Androgen Deprivation Therapy (ADT)
What is it?
- Androgens are hormones that promote male characteristics such as facial hair, sexual function and muscle mass. Testosterone is the main androgen.
- Prostate cancer cells need androgens to grow.
- Androgen deprivation therapy (ADT), a type of treatment for prostate cancer, blocks the production or effects of testosterone and other male hormones.
- ADT is most often used to treat:
- Cancer that has spread outside the prostate
- Recurrence of prostate cancer after another therapy has been used
- Men who are at high risk of experiencing cancer recurrence after surgery or radiation therapy
- “Hormone therapy” is another name for ADT. Although these terms can be used interchangeably, Prostate Cancer Canada uses ADT (it is more specific to prostate cancer treatment).
- This therapy affects the whole body rather than a particular area
How does ADT work?
There are two methods of ADT:
- Surgical removal of the testicles (orchiectomy) to prevent testosterone production (rarely used).
- Medication. The main categories include:
- Luteinizing hormone-releasing hormone (LHRH) agonists and LHRH antagonists, both of which interfere with androgen production but with somewhat different mechanisms. They are given as injections.
- Anti-androgens, which block the effects of male hormones on prostate cancer and prostate-related cells. These are oral pills.
- Estrogens or female hormones. When the brain detects an abnormally high level of female hormones (usually administered as pills), it stops producing its own hormones, both male (androgens) and female (estrogens). (Estrogens are rarely used nowadays for prostate cancer due to potentially serious side effects such as strokes, blood clots, high blood pressure and fluid retention).
Other very promising new agents include Abiraterone
(a drug which counter-acts the enzyme responsible for androgen production, thus stopping androgen production); and Enzalutamide
(a very potent anti-androgen)
What can I expect?
ADT is used in various ways
to treat prostate cancer.
- Combination ADT: Anti-androgens are combined with either a LHRH agonist or surgical removal of the testicles.
- Intermittent ADT: ADT is stopped once the PSA number is lowered and stabilized. ADT is restarted when the PSA number increases again (sometimes months, maybe years later).
ADT is used in different circumstances
to treat prostate cancer:
1. “Primary treatment”:
ADT is used as the single first-line treatment.
2. Neo-adjuvant ADT:
ADT is given before local treatment (either surgical prostate removal or radiotherapy). ADT reduces the size of the tumour to make the main treatment potentially more effective.
3. Adjuvant ADT:
Used directly after surgery or radiation “just to be safe”, in case there is a chance that cancerous cells may have remained somewhere in the body.
What are the possible side-effects and risks?
As with all treatments, ADT carries possible side-effects and risks. The following is a comprehensive list of what these might be. Don’t be alarmed: talk to your doctor and health care team to find out how your treatment might affect you and what you can do to manage any side-effects.
- Possible side-effects include:
- Hot flashes
- Decreased libido and erectile dysfunction (ED)
- Loss of energy, general weakness
- Breast enlargement and tenderness
- Emotional disturbance including depression
- Itching, dry skin, rash
- Gastrointestinal issues: diarrhea, nausea, vomiting
- Loss of muscle mass
- Weight gain (mainly due to increased body fat)
- Shrinkage of testicles
- ‘Metabolic syndrome’ (increased risk of diabetes, heart disease, and cholesterol)
Webinar: Hormone Therapy for Prostate Cancer – Cardiovascular, Metabolic, and Psychological Side Effects and How to Manage Them by Dr. Shabbir Alibhai, Toronto General Hospital
- Long-term use (over a year) may lead to:
- Lower blood counts or anemia