The Importance of Colon Cancer Screening
Published: March 9, 2020
Colorectal cancer screening is a test I recommend for all my patients who meet criteria for screening.
The U.S. Preventative Services Task Force recommends routine colorectal cancer screening between the ages of 50 and 75, and the American Cancer Society recommends that a patient at average risk start regular screenings at age 45.
Patients who are considered higher risk, such as those with a family history of colorectal cancer, should begin screening at a younger age. If you are one of those patients, talk with your doctor to determine when to start screening.
Colon cancer screening is vital, as more than 90 percent of cases occur in adults over 50 years old. And when caught early, colorectal cancer is highly treatable.
Unfortunately, only two-thirds of Americans in the recommended age range have ever been tested for colon cancer. Those are staggering statistics considering colorectal cancer is the second leading cause of cancer death in the United States, killing approximately 50,000 people a year.
The goal of colon cancer screening
The goal of colorectal cancer screening is to find and identify polyps – abnormal tissue growths – in the colon. Polyps are the most common causes of colon cancer. Screening allows doctors to identify and remove these polyps before they develop into cancer.
How to screen for colon cancer
There are several ways to effectively screen for colorectal cancer. You and your doctor will determine which type of testing is most appropriate for you based on your health and medical background.
The major benefit of a colonoscopy, the most common screening tool, is that it is the only test that can actually directly visualize the entire length of the colon. During this test, doctors can collect samples of tissue for biopsy and remove any polyps. We recommend patients have this test once every 10 years. If a lesion is found, your physician may recommend repeat testing even sooner. Your doctor may also recommend a colonoscopy if any other screening test you take is found to be positive.
From the comforts of home, a patient collects a stool sample, which is then sent in and tested in a laboratory. The lab works to determine if there is any evidence of abnormality that may indicate the presence of a colon polyp or colon cancer. In the past, the most common test looked for evidence of blood. Newer, more sensitive testing now can look for altered DNA in the stool that can be seen with colon cancer and certain types of colon polyps. Stool testing is done every one to three years depending on the type of test. There are many types of home stool testing kits. Check with your physician to see if they have a preference.
The least used screening test is sigmoidoscopy. It’s similar to colonoscopy in that it also utilizes a flexible tube to inspect the inside of the colon. However, only about half of the colon can be visualized with this scope. This test may miss lesions or polyps in the other parts of the colon. Because of this, sigmoidoscopy is generally done every five years and often is used in conjunction with stool testing.
CT colonography (virtual colonoscopy)
A newer but not yet frequently utilized option is CT colonography. By using X-ray and CT imaging, this method creates a virtual view of your colon. If an abnormality is seen, a colonoscopy will generally be recommended for follow-up. If clear, this option can be repeated every five years.
Speak with your doctor to determine which test is best for you. Your physician will want to have a thorough discussion regarding the risks and benefits of each test. Regardless of which test you choose, it's important to remember that the best test is the one that gets done.