A trial to find out how long to give chemotherapy after surgery for bowel cancer (SCOT)

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

Cancer type:

Bowel (colorectal) cancer
Colon cancer
Rectal cancer




Phase 3

This trial is comparing 12 weeks and 24 weeks of chemotherapy for people who have had surgery for bowel (colorectal) cancer.

Doctors often treat bowel cancer with chemotherapy after surgery. This helps to stop the cancer coming back. People usually have treatment for 24 weeks. But research has suggested that 12 weeks may be just as good.

Unfortunately all chemotherapy drugs have side effects and many of them can get worse as the treatment goes on. The researchers hope that giving 12 weeks of chemotherapy instead of 24 will cause fewer side effects.

The aims of this trial are to

  • Find out if 12 weeks of chemotherapy is as good as 24 weeks at helping to stop cancer coming back after surgery
  • See if 12 weeks of chemotherapy has fewer side effects

Who can enter

You can enter this trial if you

  • Have stage 3 bowel cancer (locally advanced), or stage 2 bowel cancer which your doctor thinks is at high risk of coming back
  • Had surgery for bowel cancer less than 11 weeks ago
  • Are due to have chemotherapy
  • Have normal CEA levels Open a glossary item in your blood
  • Have satisfactory blood tests
  • Are well enough for treatment (performance status 0 or 1)
  • Are at least 18 years old
  • Are prepared to use reliable contraception while taking part in the trial, if there is any chance that you or your partner could become pregnant

You cannot enter this trial if

  • You have already had chemotherapy
  • You have had radiotherapy to the abdomen (tummy) or pelvis in the past, (you can enter if you had a short course of radiotherapy before surgery for rectal cancer)
  • You have had (or are going to have) chemotherapy and radiotherapy together (chemoradiation) before or after surgery for rectal cancer
  • Your kidneys are not working as well as they should
  • You have had a heart attack or stroke in the last 12 months or have any other serious heart problem
  • You have had any other cancer in the last 5 years, apart from non melanoma skin cancer or carcinoma in situ of the cervix that has been successfully treated
  • You have, or your doctor thinks you have, a condition called DPD deficiency (which means you cannot have certain types of chemotherapy)
  • You are pregnant or breastfeeding

Trial design

This is a phase 3 trial and will recruit 9,500 people. The trial is randomised. The people taking part are put into one of two 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 one, you will have 24 weeks of chemotherapy. If you are in group two, you will have 12 weeks of chemotherapy.

Your doctor will decide which chemotherapy drugs you have. This will depend on your individual situation. You will have one of these combinations

If you have OxMdG, you have chemotherapy in 2 week cycles of treatment. On day 1 of each cycle, you have oxaliplatin and folinic acid through a drip into a vein over 2 hours. You then have an injection of 5FU into your vein. This will take a few minutes. After this, you have an infusion of 5FU continuously over 46 hours. You have no treatment during the 2nd week of the cycle.

Most hospitals can give you a portable pump so that you can go home with the 5FU infusion. But to use a pump, you also need to have a central line or a PICC line. Your doctor will discuss this with you before you start your treatment.

If you have XELOX, you have 3 weekly cycles of treatment. On day one of each cycle, you have oxaliplatin through a drip over two hours. Capecitabine is a tablet that you take once a day for the first 2 weeks of each cycle. Then you have no treatment during the 3rd week of the cycle.

Hospital visits

You will go to the hospital to see the doctors and have some tests before you take part in the trial. These include

  • Physical examination
  • Blood tests
  • ECG (electrocardiogram) Open a glossary item
  • Colonoscopy (if you didn’t have one before your operation)

Depending on the type of chemotherapy you have, you will go to hospital once every 2 or 3 weeks for treatment. You have a blood test at each visit, and the trial team will ask about any side effects you have had.

If you are in group 1 you have treatment for nearly 6 months. If you are in group 2, you have treatment for 3 months and then see your doctor once a month for another 3 months.

Everybody will then see the doctor

  • Every 3 months for 6 months
  • Every 6 months for the next year
  • Once a year for up to 7 years

You will have a CT scan every 6 months for the first 2 years, and one in the third year. Your doctor will decide if you need to have any further colonoscopies.

Side effects

The most common side effects of 5FU, capecitabine and oxaliplatin are

There is more information about the side effects of 5FU, capecitabine and oxaliplatin in the chemotherapy section on CancerHelp UK.

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 Tim Iveson

Supported by

Experimental Cancer Medicine Centre (ECMC)
Medical Research Council (MRC)
NIHR Clinical Research Network: Cancer
Oncology Clinical Trials Office (OCTO)
University of Glasgow (CaCTUS)

Questions about cancer? Contact our 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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