Hormonal therapy works by reducing the body’s natural production of testosterone. Testosterone is the male hormone that actively “feeds” prostate cancer. Hormonal therapy is used before certain types of radiotherapy to shrink the prostate gland. Research has shown that if used in this way the chance of cure is greater.
For T2 or localised prostate cancer it is usually used for 3-months before radiotherapy starts and stops after treatment. For T3 ( locally advanced) disease, treatment with hormonal therapy may need to continue for 2-3 years afterwards.
Hormonal therapy is also used for men who have advanced or widespread (metastatic) disease which has affected other areas of their body and hormonal therapy can often cause a remission of symptoms and slow down the disease process. In this way any symptoms caused by cancer in other areas of the body such as pain will usually improve. In this situation hormonal therapy is the first treatment of choice and men may experience remission of cancer for a number of years. Unfortunately the prostate cancer may gradually become resistant to this type of treatment and further treatment will be needed. For more information on advanced prostate cancer please see here.
Men who are receiving hormonal therapy alone will be reviewed every 3-6 months in clinic with a repeat PSA blood test. If the PSA level rises to around 20 a level which may indicate that the cancer is becoming resistant to hormonal therapy, then further treatment may be initiated.
There are several types of hormonal therapy available in the form of injections such as Gosrelin ((Zoladex®), Leuporelin (Prostap®) and Triptorelin (Decapeptyl®,Gonapeptyl Depot®).
They are called LHRH agonists and can be administered on a monthly or 3-monthly basis, usually by a man’s GP. They are injected into the skin of the lower abdomen although some like Prostap can be administered into the arm or leg.
Before hormone injections begin men will be given a course of tablets called anti androgens such as Flutamide, Cyproterone Acetate or Biclutamide. These tablets start to block testosterone stimulation within the prostate. They are given to prevent a sudden surge in testosterone (flare) which may be caused by giving a hormone injection on its own straight away. A sudden surge in testosterone can cause a worsening of prostate cancer symptoms.It is usual to have 2-weeks of anti-androgens before the first injection and for 2-weeks afterwards.
Hormonal therapy will cause a drop in testosterone (as 90% of testosterone is made in the testicles where testosterone is produced) and this may be reflected by a reduction in the PSA level of up to 90% or more. For instance a PSA level of 50 may fall to a level less than 2.5 usually within 3-months of treatment being started. When testosterone production is reduced by this amount cancerous activity within the prostate will slow down as the “cancer is starved”.
Hormonal therapy is the standard treatment for metastatic prostate cancer. However research is under way to see if there is any benefit in adding other treatments in combination with hormonal therapy at an early stage of treatment to see if the effects last longer. There is currently a clinical trial called STAMPEDE which is investigating this.
Sometimes if advanced prostate cancer has spread to the bones especially the spine a different type of hormonal injection may be recommended. This is called a LHRH antagonist. There is currently only one LHRH antagonist in use within the UK called Degarelix. Degaralix is able to reduce testosterone levels within a few days without the need for anti-androgens and is extremely useful for treating cancer in the bones which if pressing on the spine may cause a condition called Spinal cord compression. In this situation the pressure of the cancer on the spine can cause paralysis leading to loss of mobility. These problems may be irreversible if not caught in time. Further information on spinal cord compression can be found here.
How does Hormonal therapy work?
The hypothalamus situated in the brain is stimulated to produce pulses of Leutenising Hormone Releasing Hormone (LHRH) A. This in turn stimulates the pituitary gland to produce Follicle Stimulating Hormone (FSH) and Leutinising Hormone (LH). Leutenising Hormone travels through the bloodstream to the testicles, B where it joins with cells which secrete testosterone. An enzyme in the prostate then convert’s testosterone into a substance called dihydrotestosterone (DHT) which stimulates the growth of prostate cancer cells C.
An LHRH agonist mimics the shape of normal LHRH in the receptors on the pituitary gland. Not receiving the message from the hypothalamus, the pituitary gland does not release LH. The testicles never produce testosterone and the body’s levels drop.
Hormonal therapy is a very effective treatment but men who receive treatment with it may experience certain side effects which occur when testosterone levels are reduced. Common symptoms tend to be tiredness, weight gain, possible breast tenderness and hot flushes. Longer term use can cause conditions of the bones such as osteoporosis and it sometimes a good idea to take a supplement of calcium and vitamin D when hormone therapy is used. There is also evidence that long term use of hormone therapy can cause an increase in the risk of cardiac problems and rarely diseases such as diabetes.
Intermittent Hormonal therapy
For some men who respond well to hormone therapy there is an option of considering intermittent treatment. Hormone therapy can sometimes be stopped when cancerous activity is low and restarted when it increases. In this way men may be able to obtain some relief from bothersome side effects.
Another way of reducing testosterone levels to a minimal level is to perform an operation to remove the testicles (bilateral orchidectomy). This is only suitable for men who must stay on long term hormonal therapy. It has the same effect as LHRH agonists but is not reversible.
I am getting hot flushes from the hormone therapy. These can be quite severe. Is there any treatment that may help?
Unfortunately hot flushes are the most common side effect of hormonal therapy and can be very bothersome. There are some lifestyle changes that men can make which may help reduce them:
- Avoid too many hot spices from foods etc
- Avoid smoking, caffeine (tea, coffee, chocolate bars, fizzy drinks) and excessive alcohol.
- Try and wear cotton/ natural fabric clothing and bed sheets rather than using man made fabrics
- Take luke warm baths or showers
- Use a fan to help cool a room and try and obtain a mini portable fan for personal use or an atomizer that can be used to spray water when out and about.
The herb sage has traditionally been used to treat hot flushes in women undergoing the menopause as well as supplements such as Black Cohosh and Red Clover. However the National Institute for Health and Care Excellence (NICE) has recently suggested that these are of no value in relieving symptoms.
Deep breathing exercises may be of some help and possibly some forms of acupuncture. Up to date information on alternative health treatments from the NHS choices website can be found here.
NICE has recommended medication known as medroxyprogesterone and the anti-androgen Cyproterone Acetate to help treat persistent and bothersome hot flushes in men on hormonal therapy. Men can ask their GP or health care team about this treatment.
Breast swelling (gynaecomastia)
The use of the drug tamoxifen may help breast swelling and tenderness or it may be possible to have a limited dose of radiotherapy to the breast area. Men can ask their GP or health care team about this treatment.
Loss of libido
There are several options for men who have lost their sex drive, please see here
Last reviewed 04/06/2018. Next review 04/12/2018.
References available on request.