Hormonal therapy is a treatment option for metastatic prostate cancer. It aims to slow down the growth of the tumours.
The growth of prostate cancer cells is dependent on male sex hormones called androgens. Testosterone is the most important androgen. Androgens are mainly produced in the testicles.
Hormonal therapy either stops the production of androgens, or blocks their action. This is known as castration. Another name for hormonal therapy is androgen deprivation therapy (ADT). It can be performed surgically or with drug treatment.
In surgical hormonal therapy both testicles are removed in a procedure called bilateral orchiectomy. This procedure can be performed under local anaesthesia. Hormonal drug therapy to stop the production of androgens includes LHRH agonists and LHRH antagonists. These drugs are available as pills or as depot injections right under the skin or into the muscle. Anti-androgens are drugs that block the action of androgens. They come as a pill.
The effect of hormonal therapy will not last and leads to castration-resistant prostate cancer. You can read more about this stage of the disease in the section Castration-Resistant Prostate Cancer.
To delay castration resistance, your doctor may recommend to pause the hormonal drug therapy. This is called intermittent hormonal therapy. During the treatment pause, you will have to visit your doctor every 1-3 months. The doctor will monitor the level of prostate-specific antigen (PSA) in your blood.
What are the side effects of hormonal therapy?
Hormonal therapy stops the production or blocks the action of male hormones, and causes castration. Your body can react to castration in different ways. The most common side effects of castration are:
- Hot flushes
- Lower sex drive
- Erectile dysfunction
- Osteoporosis
- Increased risk of heart disease
- Diabetes
You could also experience pain, for example in your joints, your back, your bones, or muscles.
Changing hormone levels can affect your blood and cause high blood pressure, dizziness, and bruising. You may also be at higher risk of infection, especially in the nose or throat, or urinary tract infections.
Loss of appetite and weight loss can also be a result of castration. These may be related to diarrhoea, constipation, or vomiting caused by the hormone changes.
Other side effects may include coughing, shortness of breath, headaches, and peripheral oedema.
The different treatments may cause side effects as well.
- LHRH antagonists may cause an allergic reaction.
- Anti-androgens may cause swelling of your breasts. This is called gynaecomastia and can be painful in some cases.
- To prevent gynaecomastia your doctor may recommend radiation therapy of your chest before the start of the hormonal therapy. In rare cases, you may need surgery to remove the mammary glands.
- Anti-androgens could worsen hot flushes. These can be treated with low-dose oestrogens.
- Oestrogens can increase the risk of heart disease.
- Flutamide can cause diarrhoea.
How bothersome the side effects of hormonal therapy are, and when they appear, varies from person to person. This is related to your general health and the type of treatment you get.
It is generally recommended to visit your doctor every 3 months after you start hormonal therapy, to monitor the disease. Each visit includes a physical examination and a PSA test. These tests are used to see how you are responding to the treatment. During these visits you can discuss with your doctor if there is a treatment option to manage side effects. Your doctor will adjust the follow-up visits according to your needs.
With time, prostate cancer cells will become resistant to hormonal therapy, and the cancer will start to grow again. This is known as castration-resistant prostate cancer. How long this takes to develop varies from person to person, but it generally happens 2-3 years after starting hormonal treatment. You can read more about this stage of the disease in the section Castration-Resistant Prostate Cancer.
