Tests that require patients to collect a single stool sample at home and send it to a lab for analysis will detect about 79% of colorectal cancers, according to a new evidence review.
Published in the Feb. 4 issue of the Annals of Internal Medicine, the review of 19 studies examining eight different fecal immunochemical tests also finds that the tests will correctly identify about 94% of patients who do not have cancers of the rectum or colon.
We know the FIT is easy to use, and now we also know that it is a great tool for assessing which patients have cancer and which patients dont, Beth Liles, MD, review co-author and clinical investigator at the Kaiser Permanente Center for Health Research in Portland, Ore., said in a news release.
Colorectal cancer is the second leading cause of cancer death in the United States, according to the CDC. Yet one in three adults is not adequately screened.
FIT is simple, can be done at home, and can save lives, said Jeffrey Lee, MD, MAS, the studys lead author and post-doctoral researcher at the Kaiser Permanente Division of Research in Oakland, Calif., and the University of California, San Francisco.
The American Cancer Society and other professional organizations have recommended FIT as a screening tool for colorectal cancer since 2008, but there are still many people who dont know about it.
The U.S. Preventive Services Task Force recommends that people with normal risk for colorectal cancer should begin screening at age 50 and end at age 75. Unlike older stool tests, FIT does not require people to restrict their diets or stop taking medications. Conducted annually, the test detects small amounts of blood in the stool, and people who test positive are much more likely to have colorectal cancer. People who have a positive FIT need a follow-up colonoscopy to look for cancer or precancerous polyps.
Other screening options for colorectal cancer include sigmoidoscopy, which involves physical examination of the lower colon, recommended every five years; or colonoscopy, which examines the entire colon, every 10 years.
The evidence review, funded by the National Institutes of Health, found FITs were fairly sensitive. On average, the tests detected 79% with only one round of testing. The tests also were highly specific: On average, 94% of people who did not have cancer tested negative with a single FIT.
By comparison, studies indicate that fecal occult blood test, another at-home test, detects only about 13% to 50% of cancers after a single round of testing. The FOBT is the predecessor to FIT and requires three stool samples and medication and dietary restrictions.
According to the evidence review, no single FIT performed markedly better than another, but the authors caution only one study compared brands head-to-head. Most FITs required collection of only one stool sample. Surprisingly, the authors found brands requiring two or three stool samples were no more accurate than those requiring only one.
The 19 studies reviewed included between 80 and 27,860 patients, with the average age ranging from 45 to 63. Study settings varied, but all included patients with no symptoms of colorectal cancer. In 12 studies, all patients took the FIT and received a colonoscopy. In seven studies, patients only had a colonoscopy to follow-up on a positive FIT. Approximately two years later, researchers followed up with patients who had a negative FIT to determine whether they had been diagnosed with colorectal cancer.
Study abstract: http://annals.org/article.aspx?articleid=1819122