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Androgen Deprivation Therapy: What Is It and When Is It Used?

By Harry James “Jim” McCarty, III, M.D., radiation oncologist at Alliance Cancer Care

What is Androgen Deprivation Therapy (ADT)?  Well, first things first, androgens are a class of steroid hormones the body makes naturally.  Androgens are made by the testicles or the ovaries, as well as the adrenal glands – so both males and females produce androgens.  Males simply produce them at higher levels.  The most common androgen is testosterone, although there are others (like DHEA and DHT).

In the same way that the female hormone estrogen can stimulate breast cancers to grow, the male hormone testosterone can stimulate prostate cancers to grow.  And in the same way that doctors may prescribe treatments to block estrogen in women with breast cancers, doctors may prescribe treatments to block testosterone in men with prostate cancer.  Blocking testosterone deprives the body of that specific androgen – and is therefore called androgen deprivation therapy.  We will routinely also call it hormone therapy (although technically ADT is really an anti-hormone therapy).

Because testosterone can make prostate cancers grow – blocking testosterone acts to keep prostate cancers from growing.  It doesn’t actually kill the prostate cancer cells, it just puts them into a sort of hibernation.  This can weaken the cancer cells in such a way that radiation treatment is more effective.  Unfortunately, like any medication regimen, ADT can have side effects.  The most common side effects we see include:

  • Hot flashes (like when women have menopause and changes in their hormone levels). These can happen more often at night, so men are having to turn on a fan or take off sheets or covers.  Hot flashes are usually brief and relatively mild – so they are not usually a big hurdle.  They are typically just more of an irritation.  There are treatments that can help make hot flashes less bothersome.
  • Erectile dysfunction (because testosterone is part of the system that helps produce erections). This ED is typically temporary, lasting for as long as the hormone therapy does, plus a few months after treatment while the testosterone levels are returning to normal.  For better or worse, while men are getting ADT, they typically are not trying to get erections, because the hormone therapy also dramatically lowers the sex drive (libido).
  • Decreased muscle mass / increased fat deposits. This doesn’t always happen, but because testosterone helps build and maintain muscle mass, when testosterone isn’t there, men have a harder time keeping as much muscle.  Men can develop a bit of a “pear-shaped” body distribution, including some chance for breast swelling or tenderness, or more of a “beer belly” appearance.  Again, this is not typical but certainly can happen, especially with longer periods of hormone therapy.
  • Generalized loss of energy or endurance.
  • A chance for thinning of the skeleton (osteopenia) with long-term ADT.

Because ADT does have side effects, we don’t use this hormone therapy for all patients with prostate cancer.  In the most generic sense, if someone has low-risk prostate cancer (i.e., a PSA<10 and a Gleason Score<7*), then we typically don’t use ADT.  If someone has unfavorable intermediate-risk prostate cancer (e.g., a PSA of 10-20, or a Gleason Score of 4+3=7), then we would typically do 6 months of ADT.  If someone has high-risk prostate cancer (e.g., a PSA > 20 or a Gleason Score of 8-10), then we will often do 2-3 years of ADT.  In this situation, studies have shown that there is a benefit to starting hormone therapy about 2 months before starting radiation.  Think of the ADT as starving the prostate cancer before we come in with radiation to kill off the prostate cancer cells.

If someone has had their prostate cancer removed surgically with prostatectomy but has a rising PSA after surgery, we will often treat them with radiation after surgery for a rising PSA.  In those post-operative cases, we will also sometimes use hormone therapy along with the radiation (e.g., if the PSA or Gleason score was more elevated, or if the cancer had spread to lymph nodes).

If someone has had radiation in the past but then has a rising PSA after radiation, we will typically use hormone therapy as the next mode of treatment.  Also, if someone has had their prostate cancer spread (metastasize) to other locations, we will typically use ADT.  In these last two settings (rising PSA after radiation and/or metastatic), we will often keep the patient on hormone therapy indefinitely – or use “pulse hormone therapy”, where the patient has some time on the ADT, and then some time off the ADT, but with a plan to resume ADT if the PSA becomes more elevated.  Finally, if someone is not going to receive radiation therapy or surgery at all, we will occasionally use just hormone therapy.  Depending on the situation, hormone therapy alone can often control prostate cancer for several years.  If we are seeing an elderly patient, 4-5 years may be long enough for them to live their natural life, without having any additional treatment for their prostate cancer.

Androgen deprivation therapy is typically given as a 3-month or 6-month injection.  Doctors will very typically prescribe an oral / pill version before the first injection.  The pill form sort of helps the body prepare for the changes in hormone levels that happen with the injection.  Also, over the last 4-5 years, there have been several “second generation” hormone therapies that have been approved.  The most typical pattern is to start with traditional ADT, and if/when that therapy stops working, we will switch to the second-generation, modified hormone therapies.

To summarize, Androgen Deprivation Therapy (ADT) is an anti-testosterone therapy, which weakens prostate cancer cells and slows prostate cancer growth.  While ADT is not used in all cases, it is a very effective tool in the toolbox for many cases of prostate cancer. Please discuss ADT in depth with your doctor to determine if this is a recommended treatment for you.