If the idea of a colonoscopy makes you cringe, there are less invasive tests you can take at home that can help detect early signs of colorectal cancer. Colorectal cancer is cancer that starts in the colon or the rectum.
Not counting skin cancers, colorectal cancer is the third most common type of cancer and is the third leading cause of cancer-related deaths for both men and women. That means approximately 50,000 people will die from colorectal cancer in 2014.
The good news is that the number of colorectal cancer-related deaths has been dropping in both men and women for the last 20 years. This is in part due to successful early detection and removal of polyps in the intestines.
Polyps are growths that can form on the inside walls of the intestines. Over time, polyps may turn into cancer. Early detection and removal of polyps can reduce the odds of colorectal cancer.
The most effective method to detect both colorectal polyps and cancer is a colonoscopy. During this procedure, the doctor inserts a tiny camera mounted on a tube about the size of a finger into the intestine. This allows the medical team to look for and potentially remove polyps.
Researchers recommend that people with normal risks for colorectal cancer should have a colonoscopy every 10 years beginning at age 50.
For people who choose not to have a colonoscopy or who want to start with a less invasive method of testing, there are tests that may find colorectal cancer, but are less likely to detect polyps.
• FOBT – Fecal occult blood tests look for blood in a stool specimen or feces. Blood that cannot be seen with the naked eye is known as “occult”. FOBT uses a chemical reaction to test for blood in the stool.
Large polyps or cancer in the colon or rectum often bleed slightly as a bowel movement passes by them. This blood can be detected by the test.
Because the chemical in FOBT reacts with any type of blood – animal or human – the test can be affected by eating certain foods such as red meat. For this reason there are usually diet restrictions in the days leading up to taking the test.
This test also cannot determine whether blood found in the stool is from cancer or polyps in the intestine, or from other sources such as bleeding from an ulcer in the stomach, diverticulosis or hemorrhoids.
If the FOBT detects blood in the stool, a colonoscopy will be necessary to locate the source of the bleeding.
• FIT – The fecal immunochemical test is a newer way to detect hidden blood in a stool sample. The test, also referred to as an iFOBT, is available under the brand name InSure®.
The chemicals used in this test react to part of the human hemoglobin protein found in red blood cells. This makes the test less reactive to foods and reduces the need for dietary restrictions prior to taking the test. The test is also less likely to react to blood from a source higher up in the digestive tract such as a stomach ulcer.
Like FOBT, this test can only detect a cancerous tumor or polyp that is bleeding. If blood is found in the stool sample, a colonoscopy will be required to locate the source of the bleeding.
Both FOBT and FIT should be done every year. Collecting multiple stool samples from several consecutive bowel movements can also increase the effectiveness of the tests. Talk to your healthcare provider to assess your personal risk for colorectal cancer and to determine which test is right for you.
Sources:
About.com: Inflammatory Bowel Disease (IBD). Fecal Immunochemical Test (FIT). Web. Amber J. Tresca. February 17, 2014.
http://ibdcrohns.about.com/od/diagnostictesting/p/fit.htm
American Cancer Society. Can colorectal polyps and cancer be found early? Web. February 17, 2014.
http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorect...
American Cancer Society. What are the key statistics about colorectal cancer? Web. February 17, 2014.
http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorect...
Quest Diagnostics. Fecal Globulin by Immunochemistry (InSure®). Web. February 17, 2014.
http://www.questdiagnostics.com/testcenter/testguide.action?dc=TS_FecalG...
Reviewed February 19, 2014
by Michele Blacksberg RN
Edited by Jody Smith