5 ways to screen for colon cancer

One in every 24 people, on average, will be diagnosed with colorectal cancer (cancer of the colon or rectum).

Early detection is key to overcoming a colorectal cancer diagnosis.

A colonoscopy is the most well-known screening method for colon cancer. But it’s not the only one.

Which screening method is best for you? Well, that’s a decision you should make with your physician based on your preferences, your medical history, and your family history.

Here are five options you’ll want to discuss…

1. Colonoscopy

This screening method is considered the most thorough. It uses a tiny video camera on the end of a long, flexible tube (the colonoscope).

It’s inserted into the rectum to detect polyps (abnormal tissue growths) or changes in the colon. It can also take a biopsy or tissue sample during the screening. This eliminates the need for a follow-up test, should something abnormal be detected.

A colonoscopy takes about 30 to 60 minutes. If it comes back clear, and you don’t have an increased risk of colorectal cancer, it only needs to be repeated about every 10 years.

The drawback to such a complete test is that the colon needs to be cleared before the exam can take place. This means using an enema or laxative.

Most colonoscopies require sedation, which can take a few hours to wear off. You’ll likely have to take the rest of the day off work and have someone drive you home after the exam.

It’s also the most “invasive.” It can be uncomfortable. However, being the most thorough exam, and only needing to be done every 10 years, it might be worth the tradeoff.

2. Virtual colonoscopy (CT colonoscopy)

A CT scan creates a cross-sectional image of the abdominal organs so the doctor can see if anything looks out of the ordinary.

This procedure takes about 10 minutes and should be repeated every 5 years. Like a full colonoscopy, the colon and rectum need to be cleared before the exam, and you may need to alter medications and diet beforehand.

However, sedation is not usually required for a virtual colonoscopy.

3. Flexible sigmoidography

During this test, a thin, flexible tube with a tiny video camera on the end is inserted into the rectum. This allows the doctor to view the inside of the rectum and the lower part of the colon, which is called the sigmoid colon. The instrument can also take biopsies if needed.

This procedure takes about 20 minutes, requires no sedation, and is usually repeated every 5 years if no abnormalities are detected.

Unfortunately, any problems in the upper colon will not be detected. Follow-up tests (like a colonoscopy) will be needed if something is found to be abnormal in the lower colon.

4. Stool DNA test

You may have seen the Cologuard® commercials, where the little box walks around praising the benefits of the product.

This is a prescription-only stool DNA test that you send in to the lab, instead of having to go to the clinic. This kind of test checks a stool sample for signs of altered DNA, cancerous cells, precancerous lesions and the presence of blood in the stool.

A stool DNA test has been shown to detect up to 92 percent of colorectal cancer in a clinical study of 10,000 participants.

This kind of screening method is convenient, but it’s considered less sensitive than more thorough methods. And it can’t detect precancerous polyps or abnormalities in the colon. If abnormalities are found, your doctor will likely order a follow-up test.

5. Fecal occult blood test (FOBT) or Fecal immunochemical test (FIT)

Similar to a stool DNA test, these tests check for blood in the stool. This test can be done at home and requires no sedation or emptying of the colon. It’s usually repeated annually.

However, it does not detect polyps or precancerous cells. And it has a higher incidence of false-positive outcomes (the test indicates something is wrong when, in fact, there is nothing wrong.) If blood is detected, a follow-up test will likely be needed.

Note that screening methods are only used when there are no bowel symptoms of colon cancer. If you or someone you know is experiencing:

  • Abdominal pain or cramping
  • Change in bowel habits, such as chronic constipation or diarrhea
  • Rectal bleeding
  • Dark stool, or blood in the stool
  • Unintended or unexplained weight loss

Then it’s best to see a doctor and address these concerns right away.

If you’re at average risk for colorectal cancer with no symptoms, talk to your doctor about the best colon cancer screening option for you.

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  1. Determine your risk—and practice prevention — Colorectal Cancer Alliance
  2. Frequently Asked Questions — Cologuard®
  3. Signs and symptoms of colorectal cancer — American Cancer Society
Amanda Luft

By Amanda Luft

Amanda Luft is a writer based in Eau Claire, Wisconsin. She's written extensively in the natural health world, on everything from organic living and disease to the power of nature on your health. When she's not writing, or cooking and baking healthy food for her family, you can find her out walking in the woods, reading, and practicing yoga.