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New research finds that while cases of colorectal cancer are declining in older adults, they have significantly increased in children and teens. Klaus Vedfelt/Getty Images
  • A new study finds that colorectal cancer in children is on the rise.
  • Case numbers in older adults, however, are on the decline.
  • Learning the signs and symptoms of early-onset colorectal cancer is important.

According to a new study, colorectal cancer cases are on the rise in younger people. The greatest increase is among children ages 10 to 14, where cases have increased by 500%.

Although the total number of cases is still low, experts are working hard to understand what is driving this change.

The findings will be presented on Monday, May 20, at the Digestive Disease Week conference in Washington, D.C.

A slow and steady rise?

Colorectal cancer is the third most common form of cancer in men and the fourth in women. In 2024, in the United States, experts predict there will be 106,590 new cases of colon cancer and 46,220 cases of rectal cancer.

In older adults — who are most at risk of developing cancer in general — rates have slowly decreased since the 1980s. Between 2011 and 2019, cases dropped by around 1% each year.

However, the story is different for younger people. According to the American Cancer Society, “In people younger than 55 years of age, rates have been increasing by 1% to 2% a year since the mid-1990s.”

It’s a similar story in the United Kingdom. Healthline spoke with Jude Tidbury, a clinical nurse specialist in gastroenterology and endoscopy at East Sussex Healthcare NHS Trust in the U.K.

She explained that because colorectal cancer is increasingly common in younger people, guidelines are changing.

“We were screening people from the age of 60; this has now been lowered to 55, and that is due to be lowered again to 50 over the next few months,” Tidbury told us.

A worrying trend

The latest research was led by Islam Mohamed, MD, an internal medicine resident physician at the University of Missouri-Kansas City.

Mohamed’s analysis showed that from 1999 to 2020, the rate of colorectal cancers increased by:

  • 500% in children ages 10–14
  • 333% in teens ages 15–19
  • 185% in people ages 20–24
  • 71% in people ages 30–34
  • 58% in people ages 35–39
  • 37% in people ages 40–44

While a 500% increase in those aged 10–14 sounds huge, it is important to keep it in perspective: In 1999, there were 0.1 cases per 100,000 in this age group. In 2020, this figure had risen to 0.6 children per 100,000.

Regardless of the low overall numbers, these figures are concerning. However, according to Mohamed, because the numbers are small, screening younger age groups is not yet necessary.

Know the signs of early-onset colorectal cancer

Until fairly recently, colorectal cancer was considered a disease of old age. Now, as rates increase in younger people, Mohamed believes it is important to know the early signs and symptoms.

He explains in a press statement that the most common signs of early-onset colorectal cancer are:

  • a change in bowel habits: constipation or diarrhea
  • abdominal pain
  • rectal bleeding
  • signs of iron deficiency anemia

How to reduce risk 

Risk factors for colorectal cancer include inflammatory bowel disease, a family history of the disease, and certain genetic syndromes. While there is nothing an individual can do to reduce these risks, there are some lifestyle changes that can make a significant difference, such as:

  • keeping physically active
  • eating plenty of fiber-rich fruit and vegetables
  • reducing intake of processed meat
  • maintaining a healthy weight
  • reducing alcohol consumption
  • quitting smoking

Healthline spoke with Federica Amati, Ph.D., ANutr, a postdoctoral medical scientist and head nutritionist at ZOE, a science and nutrition company.

“These rising rates are alarming and point to the urgent need to improve our ability for prevention and detection of early colon cancer,” she explained. “​​Ensuring children and young people eat a fiber-rich diet with a variety of minimally processed foods should be a public health priority.”

While some risk factors are not well understood, there are still unanswered questions about colorectal cancer.

“What’s causing this rise is still yet to be determined,” Tidbury told Healthline. “Could it be the rise in obesity or are other lifestyle factors at play here? Is there a genetic link or are changes in the environment causing this?”

What about gut bacteria?

As investigations into early-onset colorectal cancer continue, some researchers are focusing on the role of the gut microbiome — the trillions of bacteria that live in the gut.

There is growing evidence that these microbes might be an important part of the puzzle and that altering the microbiome might lead to new treatments.

“The work we are doing at ZOE as part of the CRC UK PROSPECT team will help to identify people at risk through gut microbiome analysis and the interventions that can effectively decrease risk,” Amati told us.

This research, funded by Cancer Research UK and the National Cancer Institute, brings together researchers from across the globe. The project focuses on understanding why early-onset cancers are on the rise.

The takeaway

While rates of colorectal cancer slowly decline in older adults, they are rising in younger people.

Experts still do not know why this is, but knowing the early warning signs is increasingly important.