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Cancer and dementia: a guide for carers

Caring for a person with dementia who also has cancer can be challenging. This guide will help you understand how it might affect the person you look after, and the treatments and support available.

Cancer is a disease which starts in cells in the body – the tiny building blocks that make up our organs and tissues.

Usually, cells divide in a controlled way – this is how our bodies grow, heal and repair.

But in cancer, a cell becomes abnormal and starts dividing uncontrollably, making more and more abnormal cells. These cells may gather to form a tumour.

Cancer cells can spread into the surrounding tissues and cause damage, and to other parts of the body through the bloodstream or lymph system to form secondary tumours.

A diagnosis of cancer can be extremely challenging for a person with dementia and their family. For example:

  • they may not understand the diagnosis and how it will affect them
  • they may experience strong emotions around the diagnosis, which could affect their mood and behaviour – they might become depressed, anxious, agitated or aggressive
  • they may not have the capacity to consent to treatment
  • cancer treatments and their side effects may cause distress
  • the person may not understand why they need frequent medical appointments or time in hospital
  • they may be reluctant or forget to take medication

The main treatments for cancer are:

  • surgery to remove tumours
  • radiotherapy – radiation is used to destroy cancer cells
  • chemotherapy – medication is given as tablets or through a drip or injection to kill cancer cells throughout the body
  • hormone therapy – medication is used to tackle the hormones that cause certain cancers, eg breast and prostate cancer
  • targeted therapies – medication is used to ‘target’ the abnormalities that make cancer cells survive and multiply

The cancer treatment offered to the person you are caring for will depend on factors like:

  • where in the body the cancer started
  • the size/extent of the cancer
  • whether it has spread
  • the person’s general health
  • any other conditions they have, including dementia
  • the likelihood of the treatment succeeding
  • the risk of side effects

The person’s doctor (usually a specialist called an oncologist) will be able to discuss which treatments are most appropriate.

Some people with cancer and dementia will be able to have standard cancer treatment.

Others may have modified treatments that are less intense or invasive, such as a lower dose of chemotherapy or fewer treatments.

They will usually spend less time in hospital and have fewer side effects, but while these types of treatments may control the cancer, they won’t cure it.

If the cancer is advanced, the treatment doesn’t work, or it is decided that it would be inappropriate, the person can still be given treatment to help control symptoms such as pain.

This is called ‘supportive’ or ‘palliative’ treatment.

Before starting treatment, the person’s doctor will talk to them about what to expect, including:

  • what it involves
  • advantages and disadvantages
  • risks or side effects
  • other treatments that may be available.

After this, the person will be asked to sign a form saying that they consent to treatment.

However, for consent to be valid, the person must have ‘mental capacity’.

This is a legal term referring to whether the person is able to make important decisions.

To be considered as having capacity, the person must:

  • understand all the information given to them
  • retain that information in their mind
  • use the information to make an informed decision.

The doctor looking after the person with dementia may need to assess whether they have capacity.

If they don’t, a treatment or support plan will be drawn up in their best interests, considering any future care plans they made.

As the carer of someone with cancer and dementia, you may have to help them decide about treatment or make decisions for them, so it’s important to discuss how they would like to be cared for while they still have capacity.

This ensures that you, other family members and health and care professionals understand and respect their wishes.

With your support, the person may want to make:

  • an Advance Statement – a document setting out their preferences about future care and treatment. It is not legally binding
  • an Advance Decision to Refuse Treatment (ADRT) – a legally binding document that lists treatments that they DO NOT want, eg ventilation, resuscitation
  • a lasting power of attorney (LPA) for health and welfare – a legally binding document that appoints one or more people to make decisions about the person’s care if they lack capacity

The person with cancer and dementia is likely to have lots of medical appointments and hospital visits. You can support them by:

  • making a list of what they want to discuss, and prompting them during the appointment
  • helping them describe any symptoms or problems
  • remembering what was said or making notes
  • sharing any communication tips with the health professional – eg keeping information simple, avoiding medical words, or repeating things if necessary

If possible, it’s important to help the person you care for to think ahead about where they will be cared for in the future.

Care at home

Most people with long-term health conditions prefer to stay at home for as long as possible.

They may be helped by home carers and/or health professionals such as district nurses or palliative care nurses (nurses who provide support at the end of life).

Make sure you take into account your own ability to cope as a carer, and how you can access support.

Short-term/respite care

If you and the person you care for wish for them to stay at home, short-term or respite care may be helpful for you both. This might be to have specialised care that helps control symptoms or to give you a break from caring.

For example, they may be able to go to a day centre or have a short stay in a hospice or residential home.

The person’s GP, district nurse or palliative care nurse should be able to help you access short-term care.

Residential care/nursing homes

Residential and nursing homes offer short-term or long-term accommodation and care.

Your local authority Social Services can provide information about care homes, including what type of care they offer and any help you may be able to get with fees.

You can also talk to the person’s health professionals or social worker for more advice and information.

Hospital care

If the person you are caring for is admitted to hospital for cancer treatment, it is important that their care team knows that they have dementia and understands how it affects their needs.

If the person has a care plan, Advance Statement or ADRT, or if you have lasting power of attorney, ensure that their health professionals have a copy and are told if anything has changed.


If the person you care for becomes more unwell, they may be admitted to a hospice or a palliative care unit of the local hospital.

This may be short-term, for example to receive specialist treatment to control their symptoms, after which they return home.

Or they may be admitted at the end of life and stay there until they die, with treatment and support to keep them comfortable.

Hospices are generally smaller and quieter than hospitals and work at a gentler pace. Many encourage family and friends to visit and even stay overnight.

Hospice nurses can also visit terminally ill people at home and provide treatment to enable them to remain at home.

The person’s GP, district nurse, palliative care nurse or social worker can give you more information about hospices or hospital palliative care units.

Book an appointment with an Admiral Nurse

Our virtual clinics give you the chance to discuss any questions or concerns with a dementia specialist Admiral Nurse by phone or video call, at a time that suits you.

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