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Thinking, memory and sex hormones

This page is about how hormone changes may affect memory, thought processes and concentration. There is information about


Hormones and thought processes

Some cancer treatments lower the amount of sex hormones in the body. These hormones are oestrogen and progesterone in women and testosterone in men. Low levels of sex hormones can sometimes cause symptoms such as changes to memory, difficulty thinking, and problems with concentration.

Some people are able to have hormone replacement therapy (HRT) to control these symptoms. But some treatments for breast or prostate cancer aim to stop the body producing sex hormones or block their action. If you are taking these treatments, unfortunately you can’t take HRT to help control your symptoms.


Thinking, memory and cancer

Memory and how we process information is called cognition or cognitive ability. This includes our ability to concentrate and carry out more than one task at a time.

After treatment for cancer, some people notice changes in their memory and thought processes. You may have no problem with everyday tasks but still notice a change from before you had cancer. For example, some people say they have trouble remembering shopping lists, doing mental arithmetic or finding the right word in conversation.

woman gardening

Doctors call this mild cognitive impairment (MCI). Women with breast cancer were the first to report these changes and they linked them to their chemotherapy. So these types of changes are commonly called chemo brain. But we don’t know whether it is the chemotherapy that causes them or not. Because many people have more than one type of treatment, it is often difficult to tell whether it is a particular treatment or a combination of treatments that causes MCI. Doctors know that people with other types of cancer can also have these problems, including men with prostate cancer.

For most people these problems are mild and subtle. But they can be frustrating and may affect your self confidence and quality of life.

Research in this area is relatively new. It is difficult to pick up subtle changes with the tests that are currently available. A group of specialists and patients called the International Cognition and Cancer Task Force (ICCTF) aim to guide future research and give information about how to manage symptoms.


Thought process changes in women

The female hormone oestrogen plays an important part in cognition in women. More specifically it seems to help with remembering words, concentrating, and processing things quickly. There is already evidence that low oestrogen levels can affect cognitive function. We know from research into natural menopause that memory and information processing can be affected by hormone level changes. But the research also shows that both go back to how they were once menopause is over.

It is likely that treatments that lower oestrogen levels or block oestrogen’s action, may affect your ability to think, concentrate or remember things. A review of women with breast cancer suggests that this happens to between 17% and 50% of women. Not all women having treatment have problems. We need more research to find out who is most at risk of these changes.

Both chemotherapy and hormone therapies for breast cancer can affect oestrogen levels. They either stop oestrogen being made or block its action. 

Chemotherapy and thought processes

Chemotherapy can stop the ovaries making oestrogen and this may be why women having chemotherapy may have changes in memory and thought processes. Depending on your age, the changes may be temporary or permanent.

Hormone therapy and thought processes

There is mixed evidence on whether hormone therapies affect memory and thought processes or not. Research into hormone therapy for prostate cancer, such as goserelin (Zoladex), suggests that these drugs can alter memory. This may go back to normal when treatment stops but for some men is permanent.

Tamoxifen can affect verbal memory, such as remembering a particular word for something. The evidence about the types of hormone therapies called aromatase inhibitors is less clear. There is some research suggesting that they don’t affect cognition, but other trials have shown that aromatase inhibitors may cause mild cognitive changes. We need more research into how hormone treatments affect cognition. 

You can read about the different types of hormone therapy for breast cancer.


Thought process changes in men

There is not much research into how testosterone levels affect cognition in men. A review of studies in 2008 showed that some men having prostate cancer treatment that lowered their testosterone levels had cognitive impairment. Between 47% and 69% of the men in these studies had these types of changes. The men showed difficulty in coping with problems that involved mentally rotating objects in space (spatial ability) and problems with multi tasking.

But other researchers have shown that low testosterone levels have no effect on cognition. We need larger, more thorough studies to help us understand more about how prostate cancer treatment affects thought processes.


Tests for changes in memory and thinking

Problems with memory and thought processes can be difficult to assess. The changes are subtle and are particularly difficult to pick up. To start with, researchers used tests that were designed for dementia but these missed the subtle changes that people may have after cancer treatment. Research into this area is relatively new. We need more sensitive tests. Even small changes are important because they can significantly affect some people’s quality of life.


Tips for memory and thinking problems

It can be difficult and frustrating to cope with memory and thinking changes. But there are things that you can do for yourself

  • Don’t try and do too many things at once
  • Write lists about what you need to do, things you need to buy, and where you left things
  • Write people’s names down with a brief description to help you remember them
  • Repeat things back to people – for example, you can repeat the names of people you meet for the first time
  • When arranging to meet someone or organising an event write the details down and repeat them back to someone
  • Where possible, choose quiet settings to talk to people, where there are few distractions
  • Put up a calendar and use it
  • Stick up post it notes where you can see them to remind you to do things
  • Eat healthily, exercise, and get plenty of rest – don’t get over tired
  • Keep your mind active – try doing crosswords, Sudoku and puzzles

Treatment for memory problems

Correcting hormone levels is not always possible for people with cancer. But there has been some research into this area. A trial looked at adding oestrogen to hormone therapy that men were taking for prostate cancer. They found that the men who took oestrogen with their hormone therapy had no effects on cognition. But the men who took only hormone therapy had reduced memory and slower thought processes.

Doctors are looking into a number of treatments that may be helpful for cancer related mild cognitive impairment. It is too early to know how well these treatments will work. They include drugs that increase the blood and oxygen supply to brain cells.

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Updated: 26 June 2015