Probiotics show promise in managing radiotherapy side-effects

Bowel problems are a common side-effect from cancer radiotherapy targeted to the abdomen region. Probiotic supplements appear to have a favourable benefit in lessening these problems.

Radiotherapy is an effective treatment for certain types of cancers, but like any cancer treatment, it is not without its side effects.

Depending on what part of the body is being targeted by the radiotherapy, and the duration of the treatment, side effects can vary. Common side effects include fatigue, skin burning and inflammation, loss of appetite, swallowing problems, nausea, and diarrhoea.

If radiotherapy is being targeted to the stomach or lower abdomen, then diarrhoea is a very likely consequence. While the radiotherapy is effective in destroying cancer cells in this area, healthy cells lining the bowel can succumb to ‘friendly fire’. Up to 90% of people receiving lower abdomen radiotherapy can experience some form of ongoing disruption to their bowel habits which can persist for months to even years after treatment.

Researchers have wondered for some time if the advice to people receiving radiotherapy to follow a lower fibre diet to help mitigate some of the problems of diarrhoea and gastrointestinal problems from treatment could have some adverse consequences. One of these potential problems is causing a change in the intestinal bacterial microflora profile of the gut. Enter the idea of trialling probiotic supplements in people receiving radiotherapy to help maintain and support the normal gut bacteria population.

About probiotics

Probiotics are foods or dietary supplements that contain beneficial bacteria which are normally found in the body. Fermented milk products such as yoghurt, sour cream, buttermilk and commercial products such as Yakult are examples of foods that act as probiotics. Although probiotics are not considered essential to health, the microorganisms they contain may assist with digestion or help protect against harmful bacteria by improving the workings of the immune system.

Compiling the research

There have already been a number of small-scale clinical trials exploring the benefit that probiotics can have on radiation-induced bowel disease caused by radiotherapy. When the clinical trials are considered on their own, it is hard to see if there is a clear benefit or not. Scientists have now collated all the research together in the form of a meta-analysis to see if there is a key message from the research field.

All up, 10 randomised-controlled clinical trials were identified which used a range of probiotic supplements. Six of the clinical trials were considered of good enough quality to form part of the meta-analysis. The results appeared favourable with a significant reduction in the incidence of diarrhoea by over 50% when comparing people given probiotics against a control group. Although not achieving the level of statistical significance, there was a trend for lower use of anti-diarrhoeal medications and less reports of watery stools.

What it all means

The use of a cheap and simple nutritional intervention with probiotics shows promise in having a role in managing bowel side effects from radiotherapy treatment. With further studies likely to add to the evidence base in the future, the use of probiotics could become a standard part of some radiotherapy treatments.