A trial looking at a lower dose of chemoradiotherapy for people with anal cancer that hasn’t spread (PLATO ACT4)

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

Cancer type:

Anal cancer




Phase 2

This study is comparing standard and lower dose of chemoradiotherapy for people with anal cancer that hasn’t spread.   

Cancer Research UK supports this trial. 

More about this trial

People with anal cancer often have treatment with a combination of chemotherapy and radiotherapy (chemoradiotherapy).

Radiotherapy uses high energy x-rays to kill anal cancer cells. You usually have 28 treatments (about 5 ½ weeks). 

You also have chemotherapy at the same time. There are different drugs you can have such as: 

Chemoradiotherapy can cause side effects. Sometimes these can affect you for some years after the treatment has finished. 

Doctors know from previous research that having a lower dose of chemoradiotherapy might be as good as the standard dose at curing anal cancer. But they want to find out for sure. They also think a lower dose of chemoradiotherapy has less side effects than the standard dose.        

In this trial, you have 1 of the following: 

  • standard dose chemoradiotherapy (standard treatment Open a glossary item)
  • lower dose of chemoradiotherapy 

The main aims of this trial are to: 

  • find out if a lower dose of chemoradiotherapy is as good as the standard dose at curing anal cancer 
  • learn about the side effects of a lower dose of chemoradiotherapy 

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 squamous cell cancer of the anus that measures less than 4 cm (T1 or T2) and hasn’t spread to the lymph nodes Open a glossary item or to other parts of the body 
  • You have satisfactory blood tests results
  • Your doctor thinks you are well enough to have chemoradiotherapy
  • You are well enough to carry out your normal activities, apart from heavy physical work (performance status of 0 or 1)   
  • You are at least 16 years old
  • You are willing to use reliable contraception during treatment and for 6 months after if there is any possibility you or your partner could become pregnant

You cannot join this trial if any of these apply.

Cancer related

  • Your cancer has spread to other parts of the body 
  • You have had chemotherapy that reached your whole body (systemic) as a treatment for anal cancer 
  • You have had radiotherapy to the area between your hip bones (pelvis)
  • You have had treatment for another cancer in the last 2 years (your doctor can tell you more about this)

Medical conditions

  • You have heart problems such as angina that isn’t controlled or you have had a heart attack in the past 6 months 
  • You have had an organ transplant Open a glossary item


  • You are not able to have an MRI scan for any reason, for example you have metal implants such as a pacemaker, surgical clips, implants, pins, plates, you have a fear of being in closed spaces (claustrophobia) or you are allergic to the dye (contrast medium Open a glossary item) given during the scan 
  • You are pregnant or breastfeeding 

Trial design

This is a phase 2 trial. The researchers need about 162 people to take part.

This trial is randomised. Everyone is put into 1 of the following treatment groups by computer: 

  • standard dose of chemoradiotherapy (standard treatment)
  • lower dose of chemoradiotherapy 

Neither you nor your doctor will be able to decide which group you are. You are 2 times more likely to have a lower dose of chemoradiotherapy than the standard treatment.

Study diagram

Standard treatment
You have a CT scan. This is a radiotherapy planning scan. The scan helps the doctors know how much radiation you need and exactly where you need it. About 2 weeks later, you start radiotherapy.

You have radiotherapy every day, Monday to Friday, with a break at weekends. Each treatment takes about 10 to 20 minutes. You have 28 treatments (around 5 ½ weeks).  

You also have chemotherapy at the same time. You have 2 drugs: 

  • mitomycin C 
  • capecitabine 

Mitomycin C is an injection you have into your vein. You have it on the 1st day of radiotherapy. 

Capecitabine comes as tablets that you take twice a day, morning and evening. You take them each day you have radiotherapy. 

Lower dose of chemoradiotherapy 
You have a radiotherapy planning scan and start radiotherapy about 2 weeks later. 

You have radiotherapy every weekday. Each treatment takes about 10 to 20 minutes. You have 23 treatments (around 4 ½ weeks). 

You have mitomycin C as an injection into your vein on the 1st day of radiotherapy. And capecitabine tablets twice a day, on each day you have radiotherapy. 

Quality of life 
You complete quality of life questionnaires: 

  • at the time you join the trial
  • at the end of treatment 
  • 6 weeks after the end of treatment 
  • then after 6 months, 1, 2 and 3 years 

The questionnaires ask about how you have been feeling and what side effects you have had. They take about 15 minutes to complete each time. You can complete the questionnaires online or on paper. 
Tissues samples and scans 
The trial team might ask: 

  • to use a tissue sample of your cancer taken when you were diagnosed (stored biopsies)
  • to use a tissue sample of your cancer taken when you join this trial and if your cancer gets worse (if you have samples of tissue taken as part of your routine care) 
  • for your permission to look at the scans taken as part of this trial 

They want to study more about anal cancer, find out who is at risk of it and who is most likely to have side effects from treatment. 

You don’t have to agree to this if you don’t want to. You can still take part in this trial. 

Your name and address will be removed from the scans and tissue sample. So no one will be able to identify you. 

Hospital visits

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

  • a physical examination
  • blood tests
  • a heart trace (ECG Open a glossary item)
  • an MRI scan
  • a CT scan
  • a PET scan Open a glossary item

You see the trial doctor for blood tests and a physical examination every week during treatment. 

When you finish treatment, you see the trial doctor after 6 weeks. Then:

  • every 3 months for the first 2 years
  • every 6 months for 1 year
  • once a year

You have an MRI scan after 3 and 6 months of the end of treatment. And a CT scan every year, for 3 years. 

Side effects

The trial team monitor you during the time you have treatment and you have 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.

Radiotherapy to the anus has short term (or acute) side effects that usually start a few days after the radiotherapy begins. And side effects that can start some months or years later (long term or late side effects).  

The most common short term side effects of radiotherapy include:

  • sore skin
  • diarrhoea
  • problems passing urine- it might be difficult or painful to pass urine or you might have some incontinence  Open a glossary item
  • loss of pubic hair
  • tiredness (fatigue)
  • vaginal irritation

We have more information about short term radiotherapy side effects

And information about long term radiotherapy side effects

The most common side effects of chemotherapy include:

  • a drop in blood cells causing an increased risk of infection, bruising or bleeding
  • feeling or being sick
  • sore mouth

We have more information about the side effects of:

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
University of Leeds 

Other information

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

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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