Colorectal Cancer Rates Are Rising in Nearly All Age Groups: What the New NEJM Evidence Study Means for You

For two decades colorectal cancer was one of the quieter success stories of modern medicine. Screening caught more polyps before they turned dangerous. The overall rate in the United States kept falling. A new analysis now suggests that the trend has turned. And the increase is no longer confined to young adults, who have dominated the headlines for years.

You may not love reading about your colon on a Sunday. Few people do, which is partly why this cancer is so often caught late. So let us keep this useful and calm.

What the new study found

The analysis, “Colorectal Cancer among U.S. Adults,” covers the years 2000 through 2023 and was published in NEJM Evidence by researchers at the University of Chicago led by Caitlin Murphy, a professor of pediatrics and public health sciences. The team used the most recent data from the US National Cancer Institute.

According to the study as reported by the University of Chicago and by Reuters, the age-adjusted incidence of colorectal cancer fell from 55.2 cases per 100,000 people in 2000 to 36.7 in 2022. In 2023 it rose to 38.3. “This is the first time that we have seen an increase in the overall rate in more than 20 years,” Murphy said.

The rise now extends to nearly all age groups up to 65 to 69. The steepest increase appeared among people aged 45 to 49, where incidence climbed by 12.76 percent per year between 2019 and 2023. In people aged 70 to 74, rates have plateaued.

Why 45 to 49 is partly good news

The sharp jump in the 45 to 49 group sounds alarming, but the researchers see a large part of it as screening doing its job. In 2021 the US Preventive Services Task Force lowered the recommended starting age for colorectal cancer screening from 50 to 45. More people in their late forties are now being examined, so more cancers are being found, many of them earlier. “That means that screening is doing as we intend it to do,” Murphy said. “It’s catching cancer earlier.”

Think of it like turning on the lights in a room. The furniture was always there. You can just see it now.

Why older adults are the real puzzle

The finding that worries researchers more concerns people in their late sixties. According to the University of Chicago, about 80 percent of adults aged 65 to 69 are up to date with screening. Better screening alone therefore cannot explain why their rates are rising. The authors suggest that unknown risk factors may be offsetting the gains from screening.

One explanation the team discusses is a birth cohort effect. People born in the 1960s and later appear to carry a higher risk as they move into middle and older age. Murphy described it as “the interaction of age and time.” In plain terms: whatever began pushing up rates among younger adults years ago may now be following that generation as it gets older.

The researchers also excluded data from the pandemic years 2020 and 2021, when screening was disrupted. The increase remained. That makes a simple Covid catch-up effect an unlikely explanation.

What is known and what is not

It is important to separate facts from hypotheses here. The rising incidence is a measured fact based on national cancer registry data. The causes are not yet established. The Chicago team plans to measure environmental chemical exposures in blood samples together with a toxicologist from Emory University. Promising candidates will then be tested on organoids, small lab-grown models of the colon. Until those results are in, any article or influencer claiming to know the single culprit is guessing.

That includes the wellness corner of the internet, where gut health has become a lifestyle category with its own aesthetic. Colorful supplement jars and morning shots look great on a marble countertop. None of them replaces a screening test.

For context, the American Cancer Society reports that incidence among adults aged 20 to 49 rose by about 3 percent per year between 2013 and 2022. Colorectal cancer is the second leading cause of cancer deaths in the United States overall and, according to the ACS figures cited in the reporting, now the leading cause of cancer deaths among people under 50.

The awkwardness problem

Colorectal cancer has a communication issue that no other major cancer quite shares: people find it embarrassing to talk about. In March 2000, television host Katie Couric underwent a colonoscopy live on the Today show after losing her husband to the disease. It remains one of the rare moments when a celebrity used a morning TV slot to make an uncomfortable medical test feel ordinary. Twenty-six years later, that kind of openness still matters.

According to the reporting on the study, average-risk adults are advised to begin regular screening at 45 and continue through 75. Colonoscopy remains the reference method, while stool-based home tests and newer blood-based tests offer additional options. Which test suits you is a question for your doctor. The same goes for whether you should start earlier because of family history or other risk factors. Younger adults without risk factors are advised to pay attention to warning signs such as blood in the stool, a lasting change in bowel habits or unexplained weight loss and to seek medical advice if they notice them.

What this means going forward

The study is based on US data. Screening programs and age limits differ from country to country, so if you live in Germany or elsewhere in Europe, your national recommendations are the relevant ones. The underlying question, however, travels well: why is a cancer that medicine had pushed back for decades now creeping upward across generations?

The honest answer for now is that nobody knows yet. What is known is that screening works where it is used. That is not the most glamorous takeaway of the week. It may be the most useful one.

This article is for general information only and does not replace professional medical advice, diagnosis or treatment. If you have symptoms or questions about screening, please talk to your doctor.