A trial looking at a new way of having radiotherapy to the brain (HIPPO)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Brain (and spinal cord) tumours




Phase 2

This trial is looking at whole brain radiotherapy that avoids the hippocampus for people with cancer that has spread to the brain. The hippocampus is the area of the brain which is mainly to do with memory, particularly short term memory. You have 2 hippocampi, 1 on the left and 1 on the right side of your brain. 

It is for people with any type of cancer apart from:

  • small cell cancers (such small cell lung cancer Open a glossary item)
  • blood cancers such as leukaemia, myeloma Open a glossary item or lymphoma
  • cancer that started in the brain (primary brain tumours) or the spinal cord Open a glossary item (central nervous system) 

Cancer Research UK supports this trial.

More about this trial

Cells can break away from the cancer and spread to other parts of the body. Sometimes they can spread to the brain. This is called metastatic or secondary brain cancer

Doctors can use radiotherapy Open a glossary item to the whole brain to treat secondary brain cancer. This is to help control existing tumours in the brain and stop other tumours developing in the future. 

But having radiotherapy to the whole brain can cause side effects. You might have:

  • memory problems
  • difficulty learning, solving problems and making decisions 

This is because radiotherapy can affect the hippocampus. 

Researchers are looking into a new way of giving radiotherapy to the brain that avoids both of the hippocampi. They call this whole brain radiotherapy with hippocampal sparing.

In this trial people have 1 of the following:

  • standard whole brain radiotherapy 
  • whole brain radiotherapy with hippocampal sparing 

The main aims of this trial are to: 

  • find out how well whole brain radiotherapy with hippocampal sparing works as a treatment
  • learn about the side effects 
  • learn how well people cope with the treatment and side effects
  • find out if it is possible to do a larger study

Who can enter

The following bullet points list the entry conditions for this trial. Talk to your doctor or the trial team if you are unsure about any of these. They will be able to advise you. 

You may be able to join this trial if all of the following apply.

  • You have cancer that has spread to your brain 
  • You have no more than 10 areas of cancer in the brain 
  • You have had surgery or stereotactic radiosurgery to all the areas of cancer in your brain in the past 4 weeks
  • You’re able to care for yourself even if you cannot carry on with all your normal activities or do active work (Karnosfsky performance status of 70 or more
  • You are at least 16 years old
  • You are willing to use reliable contraception during treatment and until the end of your radiotherapy if there is any possibility you or your partner could become pregnant 

You cannot join this trial if any of these apply.

  • You have a small cell cancer, a blood cancer or a primary tumour of the brain or the spinal cord   
  • Your cancer has spread to the membranes that surround the brain (carcinoma meningitis) or the area between the brain and the spinal cord (the brainstem)
  • You have or have had an area of secondary brain cancer within 5 mm of the hippocampus    
  • You have had radiotherapy to your brain apart from stereotactic radiosurgery completed 4 to 6 weeks before starting treatment in this trial 
  • You have had stereotactic radiotherapy close to important organs, unless your doctor thinks it’s safe to have more treatment 
  • You have had surgery for secondary brain cancer unless it was a single operation 4 to 6 weeks before starting treatment in this trial (or, if you had an earlier operation for secondary brain cancer, as long as there is no sign of the secondary cancer you had operated or you have had stereotactic radiosurgery to any remaining tumour visible and completed that 4 to 6 weeks before starting treatment in this trial)
  • You have dementia that isn’t related to secondary brain cancer      
  • You are not able to have an MRI scan for any reason, for example you have metal implants such as a pacemaker, surgical clips, pins or plates or cochlear implants (for deafness), you have a fear of being in closed spaces (claustrophobia) or you are sensitive to the injection given during an MRI scan (known as contrast medium Open a glossary item)
  • You are pregnant 

Trial design

This is a phase 2 trial. The researchers hope that around 84 people in the UK will take part. 

This trial is randomised. The people taking part are put into 1 of the following treatment groups by computer:

  • standard whole brain radiotherapy
  • whole brain radiotherapy with hippocampal sparing 

Neither you nor your doctor can decide which group you are in. 

Diagram for HIPPO

Before you start radiotherapy, you have a mask made. This helps to keep your head still during treatment. 

You also have a CT scan. This is a radiotherapy planning scan. The scan helps the doctors know how much radiotherapy you need and exactly where you need it.  

How you have radiotherapy and the number of treatments you have is the same in each group. 

You have radiotherapy every day, Monday to Friday, with a break at weekends. Each treatment takes about 15 minutes. You have 10 treatments (around 2 weeks).  

The trial team will ask you to keep a diary to record:

  • changes to any medications (such steroids Open a glossary item and medications to prevent seizures)
  • when you feel unwell and any side effects you have 

This helps your doctor to understand how you are and find the best way to manage any side effects you have. 

Questionnaires and brain function tests
Everybody taking part in this trial completes 3 quality of life questionnaires:

  • before starting radiotherapy 
  • at set times after you finish treatment.

They will ask about how you have been feeling and what side effects you have had. 

You also have some brain function tests. You have these tests with a research nurse or other member of the team. They are a way of finding out how well your brain can process information, such as remembering words. The tests might be audio recorded so the team can accurately work out your score. The research team will not keep the recordings

Hospital visits

You see a doctor and have some tests before taking part. These tests might include: 

You see the doctor every week during treatment. They will see how you are and ask about any side effects. 

When you finish treatment, you see the trial doctor and have an MRI scan every 2 months for the first 6 months and then:

  • every 3 months for the 1st year
  • every 6 months for the 2nd year

Side effects

The trial team monitor you during the time you have treatment and you will be given a phone number to call them if you are worried about anything.  The team will tell you about all the possible side effects before you start the trial.

The most common side effects of radiotherapy to the brain are: 

  • tiredness (fatigue)
  • feeling or being sick 
  • headache 
  • hair loss 
  • changes to your taste 

We have more information about radiotherapy for secondary brain cancer.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Gillian Whitfield

Supported by

Cancer Research UK
Experimental Cancer Medicine Centre (ECMC)
Manchester Academic Heath Science Centre
National Cancer Research Institute (NCRI)
The Brain Tumour Charity
University College London (UCL)

Other information

This is Cancer Research UK trial number CRUK/13/017.

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Rhys was only four years old when he was diagnosed with a brain tumour

A picture of Rhys

"He went through six operations and was placed on a clinical trial so he could try new treatments.”

Last reviewed:

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