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Hot flushes and sweats in women

Lower sex hormones because of cancer or cancer treatment can cause hot flushes and sweats. Find out about the symptoms and ways to control them.

Hot flushes are one of the most common symptoms women have when they go through the menopause. About 3 out of 4 women going through the menopause (75%) will have hot flushes.

But hot flushes can also happen because of treatment for cancer.

Women having a natural menopause usually find hot flushes become less frequent and less severe during the 5 years after their last period.

Breast cancer treatment

We know from research that around 7 out of 10 women (70%) who’ve had breast cancer treatment have hot flushes. They are likely to happen more often and be more severe than in women having a natural menopause.

They happen because breast cancer treatments can lower sex hormone production.

Research suggests that if you had hot flushes during your menopause you are more likely to have hot flushes as a side effect when you take tamoxifen as a breast cancer treatment.

Tamoxifen is a type of hormone therapy. The number of hot flushes you have and their severity is about the same with tamoxifen when compared with women going through a natural menopause.

If you are close to the age that you would naturally start the menopause when you have chemotherapy, you are more likely to go into the menopause and have more severe symptoms.

How hot flushes may feel

It can start as a feeling of warmth in your neck or face. This often spreads to other parts of your body. You might have:

  • reddening of the skin
  • light or heavier sweating
  • feelings of your heart beating in your chest (palpitations) 
  • feelings of panic or irritability 

Hot flushes can last between 2 to 30 minutes. You may have a few a month or more often. The flushes usually last for a few months but for some people they carry on for longer. 

They can be very disruptive. They might make sleeping difficult, impacting on your quality of life. 

Causes of hot flushes

Low oestrogen levels can lower levels of another hormone called noepinephrine. It helps your body to regulate it's own temperature. A low level of norepinephrine can lead to a rise in your body core temperature. The rise in temperature can cause a hot flush. 

Researchers are looking into more complex causes of hot flushes. One example is that the part of the brain called the hypothalamus controls the production of many hormones. This part of the brain also controls our body temperature. It may be that the chemical messengers (neurotransmitters) the hypothalamus produces cause the hot flushes.

We need more research to find exactly what causes flushes so that we can develop treatments that work better at controlling them.

Hot flushes usually start to improve over time. 

Tips to help with hot flushes

Environment

  • Keep your room cool – use a fan if necessary
  • Wear layers of light clothing so you can easily take clothes off if you overheat
  • Have layers of bedclothes to remove as you need to
  • Wear natural fibres such as silk or cotton instead of synthetic (artificial) fabrics
  • Have a lukewarm shower or bath instead of a hot one
  • Put a towel on your bed if you sweat a lot at night
  • Cooling pads can help to keep you cool
  • Try to stay calm under pressure as heightened emotions can cause a hot flush to start

Diet

  • Cut out coffee, tea and nicotine
  • Drink alcohol only in moderation
  • Sip cold or iced drinks

If you are taking tamoxifen

Try taking half your dose in the morning and half in the evening. Always talk to your doctor before changing the dose of any prescription medicine.

If you are finding it difficult to manage your hot flushes, do talk to your doctor or specialist nurse. There are medicines that may help.

About treatment for hot flushes

Hormone replacement therapy (HRT)

The only way to completely stop hormonal symptoms is to take hormones to replace the ones your body is no longer producing. But if you are having cancer treatment that stops you producing hormones, you can’t have hormone replacement therapy (HRT).

Doctors recommend that you don’t take HRT if you have had a hormone dependent cancer such as breast cancer. Even if you have finished treatment there is concern that HRT may
increase the risk of the cancer coming back.

Medicine versus the placebo effect

There are a number of different medicines that your doctor might prescribe to help reduce and control hot flushes. But before taking any of these, there is something important to bear in mind.

When researchers want to find out how well a treatment works in a trial, they sometimes test it against a dummy treatment, or placebo. The people taking part in the trial don’t know whether they are taking the new treatment or the placebo. Many of us feel better when taking something that we think will help.

In nearly all trials looking at treatment for hot flushes, people taking the placebo said that their flushes were reduced by about a fifth (20%). It is important to bear this in mind when we are looking at other treatments. If a treatment reduces hot flushes by 20% or less, it may not be better than a placebo. 

Treatments your doctor may suggest

Vitamin E

A trial of 120 women who had had breast cancer compared vitamin E with a placebo. They found that vitamin E reduced the number of flushes by one a day. When asked the women said they did not prefer the vitamin E over the placebo. Vitamin E did not cause many side effects, so the researchers suggest it is worth trying as a first treatment.

We need more research to find out how well vitamin E really works and more about side effects.

Anti depressants

Some anti depressant medicines such as venlafaxine can help to reduce the number and severity of hot flushes.

In women who have had breast cancer, anti depressants can reduce hot flushes by just over half. But doctors don’t recommend some types of anti depressant, such as paroxetine or fluoxetine, for women taking tamoxifen. They may interfere with how well tamoxifen works.

Remember that all drugs have some side effects. Anti depressants can cause a dry mouth, headaches, feeling sick, and loss of appetite.

Gabapentin

Gabapentin is a type of anti epileptic drug. It controls fits (seizures) but it can also help to reduce hot flushes.

In trials for women with breast cancer, it reduced their hot flushes by about half (50%). It also helped with reducing the severity of hot flushes and how long they lasted. Pregabalin is very similar to gabapentin which might also reduce hot flushes.

Side effects of gabapentin include dizziness and drowsiness. Some women also develop a rash and fluid retention. We need more research to confirm how well these drugs work and find out more about side effects.

Clonidine

Clonidine is a drug used for a variety of conditions, including high blood pressure.

It can reduce the number of hot flushes women have but it doesn’t reduce their severity or how long they last.You can have clonidine as a tablet or wear a patch on your skin.

Side effects include dizziness, a dry mouth, constipation, drowsiness, and difficulty sleeping.

Progestagens

Progestagens such as megestrol acetate (Megace) are hormones.

Doctors only consider prescribing progestagens to women who have had a hormone dependent cancer if they have severe hot flushes and no other treatment is working.

There is no long term research to show whether they are safe to take for people who have had hormone sensitive breast cancer.

Progestagens can reduce hot flushes by more than 80%.  

Side effects can include:

  • skin rashes
  • fluid retention
  • dizziness
  • a dry mouth
  • an increased risk of blood clots
  • headaches
  • vaginal discharge
  • vaginal bleeding (withdrawal bleeding)

Folic acid

Researchers are looking into folic acid as a possible treatment for post menopausal symptoms.

The FOAM trial is looking at this for women who have had breast cancer or womb cancer, or who have not had cancer. The researchers want to find out if folic acid helps to control hot flushes. They will also collect blood and urine samples to see what happens to folic acid in the body.

Cognitive behavioural therapy (CBT)

The word cognitive describes the mental process that you use to remember, reason, understand, solve problems and make judgements. The word behaviour describes your actions or reactions to something.

CBT aims to help you change how you respond to certain situations or emotions. It helps you understand how your thought patterns may be contributing to your feelings of depression or fear.

This therapy also teaches you how to calm your body and mind. It helps you to control your feelings, think more clearly and generally have a more positive outlook. 

CBT research

Researchers have tried CBT to see if it can help women who have hot flushes and sweats.

One Cancer Research UK funded study (MENOS1 study) found that group CBT can reduce the effect of hot flushes and night sweats for women who have had breast cancer treatment. The reductions in sweats and flushes continued after the treatment ended. It helped women to feel better, sleep better, and have a better quality of life.

You can ask your doctor or breast care nurse whether CBT is available in your area.

Complementary therapies for hot flushes

Researchers have looked at a number of complementary therapies as treatments for hot flushes in menopausal women. There is some information about using them after breast cancer.

Acupuncture

Acupuncture  has been researched as a treatment for hot flushes in women. A small study compared acupuncture with the anti depressant venlafaxine. The treatments worked equally well at reducing hot flushes in women with breast cancer. This was only a small study and we need further research to confirm how well both treatments work.

Soy

Soy has been tried for hot flushes because women in Asia have fewer hot flushes than women in western countries. People in Asia tend to eat more soy than people in the West.

There are mixed results from research, with some trials showing that it reduced hot flushes and others showing no difference.

There is also some concern about the safety of soy for women with hormone dependent cancers because soy contains plant oestrogens. At the moment there is not enough evidence to suggest that women who have had breast cancer should take it.

Black cohosh

Black cohosh is a native plant of North America. In Germany it is used to treat menopausal symptoms. It is thought to have oestrogen like effects on the body.

Evidence from research is mixed. Some trials found that it helped to reduce hot flushes in women and others did not. But an overview of all the trial results found that it did not reduce hot flushes in women.

Red clover

Red clover is a plant that contains plant oestrogens. Some trials have found that it reduces hot flushes but others have not. There is also some concern that it could increase the risk of cancer coming back in people with hormone dependent cancers because it contains oestrogens.

Other complementary therapies

Ginseng, Angelica sinensis (Dong quai) and Evening primrose oil have been looked at as treatments for hot flushes. There is currently no evidence to show that they work. 

Information and help

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