When to Get Tested for Colon Cancer: Key Points to Know

Written on February 19, 2024 by Jillian Foglesong Stabile, MD, FAAFP. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

• What Is Colon Cancer?
• Who Gets Colon Cancer?
• Timing of Colon Cancer Screening
• Screening Tests for Colon Cancer
• Take Control of Your Health with Everlywell
• Related Content

Colorectal cancer is one of the most common types of cancer and cancer death.[1] You’ve probably heard a lot about different testing options for colon cancer, and you may have been wondering when to get tested for colon cancer. We’ll talk today about colon cancer and what you can do to take control of your health.

What Is Colon Cancer?

Colorectal cancer is a type of cancer that originates in the colon or rectum.[2] Cancer occurs when cells start to grow out of control. Colon cancers usually start as polyps, which are lump-like growths in the colon wall. These may take many years to turn into colon cancer, and not all polyps increase your risk of colon cancer. Adenomatous polyps and some types of sessile serrated polyps increase the risk of colon cancer, but hyperplastic and inflammatory polyps don’t increase the risk.

Types of Colon Cancer

Several types of cancer can occur in the colon.[3] Adenocarcinoma is the most common type. This cancer starts from the cells that line the colon. Carcinoid tumors occur in hormone-producing cells in the colon. Gastrointestinal stromal tumors are rare in the colon but occur in other parts of the gastrointestinal tract. Lymphoma is a type of immune system cancer that usually starts in the lymph nodes but can also occur in the colon.

Symptoms of Colon Cancer

Most people who have colon cancer don’t have symptoms, but some people do. Symptoms may include: [4]

• Changes in bowel habits, including changes in stool caliber, diarrhea, or constipation
• Blood in the stool
• Pain in the abdomen or cramps, gas, or pain
• Feeling of incomplete voiding during bowel movement
• Fatigue or weakness
• Weight loss

Who Gets Colon Cancer?

Anyone can get colon cancer, but certain factors put you at higher risk for colon cancer. These can be separated into conditions that you can control and conditions that you can’t.

Modifiable Colon Cancer Risk Factors

Some of the factors that increase your risk for colon cancer are things that you can control. We call these modifiable risk factors. Some of these factors include [5]:

• Being overweight or obese
• Lack of physical activity
• Diets high in red meat or processed meats and possibly fried or charred foods
• Low vitamin D levels
• Smoking
• Alcohol use

Non-Modifiable Risk Factors for Colon Cancer

There are also risk factors for colon cancer that you can’t control. These are non-modifiable risk factors. These risk factors include [5,2]:

• Age – Colon cancer risk increases with age and is more common after age 50.
• Personal history of polyps or colon cancer – Adenomatous polyps increase your risk of colon cancer. Colon cancer, even if previously treated, increases your risk of subsequent colon cancer development.
• Inflammatory bowel disease (IBD) – IBD increases your risk of colon cancer, especially if you haven’t been treated or your condition is not well controlled. IBD should be differentiated from irritable bowel syndrome (IBS]), which does not increase your risk of colon cancer.
• Family history of colon cancer or polyps – If you have a parent, sibling, or child (also known as first-degree relatives), you are at an increased risk for developing colon cancer, especially if your relative was diagnosed before age 50.
• Inherited syndromes – Several genetic or inherited syndromes increase your risk for colon cancer. The most common of these are Lynch syndrome (hereditary non-polyposis colon cancer, HNPCC) or Family adenomatous polyposis (FAP).
• Type 2 diabetes.
• Certain racial or ethnic backgrounds – American Indians, Alaska Native people, Jewish persons of Eastern European descent (Ashkenazi Jews) are at increased risk for colon cancer.

Timing of Colon Cancer Screening

Previously, colon cancer screening was recommended starting at age 50. In 2021, the United States Preventative Services Task Force (USPSTF) changed the guidelines to recommend colon cancer screening starting at age 45.[2] The recommendation applies to adults age 45 or older who are at average risk for colon cancer and who don’t have any symptoms of colon cancer. Screening tests are only done when you don’t have symptoms.

If you have one of the higher-risk recommendations mentioned above, then you may need to have a colonoscopy or other colon cancer screening at an earlier age depending on your healthcare provider’s recommendation.

Screening Tests for Colon Cancer

There are many different tests available to screen for colon cancer.[7] Which test is right for you depends on your risk factors.

Stool Tests for Colon Cancer

Three tests involve collecting a stool sample for testing:

• Fecal occult blood tests are a guaiac-based test. You get a sample of stool and smear it on cards provided by your healthcare provider. You then return the cards to the office, and your healthcare provider puts some chemical developer on the cards to detect the presence of blood. This test is performed yearly.
• Fecal immunochemical testing (FIT) uses antibodies to test for blood in the stool. This test is collected in the same way as the fecal occult blood test and is also performed yearly.
• FIT-DNA testing combines the stool test for blood as well as looking for abnormal DNA. It is performed once every three years.

Scope Tests for Colon Cancer

Flexible sigmoidoscopy is a test that looks at the lower third of your colon. It requires taking medication to prepare for the test and clean your colon out (prep). A lighted tube is put into the rectum and advanced to the junction where the transverse colon meets the sigmoid colon. The colon wall is then examined as the tube is removed. It is performed every five years or ten years if done in combination with FIT testing.

Colonoscopy is similar to flexible sigmoidoscopy but looks at the whole colon. It also requires prep and involves a flexible tube. If normal, the test is done every ten years unless a high-risk condition is present.

Imaging Tests for Colon Cancer

CT colonography is a virtual colonoscopy performed with a CT scanner. You still have to prepare for the test, similar to what you do for a colonoscopy. If normal, this test is performed every five years.

Take Control of Your Health with Everlywell

If you're interested in easy, convenient colon cancer screening, consider a FIT Colon Cancer Screening Test with at-home sample collection. This screening option is included in our at-home lab testing membership to help you take control of your health year-round.

Related Content

When to Test for HIV: Here's What to Know

How Often to Check Cholesterol: Key Points to Know

Importance of Preventive Healthcare: Here's Why It Matters

References

1. Doubeni C. Tests for screening for colorectal cancer. UpToDate. December 7, 2023. Medical Citation URL
2. U.S. Preventive Services Task Force. Colorectal cancer: screening. May 18,2021. Medical Citation URL
3. Memorial Sloan Kettering Cancer Center. Types of Colon Cancer. Accessed February 10, 2024. Medical Citation URL
4. Mayo Clinic. Colon Cancer. Published July 27,2023. Accessed February 10, 2024. Medical Citation URL
5. American Cancer Society. Colorectal Cancer Risk Factors. Published July 19, 2023. Accessed February 10, 2024. Medical Citation URL
6. American Cancer Society. What is Colorectal Cancer? Published June 29,2020. Accessed February 10, 2024. Medical Citation URL
7. Centers for Disease Control and Prevention. Colorectal Cancer Screening Tests. Published February 23, 2023. Accessed February 10, 2024. Medical Citation URL