Fecal Occult Blood Tests in Colorectal Cancer Screening: Systematic Review and Meta-analysis of Traditional and New-generation Fecal Immunochemical Tests

Abstract

Background/aim: Noninvasive fecal occult blood tests (FOBTs) are recommended by current guidelines for colorectal cancer (CRC) screening. Our aim was to assess the diagnostic performance of traditional guaiac-based FOBTs (gFOBT) and new-generation immunochemical FOBTs (iFOBT) in CRC screening by carrying out a systematic review and meta-analysis.

Patients and methods: PubMed, Embase, Cochrane Library, and Web of Science were searched for eligible articles published before February 17, 2020. Three independent investigators conducted study assessment and data extraction. Diagnosis-related indicators for use of FOBTs in the detection of CRC (as the endpoint) in a screening setting were summarized, and further stratified by the type of FOBT (gFOBT vs. iFOBT). STATA software was used to conduct the meta-analysis. Pooled sensitivities and specificities were calculated using a random-effects model. Hierarchical summary receiver operating characteristic curves were plotted and area under the curves (AUC) were calculated.

Results: The electronic search identified 573 records after duplicates were removed, of which 75 full-text articles were assessed for eligibility. Finally, a total of 31 studies were eligible for the meta-analysis. In the ROC comparison test, there was a statistically significant difference in the performance of gFOBT and iFOBT tests, with AUC=0.77 (95% confidence intervaI=0.75-0.79) and AUC=0.87 (95% confidence intervaI=0.85-0.88), respectively (p=0.0017). In formal meta-regression, test brand did not prove to be a significant study-level covariate that would explain the observed heterogeneity between the studies.

Conclusion: New-generation iFOBTs were found to have a significantly higher diagnostic performance as compared with gFOBTs, advocating the use of only fecal immunochemical tests in all newly implemented CRC screening programs.

Keywords: FIT; Fecal occult blood; HSROC; ROC; colorectal cancer screening; false negative; false positive; fecal immunochemical test; gFOBT; guaiac-based test; iFOBT; meta-analysis; sensitivity; specificity.