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Side effects of hormone therapy for prostate cancer

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This page tells you about the side effects of hormone therapy for prostate cancer. There is information about


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Side effects of hormone therapy for prostate cancer

Hormone therapy for prostate cancer can have side effects. The effects will vary depending on the type of hormone therapy but can include

Problems getting an erection (impotence)

About half the men taking hormone therapy tablets find that they can’t get an erection. All the men having injections (for example, goserelin or Zoladex) will have erection difficulties. This is because these drugs stop you producing any testosterone.

Hot flushes and sweating

Some men have hot flushes and sweats. They may gradually get better. But some men have them throughout their hormone therapy. Your doctor may be able to give you other tablets to help control them.

Feeling tired and weak (fatigue)

You may feel very tired while having hormone therapy treatment. Regular, gentle exercise can help to reduce this.

Breast tenderness

Your breasts may swell and feel sore or tender. Tamoxifen tablets can help or a dose of radiotherapy to the breasts before starting treatment.

Pain caused by tumour flare

Pain caused by the prostate cancer can worsen when you start some hormone treatments and this is called tumour flare. Your doctor will prescribe another hormone therapy to help prevent tumour flare causing bone pain. If the pain carries on, your doctor can prescribe drugs called bisphosphonates.

Possible long term side effects

Long term hormone treatment may make you put on weight. And you may feel you have more trouble remembering things or become more emotional. Long term treatment puts men at a slightly higher risk of problems such as bone fractures. And there is some evidence that if you are over 65, your risk of a heart attack may be increased.


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What causes side effects

Hormone therapies for prostate cancer cause side effects because they reduce the levels of male hormones in the body. Some side effects are common to all hormone therapies used for prostate cancer. Some effects vary from drug to drug.


Erection problems (impotence)

Difficulty getting an erection (impotence) is a common side effect of hormone therapy for prostate cancer. You will not be able to get an erection if you are taking luteinising hormone (LH) blockers, such as goserelin (Zoladex), leuprorelin (Prostap) or buserelin (Suprefact). This is because the drugs stop you producing any testosterone. It may be possible for you to have erections again once the treatment stops. This can take 3 months to a year, or even longer. For some men, erection problems are permanent. It depends on the drug you are having and how long you have been taking it.

About half the men treated with anti androgens alone, such as bicalutamide (Casodex), keep their sex drive and can get erections. This is also true for high dose treatment with Casodex. But you may still become impotent with long term treatment. About 1 in 5 men (20%) keep their ability to get an erection, even with long term treatment. Early treatment with medicines can help maintain the ability to have erections. There is information about these medicines and other ways of coping with erection problems in the sex and cancer for men section. And there is information about how prostate cancer can affect your sex life in this section.

If erection difficulties are a problem for you, ask your doctor or specialist nurse to refer you to a specialist erection dysfunction service.


Hot flushes and sweating

Hot flushes and sweating can be troublesome. They are the same as the hot flushes that women friends and relatives may have had when going through menopause. The flushes are caused by your testosterone levels dropping. They may gradually get better as you get used to the treatment. Hot flushes are most likely with LHRH blockers because these drugs cut off testosterone production altogether. Unfortunately, in some men the flushes keep on happening as long as you take the drug.

Some men find that their flushes are relieved by a short course of hormones called progestogens, and you may want to discuss this with your doctor. Recently, there has been some evidence that a drug called venlafaxine (which is usually used to treat depression) may help with hot flushes. 

Researchers in France recently compared venlafaxine, cyproterone and medroxyprogesterone as treatments for hot flushes. They found that they all improved the hot flushes but that cyproterone and medroxyprogesterone reduced the number of hot flushes more than the venlafaxine. However, they only followed the men for 12 weeks so we don't know of any long term effects. Cyproterone and medroxyprogesterone are hormone treatments and using them for hot flushes may affect how your cancer is treated. The National Institute for Health and Care Excellence (NICE) recommends medroxyprogesterone as the best treatment for hot flushes. 

Getting overheated, drinking tea or coffee, and having nicotine can all make flushes worse. We have more information about coping with hot flushes and sweats in our hormone symptoms section.


Feeling tired and weak

Hormone therapy for prostate cancer commonly causes tiredness and weakness (fatigue). You can help to reduce fatigue using the following tips.

  • Do some gentle exercise each day – this can give you more energy
  • Get support from other people – knowing others are there to help can be a real energy booster
  • Don’t push yourself too hard and stop and rest when you begin to feel tired
  • Eat a well balanced diet to try to keep your energy levels up
  • Learn to manage fatigue – get help with shopping and housework and don’t try to do it all yourself

The National Institute for Health and Care Excellence (NICE) recommends that doctors offer their patients supervised exercise at least twice a week for 12 weeks. The exercise can reduce the tiredness and weakness and can improve your quality of life.


Breast tenderness

Breast tenderness is a particular problem with high dose bicalutamide (Casodex). The breasts can become painful and swollen. Taking the drug tamoxifen can help to reduce breast tenderness in about 6 out of 10 men taking Casodex. Or sometimes it can help to have a small dose of radiotherapy to the breasts before your hormone treatment starts.

There is information about breast changes in men in our hormone symptoms section.


Tumour flare pain

Pain caused by the prostate cancer can worsen when you start hormone treatment and this is called tumour flare. Your doctor should always prescribe another hormone therapy when you start leuprorelin or Zoladex injections to help prevent tumour flare causing bone pain. If the pain carries on, your doctor can prescribe drugs called bisphosphonates to treat it.


Side effects from long term treatment

The side effects listed above can all occur as soon as you begin treatment. There are other side effects that will only happen if you take hormone treatment for a long time. These are

Weight gain

You may put on weight. You may be able to control this with diet and exercise but it is often a struggle to keep weight down when you are having hormone treatment. There is information about weight and muscle changes in our hormone symptoms section.

Memory problems

Some men feel that their memory gets worse when they have been having hormone treatment for a while. This won't improve while you are taking the hormone treatment. But there are ways to make life easier, such as making lists so you don't forget things. It is natural to feel cheated and upset if you have this particular side effect. Talk to your doctor or specialist nurse if you feel that memory changes are having a significant effect on your life. There is information about memory changes and hormones in our hormone symptoms section.

Mood swings and depression

Hormone therapy can affect your mood. Some men say they have mood swings and even depression while having treatment such as Zoladex. 

A patient with prostate cancer told us:

"I would go into real 'black dog' moods that could last for days. I would burst into tears at the slightest thing, or even for no reason at all. And I was moody and argumentative."

He found the greatest help was talking to his wife. 

"You need to share your darkest thoughts with someone you totally trust, who can pull you through these very difficult times. She forced me to think positively, to see light at the end of the tunnel." 

If you don't feel comfortable sharing your feelings with people you know, seeing a counsellor may help. There is information about counselling in our coping with cancer section.

You can also find information about mood changes and hormones in our hormone symptoms section

Bone thinning (osteoporosis)

Men taking hormone therapy for prostate cancer are at risk of bone thinning (osteoporosis). The risk of problems, such as bone fractures, is slightly higher for men having long term treatment to block testosterone (for example, Zoladex). Your specialist may ask you to have tests such as a DEXA scan to measure your bone mineral density. The scan can show if your bones have become weaker and may be at increased risk of fracture. 

If your bones are weakening due to hormone therapy, your doctor may offer you bisphosphonate treatment or a drug called denosumab. These treatments can reduce bone thinning for some men.

We have detailed information about osteoporosis risk and treatment. Your doctor may suggest taking vitamin D and calcium to help lower your risk of problems from osteoporosis. Other advice is to stop smoking, reduce the amount of alcohol you drink, and take regular weight bearing exercise, such as walking.

There is also information about bone loss in our hormone symptoms section.

Risk of earlier heart attack

There is some evidence that if you are over 65 and having hormone treatment for 6 months or longer your risk of heart problems may be higher than a man not having treatment. This includes having a heart attack. You may have regular checks for this.

If you have heart problems, your heart specialist may need to check your heart medicines before you start hormone therapy. And you may need to have check ups more often while you are having treatment.

There is information about heart problems and hormone levels in the hormone symptoms section.


More information about hormone therapy side effects

We have a section on this website about symptoms caused by hormone therapies. It has detailed information about ways of managing the side effects. You can also phone the Cancer Research UK nurses on freephone 0808 800 4040, from 9am to 5pm, Monday to Friday. They will be happy to answer any questions.

Our prostate cancer organisations page gives details of other people who can give information about prostate cancer treatments. Some organisations can put you in touch with a cancer support group.

Our prostate cancer reading list has information about books, leaflets and other resources discussing treatments.

If you want to find people to share experiences with online, you could use Cancer Chat, our online forum.

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Updated: 25 February 2014