Hormone Therapy for Prostate Cancer
Hormone therapy is an umbrella term for different methods of treating prostate cancer. A more technical term is androgen deprivation therapy or ADT. Androgens are male sex hormones, principally testosterone and dihydrotestosterone or DHT. The goal of androgen deprivation therapy is to reduce the level of male sex hormones in the body, or to limit their interactions with the prostate. This is because male sex hormones stimulate the growth and spread of cancerous cells and tumors.
To understand why, think of hormones as chemical passwords for launching the body’s organic programs. They are produced by the glands and travel through the bloodstream to the sites where they’re effective. Androgens govern the development of masculine characteristics, including reproductive organs like the prostate. And that’s the problem: androgens indiscriminately encourage the growth of cells in the prostate, both the healthy ones and the cancerous ones.
When Is Hormone Therapy Used for Prostate Cancer?
Hormone therapy is an effective method for treating prostate cancer but only under certain circumstances. Included are situations in which:
- Cancer has spread from the prostate to other parts of the body to the point that surgical or radiation treatments would no longer be effective.
- Cancer has rebounded after an earlier round of treatment.
- Hormone therapy used in combination with another treatment would make it more effective, based on a medical indicator such as a high prostate-specific antigen (PSA) score.
- Shrinkage of tumors by androgen deprivation sets the stage for radiation therapy.
It’s important to realize that, by itself, hormone therapy isn’t a cure for prostate cancer. Some cancer cells will continue to grow, even without the stimulation of testosterone and DHT. Beating prostate cancer often requires multiple therapies.
What Types of Hormone Therapy for Prostate Cancer Are There?
There are two broad approaches to hormone therapy for prostate cancer. The first approach focuses on reducing or eliminating the body’s production of androgens. The second blocks androgens’ ability to interact with the cells of the prostate.
Methods for Reducing Androgen Production
- LHRH Agonists: LHRH agonists are a category of drugs for suppressing the production of androgen. They are administered by a physician as injections or implants on a regular basis. Some common LHRH agonists are leuprolide, triptorelin, histrelin, and goserelin. These drugs are sometimes given in conjunction with anti-androgens to prevent a short-term condition called flaring, in which testosterone levels increase briefly before going into decline.
- LHRH Antagonists: Like the agonists above, LHRH antagonists are androgen suppressants and a form of chemical or medical castration. The best known LHRH antagonist is degarelix. Antagonists works like agonists, only more quickly and without the risk of flaring. Injected monthly by a physician, this method of treating prostate cancers is typically reserved for advanced cases of the disease.
- CYP17 Inhibitors: Most androgen reduction therapy focuses on the testicles. There are, however, other sites in the body that produce small amounts of androgen, including the prostate and the adrenal glands. CYP17 is an enzyme involved in male-hormone production. Abiraterone is an enzyme-blocking drug that short-circuits this process. It is taken daily in pill form, often in combination with an LHRH medication.
- Orchiectomy: Orchiectomy is surgical castration – the removal of a man’s testicles. It is a straightforward procedure handled on an outpatient basis. Orchiectomy has proven effective in slowing and sometimes reversing the growth of prostate cancer. It is, however, irreversible, and is associated with physical and psychological side effects in some patients.
Methods for Interfering with Androgen’s Effectiveness
- Anti-androgens: Anti-androgens work differently than male-hormone suppressants. Androgens bind with prostate cells in a particular fashion. Anti-androgens frustrate this process by replacing the androgens at the binding site – think of it as someone stealing a reserved seat at the theater. Leading anti-androgens are flutamide, nilutamide, and bicalutamide. They are taken daily in pill form, often together with androgen-suppressant medications.
- Estrogens: Estrogens are female hormones. Once common in the treatment of prostate cancer, they’ve been largely replaced by more recently developed androgen-suppressant therapies. Because they’re effective in some cases, physicians will still use estrogen if other treatments have failed.
- Ketoconazole: Ketoconazole is an anti-fungal medication that has also proven useful in reducing androgen levels.
What Are the Side Effects of Hormone Therapy for Prostate Cancer?
By reducing androgen levels, hormone therapy for prostate cancer can lead to a variety of potential side effects:
- Shrinkage of the male sex organs
- Diminished sex drive
- Muscle decline and fatigue
- Weight increases
- Spikes in cholesterol levels
- Loss of mental acuity
- Growth of breast tissue
- Hot flashes
Anti-androgens have fewer sexual side effects but can be associated with nausea, diarrhea, fatigue, dizziness, and liver problems.
What Should I Expect from Hormone Therapy for Prostate Cancer?
You’ll see your physician regularly while undergoing hormone therapy for prostate cancer. He or she will want to know about any side effects resulting from treatment. Many of these can be addressed medically. There will also be tests for evaluating the effectiveness of your care. Depending on the outcome of these tests, your physician may alter your treatment plan accordingly.
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