Scientists suggest they are edging closer to uncovering the reason behind a spike in bowel cancer cases among younger adults.
There has been a surge in diagnoses in those under the age of 55 with the cancer - also known as colorectal cancer - causing concern throughout the medical community who are unsure why the increase is occurring.
The disease is often linked to lifestyle, with risk increased if a person smokes, drinks over the recommended amount of alcohol or is obese. However, bowel cancer has been spotted in fit people who eat a healthy diet.
And now experts in the US are examining other potential reasons for the surge. New findings from Georgetown University suggest that a person's microbiome - the collection of microbes, such as bacteria, fungi and viruses naturally existing in the body - may be a contributing factor.
The Washington DC scientists found that tumours from younger patients were more likely to continue Cladosporium sp - a fungus found in a person's body - compared to tumours of older patients, reports The Mirror.
Bowel cancer is the third most common cancer in Scotland with 4,000 people diagnosed each year, according to NHS Inform. Bowel cancer screening is offered to those aged between 50 and 74 every two years to help identify the disease early if present.
To examine the potential reasons behind the increase, researchers studied tissue samples from 63 patients who were either under 45 or over 65.
Analysis of the tissue found that Cladosporium sp was more commonly identified in tissues from the younger group of participants.
It remains unclear how Cladosporium sp could cause a spike, but the scientists believe the fungus could be damaging cell DNA, turning them into cancerous cells.
The reason why the tumours of younger people included Cladosporium sp is also unclear, but researchers have some theories.
Gastrointestinal cancer expert Dr Benjamin Adam Weinberg said: "There was some sort of exposure we think in the 1970s or 1980s — maybe everybody started taking antibiotics for ear infections or they stopped breastfeeding — something happened where this cohort is seeing this rise and we don't know why."
The findings are set to be presented at the American Society of Clinical Oncology's annual meeting in Chicago next week.
Bowel cancer symptoms
According to the NHS, bowel cancer symptoms may include:
- changes in your poo, such as having softer poo, diarrhoea or constipation that is not usual for you
- needing to poo more or less often than usual for you
- blood in your poo, which may look red or black
- bleeding from your bottom
- often feeling like you need to poo, even if you've just been to the toilet
- tummy pain
- bloating
- losing weight without trying
- feeling very tired for no reason
It is recommended that you seek medical attention from your GP if experiencing any of the symptoms listed above for three weeks or more.
Rates in those under the age of 55 have been increasing since the 1990s, with gastrointestinal cancer expert Georgetown's Dr Weinberg telling AXIOS: "A lot of people blame obesity and diabetes.
"But we have these patients who run marathons and they eat [healthy diets] and they've got very advanced colorectal cancer."
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