The fecal immunochemical test (FIT) has been used as part of France’s organized colorectal cancer screening program (DOCCR) since 2015 to reduce the incidence and mortality associated with this cancer. However, certain cancers, known as interval cancers, can occur within two years of a negative test result. The objectives of this study were to evaluate the sensitivity of FIT and to describe the characteristics of interval cancers. A retrospective study was conducted among DOCCR participants in the Isère department between 2015 and 2018. Screening data were cross-referenced with data from the cancer registry to identify interval cancers. The sensitivity of FIT was calculated, and a multivariate logistic regression identified factors associated with these specific cancers.Among 233,202 tests performed, 516 cancers were detected following a positive FIT, 118 interval cancers were diagnosed within two years of a negative FIT, and 5 following a non-analyzable FIT that was not repeated. The overall sensitivity of the FIT was 80.8%. It was higher for distal colonic tumors (91.8%) than for proximal tumors (70.7%) and rectal tumors (78.0%). Interval cancers were more often diagnosed at an advanced stage. In multivariate analysis, a proximal (odds ratio, OR=4.3) or rectal (OR=3.3) location was significantly associated with an increased risk of interval cancer. The FIT demonstrates good overall sensitivity, but it performs less well for proximal colonic and rectal locations.