Today’s CRC screening options include colonoscopy, flexible sigmoidoscopy, CT or virtual colonoscopy, fecal immunochemical (FIT), stool MT-sDNA (Cologuard) and blood-based tests.
It is important to remember that colonoscopy is still required if a stool test or CT scan finds any abnormalities.
Any test is better than no test.
Colonoscopy is used to detect polyps, which are small growths that develop on the lining of the colon. Removing these polyps significantly reduces a patient’s risk for developing colorectal cancer. During this procedure, the gastroenterologist passes a flexible and slender endoscope tube through the patient’s rectum and into their colon. The gastroenterologist then examines the colon for polyps or any other abnormalities. If they detect any polyps, they remove them using a small device known as a snare that is passed through the endoscope. Most colorectal cancer can be prevented by removing these polyps.
A flexible sigmoidoscopy is a test that gastroenterologists perform to examine a patient’s rectum and sigmoid colon for signs of colorectal cancer, although this may not be suitable for finding precancerous polyps in other parts of the colon.
CT or virtual colonoscopy uses specialized x-rays and software to create two- and three-dimensional images of the colon that are used to detect colorectal cancer and polyps.
A fecal immunochemical test (FIT) is used to detect blood that is hidden in a patient’s stool, which can be an early sign of colorectal cancer. This is a convenient and widely utilized test that people can conduct at home. These tests are normally conducted on an annual basis once a person meets the criteria for colon cancer screening.
Multi-target stool DNA (mt-sDNA) or “Cologuard” detects blood and identifies biomarkers in the stool that are associated with colorectal cancer and polyps. This is a simple, non-invasive stool test that people can conduct at home.
ASGE recognizes the potential for blood-based tests to increase CRC screening, especially for patients who are unwilling to use the other screening options. However, ASGE does not recommend that blood-based tests be used as a first line CRC screening option. ASGE has determined that blood-based tests are inferior to colonoscopy and stool-based tests, especially when it comes to detecting advanced precancerous lesions – which can develop into CRC. Despite the increased availability and public interest in blood-based CRC screening, the scientific evidence does not support using these tests as a first line screening tool.
There are several ways to get screened for CRC and colon polyps. Primary care physicians and gastroenterologists can help their patients determine which CRC screening test is appropriate for them, keeping in mind that the best method varies for everyone based on their unique history and risk factors.
National guidelines recommend that everyone should be screened for CRC as soon as they turn 45 years old – even if they haven’t exhibited or experienced any problems or symptoms – and patients who have a higher risk of developing CRC may need to be screened before they turn 45 and/or need more frequent screening.
Those who are at higher risk include, but are not limited to, people who have a personal or family history of CRC, people who have had pre-cancerous polyps removed and people who have a long-standing history of inflammatory bowel disease (i.e., ulcerative colitis or Crohn’s disease).
ASGE ultimately believes that the best CRC screening test is the one that gets done.