What's new in cancer?: Microbiome
Taking part in cancer screening
Last week I popped some poo in the post. Not something I necessarily thought I’d be sharing with you all. But this blog is all about the power in poo and how we need to understand it better.
As an early birthday present I was invited to a pilot extension of a NHS cancer screening to submit a Faecal Immunochemical Test (FIT).
The FIT test is a bowel cancer screening tool that is available throughout the UK. The FIT looks for the tiny traces of blood in poo as an early sign of bowel cancer. If any is found then a colonoscopy is recommended. It is offered every 2 years to men and women aged 60 to 74. A pilot scheme is now offering the test to people in their fifties.
FIT test helpful for GPs trying to prioritise referrals when endoscopy capacity is tight. A Scottish study, co-authored by Lorna Porteous, Macmillan Regional Clinical Advisor, found that using 2 FIT tests instead of 1, increased sensitivity from 84.1% to 96.6%.
But screening only works if people take part and language matters. I have used 'poo' deliberately as it is a tested NHS approved term. Clear, accessible language improves public understanding and screening uptake.The microbiome in cancer development
Our bodies are home to trillions of microbes, bacteria, fungi, parasites and viruses collectively known as the microbiota. Where they gather is called a microbiome. The gut microbiome is especially interesting because of its links to digestion, immunity and, increasingly, cancer.
Some microbes, like H. pylori are already known to raise cancer risk. Others are now being studied in relation to bowel, breast and ovarian cancers. Everyone's microbiome is unique, shaped by diet, environment and even height.
Large research projects, including the US-based ‘Gut Project’ are using advanced genetic tools to explore how these microbes influence health. The most accessible way to study them? You guessed it, poo.
The microbiome and the treatment response
Immunotherapy has changed the way we treat cancers, but not everyone responds. A person's microbiome might explain why.
Certain bacteria seem to support a better immune response, possibly by interacting with T cells, a key part of the immune system. Early studies in humans suggest that people with particular gut bacteria respond better to treatment.
Trials are now exploring whether adjusting the microbiome through diet, antibiotics or probiotics could improve these outcomes. Even timing of treatment might make a difference, as the microbiome shifts throughout the day based on eating patterns.
Managing side effects
The microbiome might also help with side effects. One example is colitis, a bowel inflammation caused by some immunotherapies. If steroids don’t work, one emerging option is Faecal Microbiota Transplant (FMT) using a healthy donor’s gut bacteria to restore balance.
A study published in June 2023 showed FMT helped 10 out of 12 people with hard-to-treat colitis. While still in the early stages, it’s an encouraging area of research.
Why this matters
- FIT testing helps detect bowel cancer early and doing it twice may improve accuracy.
- The microbiome could be a key factor in how people respond to treatment and how they manage side effects.
- Clear communication, including words like “poo”, plays an important role in public health.
There’s still much to learn, but one thing’s clear: poo is now firmly part of the cancer conversation and that’s a good thing.
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