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Under 50? Learn the Warning Signs of Early-Onset Colorectal Cancer

March 02, 2024


Thirty years ago, colorectal cancer was thought of as a cancer primarily affecting older adults. Since then, cases of colorectal cancer in older adults have decreased. Simultaneously, rates of colorectal cancer in people younger than 50 have risen significantly. A recent study published in the Journal of the National Cancer Institute (JNCI) suggests four specific symptoms may be red flags for early-onset colorectal cancer. Recognizing these symptoms may help younger adults with colorectal cancer get help earlier when the cancer is easier to treat.

Understanding and detecting colorectal cancer

Colorectal cancer begins in the colon or rectum, sections of the large intestine leading to the anus. Typically, colorectal cancers start as small growths in the colon or rectum lining called polyps. When colorectal cancer develops at or before age 50, it’s considered early-onset colorectal cancer.

Early detection of colorectal cancer makes a significant difference in survival. When colorectal cancer is detected and treated before it spreads outside of the colon or rectum, nine in 10 people will live for five or more years after they’re diagnosed. When colorectal cancer spreads to distant parts of the body, fewer than 2 in 10 people will survive for five years or longer. 

Warning signs of early-onset colorectal cancer

The JNCI study published in May 2023 compared data from insurance claims to detect possible warning signs of early-onset colorectal cancer. The research team compared information from 5,000 people with this type of cancer to data from more than 22,000 people without cancer. When they looked closely at the data, they noticed a pattern.

The researchers found that people with early-onset colorectal cancer commonly reported four symptoms during a period of three months to two years before their diagnosis. These four warning signs are:


Compared to people without these symptoms, people with one of those warning signs were twice as likely to be diagnosed with colorectal cancer. Those with two symptoms had a three-fold risk of colorectal cancer, and those with three or more had six times the risk.

Preventing and recognizing early-onset colorectal cancer

The U.S. Preventive Services Task Force recommends colorectal cancer screenings begin at age 45 for those at average risk. However, with half of early-onset colorectal cancers developing in people younger than 45, knowing possible warning signs and symptoms can help identify issues early. 

In addition to the four warning signs identified in the study, symptoms of colorectal cancer may include unexplained weight loss, a change in bowel habits and the feeling that your bowel hasn’t emptied after a bowel movement.

There are also many steps you can take to help lower your risk of developing colorectal cancer, such as:

  • Avoiding smoking and other tobacco products

  • Eating a diet rich in vegetables and whole grains and low in animal fats

  • Exercising regularly

  • Limiting alcohol

  • Maintaining a healthy weight

When to see your provider

More research needs to be done to confirm the findings of the study published in JNCI. Still, being mindful of potential symptoms could lead to faster detection and treatment of early-onset colorectal cancer.

If you notice any of the four possible red-flag symptoms of early-onset colorectal cancer, talk with your primary care provider. They may recommend earlier or more frequent screening for colorectal cancer based on your symptoms and other personal factors, such as family medical history or lifestyle factors. 

A colonoscopy remains the gold standard for detecting colorectal cancer. However, it isn’t your only option. Several screening tests are available, including stool sample tests that can be done at home. Your provider can help you choose the best option for you. 

Want to learn more about preventing colorectal cancer? Talk with a St. Luke’s Health provider.

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