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The seAFOod Trial
Leeds University
Leeds Insitute of Molecular Medicine

Systematic Evaluation of Aspirin and Fish Oil Bowel Polyp Prevention Trial

Trial Summary

How many people took part?
We aimed to recruit 755 patients from the Bowel Cancer Screening Programme. We eventually recruited 709 participants to the trial.

Who was eligible to take part?
Before someone entered the trial, they had to meet certain eligibility criteria. To take part in the seAFOod trial a patient had to be:

  • A 55-73 year-old Bowel Cancer Screening Programme (BCSP) patient who had been identified as ‘high risk’ (5 or more small adenomas or ≥ 3 adenomas with at least one being ≥ 10 mm in diameter) at the first complete screening colonoscopy

Patients could not take part if they:
  • Required more than one repeat colonoscopy or flexible sigmoidoscopy within the BCSP 3 month screening window
  • Had a malignant change in an adenoma requiring Colorectal Cancer Multi-disciplinary Team management
  • Took regular (>3 doses per week) prescribed or ‘over-the-counter’ (OTC) aspirin, or regular (>3 doses per week) prescribed or OTC non-aspirin non-steroidal anti-inflammatory drug (NSAID)*
  • Were aspirin intolerant or hypersensitive, including aspirin-sensitive asthma
  • Had active peptic ulcer disease within 3 months or previous peptic ulcer (not on proton pump inhibitor prophylaxis)
  • Had fish or seafood allergy
  • Were on or planning regular (>3 doses per week) use of fish oil supplements*
  • Had a known clinical diagnosis or gene carrier of a hereditary colorectal cancer (CRC) predisposition (familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer (HNPCC))
  • Had had or are newly diagnosed with inflammatory bowel disease
  • Had had or are planned for colorectal resection
  • Were known to have bleeding diathesis or concomitant warfarin therapy or use of any other anti-coagulant or anti-platelet agent (eg. Clopidogrel)
  • Had severe liver impairment
  • Had severe renal failure (creatinine clearance <10 ml/min)
  • Were currently taking methotrexate at a weekly dose of 15 mg or more
  • Were unable to comply with study procedures and agents
  • Had a serious medical illness interfering with study participation
  • Were taking part in another interventional clinical trial
  • Failed to give written informed consent
*was not an exclusion if self-prescribed and not recommended by a Doctor and willing to stop for the duration of the Trial

What were the treatments being tested?
If a person entered into the trial, they had an equal chance to be in one of the four treatment groups:

  • Group 1 - EPA (fish oil) and aspirin
  • Group 2 - EPA (fish oil) placebo and aspirin
  • Group 3 - EPA (fish oil) and aspirin placebo
  • Group 4 - EPA (fish oil) placebo and aspirin placebo

Please note that patients allocated by chance to Group 4 (two placebo treatments) took tablets and capsules that contained no active ingredients.

What happened to someone taking part in the study?
If someone entered the trial, they were asked to complete a questionnaire about their diet, as well as provide a blood and urine sample. Everyone was required to take the study medications every day for 12 months before a ‘check-up’ colonoscopy. The trial had been designed not to interfere with the patient’s normal bowel screening care, which included a scheduled appointment after 12 months for the second routine colonoscopy. However, a specific trial visit had been included at approximately 6 months in order to collect more trial medication. Overall, during the year of participation in the trial, the person was seen by a Screening Practitioner or a Research Nurse four times in the hospital. There were also several follow-up contacts by telephone to make sure everything was going well.