Colorectal cancer used to be thought of as an older person’s disease. The numbers are telling a different story.
New 2026 data show colorectal cancer rates continuing to rise among younger adults while falling among older adults. Researchers are still trying to understand why—and doctors are emphasizing the importance of recognizing symptoms early.
For years, colorectal cancer seemed like something people had to worry about later in life.
That picture is changing.
New data from the American Cancer Society show that colorectal cancer incidence in the United States is moving in opposite directions by age. Rates have continued to decline among adults 65 and older, while they are rising among people younger than 65, particularly those ages 20 to 49.
Even more concerning, a January 2026 study published in JAMA found that colorectal cancer mortality among Americans younger than 50 increased by about 1.1% annually from 2005 through 2023. By 2023, colorectal cancer had become the leading cancer-related cause of death in this age group overall.
The trend does not mean most younger adults are developing colorectal cancer. The absolute risk remains much lower than it is at older ages.
But the change is significant enough that researchers are taking a much closer look.
A disease that is changing with age
The latest statistics reveal a striking contrast.
From 2013 to 2022, colorectal cancer incidence increased by about 2.9% per year among adults younger than 50, while incidence among adults 65 and older continued to decline. The increase among younger adults has been particularly noticeable in cancers involving the sigmoid colon and rectum.
Researchers do not yet have one explanation.
That uncertainty is important.
It is easy to blame a single food, chemical or lifestyle habit for a complicated population-level trend. Scientists, however, are investigating multiple possibilities, including changes in diet, physical activity, metabolic health, environmental exposures and the gut microbiome.
Genetic factors also matter. Some people inherit conditions that substantially increase colorectal cancer risk, including Lynch syndrome and familial adenomatous polyposis. A family history of colorectal cancer or certain polyps can also increase risk.
But inherited genetics cannot explain the entire population-wide increase.
That is why the search for environmental and lifestyle contributors continues.
The warning signs can look ordinary
One of the most important lessons from the current research is that age should not automatically dismiss a symptom.
Rectal bleeding, persistent abdominal pain, and changes in bowel habits can have many causes, most of which are not cancer. But they can also be warning signs of colorectal cancer and deserve appropriate medical evaluation when they persist or are unexplained.
Other possible symptoms include changes in stool, unexplained weight loss and persistent fatigue.
Fatigue can sometimes occur when colorectal cancer causes blood loss and anemia.
The 2026 JAMA research specifically emphasized educating clinicians and the public about red-flag symptoms such as rectal bleeding and abdominal pain because younger patients are often diagnosed at an advanced stage.
That does not mean every episode of constipation, abdominal discomfort or bleeding indicates cancer.
It means symptoms should be evaluated in context rather than dismissed simply because someone is young.
Why screening matters at 45
There is another important change in prevention.
For average-risk adults, the American Cancer Society recommends beginning regular colorectal cancer screening at age 45. Screening can detect cancer earlier, but it can also find precancerous polyps that can be removed before they develop into cancer.
The 2026 ACS statistics offer a particularly important reason to pay attention to that recommendation: half of colorectal cancer diagnoses occurring before age 50 are in people ages 45 to 49, the group already eligible for average-risk screening.
Yet screening participation remains a challenge.
That creates a preventable gap between being eligible for screening and actually receiving it.
Screening options now include stool-based tests and visual examinations such as colonoscopy. The ACS’s 2026 guideline also includes blood-based screening as an option, although the organization currently considers stool-based and visual tests preferable because they are better at detecting precancerous growths and early-stage disease.
What about people over 50?
The rise in younger adults should not overshadow an important fact: age remains one of the strongest risk factors for colorectal cancer.
About 93% of colorectal cancers are diagnosed in people ages 45 and older, according to the CDC.
For older adults, staying current with recommended screening remains important.
The ACS recommends continuing screening through age 75 for people in good health with a life expectancy greater than 10 years. From ages 76 to 85, the decision should be individualized based on overall health, previous screening and personal preferences.
This is particularly relevant because colorectal cancer incidence and mortality have been declining among adults 65 and older, a trend researchers associate in part with screening and improvements in prevention and treatment.
What can you actually control?
Researchers are still investigating why early-onset colorectal cancer is increasing, but several established risk factors are already known.
The CDC identifies insufficient physical activity, excess body weight, alcohol use and tobacco use among lifestyle factors associated with increased colorectal cancer risk. Inflammatory bowel disease, family history, previous colorectal polyps and certain inherited syndromes can also raise risk.
That does not mean lifestyle choices can guarantee prevention.
Cancer is complicated, and people who live very health-conscious lives can still develop it.
The more useful approach is to focus on what can realistically be changed: remain physically active according to your abilities, eat a varied diet, avoid tobacco, discuss alcohol use with a healthcare professional when relevant, understand your family history and keep up with recommended screening.
The bigger message
The changing age pattern of colorectal cancer is one of the more important developments in cancer prevention right now.
The encouraging news is that researchers are paying attention. Screening is available. Treatment has improved. And the decline in colorectal cancer among older adults demonstrates that prevention and early detection can make a meaningful difference.
But the rise among younger adults is a reminder that colorectal cancer cannot simply be dismissed as an “older person’s disease.”
For everyone—particularly adults approaching their mid-40s—the practical lesson is straightforward:
Know your risk. Know the warning signs. And know when you are due for screening.
The mystery of why colorectal cancer is increasingly appearing at younger ages has not been solved yet.
But recognizing the change is an important first step toward finding answers—and catching more cancers before they become harder to treat.