The fecal immunochemical test has high accuracy for detecting advanced colorectal neoplasia before age 50

Background In contrast to the decreasing incidence of colorectal cancer (CRC) in adults ≥50 years, the CRC incidence in young adults <50 years is increasing. The fecal immunochemical test (FIT) may be useful for advanced colorectal neoplasia (ACRN) screening in a young population. Aims To evaluate the diagnostic accuracy of FIT in a young population. Methods The diagnostic performance of FIT for detecting ACRN was compared among the following age groups who underwent FIT and colonoscopy as part of a comprehensive health screening program: 30–39, 40–49, and ≥50 years. Results Of 26,316 participants, 464 (1.8%) had ACRN and 805 (3.1%) showed positive FIT results. No significant differences in the sensitivity (22.1%, 17.2%, and 22.0%; p = 0.435) and specificity (97.2%, 97.4%, and 96.9%; p = 0.344) of FIT for detecting ACRN were observed among the groups. However, 30–39 age group had a significantly higher accuracy of FIT for ACRN (96.7%) than 40–49 and ≥50 age groups (95.9% and 93.8%; p < 0.001). The areas under the receiver operating characteristic curves of FIT for ACRN of three age groups were not significantly different (67.2, 66.2, and 61.7; p = 0.952). Conclusions The diagnostic performance of FIT for ACRN in a young population (<50 years) was not inferior to that in the current screening-age population (≥50 years). The FIT may be a good choice for detecting ACRN in a young population.