA) and will be or eventually become resistant to conventional treatments including ADT, abiraterone, and chemotherapies, etc...
You maybe interested in taking a look at prostate cancer stem cells in particular and cancer stem cells in general in our strategy to enhance current cancer treatments and in our goal to improve (exponentially rather than incrementally) overall clinical outcomes in the near future.
Best wishes and regards!