Medics are calling for bowel cancer screening to be introduced at the age of 45 after a sharp rise in younger people being diagnosed with the disease.
Research has found that while incidence of the disease is falling among older age groups – who are asked to undergo NHS checks every two years – it is increasing among those below the age of 50.
The study of 21 western countries, published by the Lancet, found that in the UK, rates of the disease are rising by 1.8 per cent a year among those under the age of 50, while dropping by 1.2 per cent annually in older groups.
And separate research involving more than 140 million adults found that across Europe, cases are rising by more than seven per cent a year among those in their 20s and 30s.
Experts said soaring levels of obesity, driven by unhealthy lifestyles, appeared to be driving the trend.
They urged health officials to bring down the age of screening to 45, in line with US advice, in order to detect cases earlier, when disease is more likely to be preventable.
The NHS is currently piloting checks from the age of 55 in some areas, while in others, screening is not offered until the age of 60. Officials have said they intend to lower the age to 50. In Scotland it is offered from the age of 50, while in Wales it starts at 60, and in Northern Ireland it starts at 55.
The findings come from two studies, published simultaneously.
One, published in the Lancet Gastroenterology and Hepatology journal, looked at colon and rectal cancer rates in developed countries such as the UK, New Zealand, Canada and Denmark.
Dr Marzieh Araghi, the lead author of the study from the International Agency for Research on Cancer in Lyon, said: “Although the incidence of colorectal cancer in adults younger than 50 years remains much lower compared with that in older age groups, our findings are of concern and highlight the need for action to counteract the rising burden of the disease in younger people.
“This rise in incidence among younger generations is likely to be driven in part by the changing prevalence of risk factors, such as obesity and poor diet.
“National programmes to promote healthy diets and physical activity might be the most efficient approach to ensure population-level changes.”
In a linked commentary, Professor Giulia Martina Cavestro from Vita-Salute San Raffaele University, Milan said, “In 2018, the American Cancer Society recommended that screening for colorectal cancer should start at age 45 years for all adults. Such an approach is needed, but other initiatives should be endorsed alongside this decision,” she said, calling for more campaigns to boost public awareness.
Mr Andrew Beggs, Consultant Colorectal Surgeon and Cancer Research UK Advanced Clinician Scientist, University of Birmingham, said surgeons were seeing more and more young patients being diagnosed with bowel cancer.
He said: “The reasons why this is happening aren’t clear, but it must be urgently investigated. This means the age at which bowel cancer screening needs to start may have to change to screen people at a younger age, and people under the age of 50 with any “red flag” symptoms (bleeding, a change in bowel habit, weight loss or tummy pain) should get it checked out as soon as possible.”
A second study, published in the GUT journal, found between 1990 and 2016 the number of younger people diagnosed with bowel cancer had risen at a steeper rate after 2004.
Among 20 to 29-year-olds, bowel cancer incidence rose from 0.8 to 2.3 cases per 100,000 people between 1990 and 2016.
The sharpest rise was between 2004 and 2016 at an average of 7.9 per cent per year.
Among those in their 30s, a rise of 6.8 per cent annually was seen between 2005 and 2016, bringing incidence up to 6.4 cases per 100,000 people.
Bowel cancer is the fourth most common cancer in the UK with almost 42,000 people diagnosed every year.
More than nine out of 10 new cases are in people over the age of 50.
Around 268,000 people living in the UK today have been told they have bowel cancer, while one in 15 of all men and one in 18 women will be diagnosed during their lifetime.
Kate Oldridge-Turner, from the World Cancer Research Fund, said: “We know that diet and lifestyle plays a major role in affecting people’s risk of developing cancer. In the UK over 60 per centr of adults are overweight or obese, so we need governments to prioritise cancer prevention by empowering people to lead healthier lives.”
Prof Stephen Duffy, professor of cancer screening, Queen Mary University of London, said it was too early to change policy, because incidence in people under the age of 50 remains low in absolute terms. But he called for more research into the causes of the rise.
Dr Marco Gerlinger, from The Institute of Cancer Research, London, said: “We have noticed increasing numbers of young patients with bowel cancer for some time now, and these large and high-quality studies provide solid data to support this trend.
“These results are a call to action to raise awareness among staff in GP practices and hospitals to consider bowel cancer as a diagnosis when young people come to them with pain, changes in bowel habits or blood in their stool.”
Professor Anne Mackie, Public Health England Director of Screening said: “Bowel screening at aged 50 is being rolled out over time as the risk of bowel cancer rises steeply from around age 50 to 54. The new easier to use FIT test will help spot more abnormalities at an early stage that could develop into bowel cancer if not detected.
“The independent expert screening committee will consider this new evidence and will continue to review all screening programmes on a regular basis.”