Comparative Effectiveness of FITs With Colonoscopy

Colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer
death in both men and women in the U.S., with nearly 50,000 deaths each year. Since CRC
develops over a number of years from precursor lesions called polyps, it is largely
detectable and preventable in early stages. As these polyps become larger, they, like most
CRCs, tend to bleed, which is the rationale for the use of fecal occult blood tests (FOBTs)
to detect both polyps and cancers early, while they are curable. However, early screening and
detection is much less common than it could be, with about 43% of eligible individuals
unscreened. Fecal immunochemical tests (FITs) are a type of FOBT that can be a sensitive,
specific, and low cost alternative to colonoscopy for CRC screening. Modeling studies have
shown that for population screening, a strategy of annual FIT testing from age of 50 to 75
years results in an equal number of life-years gained as compared with colonoscopy every 10
years. However, about 90% of screening in the U.S. is done with colonoscopy, the most
expensive and invasive screening test. FITs are far less costly and largely replacing the
guaiac test in CRC screening programs internationally, where only individuals with positive
results are referred for a colonoscopy. Studies done on FITs in other countries often used
FITs not available in the U.S. or studied high-risk populations; thus, results are not
applicable in the U.S. It is critical to determine the FIT(s) with the best test
characteristics in order to implement successful FIT-based screening programs in this
country.

It is estimated that 24 million more individuals will need to be screened by 2018 to reach
the "80% by 2018" goal set by the National Colorectal Cancer Roundtable. To address this
knowledge gap, investigators propose to compare the test characteristics of three Clinical
Laboratory Improvement Amendments (CLIA)-waived FITs and two automated FITs, using
colonoscopy as the gold standard. The rationale for this proposed study is that, for almost
all of the FITs currently marketed in the U.S., there is no evidence of the accuracy claimed.
Specific aims are: Aim 1: To assess the diagnostic accuracy for advanced colorectal neoplasms
of three of the most commonly used CLIA-waived FITs and two automated FITs, using colonoscopy
as the gold standard.

Aim 2: To evaluate the diagnostic accuracy of two quantitative FITs using receiver operating
characteristic (ROC) analysis. Aim 3: To assess factors associated with false positive and
false negative FIT results for each device.

These findings will provide essential information about FITs with the best test
characteristics for future expanded use of FIT, critically important to achieving the
long-term goal of reducing morbidity and mortality from CRC. FITs are more acceptable to
patients, will allow higher screening rates, and will reduce costs as compared with a
screening strategy based on colonoscopy as the primary initial screening method.

Inclusion Criteria:

- scheduled for a screening or surveillance colonoscopy

Exclusion Criteria:

- familial polyposis syndromes: ulcerative colitis or Crohn's disease: or active rectal
bleeding