Are at-home fecal immunochemical tests effective in detecting colon cancer? The answer is yes. An analysis of published studies on the topic was published in the Annals of Internal Medicine on Feb. 4. The authors looked at 19 studies and found that these simple to use tests on average detected about 79 percent of cancers. Even better news was that 94 percent of patients without cancer tested negative with just one test.
Colon cancer ranks second in the U.S. for the number of cancer deaths, following only lung cancer, according to the National Cancer Institute. In their press release, Kaiser Permanente Division of Research points out that one third of American adults have not been screened for this cancer.
The most definitive way to screen for colon cancer is the colonoscopy. The American College of Gastroenterology suggests a colonoscopy at age 50 for most adults, with additional screenings every ten years thereafter. For African-Americans, they suggest beginning the process at age 45 due to an increased risk of developing the disease.
The physician inserts a long tube called a colonoscope into the patient's rectum. The patient is usually sedated for comfort. The physician will take photos of the colon during the procedure with the device. The colonoscope is long enough to reach through the entire bowel and to the terminus of the small intestine, about ten feet in most adults.
The patient prepares for a colonoscopy by cleansing the bowel. This involves diet changes in the week before the procedure, and a cleansing routine prescribed by the physician the day prior. The cleansing involves large quantities of water and the use of strong laxatives. It produces severe diarrhea for several hours but leaves the walls of the colon clearly visible to the doctor.
The colonoscopy may be one of the most dreaded tests that patients undergo. The cleansing is unpleasant though necessary. Many patients are uncomfortable with the idea of the procedure. The sedation and the aftereffects of the cleansing often mean the loss of a day of work.
The fecal occult blood test is also a common test. A stool sample is taken by the patient using a kit provided by their physician and mailed to a laboratory. The lab determines if there is blood in the stool, a common sign of trouble in the colon.
The test requires dietary changes in the week prior, since it may react to foods such as red meat, cantaloupe or radishes. Certain medications can also affect the results. The fecal occult blood test detects blood in the stool, even if it is not visible to the naked eye.
The fecal immunochemical test (FIT) requires no dietary changes. It detects only the presence of human hemoglobin. Because blood from sources in the small intestine is digested before reaching the colon, the FIT is a more specific test for colon cancer. Because cancers do not bleed continually, this test requires samples from two different days. There are a number of tests on the market and their sensitivity and directions for use may vary. Many provide the results immediately and others require sending the samples to a lab.
The National Cancer Institute estimates that there are 102,000 new cases of colon cancer each year in the United States. An estimated 51,000 die of colon and rectal cancer. Risk factors include a family history of colon cancer, obesity, smoking, heavy alcohol use and age. The confirmation that a simple, inexpensive, at-home test provides accurate screening for colon cancer is welcome news for the one third of American adults who have never been screened.