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 metaanalysis. 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.Colorectal cancer (CRC) is the third most common cancer worldwide, with over 1.85 million new cases and over 880,000 deaths occurring in 2018 (1). Population-based screening offers an opportunity for primary prevention and early detection of CRC, with a favorable impact on mortality (2, 3). A wide variety of screening tests are available for CRC, the most widely used being tests for fecal occult blood (FOBT). The use of FOBT was shown to reduce cancer mortality in five large randomized trials (4-8). Several international and national guidelines currently recommend that both women and men at an average risk should undergo organized screening for advanced adenoma and CRC (9).For detection of FOB, guaiac-based test (gFOBT) and fecal immunochemical test (FIT or iFOBT) are commercially available. The guaiac-based tests utilize the pseudoperoxidase activity of hemoglobin (Hb; free or intact), whereby guaiac is oxidized by hydrogen peroxidase. Because this reaction takes place with any peroxidase present in stool, gFOBT tests are non-specific to human Hb, with interference by any foodstuffs with peroxidase content, by certain chemicals or even medications (9, 10). Based on a com...

Comparative Effectiveness of Fecal Immunochemical Tests versus Flexible Sigmoidoscopy for Colorectal Cancer Screening: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

“…A previous meta-analysis comparing different colorectal screening techniques also found a higher diagnostic yield of colorectal neoplasia with endoscopic screening when compared with fecal tests [13]. However, that data was based predominantly on gFOBT which have been found to be inferior to FITs [15,16]. Also, in their analysis, endoscopic screening comprised of both flexible sigmoidoscopy and colonoscopy, such that a direct comparison of sigmoidoscopy with FIT was not possible.…”

“…Flexible sigmoidoscopy has been shown to have similar efficacy to colonoscopy in identifying left-sided lesions with a reduction in incidence and mortality rates by 25% and 30% respectively, when compared to no screening or usual care [7][8][9][10][11]. Fecal immunochemical test has been reported to have better sensitivity than gFOBT in detecting CRCs and advanced adenomas and has largely replaced gFOBT as the fecal test of choice [12][13][14][15][16].…”

Colorectal Cancer Survival in 50- to 69-Year-Olds after Introducing the Faecal Immunochemical Test

“…In recent years, it has been shown that the faecal immunochemical test (FIT) is a tool that makes it possible to identify patients at the highest risk of CRC among those with symptoms [9,10]. FIT is a non-invasive test, which detects faecal haemoglobin concentrations (f-Hb), and has a high diagnostic accuracy for CRC [10][11][12], higher than that of the SIGN or NICE criteria [13] and traditional guaiac based faecal occult blood tests [14]. This test, with high sensitivity and specificity is essential for early detection and avoidance of unnecessary invasive tests.…”

Future Prospects of Colorectal Cancer Screening: Characterizing Interval Cancers

“…In a population-screening context, the FIT has a sensitivity of 86% and a specificity of 85% to detect CRC [16] and a sensitivity of 29% and a specificity of 97% to detect advanced adenoma [17]. Thus, the FIT is much less sensitive for advanced adenomas.…”