The Diagnostic Performance of Fecal Immunochemical Tests for Detecting Advanced Neoplasia at Surveillance Colonoscopy

Background and Aims An increasing burden on healthcare resources has resulted in a backlog of individuals requiring colonoscopy, with delays in surveillance possibly detrimental for individuals at increased risk of colorectal cancer (CRC). This study investigated the use of a two-sample fecal immunochemical test (FIT to establish those most likely to have advanced neoplasia (AN) and in need of prioritized surveillance colonoscopy. Methods A prospective study conducted in the tertiary care setting. Participants completed a two-sample FIT (OC-Sensor, Eiken Chemical Company) within 90 days of surveillance colonoscopy. The sensitivity of FIT for detection of AN (CRC or advanced adenoma) in moderate and high risk individuals was determined at fecal hemoglobin (Hb) thresholds between 2-80μg/g feces. Results 766 patients were included (median age 66.1y, IQR 58.1-72.9; 49.9% male), with AN detected in 8.6% (66/766, including 5 CRC). For moderate-risk individuals (with prior history of adenoma or a significant family history of CRC), sensitivity of FIT for AN ranged from 73.5% at 2μg/g feces, to 10.2% at 80μg/g feces. For high-risk conditions (confirmed/suspected genetic syndromes or prior CRC), sensitivity of FIT was similar, ranging from 70.6% at the lowest positivity threshold of 2μg/g feces, to 11.8% at 80μg/g feces. Independent variables in the whole cohort for association with detection of AN at surveillance colonoscopy were age (OR 1.03, 95%CI 1.00-1.06), and FIT Hb result ≥10μg/g feces (OR 1.81, 95%CI 1.04-3.16). Conclusions The use of FIT prior to surveillance colonoscopy provides clinicians with insights into the risk of AN. This raises the possibility of a method to triage individuals, facilitating the more efficient management of endoscopic resources.