Fecal neopterin level determination: can be a useful screening test for colorectal polyps?

Colorectal cancer (CRC) is a leading cause of cancer death worldwide. The main precursor lesion leading to CRC is the adenomatous colorectal polyp (CP). Nowadays, there is no recognized perfect screening test of CP and CRC. Neopterin is an important marker of cellular inflammation. In this study, we aimed to evaluate comparatively immunochromatographic fecal occult blood test (iFOBT) and fecal neopterin levels (FNLs) in patients with CP and controls.

One hundred eleven patients diagnosed with CP and 68 individuals with negative colonoscopy were included in the study. iFOBT and FNLs were assessed in patients and controls.

FNLs and iFOBT positivity were significantly higher in patients with CP than in controls (17.15 ± 3.55 µmol/L/g vs. 12.25 ± 2.19 µmol/L/g, P = 0.00 and 46.8% vs. 14.8%, P = 0.00, respectively). FNLs were significantly higher in cases with adenomatous polyps than in hyperplastic polyps (P = 0.002). FNL ≥14.00 µmol/L/g was the best cutoff value to differentiate between patients with CP from controls (P = 0.000). A multiple logistic regression analysis showed that high FNL was positively correlated with presence, number, diameter of CPs, and presence of adenoma (P < 0.005). The sensitivity of high FNL for CP was 81.1%, which was superior to iFOBT positivity (47.7%, P < 0.001).

FNL level is significantly increased in CPs. The FNL exhibited increased sensitivity for identifying CP and adenomatous lesions compared with iFOBT. FNL determination could have as a new screening and diagnostic test for CP.