Century-old tumours could reveal why more young people are getting bowel cancer

Bowel cancer samples stored for up to a century will be analyzed to try to unravel the disease’s mysterious rise in young people.

Although the majority of bowel cancers still occur in older adults, there is also an increase in the number of younger patients worldwide.

This includes the UK, where bowel cancer rates in people under 24 have increased by 75% since the early 1990s; but scientists cannot explain why.

There is a unique collection of tens of thousands of archived cancer samples in the basement of St Mark’s National Bowel Hospital.

These now undergo advanced scientific analysis to understand what causes each cancer and what has changed over the decades.

Holly, 27, is one of a growing number of young people infected with the disease.

Her bloating and weight loss were initially attributed to irritable bowel syndrome, until she became so ill she went to A&E.

The young actor was diagnosed with advanced bowel cancer when he was only 23 years old and required aggressive treatment.

Holly said intense chemotherapy “affected me in ways I never thought possible” and that “the hardest thing was accepting that life wouldn’t be the same.”

He currently lives with a stoma and needs regular check-ups.

Holly has been cancer-free for more than three years and is planning her wedding, but says being diagnosed at such a young age has days when it makes her “scream and cry”.

“This all feels really unfair and I’m thinking, oh why me?”

Science doesn’t have a clear answer either. Everything from obesity and overly processed foods to antibiotics, the microbiome, air pollution and microplastics have been suggested.

Consultant gastroenterologist at St Mark’s Hospital, Dr. “Bowline cancer in people under the age of 50 is increasing and becoming an increasingly problem worldwide, including in the UK,” said Kevin Monahan.

“We need to develop ways we can effectively prevent these cancers,” he added.

In the UK, rates have increased by 51% in people aged 25-49 since the early 1990s, but the majority of bowel cancers still occur in older adults.

The archives contain samples from every bowel cancer patient treated in hospital, making it “probably a unique resource anywhere in the world” for uncovering causes in young people, Monahan said.

Intestinal cancers and accompanying intestinal bacteria were preserved in paraffin wax.

They are sent to the Institute of Cancer Research (ICR) for detailed molecular analysis, which has recently become possible.

Different causes of cancer leave different marks, or signatures, on the DNA of cells that become cancerous.

Tracking how common different signatures are over time could point to the possible cause of cancer in young people.

Prof Trevor Graham from the ICR said: “Our basic idea is that there is a specific strain of E. coli living in the intestines of young people today that did not exist in the past.”

These bacteria are thought to secrete toxins that damage the DNA in the intestinal tissue and turn it into cancer. Although the question remains why are these bacteria more common now?

“If these so-called bad bugs are causing the increase, we should see a signature of these bad bugs, where damage was rare in the past and becomes increasingly common as we move into the present … we can also test other ideas,” Graham said.

But whatever is behind the increase, he said the archives are “a real treasure trove”, adding: “I think the answer may be in this room.”