The fecal immunochemical test (FIT) has gained another feather in its cap. A retrospective study of more than 7,800 patients at the Veterans Administration San Diego Healthcare System (VASDHS) found that colorectal cancer (CRC) screening rates went up after the institution switched from the guaiac fecal occult blood test (gFOBT) to FIT. These results appeared in Clinical Gastroenterology and Hepatology.
FIT has the capacity to detect colorectal polyps and CRC at higher sensitivity than gFOBT. Patients prefer it because it requires no dietary restrictions and fewer samples. Gastroenterology societies have also touted its benefits.Despite its attributes, FIT in the United States has yet to replace the more commonly used gFOBT. “Many physicians are unaware of the difference between FIT and gFOBT, and potential advantages,” Samir Gupta, MD, MSCS, AGAF, the study’s senior and corresponding author and a staff physician at VASDHS, told CLN Stat.
Some health systems and labs have been reluctant to make the change due to concerns over cost or just simple inertia, Gupta said. “One of our hopes is that the paper and other associated literature will help lab directors and primary care physicians to realize that making a simple switch could have big benefits for patients.”
To see how FIT would measure up against gFOBT in a clinical setting, investigators compared outcomes at the VA health system during a period before FIT was implemented and after it made the switch to FIT.
Stool-based CRC tests were offered as a primary care option to 7,898 VASDHS patients between the ages of 50 and 75. During the study, which took place from March 2014 through January 2015, investigators obtained 4,662 FIT orders and 3,236 gFOBT orders.
In an intention to screen analysis, which included all patients with test orders, more than 42% completed a FIT, compared with 33.4% who completed gFOBT. The ease of taking a FIT likely contributed to this increase in patient participation, Gupta said.
“The absolute increase in test completion percentage was 9.2% for FIT vs. gFOBT, and 1.5-fold higher for FIT vs. gFOBT on adjusted analyses,” they observed. FIT was also more successful in detecting advanced neoplasia (0.79%) than gFOBT (0.28%).
In light of these findings, the authors strongly urged healthcare systems to consider replacing gFOBT with FIT. With this change, “health systems can markedly increase proportion of patients up-to-date with screening, and proportion of patients receiving an opportunity for early detection and prevention of CRC,” they concluded.
Process and capacity issues remain the biggest challenges of implementing FIT in health systems, Gupta observed. Those demands may vary depending on the type of FIT used in labs.
“If the FIT used is a manually processed FIT, because of increased return rates, lab personnel will need to invest more time in processing FITs. This is not an issue if a FIT that can be batch-processed with a machine is utilized,” he explained.
Increased FIT return rates would also increase the number of patients with abnormal test results requiring colonoscopy, thus leading to more resource demands for laboratories. The investigators estimate that for every 1,000 tests, FIT would yield 51 colonoscopies, compared with 42 for gFOBT.