Reducing the cutoff value for an abnormal fecal immunochemical test result may increase detection of advanced neoplasia and colorectal cancer while doubling the demand for screening colonoscopies, according to research published in Clinical Gastroenterology and Hepatology.
Emily Berry, MSPH, of the University of Texas Southwestern Medical Center Moncrief Cancer Institute, and colleagues wrote that previous research has shown that taking the cutoff below 20 µg hemoglobin/g of feces helps improve the sensitivity of FIT screening.
“A challenge of this approach however, particularly in settings with constrained colonoscopy capacity, is lowering the threshold may also increase colonoscopy demand,” they wrote. “Particularly in the United States, ‘real world’ data specific to the impact of utilizing a lower Hgb concentration threshold on diagnostic colonoscopy demand and neoplasia detection when implemented within screening programs are sparse.”
Researchers performed a prospective study of 5,838 patients without insurance who were not up to date with screening and completed at least one FIT. They reduced the cutoff value for an abnormal FIT result from at least 20 µg hemoglobin/g of feces to at least 10 µg hemoglobin/g feces and offered patients with an abnormal result a no-cost screening colonoscopy. Then, they compared the proportion of patients with abnormal FIT results and neoplasia yield for the standard and lower cutoff values.
Berry and colleagues found 12.3% of patients had abnormal results at the lower threshold compared with 6.6% at the standard cutoff. The lower cutoff produced detection rates for advanced neoplasia and CRC of 10.2% and 0.9%, respectively, compared with 12.7% and 1.2% at the standard value.
Most patients diagnosed with either CRC (72.7%) or advanced adenoma (67.3%) had hemoglobin concentrations of at least 20 µg/g feces. However, at the lower cutoff value, there were three patients later diagnosed with CRC (3/11; 27.3%) and 36 patients diagnosed with advanced adenoma (36/110; 32.7%) who would have been missed at the standard abnormal threshold.
“Implementing a lower cutoff for abnormal FIT as part of an organized mailed outreach program may result in detection of additional patients with advanced neoplasia, though at expense of doubling the proportion of patients requiring a diagnostic colonoscopy,” Berry and colleagues concluded. “Health systems employing quantitative FIT should carefully consider the screening threshold prior to implementation, and where colonoscopy capacity permits, consider lowering the cutoff for an abnormal FIT as a potential strategy for optimizing CRC detection and prevention.” – by Alex Young
Disclosures: The authors report no relevant financial disclosures.