CASES of bowel cancer are soaring among Scots too young to qualify for screening, with children as young as 10 among those being diagnosed.

Diagnoses have doubled among Scots in their early 20s, while rates of bowel cancer in the 30 to 34 age group are at a record high.

The most striking change can be seen among children and teenagers born after 1996 - the so-called 'Gen Z'.

Case Study: 'I never thought it would be bowel cancer - not at all'

Over a 20-year period from 1992 to 2012, only one child in Scotland aged 10 to 14 was diagnosed with bowel cancer.

But in just four years, from 2013 to 2016, there were a total of eight diagnoses in this age group.

The pattern is similar among older teenagers. Between 1992 and 2011, there were just 11 cases in total among 15 to 19-year-olds, but in the five years from 2012 to 2016 there have been 32 cases.

Routine NHS bowel cancer screening is offered to Scots aged 50 to 74, with those aged 75 and over entitled to self-refer.

Professor Bob Steele, the Dundee-based surgeon and bowel cancer expert who chairs of UK National Screening Committee, said there was not yet enough evidence to justify lowering the age for screening but that the issue is one the committee is taking seriously.

Prof Steele said: "It's something that's come to attention fairly recently because the trends are only just beginning to appear.

"The problem is that although the incidence is increasing, the numbers are very small, and if we were to offer screening to people under the age of 50 we would be offering screening to a huge number of people for a relatively small amount of disease, so the balance of benefit to harm is not clear.

"We might do more harm than good by doing lots of colonoscopies as a result of false positive tests in young people.

"Without robust evidence, we're not about to the reduce the age of first screen. That's not to say we shouldn't be doing more research, however.

"We're going to be looking at this in some detail very soon. We want to get a very clear idea of what's going on."

Read more: New test sees record uptake for bowel screening in Scotland

In Scotland, in the 10 years to 2016, there were 50 cases among Scots aged 20 to 24 compared to 25 in the previous decade.

Among 30 to 34-year-olds, a record 26 people were diagnosed with bowel cancer in 2016 compared to eight in 2006 - tripling the diagnosis rate in that age group from 2.5 to 7.4 per 100,000 in a decade.

The growing prevalence of the disease among younger Scots comes at a time when overall incidence is falling.

In the decade to 2016 - the most recent year for which data is available - there was a 15 per cent decline in the total number of bowel cancer diagnoses in Scotland, to 3,700.

Among under-50s, however, incidence actually rose 19% - from 191 cases in 2006 to 227 in 2016. In 1996, there were 184 cases.

The pattern is being mirrored in the US, Europe, Australia and China.

In the US, the recommended screening age for bowel cancer was recently reduced to 45.

Rebecca Siegal of the American Cancer Society warned that the risk of bowel cancer among the so-called 'millennial generation' - those born after 1980 - had "escalated back to the level of those born in the late 1800s".

The cause remains a mystery, but low fibre diets, obesity, Type 2 diabetes, a lack of exercise, excess alcohol and increasing rates of inflammatory bowel disease are among the leading theories.

Read more: Obesity to blame for more than one in 10 bowel cancer cases

Research also points to links between bowel cancer and diets high in red meat - especially processed meats such as bacon or salami.

Deborah Alsina, chief executive of Bowel Cancer UK, said many young people wait too long for diagnosis because it is considered an "older person’s disease".

She said: "Our research shows that younger people take longer to be diagnosed and often face delays, in some cases having to see their GP more than five times before being referred for crucial tests.

"On top of this 60% are diagnosed at the later stages of the disease and around a third are diagnosed in emergency care when the chance of survival is lower.”

However, Professor Malcolm Dunlop, a specialist colorectal surgeon and scientist at the Cancer Research UK Edinburgh Centre who is leading a study into the genetics of bowel cancer among young people, remains sceptical.

He said there are still too many year to year fluctuations in bowel cancer rates among under-50s to be sure that incidence really is increasing.

Prof Dunlop said: "Every single one of them up to the age of 20 will be genetic in origin. There is no chance that that is actually environmental.

"And if it's not genetic, it will be in people who have inflammatory bowel disease.

"In the last two years I've had four to or five young men with ulcerative colitis that have had more than one bowel cancer, and unfortunately the prognosis in those cases is not good."