Eicosapentaenoic Acid and Aspirin in Preventing Colorectal Adenomas


Key Points

  • There was no evidence of treatment effect for EPA vs no EPA or aspirin vs no aspirin.
  • Adenoma detection rates at 1 year ranged from 61% to 63% among all groups.

In a UK trial (seAFOod Polyp Prevention) reported in The Lancet by Hull et al, no differences in adenoma prevention were found after treatment with omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA), aspirin, both, or placebo in patients with high-risk findings on colonoscopy.

On the double-blind, 2 × 2 factorial trial, patients aged 55 to 73 years identified during colonoscopy as being at high risk in the English Bowel Cancer Screening Programme (≥ 3 adenomas if at least 1 was ≥ 10 mm in diameter or ≥ 5 adenomas if all were < 10 mm in diameter) were recruited from 53 endoscopy units between November 2011 and June 2016. Patients were randomly assigned 1:1:1:1 to receive 2 g of EPA-free fatty acid per day (n = 179), 300 mg of aspirin per day (n = 177), both (n = 177), or placebo (n = 176).

The primary endpoint was adenoma detection rate at 1-year surveillance colonoscopy in all patients with available follow-up data.

Adenoma Detection Rates

Adenoma outcome data were available for 93% of patients in the placebo group, 85% of the EPA group, 92% of the aspirin group, and 91% of the EPA-plus-aspirin group. Adenoma detection rates were 61% in the placebo group, 63% in the EPA group, 61% in the aspirin group, and 61% in the EPA-plus-aspirin group.

There was no evidence of treatment effect for EPA vs no EPA (risk ratio [RR] = 0.98, risk difference = −0.9%, P = .81) or aspirin vs no aspirin (RR = 0.99, risk difference = −0.6%, P = .88). The mean numbers of adenomas per patient were 1.4 in the placebo group, 1.6 in the EPA group, 1.3 in the aspirin group, and 1.0 in the combination group. No colorectal cancers were detected during the study.

Adverse Events

Adverse events of any grade occurred in 44% of the placebo group, compared with 46% of the EPA group, 39% of the aspirin group, and 45% of the EPA-plus-aspirin group. The EPA group had a greater number of gastrointestinal adverse events (n = 146) compared with the placebo (n = 85), aspirin (n = 86), and combination (n = 68) groups. A total of 6 patients had upper gastrointestinal bleeding events, including 2 in the EPA group, 3 in the aspirin group, and 1 in the placebo group.

The investigators concluded, “Neither EPA nor aspirin treatment were associated with a reduction in the proportion of patients with at least one colorectal adenoma. Further research is needed regarding the effect on colorectal adenoma number according to adenoma type and location. Optimal use of EPA and aspirin might need a precision medicine approach to adenoma recurrence.”

Mark A. Hull, FRCP, of the Institute of Biomedical and Clinical Sciences, University of Leeds, St. James’s University Hospital, is the corresponding author for The Lancet article.

Disclosure: The study was funded by Efficacy and Mechanism Evaluation Programme, a UK Medical Research Council and National Institute for Health Research partnership. The study authors’ full disclosures can be found at

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