Tens of thousands of tumour samples which have been stored in the basement of a London hospital for more than 70 years could be the key to unlocking the mystery of why bowel cancer cases are rising in the under 50s, scientists believe.
Researchers at The Institute of Cancer Research, London, and St Marks Hospital are launching a pioneering study to compare bowel cancer specimens from the 1960s with modern-day cancer samples.
Using cutting-edge lab techniques, the team hopes to uncover how changes in diet, lifestyle, and environmental exposures – collectively known as the exposome – may be driving the rise in cases of early-onset bowel cancer.
Bowel cancer is the fourth most common cancer in the UK and the second leading cause of cancer deaths. While screening programmes have helped reduce cases in older adults, diagnoses among younger people have been climbing in recent years –and are expected to double between 2010 and 2030.
Early-onset cancers are found later
Some studies have shown that these early-onset cancers are diagnosed at a later stage and seem to behave more aggressively than bowel cancer in older people, so even with better treatments, the outcomes for these patients are often poor.
Research has so far been unable to determine why bowel cancer is becoming more common in younger people, although many theories have been proposed, including changes in diet and lifestyle, exposure to environmental pollutants such as microplastics, and even changes to the bugs living in the bowel (known as the microbiome).
The study, called the “Boomers Project”, will use preserved pathology specimens from St Mark’s Hospital, home to one of the UK’s oldest archives of bowel cancer samples. Early tests have shown that even after decades in storage, the samples, some of which date as far back as the turn of the 20th century remain intact and suitable for advanced molecular analysis techniques.
Mapping how DNA is altered in old samples
Different environmental exposures – such as smoking or diet – each shape the DNA inside the cancer in unique ways. The researchers plan to use genome sequencing techniques – including novel approaches developed at The Institute of Cancer Research (ICR) – to map how the DNA is altered in the cancer specimens from the 1950s compared to cases from the present day. The comparison will show how environment exposures have changed over the past decades.
If successful, the project could pave the way for a larger-scale investigation and inform new strategies for prevention, diagnosis, and treatment.
Professor Trevor Graham, Professor of Genomics and Evolution and Director of the Centre for Evolution and Cancer at 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.
'We hope to identify exactly what is driving the increase in bowel cancer diagnoses 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.”
Project co-lead Professor Kevin Monahan, Gastroenterologist and Co-Director of The St Mark’s Centre for Familial Intestinal Cancer, said:
“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.”
'We need to protect younger people and find out why more of us are being diagnosed with cancer'
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.”