What to do when you have a family history of colon cancer

Mar 03, 2020

In the United States, colon cancer is the second most common cause of cancer related deaths and the third most commonly diagnosed cancer. Yet, it remains one of the most preventable and treatable types of cancer.

Most colorectal cancers develop from a polyp which is an abnormal growth within the colon.  While not all polyps are the same, some polyps called adenomas can grow over time and transform into cancer if they are not removed.  Screening tests can detect polyps before they turn into cancer.  In fact, most colorectal cancer can be avoided through appropriate screening and early detection.

For most people, colorectal cancer screenings should begin at age 45 when the incidence of colorectal cancer increases significantly. If you have a first degree relative (parent, sibling, or child) with a history of colon cancer, it’s recommended that you start getting screened at age 40 or 10 years earlier than your relative was diagnosed, whichever is earlier (For example, if your brother was diagnosed with colon cancer at age 35, you should start getting screened at age 25.).

What is a family history of colon cancer?

A family history of colon cancer means that you have an immediate family member (or multiple other family members) who’ve had colorectal cancer. This can put you at an increased risk for the disease. Earlier screening is indicated if you have a first-degree relative (parent, sibling, or child) with a history of colorectal cancer.  If the cancer was detected at an age earlier than 60, then you are at an increased risk for colorectal cancer and you may need more frequent screening.

A family history of colon polyps may also be considered a risk factor for developing colorectal cancer. If you have a first degree relative with a history of colon polyps, specifically pre-cancerous adenomatous type polyps, you may also benefit from earlier and more frequent colorectal cancer screening.

Getting screened for colon cancer

Although there are several options available for colon cancer screening, patients with a family history of colorectal cancer or pre-cancerous polyps are strongly encouraged to undergo a colonoscopy. This is the only screening test that allows a gastroenterologist to directly visualize and examine the entire length of the colon. During this procedure, any polyp that is found is removed.  Bowel cleansing and sedation are required for this test, so it is usually necessary to take a day off from work or other activities.  If your colonoscopy is normal, you will need to repeat your colonoscopy every 5-10 years, depending on your family history and specific risk factors.  If there are abnormal findings, your physician will be able to recommend the next steps based on the results.

Screening alternatives

In patients who are average risk and without any risk factors, a fecal immunochemical test (FIT) is the screening test of choice.

The FIT test is performed annually and allows you to simply take a stool sample at home and mail it to a lab which will test for blood in your stool. Colorectal cancers and large polyps often release small amounts of blood into the stool, which can be detected by FIT testing.  If your FIT test is positive, you will then be referred for a colonoscopy.  If your FIT test is negative, you can continue to have an annual FIT test.

If you have special risk factors and cannot undergo a colonoscopy, you might be referred for a virtual colonoscopy also known as a CT colonography. Although CT colonography does not allow for biopsy or removal of polyps, it can be an alternative to a traditional optical colonoscopy.

If you have a family history of colorectal cancer or pre-cancerous polyps, talk with your doctor about whether earlier colorectal cancer screening is right for you. If you’ve had colon cancer or pre-cancerous polyps, it’s important to tell your close relatives so that they can pass along that information to their doctors and start screening at the appropriate age.  Remember, early detection saves lives!

Learn more about colorectal cancer, including details on prevention.

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