Know the Signs: Colorectal Cancer Is Increasing in Younger Adults
3/4/2026
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Posted by Sharon McLaughlin, MD, FACS
in
Health and Wellness
For many years, doctors believed colorectal cancer — cancer of the colon or rectum — mostly affected older adults. That idea is changing fast.
In the United States, colon cancer is rising in people under age 50. At the same time, it is going down in people over 50. Why? Because more older adults are getting screened. Doctors can find and remove small growths before they turn into cancer.
Why Colon Cancer Is Often Missed in Young People
Here’s one of the most important, and frustrating, parts of the problem.
When a 70-year-old has belly pain or rectal bleeding, doctors quickly think about cancer. But when a 25-year-old has the same symptoms, they may be told it is stress, hemorrhoids, or a stomach bug.
Because of this, young people are often diagnosed later, when the cancer is harder to treat.
Warning Signs Young People Should NOT Ignore
Young people do not need to panic, but they do need to pay attention to their body. Colon cancer in young adults often causes symptoms. If you or a loved one is experiencing anything on the list below, tell a doctor.
Symptoms that should prompt a medical visit:
- Blood in the stool or on toilet paper
- Diarrhea or constipation that lasts more than a few weeks
- Stool that looks thinner than usual
- Ongoing belly pain or cramping
- Unexplained weight loss
- Feeling very tired
Red flags that may warrant screening before age 45:
- Symptoms that do not improve
- A family history of colon cancer or large polyps
- Crohn’s disease or ulcerative colitis
- Unexplained low iron levels
No one should ignore these symptoms just because they are young.
Why Are Colon Cancer Rates Rising for Young People?
Many people eat more fast food, sugary drinks, and packaged snacks. These foods are low in fiber. Fiber works like a broom in our body. It helps move waste out of the colon. When we do not get enough fiber, waste stays in the colon longer. Over time, this can irritate the bowel and may raise the risk of cancer.
Another clue is the tiny bacteria that live in our gut. This group of bacteria is called the gut microbiome. Most of these bacteria help keep us healthy. But some harmful bacteria can damage cells in the colon.
Less movement may also play a role. Many of us sit for long hours at school, work, or home. Not moving enough can lead to weight gain and long-term inflammation. Inflammation is like a slow, hidden fire inside the body. Over time, it can make it easier for cancer to grow.
What Can We Do?
- Eat the rainbow: Fruits, vegetables, beans, and whole grains give us fiber.
- Move regularly: Walking, sports, dancing, our gut loves movement.
- Speak up: If something feels wrong, tell a trusted adult or healthcare provider.
- Trust persistence: If symptoms continue, keep asking questions.
Get Screened
Colon cancer is one of the most preventable cancers, but only if we find it early. Most people should start screening at age 45. If you’re younger and experiencing symptoms of colorectal cancer, talk to your doctor.
Screening options include:
- Colonoscopy (the gold standard): A doctor looks at the whole colon and can remove polyps before they turn into cancer.
- Cologuard: A non‑invasive, at‑home stool test that looks for hidden blood or anything wrong with DNA. It’s usually done every 1–3 years. If anything concerning comes back in the results, a colonoscopy is needed.
The most important message is this: The best screening test is the one you do.
If you or a loved one has symptoms or risk factors, talk to a doctor. Listening to your body could save your life.