Why the contents of a hospital basement may help shed light on one of cancer’s deadliest killers
Thousands of tumour samples stored in the basement of a London hospital for the past century could unlock the key to understanding why so many under 50s are being diagnosed with bowel cancer.
St Mark's National Bowel Hospital has one of the largest and oldest repositories of pathology specimens in the UK dating back to the 1930s when surgeons' notes included hand-drawn sketches of tumours to accompany samples preserved in wax.
The Institute of Cancer Research and St Marks will compare bowel cancer specimens from the 1960s with modern-day samples to see if changes in diet, lifestyle and environmental factors are behind the increase.
The Boomers initiative will employ advanced molecular analysis techniques meaning samples which until recently held little more than historical value can now be utilised by scientists.
Bowel cancer is the fourth most common cancer in the UK and the second leading cause of cancer deaths and, while screening programmes have helped reduce cases in older adults, diagnoses among younger people has risen in recent years.
This figure is expected to double between 2010 and 2030.
Some studies have shown that early-onset cancers behave more aggressively than bowel cancer in older people so even with better treatments, outcomes are often poor.
To date, research hasn't been able to show why bowel cancer is becoming more common among the young.
Theories include changes in diet and lifestyle, exposure to environmental pollutants such as microplastics, and even exposure during childhood to bacterial toxins like colibactin.
Different environmental exposures - such as smoking or diet - shape the DNA inside the cancer in unique ways and researchers plan to use genome sequencing techniques - including novel approaches developed at The Institute of Cancer Research (ICR) - to map how DNA is altered in cancer specimens from different eras.
The comparison will show how environment exposures have changed over the intervening decades.
Researchers are particularly interested in the role of the gut microbiome - the bacteria that live in our bowel - and how changes to which bugs live in the bowel could underlie the increase in bowel cancers in young people.
The ICR team, led by Professor Trevor Graham, have recently been awarded funding for a pilot study to validate their approach.
If successful, it could pave the way for a larger-scale investigation and inform new strategies for prevention, diagnosis, and treatment.
The research forms part of a broader effort led by the UK Early Onset Colorectal Cancer Academic Consortium, co-chaired by Professor Kevin Monahan of St Mark's Hospital and Professor Colin Rees, professor of gastroenterology at The Population Health Sciences Institute at Newcastle University.
The consortium brings together more than 100 researchers, clinicians, and patients to investigate risk factors, diagnostics, and patient experiences.
Professor Trevor Graham from the Institute of Cancer Research, London, said: “People in the 1960s lived differently to people today. We believe that the exposome - the changes in diet, lifestyle and environmental factors we are exposed to - is contributing to the increase in cases and deaths from bowel cancers in younger adults.
“By performing detailed molecular analysis of bowel cancers from the 1960s and comparing the results to bowel cancers from today, we hope to identify exactly what is driving the increase in bowel cancer diagnoses in younger adults.
"This could lead to new strategies for bowel cancer prevention and treatment.”
Holly Masters was diagnosed with stage three rectal cancer over four years ago, when she was just 23.
The actor and access support worker from East Anglia was successfully treated with chemo-radiation, combined chemotherapy and major surgery.
Holly said: “I'd known that something wasn't right a year before my diagnosis. I had all the symptoms of bowel cancer. But the doctors told me I had IBS and I was eventually diagnosed through emergency admission at A&E.
"I went through a range of emotions when I was told I had cancer - up until that moment it hadn't even crossed my mind.
"It did feel unfair to be diagnosed at such a young age. I lost all my innocence and realised how harsh life can be.
"I now have a stoma which did take some getting used to and it took me a long time to accept the most difficult consequence-the fear that the cancer will come back. 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 find out why more of us are being diagnosed with cancer.”
Professor Kevin Monahan, Co-lead for the project and Gastroenterologist and Co-Director of The St Mark's Centre for Familial Intestinal Cancer, added: “We have a lot to learn about the causes of bowel cancer in young people, and why this has been increasing in recent decades.
“We don't yet know whether it's one factor or many ranging from diet and genetics to microplastics and sedentary lifestyles.
"What's striking is that many younger patients show no obvious signs of poor health yet are being diagnosed with aggressive forms of bowel cancer.
“We believe that our unique resource of historical tumour samples at St Mark's Hospital will open a window to new approaches to prevention of bowel cancer in the young.
“A healthy diet and regular exercise, as well as speaking to your GP if you have new bowel symptoms such as bleeding from the back passage, or a change in how often you open your bowels, remain some of the most important ways of reducing the risk of bowel cancer.”