Symptoms and side effects in someone with cancer and dementia
Symptoms or side effects of cancer are sometimes similar to ones caused by dementia.
Managing symptoms and side effects
The person you care for may have symptoms or side effects caused by cancer or cancer treatment. Symptoms and side effects can usually be prevented or well controlled.
Symptoms or side effects will depend on the type of cancer or treatment. We have more information about the most common side effects.
The person you care for may not be able to tell you if they have symptoms or side effects. You may have to ask them regularly. If they have problems communicating, it can help to look for signs in their body language, such as restlessness. Or there may be changes in their facial expression, such as frowning.
Some symptoms or side effects of cancer may be like the ones caused by dementia. During cancer treatment, if you are worried about symptoms, always contact the cancer team for advice.
Memory or concentration problems
Some people having treatment for cancer may have:
- memory problems
- difficulty with thinking clearly or concentrating
- extreme tiredness (fatigue)
- low mood.
These changes are sometimes called chemo brain. This is because the symptoms were first linked to chemotherapy. But changes in memory and concentration can affect people having other types of cancer treatment.
Memory loss can be a symptom of any type of dementia. People with dementia and cancer are more likely to have this side effect. For some people having cancer treatment, dementia symptoms may get worse temporarily. For others, this change may be permanent.
Poor appetite and eating problems
Sometimes, cancer and its treatment can cause problems with eating. Some problems are temporary and improve after treatment. Others may last longer. The person you care for may find it more difficult to eat. Problems that can affect eating include:
- taste changes or loss of appetite
- feeling or being sick
- a sore mouth
- difficulty swallowing
- diarrhoea or constipation.
Having dementia can also have an effect on a person’s appetite and their ability to eat and drink.
Who can help?
Some cancer treatments can damage the cells that line the mouth or throat. The person you care for may develop a sore mouth, which may cause problems with eating. The healthcare team can prescribe medicines to help with a sore mouth. It is important to follow any advice they give. Any soreness is usually temporary, and usually gets better when treatment ends.
If you think the person you care for is not eating well, ask their GP, cancer doctor or specialist nurse to refer them to a dietitian. Qualified dietitians can give advice on which foods are best for them and whether any food supplements would be useful.
Speech and language therapists (SLTs) can assess for any difficulties with swallowing. They can offer support and advice. If you think the person you care for has problems with swallowing food, ask their GP, cancer doctor or specialist nurse to refer them.
Constipation
Helping a person with cancer and dementia to maintain a healthy diet can be difficult. But it is important to encourage them to eat as well as they can. This can help stop problems such as constipation and dehydration.
Some people with cancer and dementia are more likely to become constipated. It is important for someone with dementia to avoid constipation. This is because it can make them more confused.
The main reason people with cancer and dementia get constipated is that they are not drinking enough. They may also get constipated because they:
- are not eating enough
- cannot move around enough
- are taking painkillers that cause constipation.
Try to encourage the person you care for to drink more fluids and eat more fruit and high-fibre foods. About 2 litres (3 1/2 pints) can help prevent constipation and dehydration. If constipation is a problem, tell their GP, district nurse or specialist nurse. They may recommend medicines to help.
It can help to keep a note of the person's bowel movements. This may help you prevent or treat constipation before it becomes severe or makes them more confused.
We have more information about:
Dementia UK has information on supporting a person with dementia with eating and drinking and mouth care.
Pain
Many people with cancer will have pain at some point in their illness. But for most people, pain can be managed by using non-drug treatments or different medicines, such as painkillers.
Some people with dementia may not be able to tell their carers they are in pain. Look for signs of pain in the behaviour of the person you care for. For example, they may:
- have changes in body language, such as fidgeting or restlessness
- start shouting out
- hold the part of their body that is sore
- change their facial expression or clench their teeth
- become pale or sweaty
- refuse help or care
- become withdrawn
- refuse food or have other changes in appetite.
If you think the person you care for is in pain, it is important that you support them in telling their healthcare team. Different healthcare professionals may be involved in treating and controlling the person’s pain.
Non-drug treatments for pain
Sometimes, simple things can help to improve cancer pain. You could try:
- changing their position
- using heat or cold – for example, a hot water bottle in a cover may help ease aches and stiffness
- asking whether they would like a massage.
It is important to explain what is going on, and to stop if the person seems to be in any discomfort.
Painkillers
Sometimes painkillers are prescribed to help control cancer pain. Painkillers are usually tablets, capsules or liquids taken by mouth (orally). The person you care for may have problems swallowing medicines or remembering to take them. If this happens, their GP, cancer doctor or pharmacist can prescribe other ways to take painkillers, such as patches that stick to the skin.
You could also offer them over-the-counter or prescribed painkillers regularly. You should give these exactly as instructed on the packet. Always check with their GP or cancer team that these painkillers are safe to use with other treatments, such as chemotherapy.
Sometimes the person you care for may need specialist help to assess their pain and symptoms. The doctors and nurses can adjust the dose of medicines or add new ones to control symptoms. Some people may have a short stay in the hospice to do this. Once their symptoms are controlled, they may be able to go home again.
We have more information about pain and ways to manage it.
Dementia UK has a leaflet on pain in dementia.
Sleep problems
Both cancer and dementia may cause problems sleeping at night. Feeling very tired during the day can make symptoms of dementia worse.
There are different reasons why someone may not be sleeping well. It can help to look for changes in sleep patterns. If there are changes, try to find out if something is causing them. There may be things you can do to help.
Keeping physically active during the day may help the person sleep at night. If they can do some gentle exercise, you could try doing it with them. For example, you could go on short walks together.
If physical problems such as pain, discomfort or feeling unwell are stopping them from sleeping, talk to their GP, district nurse or specialist nurse. They may be able to give the person medicines that help with the symptoms of cancer or side effects of cancer treatment. You may also be able to get equipment that may make them more comfortable, such as a pressure-relieving mattress.
Some people find that anxiety, worry and emotional distress are keeping them awake at night. To support the person you care for, you could let them know that you are there to listen or talk things through with them.
We have information on starting conversations and listening, managing sleep problems and advice on ways to get a good night's sleep.
Dementia UK has resources about dementia and sleep. Including information about how to cope with the effects of 'sundowning'. This is when a person's dementia symptoms get worse in the evening.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our cancer and dementia information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
National Institute for Health and Care Excellence (NICE). Decision-making and mental capacity. NICE guideline [NG108]. Published 03 October 2018. Available from: www.nice.org.uk/guidance/ng108 [accessed June 2023].
Surr CA, Kelly R, Griffiths AW, Ashley L, Cowdell F, Henry A, et al. Enabling people with dementia to access and receive cancer treatment and care: the crucial role of supportive networks. Journal of Geriatric Oncology. 2020;11(7): 1125–1131. Available from: www.doi.org/10.1016/j.jgo.2020.03.015 [accessed July 2023].
Dr Chris Jones
Reviewer
Speciality Registrar in Clinical Oncologist and Clinical Lecturer in Clinical Oncology
Date reviewed
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