Hormonal therapy treatment metastatic prostate cancer
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.
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.
Bilateral orchiectomy, or surgical castration, is a surgery to remove both testicles. It is a treatment option for metastatic prostate cancer and aims to stop the production of androgens. The surgery can be done under local anaesthesia.
If you have a history of cardiovascular disease, your doctor may advise you to see a cardiologist before starting with hormonal therapy.
How is bilateral orchiectomy performed?
During surgery, you will lie on your back. You generally receive local or spinal anaesthesia. In some cases your doctor may recommend general anaesthesia. The surgeon makes an incision in the scrotum to remove both testicles. Because the tissue that surrounds the testicles is not removed, the scrotum will not look totally empty.
How do I prepare for the procedure?
Your doctor will advise you in detail about how to prepare for the procedure. If you need general anaesthesia, you must not eat, drink, or smoke at least for 6 hours before surgery. If you are taking any prescribed medication, discuss it with your doctor. You may need to stop taking it several days before surgery. Your doctor will advise you on when you can start taking it again.
What are the side effects of the procedure?
Complications after a bilateral orchiectomy are rare and include pain around the scrotum, bleeding, infection, or delayed healing of the wound. In most cases, the way the scrotum looks will not be affected by the surgery.
Recommendations for 2-3 weeks after the surgery:
- Avoid heavy exercise
- Avoid hot baths
- Avoid the sauna
You have to see your doctor or go back to the hospital if you experience one of the following symptoms:
- Severe pain
- The wound starts to bleed or leak a transparent fluid
Bilateral orchiectomy results in permanent castration. This has physical and emotional consequences. Do not hesitate to discuss any concerns with your doctor. Together you can decide if other treatment options are more suitable for you.
If you prefer not to undergo surgical hormonal therapy, there are drugs which can stop the production of androgens. The most common drugs are LHRH agonists and LHRH antagonists. The aim of these drugs is to stop the growth of the tumour by chemical castration. How they do this varies for each group of drugs. Each drug is different in how it is applied.
If you have a history of cardiovascular disease, your doctor will advise you to see a cardiologist before starting with hormonal therapy.
The production of testosterone is regulated by the brain. The brain produces several hormones which help regulate other hormones. These are called releasing hormones. The specific releasing hormones of androgens are called luteinizing-hormone releasing hormones (LHRH). In prostate cancer treatment, drugs that affect LHRH are used to stop the production of androgens.
LHRH agonists stop testosterone production in the testicles. They are the most commonly used drugs to treat metastatic prostate cancer. The drug is administered as a depot injection right under the skin or in the muscle. These injections can last for 1, 3, 6 or 12 months. Discuss with your doctor which option is best for you.
In the first days after the first injection, LHRH agonists increase your testosterone level, before they decrease it. This is known as a flare. The increase in testosterone level can cause the tumour to swell. In rare cases this could be dangerous and can cause difficulties urinating. Your doctor might give you a low dose of anti-androgen drugs to prevent damage from rising testosterone levels.
LHRH antagonists are a new form of hormonal therapy. They do not need to be combined with an anti-androgen for the first weeks because they do not cause a flare. Degarelix is the most commonly used LHRH antagonist. It needs to be administered every month by an injection under the skin.
Anti-androgens block the action of testosterone. As a result, the tumour and metastases will grow slower or stop growing completely. The most commonly used anti-androgens are cyproterone acetate, flutamide, and bicalutamide. They all come as a pill, and are taken every day.
Cyproterone acetate is usually administered in two or three daily dosages. Flutamide is administered three times daily. Bicalutamide is the most common anti-androgen, and it is taken once a day.
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
- Increased risk of heart disease
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. Read more about how to deal with the side effects of hormonal therapy in the section Support for Hormonal Therapy.
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.