Colorectal Cancer Screening
Colorectal cancer screening should begin at age 45 for individuals of average risk. In some cases, individuals should begin screening earlier if they have certain risk factors for colorectal cancer, including tobacco use, alcohol use, obesity and diabetes.
Types of colorectal cancer screening tests
Screening should also begin earlier for individuals at an increased risk of developing colon cancer, including African Americans, those with a history of inflammatory bowel disease, specific genetic syndromes, history of radiation therapy to the stomach or pelvis, and those with a family history of polyps or colon cancer.
Several methods are available for colorectal cancer screening and a decision on the best approach for an individual should be made with the guidance of a physician. Routine testing can be lifesaving, as it can lead to cancer prevention.
Endoscopic and radiologic examinations:
- Colonoscopy (recommended) – A colonoscopy is one of the most sensitive screening methods for colorectal cancer. A colonoscopy is an outpatient procedure in which a flexible scope allows the doctor to view the rectum and entire colon (right and left colon.) A colonoscopy can accurately evaluate for polyps which can be removed or tested for cancer with a biopsy. The decision to remove or sample a polyp is generally based on its appearance and size. If the colonoscopy is normal and no abnormalities are found, the next exam is repeated in 10 years.
- CT colonography (CTC, formerly referred to as "virtual colonoscopy") – A series of computerized tomography (CT) scans are taken of a patient’s colon after a small tube (catheter) is inserted into the rectum and used to fill the colon with air to improve image quality. A physician will then review the images to check for signs of colorectal cancer.
- Flexible sigmoidoscopy; can be combined with FIT or sensitive gFOBT – A flexible tube (sigmoidoscope) with a small camera attached to the end is inserted into a patient’s rectum. A flexible sigmoidoscopy only evaluates the left colon and is generally performed every five years. If small polyps are detected, the physician may remove them during the procedure for further testing. If cancer is suspected, a follow-up colonoscopy may be recommended.
Non-invasive options for screening include stool-based and radiographic testing. We recommend discussing with your doctor which test is best for you. These tests can usually be taken at home and with a small sample of feces it can detect blood or molecular markers which may indicate the presence of a cancer or polyp in the colon.
- Guaiac-based fecal occult blood test (gFOBT) – The more sensitive gFOBT test should be used, if this method is chosen. Typically performed annually.
- Fecal immunochemical test (FIT) – The quantitative test should be performed when available; may use the qualitative test if quantitative tests are not available. Typically performed annually.
- FIT-DNA (multitargeted stool DNA test, combining fecal DNA, FIT, and DNA methylation assays) – Cologuard assay available in the United States. Typically performed every three years.
Because colon cancer is one of the only cancers that can be easily and reliably detected in people who do not have symptoms, Moffitt Cancer Center encourages individuals to stay up-to-date with their screenings. If the results of a colon cancer screening test show the presence of a precancerous polyp or cancerous lesion, our expert oncologists can develop an individualized treatment plan.