Research shows that colon cancer among people under the age of fifty is increasing worldwide

The number of people under 50 being diagnosed with bowel cancer is increasing worldwide, according to research which also shows that rates are rising faster in England than in almost any other country.

For the first time, global data suggests doctors are seeing more young adults developing bowel cancer at a young age, from Europe and North America to Asia and Oceania.

An increase in rates was reported in 27 of the 50 countries surveyed, with the largest annual increases observed in New Zealand (4%), Chile (4%), Puerto Rico (3.8%) and England (3. 6%).

Experts are still in the early stages of understanding the reasons behind the increase. The authors of the study, published in the Lancet Oncologysaid junk food consumption, high levels of physical inactivity and the obesity epidemic were likely among the factors.

“The increase in early-onset colorectal cancer is a global phenomenon,” said Hyuna Sung, senior principal scientist in cancer surveillance research at New York University. American Cancer Society and lead author of the study. “Previous studies have shown this increase in predominantly high-income Western countries, but now it has been documented in several economies and regions around the world.”

The escalating trend of colon cancer among young adults is now so significant that it could also lead to a higher incidence among older people, whose rates are stable or declining – potentially reversing decades of progress in the fight against the disease.

“The global scope of this worrying trend highlights the need for innovative tools to prevent and control cancers linked to diet, physical inactivity and obesity,” Sung said.

“Continued efforts are essential to identify the additional factors behind these trends and develop effective prevention strategies tailored to younger generations and local resources worldwide.”

The study found that rates of bowel cancer in people aged 25 to 49 increased in 27 of the 50 countries surveyed in the ten-year period to 2017, the most recent year for which the rates were analysed.

It found that young women showed a faster increase in the rate of early bowel cancer than men if they lived in England, Norway, Australia, Turkey, Costa Rica or Scotland.

Colon cancer is the third most commonly diagnosed cancer and the second most common cause of cancer death, responsible for more than 1.9 million new cases and nearly 904,000 deaths in 2022 worldwide.

Michelle Mitchell, the CEO of Cancer Research UK, said: “This flagship study shows that the increasing number of cases of early-onset bowel cancer, in adults aged 25 to 49, is a global problem.

“Worryingly, this research has shown for the first time that interest rates are rising more sharply in England than in many other countries around the world. A cancer diagnosis at any age has a huge impact on patients and their families – so while it is important to note that rates are still very low in younger adults compared to people over 50, we need to understand what is driving this trend in younger people.”

There were several limitations to the study. It only reported bowel cancer rates up to 2017, so these may not accurately reflect current trends. The study also used data from subnational registries that often represent a small portion of a country’s population, which may limit generalization at the population level.

David Robert Grimes, assistant professor of biostatistics at Trinity College Dublin, who was not involved in the study, urged caution in interpreting the findings. “Comparing international data on cancer rates is a difficult undertaking because there is significant variation in the quality and availability of data… we must resist the urge to jump to conclusions, especially when dealing with conflicting and complicated data,” he said.

The rate at which bowel cancer was increasing among those under 50 was also much lower than in England in Wales (1.55%), Scotland (0.64%) and Northern Ireland (0.54%), raising further questions about the facts.

Katrina Brown, a senior cancer intelligence manager at Cancer Research UK, said it was “difficult to say for sure” why rates in England were rising faster than in the other British countries. “More research is needed to understand whether there are real differences between countries, and how to address them,” she said.

She added that the overall number of cases in young adults was still low, with only around one in 20 cases of bowel cancer in Britain diagnosed in people under the age of 50.

Sung said it was crucial that more people know the symptoms. “Increasing awareness of the trend and obvious symptoms of early colorectal cancer (e.g., rectal bleeding, abdominal pain, altered bowel habits, and unexplained weight loss) among youth and primary care providers can help reduce delays in diagnosis and reduce mortality,” said them.