Colonoscopies and annual fecal immunochemical tests (FITs), are 2 of the preferred modalities for colorectal cancer (CRC) screening endorsed by the US Preventive Services Task Forces as well as the US Multi-Society Task Force of Colorectal Cancer, which represents the American Gastroenterological Association, American College of Gastroenterology, and the American Society of Gastrointestinal Endoscopy.1,2 The recommendations include proper patient selection (patients aged 50 - 75 years with a life expectancy of at least 10 years), and a discussion with the patient regarding both options.
Background
It is known that patients with a positive FIT are at an increased risk for CRC. Lee and colleagues found that patients who do not undergo subsequent colonoscopy after a positive FIT have a 1.64 relative risk of death from colon cancer compared with those who undergo follow-up colonoscopy.3 Studies also have shown that longer wait times (10 months vs 1 month) between a positive FIT and colonoscopy also are associated with a higher risk of CRC.4 FIT utilize antibodies specific for the globin moiety of human hemoglobin and measure the development of antibody-globin complexes using immunoassay techniques. FIT has largely replaced the fecal occult blood test (FOBT), which depends on the detection of heme in feces through oxidation.
A US Department of Veterans Affairs (VA) study found that a longer time to colonoscopy was associated with a higher risk of neoplasia in veterans with a positive FOBT (odds ratio [OR], 1.10).5 It is thus crucial that a positive FOBT or FIT be investigated with follow-up colonoscopy. However, a retrospective study at a single safety-net hospital in San Francisco found that only 55.6% of patients with a positive FIT completed colonoscopy within 1 year.6 Importantly, almost half the patients examined in this study lacked documentation of the result of the FIT or counseling regarding the significance of the positive FIT by the patient’s primary care provider who ordered the test. A VA study looked at veterans aged > 70 years at 4 VA medical centers who did not receive a follow-up colonoscopy within 1 year and reported that 26% of patients studied had a documented refusal to undergo colonoscopy.7
It also is clear that FOBT is used inappropriately for colon cancer screening in some patients. A 2005 single-center VA study looked at inappropriate fecal occult blood tests and found that 18% of veterans for whom FOBTs were ordered had a severe comorbid illness, 13% had signs or symptoms of gastrointestinal (GI) blood loss, and 7% had a history of colorectal neoplasia or inflammatory bowel disease.8 An additional national VA study looked at all veterans aged ≥ 50 years who underwent FOBT or screening colonoscopy between 2009 and 2011 and found 26% to be inappropriate (13.9% of veterans not due for screening, 7.8% with limited life expectancy, and 11% receiving a FOBT when colonoscopy was indicated).9
An often-misunderstood additional requirement in utilizing FIT for CRC screening is that negative tests should be repeated annually.2 A study from Kaiser Permanente in California found that 75.3 to 86.1% of eligible patients underwent yearly FIT.10 In this study, programmatic FIT detected 80.4% of all patients with CRC detected within 1 year of testing.
Since most of the VA-specific studies are based on inappropriate or inadequate use of FOBT, we feel it is essential that further data be gained on appropriate and inappropriate testing. The aim of this study is to determine the frequency at which improper FIT occurs because of failure to obtain serial FIT over time with a negative result, failure to follow-up a positive FIT result with a diagnostic colonoscopy, or performance of FIT in veterans undergoing a recent colonoscopy with adequate bowel preparation. This quality assurance study received an institutional review board exemption from the VA Pittsburgh Healthcare System (VAPHS) in Pennsylvania.
Methods
VAPHS has a data repository of all veterans served within the health care system, which was queried for all veterans who underwent a FIT in the system from January 1, 2015 through December 31, 2017 as well as the number and results of FITs during the interval. In addition, the data repository was also queried specifically for veterans who had at least 1 colonoscopy as well as FIT between 2015 and 2017. The ordering location for each FIT also was queried.