June 15, 2021

When Should You Start Colon Cancer Screenings?

When Should You Start Colon Cancer Screenings?

Colon cancer usually starts as a polyp, a small growth that develops on the colon or rectum lining. Some polyps are not cancerous (and will never become cancerous), some can be precancerous and have a chance of turning into cancer, and sometimes polyps develop into early-stage cancer. It's common not to have any symptoms at all with colon cancer.

That is why it is important to have screening tests done for colon cancer even when you don't have symptoms.

However, you may be wondering when you should actually start screening, especially since recommendations have changed. Let’s go over the details of the typical colon cancer screening schedule.

When to Begin Colon Cancer Screenings

Screening tests are used as a way to detect disease, even if you don’t have symptoms yet. Detecting colorectal cancer early on can help with treatment options and prognosis. Guidelines for colon cancer screenings are made by healthcare organizations such as the National Cancer Institute, the American Cancer Society (ACS), the Centers for Disease Control, and the American Society of Clinical Oncology.

Recently, the ACS recommended beginning colon cancer screenings at age 45. This was a change from their prior screening guidelines to begin screening at age 50 for someone at average risk of developing the disease. The change came after researchers noted a slight increase of colon cancer in individuals younger than age 50.

Cancer researchers are still trying to understand why younger people are being diagnosed with colon cancer. However, it is already known that lifestyle choices can contribute to cancer. Diet, exercise, and weight are all key factors in your risk level. Smoking and heavy alcohol use also contribute to a high risk of cancer.

Screening recommendations for colon cancer differ based upon whether a patient is at average risk or at high risk for the disease. Your primary care doctor will recommend the best method of screening for you based on your age, risk, and family history.

Why Is Colon Cancer Screening Important?

Screening helps discover precancerous polyps and cancer at early stages. When colon cancer is found at an early stage, treatment is more effective, and your chances of living longer improve. Once you start showing symptoms, it may mean that cancer has already developed or even spread to other organs. Remember that screenings need to be done regularly.

How Do I Know if I Have an Average or High Risk of Developing Colon Cancer?

Your doctor will recommend screening tests based on your individual needs and your personal amount of risk based on different factors. The following explanations should help you to understand the difference between average risk or if you are considered high risk for developing colon cancer.

  • Average risk means you are generally healthy and have no family history of colon cancer or other cancers. With average risk, according to the American Cancer Society's new guidelines, men and women should start screening at age 45 and continue to receive screenings until age 75. You need to discuss all recommendations with your doctor, including screening after age 75.
  • High risk means you have certain contributing factors that could make you more likely to develop colon cancer. These include a personal or family history of colon or rectal cancer, a history of certain types of polyps, previous radiation of the pelvic region, or a history of inflammatory bowel diseases such as ulcerative colitis or Crohn's disease. In this high-risk group, the recommendation is to start screenings before you reach age 45. You will also need more frequent screenings than the average-risk group. Your doctor will give you specific recommendations based on your total health and age.

What Methods are Used for Colon Cancer Screening?

There are two types of screening tests used to check for colon cancer:

  • Stool-based tests: These tests check your stool for signs of cancer. These tests are considered less invasive, but you need to do them more often. Since these tests are done at home by providing a sample of your stool, most people are willing to do these tests. If any of the stool-based tests are abnormal, you will need to have a visual exam. If you are at average risk of colon cancer, your doctor will usually suggest a stool-based test as the first screening test used.
  • Visual exams: These tests look at the colon and rectum for any abnormal areas or polyps. This is done either with a colonoscope (a tube-like instrument that has a light and small video camera) put into the rectum or with special x-ray tests. This is most often referred to as a colonoscopy, although there are a few different types of technology that make visual exams possible.

Stool Sample Tests for Colon Cancer Screening

Guaiac-based fecal occult blood test (gFOBT)

The guaiac-based fecal occult blood test (gFOBT) looks for occult (hidden) blood in the stool through a chemical reaction. The gFOBT can't determine if the blood came from the colon or from other parts of the digestive tract. This test must be done every year, and it checks more than one stool sample. You will get a kit from your doctor's office for the test and directions on how to take stool samples at home. Usually, samples from three separate bowel movements are needed. You will return the test to the doctor's office or medical lab for testing.

Certain foods or medications can affect the gFOBT results, so you may be told by your healthcare provider not to take any of the following before you do the test at home.

  • Non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen (Advil), naproxen (Aleve), or aspirin, because they might cause bleeding, which can result in a false-positive test. (NSAIDs may cause bleeding, which can lead to a false-positive result.) However, if you take these medicines for heart problems or other health issues, you need to first talk with your doctor before stopping them.
  • More than 250 mg for 3-7 days prior to testing because it can affect the chemicals in the test and give a false positive, even if blood is present.
  • Avoid eating red meats (beef, lamb, or liver) for three days before testing.

Fecal immunochemical test (FIT)

Another test used to screen for colon cancer is the fecal immunochemical test (FIT), which checks for blood in the stool from the lower intestines. This test must be done each year. It is done in the privacy of your own home by you providing a sample of your stool. Your doctor will give you the FIT kit that you will need for testing with step-by-step instructions on how to collect the samples.

Stool DNA test

A stool DNA test checks for abnormal sections of DNA from cancer or polyp cells and for occult (hidden) blood. Cologuard® is currently the only stool DNA test available in the United States. It tests for both DNA changes and blood in the stool (FIT). This test needs to be done by you at home every three years. Although it requires a full stool sample, no medication or food

limitations are needed before taking the test.

The test supplies used to collect your stool sample at home will include:

  • A sample container
  • Bracket for positioning the container in the toilet
  • LIquid preservative
  • Tube
  • Labels
  • Shipping box

For more information about how to conduct the test, reach out to your doctor directly. Remember, with any of the stool sample tests, if your test is positive, your doctor will most likely recommend a colonoscopy.

Visual Colon Screening Tests

Visual colon screening exams or tests view the inside of the colon and rectum for any signs of polyps. These tests are done less often than stool-based tests, but they require more preparation ahead of time.

Flexible sigmoidoscopy

A flexible sigmoidoscopy is used to examine the lower part of the colon. A sigmoidoscope (a flexible, lighted tube with a small video camera on end) is put in the rectum and then moved into the colon. Images gathered from the scope are then seen on a video screen. If any polyps are found during the test, the doctor may remove them with a small instrument passed through the scope. The polyps will be looked at in the lab. If a precancerous polyp or colon cancer is found, you'll need to have a colonoscopy later to look for polyps or cancer in the rest of the colon. Since this test only examines the rectum and only the lower part of the colon, it is not used often.


A colonoscopy is used to examine the rectum and entire colon. You will be lightly sedated during the procedure. A colonoscope (a flexible, lighted tube with a small video camera on end) is put in the rectum and then moved into and through the colon. If any polyps are found during the test, the doctor will remove them with a small instrument passed through the scope, and the polyps will be sent to the lab to check for cancer.

CT colonography (virtual colonoscopy)

This test is a type of computed tomography (CT) scan of the colon and rectum that may be able to identify polyps or other signs of cancer. CT colonography uses both x-rays and a CT scan to make three-dimensional pictures of the inside of the colon and rectum. No sedation is needed, and unlike colonoscopy, no instrument or scope is put into the rectum or colon. You may be asked to drink a special contrast solution before taking the test so that your doctor can easily identify any remaining stool left in the colon or rectum.

The CT colonography may be useful for people who either can't have or aren't comfortable with more invasive tests. However, if polyps are detected, a colonoscopy will still be needed to remove them or to explore the area fully.

Know When you Should Get Your Colon Cancer Screening

It's important to stay in communication with your physician about your colon cancer screening. If you or a loved one receive a diagnosis of colorectal cancer, the Cancer Cancer Care Centers of Brevard are here to help. Our dedicated oncologists can work with you to create a customized treatment plan that works for your needs.

Categories: Colorectal Cancer