A trial looking at higher doses of chemoradiotherapy for people with locally advanced anal cancer (PLATO ACT5)

Cancer type:

Anal cancer




Phase 2

This trial compared standard dose chemoradiotherapy with higher doses of chemoradiotherapy. It was for people whose anal cancer was over 5cm long or had spread to their lymph nodes Open a glossary item. This is called locally advanced anal cancer.

The trial was supported by Cancer Research UK. It was open for people to join between 2017 and 2023. The team published some early results about side effects in 2023. They plan to publish more results at a later date.

More about this trial

Doctors often treat locally advanced anal cancer with a combination of chemotherapy and radiotherapy. This is called chemoradiotherapy or chemoradiation.

When this trial was done, the standard chemotherapy drugs used were mitomycin C and either capecitabine (Xeloda) or fluorouracil (5FU).

In this trial, everyone had the standard dose of chemotherapy. But some people had a higher dose of radiotherapy. Doctors wanted to find out if having higher dose chemoradiotherapy helped stop anal cancer coming back.

Radiotherapy is measured in units called Gray (Gy). The total dose is divided up into smaller doses called fractions. People in this trial had 28 individual fractions of radiotherapy, one a day (Monday to Friday) for 5 and a half weeks.

The people taking part were put into a treatment group at random. People in each group had 28 fractions of radiotherapy:

  • group 1 had 1.9Gy of radiotherapy per fraction (standard treatment)
  • group 2 had 2.1Gy of radiotherapy per fraction
  • group 3 had 2.2Gy of radiotherapy per fraction

The main aims of this trial were to find out:

  • which dose of chemoradiotherapy is best
  • the side effects of a higher dose of chemoradiotherapy 

Summary of results

In 2022 the trial team presented some results about the short term (acute) side effects for some people in this trial.

The team will publish more results in the future about:

  • how well the different treatments worked
  • the short term and long term side effects for everyone in the trial

We hope to update this page once these results are available.

These results are for the first 140 people who took part. They joined the trial between 2017 and 2020. To begin with there were:

  • 47 people in group 1
  • 47 people in group 2
  • 46 people in group 3

Four people moved into group 1 because they weren’t able to have the treatment in group 2 or 3. So then there were:

  • 51 people in group 1
  • 46 people in group 2
  • 43 people in group 3

Short term side effects  
Everyone taking part had at least one side effect from treatment. Many were mild or didn’t last long. 

Some people had more severe side effects during treatment. The team found it was:

  • 25 out of 51 people (49%) who had standard treatment in group 1  
  • 24 out of 46 people (52%) who had higher dose treatment in group 2
  • 19 out of 43 people (44%) who had slightly higher dose treatment in group 3

These side effects included pain, bowel problems such as diarrhoea, and sore skin.

The number of people having severe side effects 6 weeks after treatment was much lower. And by 3 months after treatment, it was one person in group 1 and one person in group 3.

The people taking part filled out quality of life questionnaires Open a glossary item before, during and after treatment. The results showed people’s quality of life:

  • was worst during the last week of treatment
  • went back to their normal by 6 weeks after treatment
  • was similar in all 3 groups

These early results show that early side effects from treatment was similar in all 3 groups. 

We will add more information about other results from this trial when they are available.

More detailed information
There is more information about this research in the reference below. 

Please note, the information we link to here is not in plain English. It has been written for healthcare professionals and researchers.

Standard vs dose escalated chemoradiotherapy in anal cancer: Phase II results of the PLATO-ACT5 RCT
A Gilbert and others
ESTRO conference, Copenhagen, 2022. Presentation OC-0269.

There is also a plain English summary prepared by the trial team on the following link.

ACT5 Early Results Lay Summary
CTRU Leeds Research Portal website
Accessed May 2024

Where this information comes from    
We have based this summary on the information in the article above. As far as we are aware, it has not been reviewed by independent specialists (peer reviewed Open a glossary item) or published in a medical journal yet. We have not analysed the data ourselves. As far as we are aware, the link we list above is active and the information is free and available to view.

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

Professor David Sebag-Montefiore 

Supported by

Cancer Research UK
Leeds Institute of Clinical Trials Research, University of Leeds 
Stand up to Cancer

Other information

This is Cancer Research UK trial number CRUK/15/007.

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.

Last reviewed:

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