A team of investigators, led by Professor Mark Hull from the University of Leeds, studied patients diagnosed with the rare inherited condition familial adenomatous polyposis (FAP), thought to be responsible for approximately one in every 100 bowel cancers.

Scientists observed a significant reduction in the size and number of pre-cancerous growths, or polyps, during a six month trial of the omega-3 preparation. Now Professor Hull and his team say that further research is needed to find out whether this new agent, eicosapentaenoic acid (EPA), could help prevent the non-hereditary form of bowel cancer, which is the third most common cancer in the UK and is diagnosed in approximately 37,000 people each year.

FAP causes a large number of polyps to form in the lining of the large bowel. Patients usually undergo bowel surgery but remain at risk of developing polyps and cancer in any remaining bowel, so regular endoscopic (camera test) checks are required.

Professor Hull said: ‘A safe and effective drug therapy may reduce the number of invasive check-up procedures, which can be unpleasant and always involve a small amount of risk.

During a randomized, placebo-controlled trial, the team observed the condition of 55 patients over six months. Twenty-eight patients were given 2 grams daily of a new, highly purified formulation of the omega-3 polyunsaturated fatty acid EPA (‘Alfa’). Researchers observed a significant reduction in the number and size of polyps in this group, whereas the placebo group showed an increase in polyp number and size over the same period.

‘The particular preparation of EPA that we used delivers approximately four times as much beneficial polyunsaturated fatty acid per day as is derived from eating two to three portions of fish a week. The drug is also designed to be released into the small intestine, minimising nausea and halitosis often associated with taking over-the-counter fish oil supplements,’ said Professor Hull.

The paper ‘Eicosapentaenoic acid reduces rectal polyp number and size in familial adenomatous polyposis’ is published in GUT.