RecruitingInterventional

Dietary fibre supplementation to reduce side effects of prostate radiotherapy (DIETRICH study)

The DIETRICH study is investigating if a fibre supplement can reduce common side effects of radiotherapy for prostate cancer. Radiotherapy is a treatment that can help fight prostate cancer, but it often leads to problems like diarrhoea, discomfort, and needing to pee more often. These side effects can affect up to half of men and sometimes last a long time, impacting their daily lives. Inulin, a natural fibre from plants like chicory, is thought to help by boosting good gut bacteria and reducing swelling in the bowel. Researchers will give 220 men either inulin or a dummy supplement for a period before, during, and after their radiotherapy to see if those taking inulin experience fewer gut and bladder issues.

At a glance

Status

Recruiting

Enrolment target

220

Start

01 Jun 2026

Estimated completion

30 Jun 2027

Prevention of acute bowel toxicity and urinary side effects in men undergoing radiotherapy for prostate cancer.

What is this study about?

When men have radiotherapy for prostate cancer, it's a really important treatment that can help get rid of the cancer. However, it can sometimes cause tricky side effects, especially problems with their bowel and bladder. Things like needing to go to the toilet more often, having diarrhoea, or feeling uncomfortable in the tummy or bladder can happen for many men. For about half of those treated, these side effects can be quite noticeable and can even continue for a while after the treatment has finished, making everyday life a bit harder.

This study, called DIETRICH, wants to find out if taking a simple dietary fibre supplement could help reduce these unwanted side effects. We know that certain fibres, like inulin, can be good for your gut health. Inulin is a natural ingredient found in plants like chicory root, and it works by helping the 'good' bacteria in your gut to grow. These good bacteria can help calm down any swelling in the bowel, which might then lead to fewer problems during and after radiotherapy for prostate cancer.

Researchers are looking for 220 men who are going to have radiotherapy for their prostate cancer. They will be split into two groups: one group will take the inulin supplement, and the other group will take a 'dummy' supplement (a placebo) that looks and tastes the same but doesn't contain fibre. By comparing these two groups, the study hopes to learn if taking inulin really does help reduce bowel and bladder problems, improving the experience for men undergoing this important cancer treatment.

Key takeaways

The study aims to reduce radiotherapy side effects for prostate cancer patients.
It tests a natural fibre supplement called inulin.
Participation involves taking a supplement and answering questions for 18 weeks.
Half of participants get fibre, the other half a dummy supplement.
Helping researchers understand how to improve patient well-being is a key benefit.

Who may be eligible?

This study is looking for men who have been diagnosed with prostate cancer that is considered intermediate or high risk, meaning it needs treatment. You should be planning to have radiotherapy to treat this cancer. You must be at least 18 years old and feel well enough to carry out most of your normal daily activities without too much difficulty.

However, some things would mean you can't join the study. For example, if you've already had major bowel surgery, previous radiotherapy to your prostate, or certain other health conditions like poorly controlled diabetes or coeliac disease. Also, if you know you're allergic to inulin or a common ingredient called maltodextrin (which is in the dummy supplement), you wouldn't be able to take part.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you a man undergoing radiotherapy for prostate cancer?
Is your prostate cancer considered intermediate or high risk?
Are you 18 years or older?
Do you feel well enough for normal daily activities?
Have you NOT had major bowel surgery, previous prostate radiotherapy, or certain other specific health conditions?

Answer every question to see your result.

What does participation involve?

If you decide to take part in the DIETRICH study, your involvement will last for a total of 18 weeks. You'll be given either the fibre supplement (inulin) or a dummy supplement – you won't know which one you're taking. You'll start taking it two weeks before your radiotherapy begins, continue throughout your four weeks of treatment, and for another three weeks afterwards.

During this time, you'll be asked to fill out some questionnaires about your symptoms and your diet. This helps the researchers understand how you're feeling and eating. You'll also be asked to provide some stool (poo) samples: one before your radiotherapy and another after it finishes. These samples will help the researchers study the bacteria in your gut and understand how the supplement might be working to improve your gut health.

Potential risks and benefits

Participating in this study might mean you experience fewer gut and bladder problems from your radiotherapy, but this isn't guaranteed. Your involvement will definitely help doctors learn more about how diet can support men during cancer treatment. Risks are generally low; some people might notice mild changes in their digestion from the fibre supplement, like a bit of bloating or gas, but these are usually temporary and mild. Remember, you can choose to leave the study at any time, for any reason.

Locations (8)

Aberdeen Royal Infirmary
Approximate
Aberdeen, Scotland
Edinburgh Cancer Centre
Approximate
Edinburgh, Scotland
Beatson West of Scotland Cancer Centre
City only
Glasgow, Scotland
St James's Teaching Hospital
City only
Leeds, England
The Clatterbridge Cancer Centre NHS Foundation Trust
City only
Wirral, England
The Christie
Approximate
Manchester, England
Mount Vernon Cancer Centre
City only
Northwood, England
Rosemere Cancer Centre
City only
Preston, England

Common questions

What is inulin?

Inulin is a natural type of fibre found in plants, like chicory root. It helps boost the good bacteria in your gut.

Will I know if I'm taking the fibre or the dummy supplement?

No, neither you nor the study team will know which one you're taking until the study ends. This helps make the study fair.

How long will I be involved in the study?

Your involvement in the study will be for a total of 18 weeks, starting before your radiotherapy and finishing a few weeks after.

Do I have to change my diet for this study?

You won't have to drastically change your diet, but you will be asked to answer some questions about what you eat.

What happens to the poo samples I give?

The samples will be used to study the bacteria in your gut. This helps researchers understand how the supplement might affect your gut health.

How to find out more

Kirsteen Goodman

dietrich@abdn.ac.uk +44 1224 438103 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.