Hormonal therapies for breast cancer in men
Hormonal therapy works by lowering the level of oestrogen in the body, or by preventing oestrogen from attaching to the cancer cells.
Hormonal therapy only works for men who have oestrogen-receptor positive cancers. However, most men who have breast cancer (about 9 out of 10) have ER positive breast cancer, so hormonal therapy is one of the main treatments for breast cancer in men.
The most commonly used hormonal therapy is tamoxifen, but other types may sometimes be used. Hormonal therapy is usually given for a number of years to reduce the risk of breast cancer coming back. You’ll usually start it after surgery or after chemotherapy, if you’re having it.
Hormonal therapy can also be used to control breast cancer that has come back (recurrent cancer) or spread to another part of the body (secondary breast cancer). In this situation, the treatment is usually given for as long as it’s working to control the cancer. Men who have already had treatment with tamoxifen would be offered a different type of hormonal therapy.
Types of hormonal therapy
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Tamoxifen has been shown to be effective at treating breast cancer in men. It is an anti-oestrogen drug that works by preventing oestrogen in the body from attaching to breast cancer cells and encouraging them to grow. Tamoxifen is taken daily as a tablet, usually for five years.
Another type of hormonal therapy is a group of drugs called aromatase inhibitors (AIs). These drugs reduce oestrogen levels in men by stopping male hormones (androgens) from being made into oestrogen. Aromatase inhibitors include the drugs letrozole, anastrozole and exemestane.
Your specialist will advise you if one of these drugs is suitable for you. Although they may be used in men, they’re currently only licensed in the UK for women with breast cancer who have been through the menopause.
We know that aromatase inhibitors are effective in women with breast cancer, but it’s not yet known the best way to use these drugs in men. This is because not all of the oestrogen that men make comes from androgens (20% is made by the testicles). For this reason, doctors often prescribe another type of hormonal therapy called goserelin (Zoladex®) to be used alongside an aromatase inhibitor.
Normally the testicles are stimulated to make oestrogen and testosterone by messages sent from the pituitary gland in the brain. Goserelin blocks these messages so that the testicles stop making oestrogen and testosterone. Goserelin is given as a slow release implant that is injected just under the skin once every 1-3 months.
Fulvestrant is a newer type of anti-oestrogen that is given as an injection. It may occasionally be used to treat men who have already had other hormonal therapies for breast cancer.
Your cancer specialist will explain which drug (or drugs) are best for your situation and how long you should take them for.
Side effects of hormonal therapy
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Hormonal therapies are usually well-tolerated but side effects can vary from person to person. Some men have only a few mild side effects, while others experience more. Tell your doctor or specialist nurse if you have problems as there are often things that can be done to help to relieve or manage side effects.
Sometimes, if side effects are very troublesome, a man may have to stop taking a particular treatment and a different drug may be prescribed. Here we describe some of the more common possible side effects.
Often side effects gradually ease over the first 3-6 months of taking the treatment.
Lower sex drive and erection difficulties
If this happens it may continue for as long as the treatment does. Many men say this is one of the most difficult aspects of hormonal treatment to deal with. However, treatments are available that can help you achieve an erection. Although it can feel embarrassing, most health professionals are used to talking about this kind of side effect, so do mention it if you’re affected.
Hot flushes and sweats
In some men, these side effects decrease in frequency and intensity over time as their bodies adjust to treatment.
There are also some medicines that can be prescribed to relieve hot flushes.
If you get headaches as a side effect, they can usually be relieved with mild painkillers.
Sometimes hormonal therapies can cause you to feel sick. If your hormonal therapy is taken as a tablet you may find taking it with food can help.
You may feel irritable or low in mood (depressed) when taking hormonal therapies. There are treatments your doctor can prescribe to help with this.