Hi Andrew,
As I understand it, the reason that many oncologists prefer to delay the start of HT in such circumstances is because every HT drug has a limited period of time for which it will work, hence the desire is to administer the drug at the time that it will have the greatest benefit. If the drug is given too early in the progression of the cancer, there is not much for it to do, and then once the disease has become more advanced, the opportunity to use that drug has gone.
Hope that’s of some help,
Chris