The colon is the first and longest part of the large intestine, which is part of the digestive system that helps break down food for the body to use. Colon cancer is abnormal growth of cells in the colon that can cause masses and other symptoms.

While colon cancer doesn’t typically have symptoms until later stages, there are several screening and diagnostic tests that can be done to detect abnormal cells.

Medicare beneficiaries older than age 50 or with certain risk factors are at higher risk for colorectal cancer, so it’s important to take advantage of preventive services available to detect abnormalities early. Read on to learn more about Medicare coverage for colorectal cancer screenings, including virtual colonoscopies and others.

What is colon cancer?

Colon cancer, or colorectal cancer, typically begins as small clumps of cells called polyps that form inside the colon. While polyps are not always cancerous, some can turn into colon cancers over time.

Colon cancer happens when cells in the colon develop changes in their DNA, causing the cells to multiply too quickly. Cells continue to live when healthy cells die (as part of the natural lifecycle), which causes too many cells that can form a mass. These cells can then invade and destroy healthy cells and body tissue, and over time, they can even spread to other parts of the body.

To detect colon cancer, your provider may recommend a colonoscopy or other colon cancer screening.

Risks for colon cancer

Doctors aren’t certain what causes most colon cancers, but there are some factors that can increase your risk.

The primary risk factor is age. Colon cancer can happen at any age, but most people with colon cancer are 50 years or older.

Other risk factors include race, a personal history of colorectal cancer or polyps, inflammatory bowel diseases, inherited syndromes that increase colon cancer risk, and family history of colon cancer. A low-fiber, high-fat diet, not exercising regularly, diabetes, obesity, smoking, and drinking alcohol can also increase risk.

Symptoms of colon cancer

Most people with colon cancer don’t have symptoms at first, but when symptoms do appear, they will depend on the cancer’s size and location in the large intestine. Symptoms can include a change in bowel habits, such as more frequent diarrhea or constipation, ongoing discomfort in the belly (like cramps or gas), rectal bleeding or blood in the stool, feeling like the bowel doesn’t empty all the way during a bowel movement, weakness or tiredness, and losing weight without trying.

What is a virtual colonoscopy?

A virtual colonoscopy is a less invasive way to check for cancer in the large intestine. Known as screening CT colonography, a virtual colonoscopy uses a CT scan to take hundreds of 2- or 3-D cross-sectional pictures of your inside organs, including your colon and rectum. The pictures are added together to create a complete view of the inside of the colon and rectum.

A virtual colonoscopy is not for everyone: You aren’t able to have a virtual colonoscopy if you have a history of colon cancer or polyps, a family history of colon cancer or polyps, Chron’s disease or ulcerative colitis, or acute diverticulitis.

That said, a virtual colonoscopy finds large polyps and cancer at about the same rate as a standard colonoscopy, and because it looks at the entire abdomen and pelvic area, it can also detect other diseases related to the kidneys, liver, or pancreas.

Other types of colon cancer screenings

A standard colonoscopy is an exam used to look for changes, such as swollen, irritated tissues, polyps, or cancer, in the large intestine and rectum. During this procedure a long, flexible tube (colonoscope) with a tiny camera at the end is inserted into the rectum, allowing the doctor to see inside the colon.

If necessary, polyps or abnormal tissue can be removed through the scope, or tissue samples (biopsies) can be taken.

Then, in addition to a colonoscopy and virtual colonoscopy, there are other types of colon cancer screenings.

• A fecal occult blood test (FOBT) is a test to check stool for blood that can only be seen under a microscope. Blood in the stool may indicate polyps, cancer, or other conditions. There are two types of FOBTs: A guaiac FOBT, in which the sample of stool is tested with a chemical, and an immunochemical FOBT, where a liquid is added to the sample and injected in a machine that can detect blood. This is also called a fecal immunochemical test (FIT).
• A sigmoidoscopy is a procedure to look inside the rectum and sigmoid (lower) colon for polyps and abnormal areas. A sigmoidoscope (thin, tube-like instrument with a light and camera) is inserted through the rectum into the sigmoid colon.
• Finally, a DNA stool test checks DNA in stool cells for genetic changes that could be a sign of colorectal cancer.

Who should get a colonoscopy?

Your doctor may recommend a colonoscopy for a variety of reasons, such as to investigate intestinal signs and symptoms (such as abdominal pain, rectal bleeding, chronic diarrhea, and other intestinal problems), to look for more polyps if you’ve had polyps before, to treat an issue, or more commonly, as a preventive screening for colon cancer.

If you are age 45 or older and at average risk for colon cancer, your doctor may recommend a colonoscopy every 10 years. You may qualify for other types of colon cancer screening tests more often depending on your risk and individual circumstances.

If you have other risk factors, your doctor may recommend a screening more often.

Getting a screening colonoscopy is an important part of early detection, when the cancer is most likely to respond to treatment. There are several types of screening exams for colon cancer, so talk to your doctor about the best option for you.

Medicare coverage for a virtual colonoscopy

Typically, a virtual colonoscopy is not covered by Original Medicare.

The Centers for Medicare and Medicaid Services (CMS) has specific requirements for when a virtual colonoscopy may and may not be covered. For example, it is not covered when used for a screening or in the absence of signs of symptoms of a disease or risk factors.

However, a virtual colonoscopy may be covered by Medicare Part B (medical insurance) if a diagnostic or standard colonoscopy of the entire colon is not able to be completed due to an inability to pass the scope. The incomplete standard colonoscopy must be due to an obstructing growth, intrinsic scarring or other obstruction, or extrinsic compression.

It may also be covered if the beneficiary is at increased risk for bleeding or has high sedation risk (such as from severe chronic obstructive pulmonary disease or previous anesthesia adverse reaction). Note that these risks must be well documented in the beneficiary’s medical record.

In most cases, a virtual colonoscopy is intended to be used in planning for an operation when imaging of the colon is necessary and cannot be done with a standard colonoscopy.

Does Medicare cover colorectal cancer screening tests?

Medicare Part B covers preventive screening colonoscopies:

• Once every 24 months if you’re at high risk for colorectal cancer
• Once every 120 months (or 48 months after a previous flexible sigmoidoscopy) if you are not at high risk

There is no minimum age requirement.

Medicare will also cover a FOBT if you get a referral from your provider, a flexible sigmoidoscopy, and a multi-target stool DNA test if you meet certain requirements. Ask your doctor which type of colorectal cancer screening test is right for you.

Additionally, if you have a non-invasive stool-based screening test (fecal occult blood tests or multi-target stool DNA test) and receive a positive result, Medicare will cover a follow-up colonoscopy as a screening test.

Part B also covers a diagnostic colonoscopy if you have symptoms of colon cancer.

As long as your provider accepts assignment, you will pay $0 for this screening test.

However, if your provider finds and removes a polyp or other tissue, you will pay 15% of the Medicare-approved amount for your doctors’ services. If you are in a hospital outpatient setting or ambulatory surgical center, you may also pay a 15% facility co-insurance.

The Part B deductible does not apply.

Medicare Advantage plans (Part C) are required to provide the same coverage as Original Medicare, so if you have a Part C plan, both preventive and diagnostic colorectal cancer screenings are covered if you meet eligibility requirements. This includes a virtual colonoscopy. Check with your plan to learn more about requirements and out-of-pocket costs you may have.

Additional resources

• ClearMatch Medicare: Find a Medicare Plan
• Medicare.gov: Colonoscopies
• CMS.gov: Virtual Colonoscopy (CT Colonography)
• National Cancer Institute: Colorectal Cancer Screening