Tens of thousands of bowel cancer tumour samples stored for more than 70 years in the basement of a London hospital could help scientists uncover why bowel cancer rates are rising sharply among people under the age of 50.
Researchers at The Institute of Cancer Research, London, working alongside clinicians at St Mark’s Hospital, are launching a pioneering study that will compare bowel cancer specimens collected in the mid 20th century with samples taken from patients today. By analysing how these cancers differ at a molecular level, the team hopes to identify environmental and lifestyle factors that may be driving the increase in early onset bowel cancer.
Bowel cancer is the fourth most common cancer in the UK and the second leading cause of cancer related deaths. While national screening programmes have successfully reduced diagnoses among older adults, cases in younger people continue to rise. Current projections suggest diagnoses in people under 50 could double between 2010 and 2030, raising urgent questions about what has changed over recent decades.
Historically, bowel cancer has been considered a disease of later life. As a result, younger people are less likely to be screened and may not immediately recognise symptoms as potential signs of cancer. This has serious consequences.
Studies show that bowel cancers in younger adults are often diagnosed at a later stage and may behave more aggressively than those found in older patients. Even with advances in treatment, outcomes for younger patients are often poorer, with higher rates of advanced disease at diagnosis.
Despite extensive research, scientists have yet to pinpoint a clear cause for the rise in early onset bowel cancer. A range of theories have been proposed, including changes in diet, increasing obesity, sedentary lifestyles, environmental pollution, exposure to microplastics, and alterations in the gut microbiome.
The new study aims to bring clarity by looking directly at how bowel cancer itself has changed over time.
St Mark’s Hospital is home to one of the UK’s oldest and most extensive collections of bowel cancer pathology specimens. The archive includes tens of thousands of tumour samples preserved in wax blocks, some dating back to the early 1900s.
These samples were collected long before many modern lifestyle factors became widespread. Early testing has shown that, despite decades in storage, the tissue remains intact and suitable for advanced molecular analysis.
This presents a rare opportunity for researchers. Instead of relying solely on modern samples and historical records, scientists can directly compare cancers from different eras using the same analytical tools.
The study, known as the Boomers Project, focuses on the role of the exposome. The exposome refers to the total range of environmental exposures a person experiences throughout their lifetime, including diet, physical activity, pollution, chemicals, infections, and social factors.
Unlike genetic risk, which remains relatively stable across generations, the exposome changes as societies evolve. People living in the 1950s and 1960s ate different foods, were generally more physically active, and were exposed to a very different mix of environmental factors compared to people today.
Researchers believe these differences may leave distinct patterns of damage in the DNA of cancer cells. Certain exposures are known to create specific mutational signatures, which can be detected using genome sequencing.
By identifying and comparing these signatures in historical and modern tumour samples, the research team hopes to determine how changes in environment and lifestyle may be contributing to the rise in bowel cancer among younger adults.
Using cutting edge genome sequencing techniques, including novel methods developed at The Institute of Cancer Research, scientists will analyse how DNA has been altered in bowel cancer samples from different time periods.
The project will compare specimens from the 1950s and 1960s with cancers diagnosed in recent years. This will allow researchers to identify patterns linked to specific environmental exposures and track how these have changed over time.
If successful, the study could reveal previously unrecognised risk factors and provide crucial insights into why bowel cancer is becoming more common in younger people.
Professor Trevor Graham, Professor of Genomics and Evolution and Director of the Centre for Evolution and Cancer at The Institute of Cancer Research, London, explained the importance of this approach.
“People in the 1960s lived very differently to people today. We believe that changes in diet, lifestyle, and environmental exposures are contributing to the increase in bowel cancer cases and deaths among younger adults.
“By performing detailed molecular analysis of bowel cancers from the 1960s and comparing them with bowel cancers from today, we hope to identify exactly what is driving the increase in diagnoses in younger people. This could lead to new strategies for prevention, earlier diagnosis, and more effective treatment.”
Understanding what is driving early onset bowel cancer is critical for public health. If specific environmental or lifestyle factors can be identified, this knowledge could inform new prevention strategies and policy decisions.
It may also lead to improved screening approaches for younger people and help clinicians identify those at higher risk earlier. In the longer term, insights from this research could support the development of more targeted treatments based on the biological characteristics of early onset cancers.
Professor Kevin Monahan, Gastroenterologist and Co Director of The St Mark’s Centre for Familial Intestinal Cancer, is co leading the study and believes the hospital’s archive is a national treasure.
“We have a lot to learn about why bowel cancer is increasing in young people,” he said. “We do not yet know whether it is driven by one factor or a combination of many, ranging from diet and genetics to microplastics and sedentary lifestyles.
“What is striking is that many younger patients show no obvious signs of poor health, yet are diagnosed with aggressive forms of bowel cancer. Our unique collection of historical tumour samples gives us an unprecedented opportunity to explore this problem and develop new approaches to prevention.”
He also stressed that existing advice remains vital. Maintaining a healthy diet, staying physically active, and seeking medical advice for new bowel symptoms such as bleeding or changes in bowel habits are still among the most important ways to reduce risk.
Behind the statistics are people whose lives have been profoundly changed by a diagnosis at a young age. Holly Masters was just 23 when she was diagnosed with stage three rectal cancer.
The actor and access support worker from East Anglia underwent intensive treatment, including chemo radiotherapy, combined chemotherapy, and major surgery. While her treatment was successful, the experience continues to shape her life.
“I knew something was wrong for about a year before my diagnosis,” Holly said. “I had the symptoms of bowel cancer, but I was told it was IBS. I was eventually diagnosed after an emergency admission to A and E.
“It never crossed my mind that I could have cancer at that age. Being diagnosed so young felt incredibly unfair. I lost my sense of safety overnight.”
Holly now lives with a stoma and with the ongoing fear of recurrence. “I have to live with the mental and physical effects of my diagnosis for the rest of my life. We need to protect younger people and understand why more of us are being diagnosed with cancer.”
If the Boomers Project is successful, it could pave the way for a much larger scale investigation into early onset bowel cancer. The findings could help shape future prevention campaigns, influence dietary and environmental policy, and improve outcomes for younger patients.
The study also highlights the enduring value of historical medical collections. Samples preserved decades ago for routine pathology could now help answer some of the most pressing questions in modern cancer research.
As scientists analyse these tumour samples, they are not only looking back at how cancer has changed over time. They are working towards a future where fewer young people face a diagnosis that arrives too late and changes their lives forever.
Source: ICR News | 07 January 2026
This article is for informational purposes only and does not constitute medical advice. Individuals concerned about bowel cancer symptoms or risk should seek advice from a qualified healthcare professional.
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