Male hormones are the fuel for prostate cancer. In turn, a tumor can’t grow without these hormones. Hormone Therapy is used to slowly starve the tumor. Also known as androgen-deprivation therapy or ADT, hormone therapy is designed to stop testosterone from being released or to prevent it from acting on prostate cells.
Hormone therapy is an important treatment for men with advanced prostate cancer as it is increasing in use before, during and/or after other treatments.
Good candidates for hormone therapy are men who have had prostate cancer already move outside of the prostate, men who plan on surgery and want to shrink the tumor to enhance the effectiveness of surgery and for men who have already had primary treatment (surgery and/or radiation) and the prostate cancer has returned.
In many cases, prostate cancer tumors respond to the removal of testosterone. However, some cancer cells grow independently of testosterone and remain unaffected by this treatment. These hormone-independent cells continue to progress and hormone therapy will have less and less of an impact on the tumor over time.
For this reason, hormone therapy cannot stop cancer. However, it is an important treatment in managing advanced disease and is part of the treatment regimen in most cases during recurrent or advanced prostate cancer.
Hormone therapy is usually used during a time of rising PSA. But be sure to form a team of doctors and get opinions on when it might be best for your individual case. Watch our expert medical oncologist, Alicia Morgans, discuss hormone therapy.
Types of Hormone Therapy
The table at the right provides an overview of three commonly used types of hormone therapy. These and others are discussed below. While hormone therapy is commonly used, side effects of the treatment are reported as well. They range from erectile dysfunction, hot flashes, weight gain and loss of bone density.
An orchiectomy is the removal of the testicles (which makes more than 90 percent of the testosterone in the body). Men who prefer a one-time, low-cost procedure may go with this option. However, the procedure is permanent and irreversible. That’s why most men opt for drug therapy instead.
Luteinizing-hormone releasing hormone is a key hormone released into the body prior to producing testosterone. Blocking the release of LHRH with the use of LHRH therapies is the most common hormone therapy used on prostate cancer patients. Drugs in this class include Lupron, Viadur, Zoladex, Trelstar and Eligard. They are administered as regular shots ranging from once per month to once per year. LHRH agonists cause what is known as a “flare” reaction of a rise in testosterone over the first several weeks following a shot before the drug starts to take action.
Antagonist medications are a newer class of drugs that can block LHRH from stimulating testosterone production without causing a surge of testosterone (which can cause a temporary additional rise in PSA). This class includes Firmagon and it’s given as a monthly shot.
The “flare” or rise in testosterone associated with LHRH drugs can be prevented with anti-androgens such as Casodex, Eulexin and Nilandron. They can help block the action of testosterone in prostate cancer cells and are used in conjunction with LHRH agonists.
These drugs come with positives and negatives. Anti-androgens can cause less sexual side effects as agonists but are not as effective as an orchiestomy or LHRH agonists in treating the disease, leaving it a poor choice for many men with metastatic prostate cancer.
These initial hormone therapies are effect for only a few years. Inevitably, cells become castrate resistant and grow strong enough that hormone therapies have a lessening effect on the cancer. However, a number of “secondary” or inhibitor and blocker hormone therapies can be used to slow the spread of disease.
Inhibitors and Blockers
New hormonal medications that inhibit the synthesis of androgen, Zytiga, and block androgen receptor signaling, Xtandi, are now FDA-approved with the help of ZERO – The End of Prostate Cancer supported federal funding for research. Each of these drugs is for men with metastatic disease.
Both Zytiga and Xtandi are oral medications, meaning they are pills that you take by mouth. It is important to take the medication as prescribed by the doctor to receive the maximum benefit of the anti-cancer treatment.
About 10 percent of the body’s testosterone is created by the adrenal glands and so few therapies focus on shutting down this production until it becomes absolutely necessary to rid the body of all testosterone.
Zytiga is used with steroids to shut down the adrenal glands while avoiding the effects of the adrenal glands being shut down and prolongs life in men with metastatic prostate cancer.
Xtandi blocks androgen receptors to slow the production of testosterone without the use of a steroid. You can also watch expert medical oncologist, Alicia Morgans, discuss Xtandi and Zytiga in the video below:
There are other treatments in the research pipeline for castrate resistant prostate cancer patients.
Side effects of Hormone Therapies include:
- Breast pain or enlargement
- Cardiovascular events
- Cholesterol level changes
- Erectile dysfunction/lower libido
- Diarrhea and/or constipation
- Increase in belly fat
- Increased risk of osteoporosis
- Concentration, learning, and memory problems
In addition, hormone therapy is correlated with a higher risk for developing Alzheimer’s.