Colorectal Cancer Screening Guidelines

Colorectal cancer is the third-most commonly diagnosed cancer and the third-leading cause of cancer death in men and women combined in the United States. The American Cancer Society estimates the risk of developing colorectal cancer at about 1 in 23 for men and 1 in 26 for women.

If cancer begins in the colon, which is the first four to five feet of the large intestine, it may be referred to as colon cancer. If the cancer begins in the rectum, which is the last several inches of the large intestine leading to the anus, it is called rectal cancer.

If caught early when only in the bowel, colorectal cancer is highly treatable and often curable. 

Because early detection is key, rectal and colon cancer screening guidelines recommend that people of average risk begin screening at age 45. But if you have a family history or symptoms, you should talk with your health care provider about starting earlier. 

Continue regular screening through 75. If you are over 75, talk with your doctor about whether screening is right for you.

Colon and Rectal Cancer Risk Factors

Several factors can increase your rectal and colon cancer risk factors. 

  • Age – Most cases occur in people over the age of 50. However, cases can also occur in younger individuals.
  • Personal or family history – If you have a history of colon or rectal cancer or certain non-cancerous colon polyps, you have a higher risk. Additionally, having a family history of colorectal cancer, increases your risk.
  • Inherited gene mutations – Certain inherited gene mutations, such as Lynch syndrome or familial adenomatous polyposis, significantly increase your risk of colon or rectal cancer.
  • Inflammatory bowel disease (IBD) – People with long-standing inflammatory bowel diseases, including ulcerative colitis or Crohn's disease, have an increased risk of colorectal cancer.
  • Diet – A diet high in red and processed meats and low in fiber, fruits and vegetables increases your risk.
  • Lifestyle – Lack of physical activity, smoking, excessive alcohol consumption and not maintaining a healthy weight have been associated with an increased risk of colon or rectal cancer.
  • Racial and ethnic backgrounds – Some racial and ethnic groups, including Blacks and Ashkenazi Jews, have a higher risk of colon or rectal cancer.
  • Type 2 diabetes – People with Type 2 diabetes may have an increased risk of colon or rectal cancer.
  • Radiation exposure – Previous radiation treatment for certain cancers, such as pelvic radiation therapy, may increase your risk.

Having one or more of these risk factors does not guarantee that you will develop colon or rectal cancer. 

Colorectal Cancer Screening Tests

Several screening tests are available for early detection of colon and rectal cancer. These tests can help identify precancerous polyps or detect cancer early, when it is more treatable. 


This is considered the gold standard for colon cancer screening. During a colonoscopy, a long, flexible tube with a camera (colonoscope) is inserted into the rectum to examine the entire colon. It allows the doctor to visualize the colon and rectum, remove polyps and take tissue samples for analysis.

Flexible sigmoidoscopy

This procedure involves the insertion of a flexible, slender tube with a camera (sigmoidoscope) into the rectum and lower part of the colon. It allows visualization of the rectum and sigmoid colon but not the entire colon. A follow-up colonoscopy may be necessary if polyps or suspicious areas are found.

Stool-based tests

Stool-based tests look for problems after they happen, while a screening colonoscopy looks for anything that might cause a problem. Stool tests are only appropriate for those considered low risk for colorectal cancer. You will need a colonoscopy if the test returns positive.

  • Fecal immunochemical test (FIT) – This stool test checks for hidden blood in the stool, which can be an early sign of colon or rectal cancer. You perform the test at home by collecting a stool sample and sending it to a lab for analysis.
  • Fecal occult blood test (FOBT) – Similar to FIT, FOBT detects hidden blood in the stool. However, FOBT uses a chemical reaction to detect blood, while FIT uses antibodies.
  • Stool DNA test – This test combines the detection of blood and genetic changes in the stool to identify potential cancer or precancerous abnormalities. It is also performed at home by collecting a stool sample and sending it to a lab for the test result.

What to Expect During a Colonoscopy

Preparation begins the day and night before the procedure. Your doctor will also prescribe a colon cleanse beverage and anti-gas medication along with fasting. Cleansing the colon is essential for accurate screening.

The procedure takes about 30 minutes, and complications and risks are low.

First, you are sedated. Many people describe it as the best nap they have ever had. Next, the doctor will perform the colonoscopy. Because you will be sedated, you will need someone to go with you to drive home.

You will wake up in the recovery room. After a short observation and recovery from the sedative, you can eat and go about your day.

Get Started

The most appropriate screening test depends on various factors, including individual risk, personal preferences and your primary care provider’s recommendation.

Talk to your primary care provider about your risk factors and when to be screened for colorectal cancer. 

Cancer Risk Assessment Hero

Colorectal cancer health risk assessment

Colorectal cancer is the third most common cancer diagnosis in men and women. This quick assessment estimates your lifetime colorectal cancer risk. It looks at your lifestyle, genetics and personal health history. This makes it easy to talk to your provider about maintaining a healthy lifestyle and when to start screenings.
Take the assessment


Colon Cancer Screening Blog
Most common colon cancer symptoms

When colon cancer is caught before it spreads to any other tissue, the survival rate is 91%.

Colon Cancer Screening blog
Colon cancer screening: Easy and worth it
If you’re unsure whether a colonoscopy or an at-home screening method is right for you, talk to your doctor.
Cancer Screening Recommendations Blog
Cancer screening recommendations
At what age we should be screened depends on our average risks and exposures to cancer-causing substances.