Brand Name: Cologuard (colorectal screening test)
Device Type: Stool DNA testing using gene amplification technique
Similar Device: FIT (Fecal Immunochemical Test)
Manufacturer: Exact Sciences Corporation
FDA Approval Date: August 2014
What is Cologuard and how does it work?
Colorectal cancer is one of the most common cancers in the world. It is the third most commonly diagnosed cancer in man and the second in women. More than 50,000 patients die of colorectal cancer each year in the United States. However, if screened and detected early enough, the mortality rate can be significantly decreased.
Cologuard test is a noninvasive colorectal cancer screening test that uses advanced stool DNA technology. Naturally the lining of human colon shed cells every day. In the presence of cancer or pre-cancer, abnormal cells are shed into the colon and excreted in the stool. Cologuard is a sensitive chemical test that detects DNA and hemoglobin changes associated with colorectal cancer.
When a doctor orders Cologuard, the Collection Kit is shipped to the patient's home. The patient uses the Cologuard kit to collect and ship a stool sample back to the lab using a pre-addressed package. The lab screens for altered DNA associated with colorectal cancer and the result is sent to your doctor.
What is the Cologuard test used for?
Cologuard test is used for screening for colorectal cancer in individuals 50 years and older who are at average risk of colorectal cancer. Cologuard is not a confirmatory test for colorectal cancer. A follow-up colonoscopy is required if the Cologuard screening test is positive.
What other methods are available to screen for colorectal cancer?
Sigmoidoscopy is used for examining the rectum and sigmoid colon using a flexible tube with a lens and light. Abnormal tissue can be removed for biopsy during sigmoidoscopy. The lower colon must be cleared of stool before the exam, and most patients do not receive sedation for sigmoidoscopy.
A colonoscopy examines the entire colon using a flexible tube with a lens and light. The doctor can see the lining of the entire colon, even the upper parts of the colon where sigmoidoscopy cannot reach. Abnormal tissues are removed during colonoscopy for biopsy. The entire colon must be thoroughly cleared out of stool before the exam and most patients receive some form of sedation during the exam.
High-sensitivity fecal occult blood test (FOBT) checks for blood in stool since polyps and colorectal cancers can bleed. There are two types of FOBT approved by the FDA. They are guaiac FOBT (gFOBT) and the fecal immunochemical test (iFOBT). The gFOBT detects a component of the blood, heme, which can also be found in certain food like red meat. The patient should avoid certain food before having gFOBT. The iFOBT uses antibodies to detect blood and dietary restriction is not required.