March 16, 2009 -- Question: What is androgen suppression/deprivation therapy, and how is it achieved?
Answer: Androgen suppression therapy is the ability to block the production of testosterone or its effects on cancer cells. There are really three ways to do this. The first and oldest way is to simply remove the source of the testosterone which are the testicles and that's done with a surgical procedure called an orchiectomy. About 25 years ago it became possible to block the signals to the testicle that come from the brain and in particular the pituitary gland, and this is done with drugs that inhibit the pituitary gland from secreting master hormones called LSH and FSH. Those normally go down and interact with the testicle to stimulate testosterone and when you use drugs like Lupron or Zoladex it stops the pituitary from sending out those signals.
A second general way of blocking testosterone is to block its conversion to a more active form. And drugs like finasteride or Proscar, another one is Avodart actually block the conversion of testosterone to dihydrotestosterone, which is ten times more potent than native testosterone made by the testicles.
And then the last way of blocking in general is to use drugs that block the testosterone interaction with receptors in cancer cells and other cells, and that's done with drugs that block this receptor like Casodex and it prevents testosterone from binding to its receptor.