Colorectal cancer myths and facts

By Mayo Clinic staff

It can be easy to feel confused by screening recommendations for common types of cancer. Your health care team is a trusted resource for keeping you up to date on screenings, including screening for colorectal cancer.

Test your knowledge of why, when and how you can be screened with these myths and facts:

Colorectal cancer is rare.

Myth. Colorectal cancer is the second-leading cause of cancer-related death in men and women combined. Roughly 1 in 25 women will have colorectal cancer, and about 1 in 23 men will have colorectal cancer. To put that in perspective, when watching a football game, of all the players on the field, about one player would be diagnosed with colorectal cancer in their lifetime.

Colorectal cancer can happen when you are young.

Fact. The rate of colorectal cancer is increasing in people under 50. Rates of colorectal cancer in people under 50 have doubled since 1990. In people over 65, the diagnosis rates have been decreasing, most likely because of colorectal cancer screening.

Screening for colorectal cancer starts at age 45.

Fact. In 2021, the recommendation for colorectal cancer was updated to begin screening at age 45. This is because the rate of diagnosis is increasing at younger ages.

Colorectal cancer can be prevented with screening.

Fact. The goal of colorectal cancer screening is to prevent cancer, not just find it when it has already developed. Most colorectal cancer develops from a polyp, a small, precancerous growth. The presence of polyps can easily be identified using colonoscopy screening tests. Polyps can be removed during a colonoscopy to prevent them from developing into cancer.

Family history is the only risk factor for colorectal cancer.

Myth. While a family history of colorectal cancer influences your risk of developing cancer, other important risk factors increase the risk of developing colorectal cancer. Medical conditions include obesity and inflammatory bowel disease (IBD), and lifestyle choices, such as a diet high in red meats, smoking and alcohol use, increase risk. Because colorectal cancer is common, all adults over 45 should be screened regardless of family history.

African Americans have a higher risk of developing colorectal cancer, and American Indian/Alaska Native people have the highest risk of colorectal cancer.

A positive stool-based screening for colorectal cancer is the same as a cancer diagnosis.

Myth. A stool-based test looks for more than cancer and can identify precancerous lesions or polyps. Stool-based tests do not address the polyp if a polyp is present in the colon. A follow-up colonoscopy is needed to identify the polyp and potentially remove it.

Talk with your health care team about screening options for colorectal cancer at age 45. — Dr. Derek Ebner specializes in gastroenterology in Rochester, Minnesota.

Learn more

Learn more about colon and rectal cancer.

Also read these articles:

• "Gen Z and Millennials: Do you know the signs of early-onset colorectal cancer?"
• "Dear Mayo Clinic: Advances in screening for colon cancer"
• "Mayo Clinic Minute: What’s the right colorectal cancer screening option for you?"
• "Mayo Clinic Minute: Why millennials should know colon cancer symptoms"
• "Mayo Clinic Minute: Who should be screened for colorectal cancer?"

A version of this article was originally published on the Mayo Clinic Health System's Hometown Health blog.