What is Colorectal Cancer?
Colorectal cancer is a disease of abnormal cells developing in the digestive organs of the intestines or rectum. When abnormal cells develop in either the colon or rectum, cancer starts. Colorectal cancer most often starts growing in polyps, which can be precancerous lesions in the colon.
Screening tests for colorectal cancer are meant to catch the cancer (if present) at an early stage before it’s causing any symptoms. Per the U.S. Preventive Services Task Force, colon cancer screening is recommended for those aged 45 to 75. Those who are aged 76 to 85 should have a conversation with their healthcare provider about the need to continue screening.
Multiple screening options exist for colorectal cancer.
These include:
● Stool tests
● Flexible sigmoidoscopy
● Colonoscopy
● CT colonography
Stool tests
There are tests that can be run on samples of stool. The sample is generally collected at home and returned to a lab for testing. One test, called a fecal occult blood test, looks for the presence of blood in the stool that isn’t visible to the naked eye.
Another stool test is called a FIT-DNA test. FIT stands for fecal immunochemical test, which looks for blood in the stool. It is combined with a DNA test that looks for the presence of any DNA changes which might suggest the presence of cancer.
Flexible sigmoidoscopy
A flexible sigmoidoscopy is a test in which a flexible camera is inserted into the rectum. This looks for the presence of cancer cells in the rectum and lower third of the colon. This test does not evaluate the entire colon.
Colonoscopy
A colonoscopy is a test which looks at the rectum and the entire colon. It can be done as a screening test itself or is done if any of the other screening tests are positive and there is a need for further evaluation. In the day or two before a colonoscopy, laxative medications will be taken to help induce frequent bowel movements to clean out the colon so the gastroenterologist will be able to see the colon well. The procedure is done with sedation so you’re not awake during the procedure.
If there are any suspicious areas in the colon, such as polyps, they can be removed during the colonoscopy and tested to see if cancer cells are present.
CT colonography
This exam, sometimes referred to as a virtual colonoscopy, it is performed using a CT (computed tomography) scan. Using a CT machine, pictures are taken of the colon and images are reconstructed to look for any suspicious areas. This type of test may be best for people who are at risk for complications of anesthesia needed for standard colonoscopy.
Early detection is key in colon cancer, and screening is the best way to achieve that. Screening tests can find precancerous polyps so they can be removed before becoming cancer. They can also find colon cancer early when it is easier to treat. The bottom line is this: if you are 50 years old or older, you should get screened for colon cancer.