Can Noninvasive Tests Substitute Endoscopy for Diagnosis of Colonic Diseases?

Background and Aims: Fecal calprotectin was approved as a non-invasive screening tool for organic colonic diseases. The aim of this study was to evaluate fecal calprotectin and inflammatory indices as non-invasive markers for diagnosing and differentiating inflammatory bowel diseases (IBD) and colorectal cancer (CRC) in comparison to irritable bowel syndrome (IBS) in a cohort of Egyptian patients.

Methods: In this cross-sectional study, fecal calprotectin, neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR) and systemic inflammatory index (SII) were assessed in 40 IBD patients, 40 CRC patients, and 20 IBS patients.

Results: Fecal calprotectin was significantly higher in IBD and CRC groups compared to IBS control group (P= 0.018 and 0.022 respectively), with no significant difference between IBD and CRC groups. PLR, NLR and SII showed no significant differences between the 3 studied groups (P= 0.469, 0.101 and 0.84 respectively). At a cut-off value 113, fecal calprotectin had the ability to differentiate CRC patients from IBS patients with 75% sensitivity and 60% specificity, while At cut-off value of 116, fecal calprotectin had the ability to differentiate IBD patients from IBS patients with 67.5% sensitivity and 65% specificity.

Conclusion: Inflammatory indices tested in our study (PLR, NLR, SII) showed no role for the differentiation between IBD, CRC, and IBS. Fecal calprotectin should be used with caution as a primary step for screening of colonic diseases as it cannot differentiate IBD from CRC. It has only moderate sensitivity in differentiating IBD and CRC from IBS. Unfortunately, neither fecal calprotectin nor inflammatory indices can substitute endoscopy in the screening or diagnosis of IBD and CRC.