Fecal immunochemical test followed by colonoscopy in opportunistic screening for colorectal neoplasm

Abstract

Objective To assess the fecal immunochemical test (FIT) followed by colonoscopy in opportunistic screenings for colorectal neoplasm. Methods Total 6 193 patients, who underwent opportunistic colorectal cancer (CRC) screening, were classified into four groups: 3 812 patients underwent direct colonoscopy (group 1), 1 244 patients received one FIT followed by colonoscopy (group 2), 341 patients received two FITs followed by colonoscopy (group 3), and 796 patients received three FITs followed by colonoscopy (group 4). Results Total 97 (1.6%) patients with CRC and 1 038 (16.8%) with colorectal adenoma were detected. The positive predictive value of 1, 2 and 3 positive tests out of three FITs for CRC were 4.53%, 5.62% and 8.94%, respectively, which was higher than that of direct colonoscopy (1.52%). One or more positive tests out of three FIT had the largest area under receiver operating characteristic curve (0.743). For colorectal adenoma, detection rate of direct colonoscopy (17 581.25/105) was higher than all FIT strategies (3 732.30/105-13 127.41/105). Conclusions Single or repeated FIT and colonoscopy have different screening utility. One or more positive tests out of three FIT followed by colonoscopy is preferred to screen CRC, and direct colonoscopy is better for detection of colorectal adenoma. Key words: Colorectal neoplasms; Screening; Colonoscopy; Fecal occult blood test; Fecal immunochemical test