A trial using a scan to improve treatment for oropharyngeal cancer during chemoradiotherapy (PEARL)

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

Cancer type:

Head and neck cancers
Mouth (oral) cancer




Phase 2

This trial is to re-plan radiotherapy treatment half way through so they can reduce the amount of radiotherapy to the nearby healthy tissue.

It is open to people who have cancer where the back of the mouth and throat meet (oropharyngeal cancer). And human papilloma virus (HPV) is the cause of the cancer.  

More about this trial

One of the treatments for oropharyngeal cancer is a combination of chemotherapy and radiotherapy (chemoradiotherapy).

Researchers are looking for ways to improve treatment. One way might be to reduce the area of radiotherapy half way through the course of treatment. 

You have planning for radiotherapy before you start. This is to work out where you have treatment and how much you have. During the course of treatment Open a glossary item the area of cancer reduces. 

Researchers want to plan your radiotherapy again half way through treatment. So where you have treatment matches the smaller area of cancer. By doing this they hope this reduces the amount of radiotherapy to the healthy tissue. And this will decrease the side effects of radiotherapy. 

The aims of this trial are to find:

  • how well this works
  • if it is possible to do
  • how it affects the side effects 
  • how it affects quality of life Open a glossary item

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. 

Who can take part

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

  • have oropharyngeal cancer that is a squamous cell carcinoma
  • have cancer that has tested positive for human papilloma virus (HPV Open a glossary item)
  • are having chemoradiotherapy Open a glossary item
  • have satisfactory blood test results 
  • are willing to use reliable contraception during the trial and for 6 months after if there is any chance you or your partner could become pregnant
  • are at least 18 years old

Who can’t take part

You cannot join this trial if any of these apply. You:

  • have cancer that has spread into the nearby areas such as the jaw and voice box (stage T4)
  • have cancer that has spread to other parts of the body
  • have cancer that has spread to 2 or more lymph nodes Open a glossary item
  • have a cancer that can’t be seen on a PET CT scan Open a glossary item 
  • have had previous radiotherapy to your head and neck
  • have had another cancer in the past 5 years apart non melanoma skin  Open a glossary itemcancer and carcinoma in situ Open a glossary item of the cervix
  • have or had a medical condition that affects how you swallow
  • are a smoker or you have stopped smoking within the past 2 years
  • have diabetes Open a glossary item 

Trial design

This is a phase 2 trial. The team need 50 people to join. 

Before starting your chemoradiotherapy you have a radiotherapy planning appointment. This is to work out where to give the radiotherapy and how much to give. 

You have 33 treatments of radiotherapy over 6 weeks. 

For the first 3 weeks you have it once a day Monday to Friday (15 treatments). 

For the second 3 weeks you have an extra treatment of radiotherapy each week (18 treatments). 

You have the extra treatment either by having your radiotherapy twice on 1 day during the week. Or by having treatment on the weekend. 

You have your chemotherapy during radiotherapy either once a week or once every 3 weeks. Your doctor will talk to you about this. 

PEARL-T sub study 
You give blood samples and saliva (spit) samples:

  • before starting treatment
  • 2 weeks after starting treatment
  • at the end of treatment then 
  • after treatment at 1 month 
  • 3 months
  • 1 year
  • 2 years

Researchers use these samples to look for substances (biomarkers Open a glossary item) that they hope can help predict which people might do well or not do well with standard treatment. 

You don’t have to give these samples if you don’t want to. You can still take part in the PEARL trial. 

Quality of life
You fill in questionnaires:

•    before starting treatment
•    a month after you finish treatment
•    then at 6 months
•    1 year
•    2 years

This is a quality of life study.

Hospital visits

You see the doctor to have tests before taking part. These tests include:

  • a physical examination
  • blood tests
  • test to see how well you swallow
  • PET CT scan

You see the doctor each week during treatment to find out how you are. 

After treatment you see the doctor at:

  • 4 weeks
  • 3 months
  • 6 months
  • 1 year
  • 2 years

This to find out how you are and to test your swallowing. 

You have a PET CT scan after 2 weeks of chemoradiotherapy and then at 3 months. 

Side effects

The trial team monitor you during treatment and afterwards. Contact your advice line or tell your doctor or nurse if any side effects are bad or not getting better. 
The early side effects of radiotherapy happen during treatment and between 1 to 3 months after. These include:

  • loss of taste
  • dry mouth
  • ulcers in the throat causing pain when swallowing
  • a skin reaction like sunburn 

Some side effects of radiotherapy can continue or happen after 3 months. These late side effects include:

  • dry mouth
  • swallowing problems
  • teeth problems such as decay 

We have information about the side effects of head and neck radiotherapy.

The chemotherapy used for oropharyngeal cancer is either:

Your doctor or a member of the trial team will talk to you about the possible side effects before you agree to join. 

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 Thomas Rackley
Dr Mererid Evans

Supported by

Velindre NHS Trust 
Cancer Research Wales 
Velindre Radiotherapy Charitable Funds (Moondance) 
Centre for trials Research 

If you have questions about the trial please contact our cancer information nurses

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.

Around 1 in 5 people take part in clinical trials

3 phases of trials

Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.

Last reviewed:

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