Research looking at cognitive changes (chemo brain)

Cognitive changes include problems with memory, concentration and the way a person is able to think. Your doctor might call this cancer related cognitive impairment. It is also known as chemo brain or chemo fog. 

Research into the possible causes of cognitive changes

We don’t know for sure what causes cognitive impairment. But research suggests that there might be a number of factors that contribute to it. These include the cancer itself, different cancer treatments and other factors such as age. 

Treatment and the cancer

Research continues to look at how cancer and its treatment causes cognitive impairment.

For example, some studies have looked at whether some chemotherapy drugs are more likely to cause cognitive problems than others. Studies are also starting to look at newer targeted cancer drugs. It’s possible that some of these drugs could cause cognitive problems. But we need more research to know for sure.

Studies in the UK are looking at thinking and memory problems in men who are having hormone therapy for their prostate cancer. The researchers want to find out why some men have these problems and others don’t.

Knowing which treatments are more likely to cause problems could help doctors make decisions about treatment. And it could help them identify those patients who are more likely to need the relevant information and support.  

Effects on the body

Researchers are also trying to understand how cancer or its treatment affects the body.

Cytokines are proteins made by the body as part of the immune response. Researchers have looked at blood levels of cytokines in people who have had cancer treatment, particularly women who had treatment for breast cancer.

Early research shows that cytokines might have a role in the development of cognitive impairment. But the results were not conclusive enough and more research is going on.

Other researchers are looking at the effect of cancer and its treatment on the brain itself. For this they are taking scans before, during and after treatment. They will compare these scans to see if there are any differences.

Research into treatment for cognitive changes (chemo brain)

At the moment there is no treatment for the cognitive problems caused by cancer and cancer treatment. Researchers are looking into a number of different drugs that might help. This includes drugs used for other conditions that cause cognitive impairment. For example donepezil hydrochloride, which is a treatment for Alzheimer’s.

Another example is metformin, normally a treatment for diabetes. Research in mice has shown that metformin can protect against nerve damage that some chemotherapy treatments cause.

All this research is at the very early stages. These drugs are not available as standard treatments to prevent or reduce cognitive changes. 

Research into coping

A study in the UK has looked at whether an intervention programme helped reduce cognitive changes caused by cancer treatment. This programme involved:

  • education about cognitive impairment
  • relaxation techniques
  • lifestyle advice

Research in America is looking at a combination of exercise and low dose ibuprofen for people who are having chemotherapy for bowel cancer. Ibuprofen is an anti inflammation medicine used to relieve pain. The researchers hope that this combination will prevent and reduce any cognitive difficulties caused by chemotherapy

International Cognition and Cancer Task Force (ICCTF)

In 2006 a group of specialists and patients set up the International Cognition and Cancer Task Force (ICCTF). This group aims to guide future research and give information to patients and doctors about how to manage the symptoms of cognitive impairment.

Its members carry out local, national and international research. They have working groups looking at different areas of research. These include:

  • the best way to identify and assess those people who have (or who are at risk of) cognitive impairment
  • research possible treatments that can then be tested in clinical trials

Other research

Researchers think that having very mild cognitive changes before starting treatment might be made worse by having cancer treatment. They are doing tests, for example memory tests, before starting treatment and afterwards to find out more.

  • Neurotoxic Effects of Anthracycline- vs Nonanthracycline-Based Chemotherapy on Cognition in Breast Cancer Survivors

    R Shelli and others

    JAMA Oncology, 2016, Volume 2, (2), Pages 185–192

  • Post-chemotherapy cognitive impairment in patients with B-cell non-Hodgkin lymphoma: a first comprehensive approach to determine cognitive impairments after treatment with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone or rituximab and bendamustine.

    P Zimmer and others

    Leukaemia and Lymphoma, 2015. 56(2), Pages 347-52

  • Phase II study of donepezil in irradiated brain tumor patients: effect on cognitive function, mood, and quality of life

    E G Shaw and others

    Journal of Clinical Oncology, 2006. 20,24(9), Pages 1415-20

  • Non-pharmacological interventions for cognitive impairment due to systemic cancer treatment
    C J Treanor and others 
    Cochrane Database of Systematic Reviews, 2016. Issue 8. Art. No: CD011325

  • A feasibility study exploring the role of pre-operative assessment when examining the mechanism of ‘chemo-brain’ in breast cancer patients 
    V Jenkins and others
    SpringerPlus, 2016. 5:390, pages 1 to 11

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.

Last reviewed: 
27 Aug 2020
Next review due: 
27 Aug 2023

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