Colorectal cancer screening methods
There are many choices for early detection
Colorectal cancer screening tests saves lives
Screening tests help your doctor find polyps or cancer before you even have symptoms. This early detection may prevent polyps from becoming cancer and could jumpstart treatment earlier, when it is most effective.
Though it is usually recommended to start getting screened at age 50, you may need to be screened earlier depending on your family’s health history and risk factors.
Types of screening chart
|METHOD||WHAT & HOW||FREQUENCY||PROS||CONS||SENSITIVITY/ SPECIFICITY
FOR DETECTING CANCER
|Colonoscopy||Simple and safe procedure in which your doctor uses a long tube with a light and camera to detect polyps||Every 5-10 years depending on whether polyps are found||Views the entire colon. Polyps can be removed during the procedure if found||Dietary restrictions 1-3 days prior to procedure and prep to clean out the colon is needed||Sens 95%
|Fecal Immunochemical Test (FIT or iFBOT)||Tests for blood. Swab bowel movement and place on card||Annually||No prep. Done at home. Fairly Inexpensive||Accuracy. Need a colonoscopy if blood is detected. Requires 1-2 separate samples||Sens 73.8%
|Guaiac Fecal Occult Blood Test (FOBT)||Tests for blood. Swab bowel movement and place on card||Annually||No prep. Done at home. Inexpensive||Accuracy, Dietary restrictions, Need a colonoscopy if blood is detected. Requires 3 separate samples||Sens 70%
|Flexible Sigmoidoscopy||Detects polyps. Done at a doctors’ office||Every 5 years, may be combined with annual stool test||No sedation required. Can biopsy if small polyp detected||Only views part of the colon. Need a colonoscopy if larger polyps or other issues are detected||Sens 95%
Only left sided cancers
|Virtual Colonoscopy||Uses x-rays and computers to take 2- or 3-D images of your colon and rectum||Every 5 years||Quicker and less invasive than colonoscopy. No sedation is needed||Expensive and not covered by all insurance carriers, Dietary restrictions 1-3 days before the procedure, full bowel prep is required, If a polyp is found, will need a colonoscopy||Sens 84%
|Stool DNA||Tests for abnormal DNA and blood in stool. Collect bowel movement and send back to the lab for analysis using collection apparatus provided with kit.||Every 3 years (according to ACS guidelines)||No prep, dietary restrictions, or changes to medications necessary. Greater accuracy than FIT.||More expensive than FIT if test not covered by insurance. Follow-up colonoscopy necessary if test indicates precancer or cancer.||Sens 92%
|Double Contrast Barium Enema||Air and barium are pumped into your rectum. The solution will show polyps or tumors on X-rays.||Every 5-10 years||Done without sedation. Less expensive than colonoscopy||Laxative preparation is required. Polyps cannot be removed during the procedure. If polyps are found, a colonoscopy will be needed||Very low sensitivity and specificity|
Click on the name of each method above to learn more.
Sensitivity-true positives- this percentage indicates the number of people WITH colorectal cancer that are correctly identified, so if the sensitivity is 80% then out of 100 people with the disease it will correctly identify 80 people with the disease and incorrectly identify 20 people as not having the disease that do have it.
Specificity-true negative- this percentage indicates the number of people WITHOUT colorectal cancer that are correctly identified, so if the specificity of a test is 60% then out of 100 people without the disease it will correctly identify 60 people that do not have the disease and incorrectly identify 40 people as having the disease who do not have it.