Comparison of the performance of guaiac-based and two immunochemical fecal occult blood tests for identifying advanced colorectal neoplasia in Taiwan

Objectives We aimed to evaluate the performance of fecal occult blood tests (FOBT) for the screening of colorectal cancer (CRC). Methods We selected participants from a medical center in Taiwan, China from November 2009 to June 2011. All participants underwent screening colonoscopy and were asked to provide their stool samples for qualitative immunochemical FOBT (qlFIT), quantitative immunochemical FOBT (qnFIT) and the guaiac-based FOBT(GT). The receiver operating characteristic curve was utilized to determine the optimal cut-off value of qnFIT. We measured the detection ability of the FOBT for colonic polypoid lesions. Results In all, 699 participants were enrolled in this study. For qnFIT, we found increased levels of fecal hemoglobin in participants with polyps 10mm (251.0ng/mL), villous-containing adenomas (98.7ng/mL) and advanced adenomas (187.9ng/mL). The optimal cut-off value for qnFIT was 25ng/mL for detecting advanced colorectal neoplasms (ACRN). All three FOBT had a similar but low estimate in detecting small and tubular adenomatous polyps. The qnFIT had a better detection ability for large adenomas (positive likelihood ratio [PLR], 5.6 vs 3.1 vs 0.3) and adenomas with villous-components (PLR 3.7 vs 3.3 vs 0.3) than qlFIT and GT. For the ACRN group, qnFIT also showed the best screening ability with a sensitivity of 56.8%, accuracy of 86.7% and PLR 5.0. Conclusions Both qnFIT and qlFIT perform better than GT in detecting advanced adenomas and CRC in the Taiwanese population.