70-Year-Old Tumor Samples May Help Shed Light on the Rise of Colorectal Cancer in Younger Patients

There has been an undeniable but (so far) inexplicable increase in colorectal – or bowel – cancer among young people. Potential explanations involving E.coli and unprocessed foods have been suggested, but as of yet, there is no definitive cause.

Now researchers at the Institute of Cancer Research (ICR) in the United Kingdom are turning to 70-year-old tumor samples hidden in the basement of a London hospital in the hope of solving the mystery.

“People in the 1960s lived differently than people today,” Trevor Graham, professor of genomics and evolution and director of the ICR Center for Evolution and Cancer, said in a statement.

“We believe that the exposome – the changes in diet, lifestyle and environmental factors to which we are exposed – contributes to the increase in cases and deaths from bowel cancers in young adults. »

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The baby boomers project

The study is called ‘Project Boomers’ and will involve going through a large collection of colorectal cancer samples stored at St Mark’s Hospital, which has thousands of specimens, some dating back to the 1930s. Tests have shown that, despite their age, these samples are remarkably well preserved.

By comparing the specimens with modern samples, the team aims to determine what changes in diet, lifestyle and environment may be driving the increase in cases. Specifically, the researchers plan to use genome sequencing and advanced molecular analysis techniques.

The hope is that this will allow scientists to discover how various environmental exposures, from diet to pollutants, changed the DNA in each of the samples — and how those exposures changed over time. The team is particularly interested in changes in the intestinal microbiome, the bacteria present in the intestine.

“We don’t yet know whether it’s a single factor or several, ranging from diet and genetics to microplastics and sedentary lifestyles,” Kevin Monahan, a gastroenterologist and co-director of the St Mark’s Center for Familial Bowel Cancer, said in a statement.

“What is striking is that many younger patients show no obvious signs of poor health, but are diagnosed with aggressive forms of bowel cancer. »

Bowel cancer cases are increasing worldwide

Practitioners around the world have noticed an alarming trend in recent years: while bowel cancer is more common among older adults, the number of cases reported among those 54 and younger has been steadily increasing. According to the American Cancer Society, the increase equates to 2 percent per year. In contrast, the incidence among people aged 65 and over has decreased.

This means that in 2019, 1 in 5 patients diagnosed with bowel cancer in the United States were aged 54 or younger, double that reported in 1995. Similar trends have been documented in the United Kingdom, Canada, and many other countries around the world.

According to the ICR, early cases like these tend to be diagnosed later and appear to act more aggressively than those in older people – a situation that can lead to poorer outcomes.

What could be causing the increase in cancer diagnoses?

Various explanations have been put forward for this worrying trend, from sedentary lifestyles to ultra-processed foods to microplastics, according to studies conducted in Cancer epidemiology, JAMA Oncology, And J.NCI Cancer Spectrum. Some even suggest that this increase, which, according to a study in the Journal of the National Cancer Institute, began in the 1960s, is linked to exposure to a specific type of E.coli in childhood.

But so far there is not enough evidence to say with a high level of certainty that the increase in bowel cancer among young people is linked to a single factor. This is something ICR researchers hope to change.

“We believe our unique resource of historical tumor samples at St Mark’s Hospital will open a window into new approaches to [the] prevention of bowel cancer in young people,” Monohan said.

This article does not offer medical advice and should be used for informational purposes only.

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