Fecal CEA Has an Advantage in the Diagnosis of Colorectal Cancer at Early Stage.

PURPOSE: Serum carcinoembryonic antigen (SCEA) level is often measured in patients with CRC but suffers from poor sensitivity and specificity as a diagnostic biomarker. CEA is more abundant in stool than in serum, but it has not been widely studied. This study aimed to elucidate the efficacy of fecal CEA (FCEA) as a potential non-invasive biomarker for early diagnosis of CRC. MATERIALS AND METHODS: We retrospectively analyzed the determination of FCEA and SCEA levels by electrochemiluminescence. We evaluated the diagnostic accuracy of FCEA and SCEA levels in early-stage CRC patients and healthy controls using ROC curve. RESULTS: A total of 298 people were included: 115 patients with CRC, 35 patients with adenomatous polyp (APC), 46 patients with non-gastrointestinal cancer (NGC), and 102 healthy controls (HC). The FCEA concentrations in CRC and APC patients were significantly higher than that of NGC and HC, and this is different from SCEA expression in APC and NGC. As a diagnostic biomarker of CRC, FCEA had significantly larger AUC compared with SCEA (.802 vs .735, P < .001). For identifying early-stage colorectal cancer, FCEA showed better diagnostic efficacy (AUC: .831) than SCEA (AUC: .750), and the combination of the 2 biomarkers was even higher (AUC: .896). The sensitivity of FCEA was higher than that of SCEA (78.7% vs 29.8%). When SCEA was negative, 80.3% of CRC and 54.6% of APC cases could be identified by FCEA. CONCLUSION: Compared with SCEA, FCEA has more advantages in the diagnosis of the early stage of colorectal cancer and adenomatous polyps.

Superiority of fecal carcinoembryonic antigen as diagnosis marker for adenomatous polyposis coli and asymptomatic colorectal cancer.

BACKGROUND: Non-invasive diagnostic tools of adenomatous polyposis coli (APC) and asymptomatic colorectal cancer (CRC) are urgently needed. Although fecal carcinoembryonic antigen (FCEA) has been documented in some studies, the diagnostic potential for the detection of APC and asymptomatic CRC has not been described yet. METHODS: This is a retrospective study. The pre-diagnostic serum carcinoembryonic antigen (SCEA) and fecal occult blood test (FOBT) levels were retrospectively analyzed in 212 patients with intestinal diseases group (IDG) and 224 controls. The levels of FCEA across all the studied groups were measured using electronic chemiluminescence immunoassay (ECLIA), and their sensitivity and specificity were used to evaluate their diagnostic potential. The individual diagnostic accuracy of the three indices, as well as their combined diagnostic potential, was compared using the receiver operating characteristic (ROC) curve and chi-square test. RESULTS: The FCEA had low sensitivity (50%) and high specificity (93.91%) for the diagnosis of IDG, with the area under the curve (AUC) value of 0.781. The AUC of FCEA was higher than that of SCEA for the diagnosis of APC and CRC in the APC, asymptomatic CRC, and APC + CRC-stage I patients. The AUCs of FCEA were 0.708 and 0.691 for the 'double-negative patients' and 'triple-negative patients', respectively. In addition, FCEA could diagnose 45.5% of the 'double-negative' patients, 43.3% of the asymptomatic patients, and 42.9% of the 'triple-negative' patients. The combination of FCEA and FOBT improved the diagnostic value (AUC = 0.916). CONCLUSION: FCEA has been demonstrated to be a favorable diagnostic marker in intestinal diseases, especially in the APC, asymptomatic CRC, and 'double-negative' or 'triple-negative' CRC patients.