Colon Cancer Screening
Screening tests detect cancer’s hidden warning signs long before symptoms appear and when the disease is most treatable. Understand your screening needs and complete the cancer screening and prevention questionnaire to manage your cancer risk.
Although most cases of colon cancer are diagnosed in people older than 50, colon and rectal cancer is becoming more common among younger adults. For this reason, Roswell Park recommends that everyone at average risk begin regular colon and rectal cancer screening at age 45, and earlier if you have certain risk factors, such as a family history of the disease or an inherited genetic condition, such as Lynch Syndrome.
Several types of colorectal screening tests are available and can detect early warning signs, long before any symptoms would appear, by:
- Testing a stool sample for microscopic traces of blood or to determine if there are DNA mutations or changes in certain cells
- Examining the inside of the colon and rectum to detect any polyps, abnormal growths or precancerous lesions in the colorectal lining
Stool-Based Screening Tests
These screening tests analyze your stool (fecal matter) for DNA changes in certain cells, or for microscopic or hidden (occult) blood. Any blood found in your stool may be the result of a number of conditions, such as polyps, hemorrhoids, infection, benign inflammatory condition or a cancerous lesion. These tests do help reduce the number of deaths from colorectal cancer and are less invasive and don’t require bowel cleansing preparation. They include:
- Fecal immunochemical test (FIT) that uses antibodies to detect any hemoglobin (a blood protein).
- Guaiac-based fecal occult blood test (gFOBT) checks for heme, the part of your blood that contains iron.
- Stool DNA test looks for certain changes or mutations in the DNA from cancerous or polyp cells that shed through your stool. This test, Cologuard,® looks for both microscopic blood and DNA changes.
If your results from any of these tests are abnormal, then you’ll need a structural exam, such as a colonoscopy, to determine the blood’s source or detect a cancerous polyp or tumor.
Colonoscopy — What Is It?
A colonoscopy is a procedure that examines the inside of the entire length of the colon and rectum to look for any polyps or suspicious growths. This colorectal screening is considered the “gold standard” because it can also remove any polyps or small growths on the spot. By removing polyps before they can become malignant, colorectal cancer can be prevented.
During this procedure, a gastroenterologist or surgeon uses a colonoscope (a thin, flexible tube equipped with a light source and camera) to examine the lining of your colon and rectum. If polyps are identified, then they are removed for testing. A colon-cleansing preparation is required before this procedure. A colonoscopy should be repeated once every 10 years, or more frequently if you’re at higher than average risk or if polyps were found during a previous procedure.
Other Colorectal Exams
Other structural exams look at the inside of the colon and rectum for polyps or other growths, but they are not as thorough as colonoscopy. If any of these tests find abnormalities, you’ll need a colonoscopy anyway.
- Double-contrast barium enema (DCBE) or lower GI series involves having an enema that contains a barium solution. Air is introduced into the colon, and a series of x-rays are taken. DCBE detects only about 30–50% of the cancers that can be found with a colonoscopy.
- Sigmoidoscopy uses a thin, lighted tube (called a sigmoidoscope) to examine the lower portion of the colon and rectum for polyps or suspicious lesions. Any abnormalities can be biopsied at this time. Like colonoscopy, this procedure also requires a colon-cleansing preparation.
- Virtual colonoscopy uses special x-ray equipment (rather than an inserted colonoscope) to take pictures of the interior of the colon. A computer creates detailed images highlighting any abnormalities, such as polyps. Like colonoscopy and sigmoidoscopy, this procedure does require colon cleansing.