Many young people assume colorectal cancer is only an older person’s disease. In fact, one in five new cases are in people under age 55, nearly double the rate in 1995.

Ignoring early symptoms of colon or rectal cancer because you think you’re not at risk can delay care, allowing the cancer to grow. That’s why people in their 40s, 30s, and even their 20s need to know the facts.

Anju M. Malieckal, MD, a gastroenterologist at NYU Langone Health who specializes in preventive screening for colon and rectal cancer, breaks down five myths that matter most for younger adults.

Myth 1: I’m Too Young to Get Colorectal Cancer

Rising rates of colorectal cancer among people under 50 led the U.S. Preventive Task Force to lower the recommended screening age to 45.

“The cancers we diagnose in people under 50 are usually not caused by inherited genetic disorders,” explains Dr. Malieckal. “More often, colorectal cancer develops after growths called polyps change over time.”

A variety of lifestyle and environmental factors may be causing these changes. Known risk factors include smoking, alcohol use, being overweight, sedentary living, and diets low in fiber and high in red and processed meats. Researchers are also studying how the gut microbiome, insulin resistance, and ultra-processed foods might contribute to early-onset colorectal cancer.

Many younger people assume symptoms like rectal bleeding or fatigue are temporary or pose no real threat. That delay gives the cancer time to grow.

“A lot of people think, ‘I’m young, I’m healthy. I don't need to worry about this,’” says Dr. Malieckal. “That’s a mindset we need to shift in younger adults.”

Myth 2: Rectal Bleeding Is Just Hemorrhoids

Rectal bleeding is one of the most common early symptoms of colorectal cancer. “A lot of people will come in for rectal bleeding—maybe intermittent episodes brushed off as hemorrhoids,” Dr. Malieckal observes.

Hemorrhoids are common and usually benign, but you cannot tell the difference between hemorrhoid bleeding and cancer-related bleeding without a proper evaluation. Even one episode of rectal bleeding deserves a visit with your doctor. “Rectal bleeding and blood in the stool are things that should never be ignored,” Dr. Malieckal adds. “Take any new or persistent symptoms seriously enough to mention them to your doctor.”

Myth 3: My Fatigue and Bowel Habits Are Due to Stress and IBS

It’s easy to dismiss fatigue as a symptom of stress or a busy life. Likewise, you might link changes in your digestion to irritable bowel syndrome (IBS). But when symptoms persist, especially when combined with unintentional weight loss, they’re worth checking out.

Another sign to watch for: unexplained anemia. Although anemia is common in menstruating women, it is seen less often in younger men. “Any time I have a male patient that’s anemic, it’s a red flag for me,” says Dr. Malieckal. It’s potentially a sign of blood loss from the intestine.

Myth 4: At-Home Screening Tests Are as Good as Colonoscopy

At-home stool tests like Cologuard and FIT (fecal immunochemical test) are convenient, noninvasive, and accessible. But they have real limitations.

“They’re both good tests, but they’re not 100 percent,” Dr. Malieckal explains. “You can have false positives and false negatives, and not everyone is eligible to have those tests done.” If the stool test is positive, meaning the results are abnormal, then a follow-up colonoscopy is needed.

In addition, these tests are not for people who are at increased risk. Here’s when to skip at-home tests and go straight to getting a colonoscopy:

• You have a family history of colorectal cancer or polyps.
• You have rectal bleeding or blood in your stool.
• You have inflammatory bowel disease.
• You have any signs or symptoms that could suggest colorectal cancer.

There’s another reason colonoscopy remains the gold standard: it’s both diagnostic and therapeutic. It can find cancer and precancerous polyps, and your doctor can remove the polyps during the same procedure, before they cause symptoms or require more-invasive surgery.

Most people should start screening at age 45. But if you have a family history of colorectal cancer, polyps, or a known genetic condition, talk to your doctor about earlier screening. And any time symptoms or warning signs appear, don’t wait for an age milestone. See your primary care doctor or gastroenterologist, who can order a colonoscopy if needed.

Myth 5: If I Get Colorectal Cancer When I’m Young, My Outlook Is Worse

It’s not that colorectal cancer is more aggressive in younger people. “It’s that by the time a symptom develops, the cancer has grown,” Dr. Malieckal explains.

That’s why catching symptoms early is key. Young, generally healthy people respond well to modern treatments, including immunotherapy, targeted treatments, and robotic surgery.

At NYU Langone Health, the Early Onset Cancer Program ensures that adults age 50 and under receive personalized treatment for colon and rectal cancers. The Survivorship Program at Perlmutter Cancer Center helps cancer survivors thrive after a cancer diagnosis and during and after treatment.

“Advances in treatment give patients a better quality of life while we’re treating their cancer,” Dr. Malieckal says. “People are no longer bedridden for weeks—they’re living and going to work.”

Cut Your Risk and Catch Cancer Early

Not all colorectal cancers can be prevented. But you can take steps to reduce your risk:

• Move your body. Regular physical activity reduces colorectal cancer risk. You don't need to train for a marathon; even brisk walking helps.
• Be mindful about what you eat. Focus on fiber, limit alcohol and red meat, and reduce processed foods. Your diet directly affects your colon health.
• Know your family history. Understanding who in your family has had cancer or polyps helps you know your risk and recognize when to get screened.
• Most important: listen to your body. If you have rectal bleeding, blood in the stool, a change in bowel habits, unexplained anemia, persistent bloating, abdominal discomfort, unexplained fatigue, or unintentional weight loss, don't dismiss it. Talk to your doctor.

Remember, if you’re 45 or older, schedule a screening colonoscopy. And if you have signs or symptoms, at any age, see a doctor for evaluation because you may need a colonoscopy. To find a gastroenterologist near you, visit NYU Langone’s Colon Cancer Screening and Prevention Program.