Androgen Deprivation Therapy (ADT)
ADT is a systemic modality that treats—and affects—the entire body, not just the localized area of the prostate gland. This treatment impedes the production of hormones (androgens) and blocks the body from absorbing any androgens such as testosterone produced naturally in your body.
ADT is effective because prostate cancer cells develop and grow in the presence of testosterone, the male androgen produced mostly by the testes. Limiting production of testosterone and preventing any androgen that is produced from interacting with the cancer cells, forces the cancer cells into stasis, possibly delaying their harmful effects by years. In effect, ADT, when it employs medications (see below) causes the male body to experience castration without surgery.
Unlike surgery, when chemically induced ADT is no longer required the positive emotional and physical benefits of testosterone may return. However, there is no guarantee that the testosterone will eventually return and no way to know how long the return might take.
ADT is often called “hormone therapy.” This is an inaccurate description. In fact, ADT should be called “anti-hormone therapy” because its function is to halt production of the hormone testosterone in a man’s body.
Your doctor will usually recommend ADT if:
- — Salvage therapy fails, or
- — You are initially diagnosed with advanced prostate cancer with a PSA above 10.0, or
- — There is other evidence that the cancer has already moved beyond the prostate gland (such as positive scans or symptoms such as blood in the urine), or
- There a bio-chemical recurrence with a PSA greater than 10.
Prostate cancer that responds to ADT is said to be hormone- or androgen-dependent. Unfortunately, in most cases, the cancer eventually “learns” how to grow without requiring testosterone derived from the testis making the ADT ineffective. At this point, the cancer is called “castrate resistant prostate cancer” (CRPC). Many studies in the literature have suggested that ADT will only work for a short period of time, probably not much longer than 18 to 24 months, before the cancer becomes castrate resistant. However, in my experience (not scientific) most men benefit from ADT for many years before becoming castrate resistant. I know many men who have been successful for over ten years, with one man now approaching his 16th year. In a study that looked at long term ADT using Lupron 90% of the subject men still remained hormone responsive at 10 years (J Clinical Oncol 32 2014; (suppl; abstr e16077; Peter Hammerer, Manfred Wirth)
On the flip side, there are individuals who never achieve a good response from ADT.
Drugs used in ADT have improved greatly over the past few years and that we are now able to employ intermittent therapy (which is discussed later) successfully. Although there is no way of knowing, it’s not unreasonable to anticipate many years of successful ADT.