Bowel cancer is on the rise among the under-50s in the UK, leading to calls to drastically lower the screening age.
Colon cancer cases among the group have risen almost two per cent in a decade, with the biggest rise coming in the those aged 20 to 39.
People are routinely screened for bowel cancer at 55 or 60 in England, with these checks thought to have sent rates of the disease falling in older people.
Public Health England has committed to screening which begins at 50, but international experts are now calling for this to be lowered yet further.
Bowel cancer is thought to be rising in younger people because of obesity, drinking and poor diets high in red and processed meat, while antibiotics given in childhood may also be a factor.
The new statistics come from two separate studies published in the Lancet Gastroenterology and Hepatology journal and the British Medical Journal.
The Lancet’s study, led by the International Agency for Research on Cancer, in France, found British rates of colon cancer rose 1.8 per cent among under-50s in the decade to 2014.
Over-50s, who are more likely to be screened, saw their rates rise by only 0.3 to 0.4 per cent.
The BMJ researchers, led by Erasmus Medical Centre in the Netherlands, reported a rise in bowel cancer of 10.3 per cent a year between 2009 and 2016 for people aged 20 to 39.
Andrew Beggs, a consultant colorectal surgeon and Cancer Research UK advanced clinician scientist at the University of Birmingham, said: ‘I think this provides some evidence that we need to lower the age for screening.
‘In an ideal world we would start screening everyone at the age of 35 or 40, because I am now seeing a lot of people who are being diagnosed with bowel cancer in their late thirties.
‘Going down to 45 needs to be the starting point, although we must be aware that younger people may not carry out screening.
‘We are seeing more and more young people with bowel cancer, when we hardly used to see any, which may be due to obesity and poor diet but may also be influenced by greater awareness.’
When young people are diagnosed with bowel cancer, it is more likely to have advanced and spread by the time of diagnosis, which lowers their chances of survival.
But there is a dearth of reported figures on young patients, prompting two sets of researchers to analyse national figures for various countries including the UK.
The Lancet study found colon and rectal cancer rose by 1.8 and 1.4 per cent respectively in the decade to 2014 among under-50s.
In those aged 50 to 74, rectal cancer fell by 1.2 per cent and colon cancer rose by only 0.3 per cent. In over-75s, rectal cancer fell further by 1.7 per cent, while colon cancer rose by 0.4 per cent.
The study suggests screening could be a factor in falling rates of bowel cancers among younger people, noting that the American Cancer Society has adopted guidelines calling for cancer screening from the age of 45.
It says obesity, a lack of fibre, red and processed meat could raise people’s risk of bowel cancer, with children given antibiotics seeing changes in their gut bugs linked to inflammatory bowel diseases which can lead to bowel cancer.
The authors of the BMJ study say rates of bowel cancer among people aged 40 to 49 rose by three per cent a year between 2007 and 2016.
Bowel cancer is the fourth most common cancer in the UK, with almost 42,000 people diagnosed every year. It is responsible for 16,000 deaths, around 44 a day.
Deborah Alsina, chief executive of Bowel Cancer UK, said: ‘In 2018, both England and Wales committed to lower the bowel cancer screening age to 50, in line with Scotland. It’s crucial that Northern Ireland also reassess their screening age.
‘Screening is the best way to diagnose bowel cancer early when it is treatable and curable.’
The bowel cancer screening programme was one of a three cancer treatment schemes slammed as ‘unfit for purpose’ last week by an influential panel of MPs.
Currently only around 60 per cent (2.6million people) of those eligible are screened every year.