Trial to investigate if chemical in red grapes can prevent bowel cancer

Scientists will explore if a chemical mostly found in red grapes – and products made from red grapes, such as wine and juice – can help prevent bowel cancer as part of a major new trial.

The study, known as Colo-Prevent, has been hailed as a “unique experiment” which could have “big implications” for people at risk of the disease.

It will also look at other potential treatments to prevent bowel cancer, including aspirin and metformin, a medication prescribed to help people with type 2 diabetes control their blood sugar.

It is hoped around 1,300 patients will be taking part in the trial across 60 locations in England and Wales by the start of 2028.

Researchers will use a purified resveratrol, which is a natural compound mostly found in red grapes, as well as blueberries, raspberries and peanuts.

Karen Brown, a professor of translational cancer research at the University of Leicester, is leading the study, with her previous research having found that purified resveratrol can hinder the growth of cancer cells in small doses.

She described the trial as a “unique experiment” to see how drugs could stop bowel polyps from growing.

“This trial could have big implications for how we prevent bowel cancer in people who are most likely to develop the disease as they get older,” Professor Brown said.

Experts are recruiting people aged between 50 and 73 who have taken part in the NHS bowel screening programme and been found to have bowel polyps, which are small growths that are usually not serious but can develop into cancer if left untreated.

Patients will have their polyps removed and will be given either aspirin by itself or a combination of aspirin and metformin, for the main trial.

Others will take purified resveratrol or a placebo as part of a sub-study.

Those in the aspirin and metformin groups will take the drugs daily for three years, while those on resveratrol or the placebo will take it for one year.

All patients will then be given a colonoscopy – when a long thin tube with a camera on the end is inserted into the bottom to help doctors see inside the colon – to determine if the polyps have started growing again.

Bowel cancer is the fourth most common cancer in the UK, with an estimated 44,000 people each year – or about 120 a day – diagnosed with the disease.

It is not always known what causes it, but the NHS advises people to exercise regularly, eat more fruit and vegetables, drink less alcohol and quit smoking to reduce their risk.

Bowel cancer screening is also offered to everyone aged between 54 and 74 every two years.

People are sent faecal immunochemical test (FIT) kits – which look for blood in poo – through the post, allowing them to collect the sample at home.

Dr Iain Foulkes, executive director of research and innovation at Cancer Research UK, which is funding the trial, said the trial opens the door to “a new era of cancer research” where cancer becomes much more preventable through cutting-edge science.

“The insights gained from the trial will change how we think about cancer prevention and give more people the chance of longer, better lives, free from the fear of cancer,” he said.

David Trusler, 66, is one of the first patients to take part in the study and said he is doing so for his father, who died with bowel cancer when David was a teenager.

Mr Trusler, from Market Harborough in Leicestershire, was diagnosed with prostate cancer 11 years ago, and after successful surgery, it has not returned.

He has been taking part in the NHS bowel screening programme since 2018 and, after receiving an abnormal result earlier this year, a colonoscopy revealed two large polyps.

“My first thought was, ‘oh no, not again’,” Mr Trusler said. “I lost my dad when I was 17 to bowel cancer.

“We had such a strong bond. I’ll never forget how angry it made me to lose that time with him. When my dad was diagnosed in the 1970s, there was no MRIs, no ultrasound. Many of the advances in cancer treatment we have now simply didn’t exist then,” he said.

“I’m taking part in this trial for my dad, to give future generations the kind of treatments he never had,” he added.

Professor Brown added that there are ways to decrease the risk of developing bowel cancer, including maintaining a health weight, reducing alcohol consumption and having a healthy, balanced diet.

“But we can enhance those efforts by embracing therapeutic prevention, which uses our growing knowledge of the biology of cancer to find drugs which can stop it in its earliest stages,” he said.