Accuracy of Fecal Immunochemical Tests for Colorectal Cancer: Systematic Review and Meta-analysis

Abstract

BACKGROUND: Performance characteristics of fecal immunochemical tests (FITs) to screen for colorectal cancer (CRC) have been inconsistent. PURPOSE: To synthesize data about the diagnostic accuracy of FITs for CRC and identify factors affecting its performance characteristics. DATA SOURCES: Online databases, including MEDLINE and EMBASE, and bibliographies of included studies from 1996 to 2013. STUDY SELECTION: All studies evaluating the diagnostic accuracy of FITs for CRC in asymptomatic, average-risk adults. DATA EXTRACTION: Two reviewers independently extracted data and critiqued study quality. DATA SYNTHESIS: Nineteen eligible studies were included and meta-analyzed. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of FITs for CRC were 0.79 (95% CI, 0.69 to 0.86), 0.94 (CI, 0.92 to 0.95), 13.10 (CI, 10.49 to 16.35), 0.23 (CI, 0.15 to 0.33), respectively, with an overall diagnostic accuracy of 95% (CI, 93% to 97%). There was substantial heterogeneity between studies in both the pooled sensitivity and specificity estimates. Stratifying by cutoff value for a positive test result or removal of discontinued FIT brands resulted in homogeneous sensitivity estimates. Sensitivity for CRC improved with lower assay cutoff values for a positive test result (for example, 0.89 [CI, 0.80 to 0.95] at a cutoff value less than 20 µg/g vs. 0.70 [CI, 0.55 to 0.81] at cutoff values of 20 to 50 µg/g) but with a corresponding decrease in specificity. A single-sample FIT had similar sensitivity and specificity as several samples, independent of FIT brand. LIMITATIONS: Only English-language articles were included. Lack of data prevented complete subgroup analyses by FIT brand. CONCLUSION: Fecal immunochemical tests are moderately sensitive, are highly specific, and have high overall diagnostic accuracy for detecting CRC. Diagnostic performance of FITs depends on the cutoff value for a positive test result. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute.