A study looking at a possible new way to treat cancer of the back passage (TREC)

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

Cancer type:

Bowel (colorectal) cancer
Rectal cancer




Phase 2/3

This study is looking at whether radiotherapy followed by surgery to remove the part of the back passage (rectum) affected by cancer works better than surgery to remove the whole rectum. This study is supported by Cancer Research UK.

If you have cancer in your rectum that is at an early stage Open a glossary item, there is a very good chance that it can be cured with surgery. In the standard operation, the surgeon will remove the whole rectum (radical surgery). We know that this can cure most of these cancers. But it can have serious side effects, and rarely, people may die as a result of this surgery.

A new way to treat these cancers is to have radiotherapy to the rectum to shrink the cancer. Then to have surgery to remove the part of the rectum affected by cancer, through the opening of the back passage (the anus). The team in this study hope that people treated this way would have fewer side effects, and a better quality of life Open a glossary item compared with those having radical surgery to remove the whole of the rectum. But they do not know for sure. A disadvantage of the smaller operation may be a greater risk of the cancer coming back in the future, which may then be harder to treat.

The first part of this study is a feasibility study, looking at how well radiotherapy shrinks the cancer, how many people can then have the smaller operation, and at peoples’ quality of life. The researchers also want to learn what is important to people when deciding what treatment to have, and try to improve how doctors talk to people about their cancer, possible treatments and clinical trials Open a glossary item.

The second part of the study will directly compare the risks and benefits of each of the treatments used in TREC so they can be certain which is best. The aim of this whole study is to find out whether the new treatment is better than standard radical surgery for people with small rectal cancers.

Who can enter

You may be able to enter this study if

  • You have cancer of the back passage (rectum)
  • Your cancer has not grown past the muscle wall of your bowel (stage T1 or T2 bowel cancer)  or you have had a small growth in your bowel removed called a villous adenoma, but test results show that it had grown into your bowel tissue by up to 3 cm
  • You are at least 18 years old

You cannot enter this study if

  • You have cancer that is stage T3 or above
  • Your cancer has spread to your lymph nodes Open a glossary item or another part of your body
  • You would not be able to have radiotherapy for any reason
  • You have already had radiotherapy to the area between your hips (your pelvis)
  • You are pregnant or breastfeeding

Trial design

This is a feasibility study. It will recruit 46 people. If successful, the team will use what they learned to plan a phase 3 trial, comparing the 2 treatments in many more people.

The feasibility study is randomised. The people taking part will be put into treatment groups by a computer. Neither you nor your doctor will be able to decide which group you are in.

If you are in group 1, you will have the radical surgery. You will have a general anaesthetic Open a glossary item. The surgeon will remove your back passage (rectum) either through a cut in your tummy, or a tiny hole in your tummy (keyhole surgery). They will then connect the remaining bowel to the anus Open a glossary item, so you can go to the toilet to pass stools normally again. If your cancer is very close to the anus, your surgeon will have to remove your anus as well. They would then pass the remaining bowel to a small opening they will make in your tummy wall. This is called a stoma. You would then need to wear a bag over the opening for the stools to pass into, instead of passing them the normal way. Your surgeon will be able to tell you before your surgery if you are likely to need this procedure (also called a colostomy), and wear a bag on your tummy. The team expect you to recover fully within about 3 months. This may be quicker if you have keyhole surgery.

If you are in group 2, you will have radiotherapy to shrink the cancer before having the smaller operation. You will have radiotherapy every week day for one week. Each session will take about 10 minutes. You then wait for 8 to 10 weeks to give the cancer a chance to shrink, or even disappear. You then have a small ‘keyhole’ operation through the anus to remove just the part of your back passage affected by the cancer. You may hear your surgeon call this surgery ‘transanal endoscopic microsurgery (TEMS)’ or a ‘transanal endoscopic operation (TEO)’. You have this surgery under general anaesthetic, and go home the next day. The team expect you to recover fully within a week.

The team will ask you to fill out a questionnaire before you start treatment and then at 3, 6, 12, 24, 36, 48 and 60 months after your surgery. The questionnaire will ask how healthy you feel and how well your bowels work. This is called a quality of life study.

As part of the feasibility study of TREC, the team are also trying to improve how they talk to people to make sure they understand the discussions about their cancer. And, about treatment, risks and benefits of each treatment, and why studies like TREC are important. They may ask if you would let them tape or film your second doctor’s appointment, and then ask what you understood from the appointment. You do not have to agree to be recorded if you don’t want to. You can still take part in the rest of the study.

If you agree, the team would also like to take an extra blood sample before you start treatment. And, collect some of the tissue from the biopsy you had to diagnose your cancer, and from your surgery when you have it. They want to see if measuring DNA or other chemicals from the cancer could one day help doctors predict which treatment will work best for individual people. They will treat this information anonymously, so no one outside the study team will be able to link the results to you.

Hospital visits

If you are in group 1, you will probably stay in hospital for between 4 and 10 days.

If you are in group 2, you will

  • Visit the hospital on 5 separate weekdays for radiotherapy, plus a day to plan your radiotherapy
  • Stay in hospital overnight after your surgery
  • Visit the hospital after your treatment to find out how well the treatment worked, and if you would need to also have radical surgery if it failed

Everyone in both groups will see the team regularly for at least 5 years, at

  • 6 weeks after you go home from your surgery
  • Every 3 months for the first year
  • Every 6 months for the next 4 years after this

You will have an MRI scan 3 months after surgery and then every year.

Side effects

If you are having radical surgery (group 1), possible risks and complications include

  • Leaking of stool (faeces) from the bowel where the surgeon has joined your bowel to the anus – this will need more surgery, and usually you will need to have a stoma on your tummy
  • Needing to visit the toilet more often before your bowel is empty
  • Having less warning before your bowels open
  • Stool (faeces) leaking without warning
  • Difficulty passing urine (in men)
  • Not being able to get an erection

Like any major operation, radical surgery may result in serious side effects or rarely even death. The risk of death due to radical surgery is about 4 in every 100 operations (4%). Your own level of risk depends upon your age and overall physical fitness.

If you are having radiotherapy and the smaller operation (group 2), the biggest risk is that it may not be as successful in stopping the cancer coming back, and if it does come back, it may be harder to treat. As very few people have had this treatment, the team can’t be sure that the risk will be low, and similar to the standard radical treatment. Once the team have removed the cancer they will look at it under the microscope. If they don’t think the cancer has responded well to radiotherapy, they will recommend that you have radical surgery to remove the whole back passage (like the standard treatment in group 1), one or 2 months later. It is possible that the radiotherapy and smaller operation may also cause

  • The need to visit the toilet more often to open your bowels
  • Less warning of the need to visit the toilet
  • Inflammation Open a glossary item of the bowel wall, possibly causing bleeding

We have more information about surgery for rectal cancer and radiotherapy for rectal 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

Mr Simon Bach

Supported by

Cancer Research UK
NIHR Clinical Research Network: Cancer
National Cancer Research Institute Colorectal Cancer Clinical Studies Group
University of Birmingham

Other information

This is Cancer Research UK trial number CRUK/09/032.

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.

Charlie took part in a trial to try new treatments

A picture of Charlie

“I think it’s really important that people keep signing up to these type of trials to push research forward.”

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