The impact of high-fibre diets on the unpleasant side effects of radiotherapy treatment for prostate cancer is being investigated by Aberdeen and Manchester researchers.

Led by the University of Aberdeen’s Rowett Institute and the University of Manchester and supported by a £660,000 grant from Prostate Cancer UK, the DIETRICH study will recruit more than 200 men awaiting treatment for prostate cancer. 

Radiotherapy, the primary treatment route for prostate cancer, comes with a host of unwanted side effects, including diarrhoea, bowel bleeding and bladder problems.  

Half the volunteers in the DIETRICH study will have their diet enriched with a fibre supplement derived from plants called inulin before, during and after their treatment to explore whether these symptoms can be made less severe or even eliminated.

Professor Anne Kiltie of the Rowett Institute, the study’s co-lead, said:

“This study will test the value of inulin, a dietary fibre supplement with known health benefits, in men undergoing radiotherapy for prostate cancer.

“We anticipate that this will reduce intestinal and urinary side effects that men can experience from prostate radiotherapy and will allow us to confirm our laboratory findings.

“If our trial is successful, this will lead to us undertaking a much larger study on the benefits of inulin in men undergoing prostate radiotherapy.”

Early studies in animals suggest fibre supplements may also boost radiotherapy’s ability to kill cancer cells, which this trial will also explore.

Half the participants will receive a ‘dummy’ supplement with no active ingredient for the same period.

Closely tracking the study is a cancer scientist who took early retirement following the severe side effects he experienced during radiotherapy following his prostate cancer diagnosis, Dr Tim Ward, who said:  

“If the DIETRICH study had been available when I first started my radiotherapy, I would most certainly have signed up for it and hopefully my side effects would have been much less of an issue. 

“I think it is now clear that modifying the gut bacteria is going to be important in future radiotherapy treatments.”

Simple solutions to a significant problem

Patients in Edinburgh, Glasgow, Liverpool, Preston, Leeds and Mount Vernon will be recruited, as Scotland and north-west England have the highest proportion of men whose prostate cancer is diagnosed late. 

One in three men in Scotland and one in five in the north-west of England are diagnosed with prostate cancer at stage four. 

Dr Matthew Hobbs, Director of Research at Prostate Cancer UK, said: 

“For thousands of men with early-stage prostate cancer, radiotherapy is a highly effective and potentially curative treatment.

“Sadly, however, some men can experience debilitating side effects as a result of their radiotherapy, like bowel and urinary problems, which can significantly impact their quality-of-life. 

“We’re really excited to be supporting this trial which is testing a relatively simple solution to tackle this significant problem. If shown to be effective, a fibre-rich diet could drastically reduce the severity of side effects that men experience as a result of their radiotherapy, resulting in faster recovery and a better quality of life.  

“It’s particularly great to be funding ground-breaking research across Scotland and the north-west, two regions where far too many men are being diagnosed with later-stage prostate cancer. 

“Our schemes are deliberately designed to support different types of research and Research Innovation Awards exist to support novel, game-changing projects just like this.” 

All trial participants will complete the same surveys and medical tests and, if the trial is successful and confirmed on a larger-scale, inulin supplements could become a routine part of cancer treatment. 

The researchers explained that if fibre supplements become part of routine treatment, not only could patients have a more comfortable experience, but NHS could see a reduction in the costs of treating side effects.

Electronic collection of patient information will be led by the University of Aberdeen’s Centre for Healthcare Randomised Trials (CHaRT) using a specialised web-based data collection tool. 

CHaRT director Professor Graeme MacLennan said the centre is “excited” to have supported the design of the trial and to now collaborate on delivering the trial.

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