Clinical value of combining serum tumor marker detection with fecal occult blood testing in diagnosing colorectal cancer.

This study aimed to investigate the value of combining the detection of serum tumor markers, namely, carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 199, CA 242, and CA 50, with fecal occult blood (FOB) testing in the diagnosis of colorectal cancer (CRC). One hundred patients with CRC who were diagnosed and treated at the First Hospital of Jiaxing, Zhejiang Province, China, between January 2019 and April 2020 were enrolled as the case group, and 200 healthy people who underwent a physical examination at the hospital during the same period were recruited as the control group. The concentrations of CEA, CA199, CA242, and CA50 in serum were measured alongside FOB indicators. Compared with the control group, the concentrations of CEA, CA199, CA242, and CA50 in the case group were significantly higher, and they were related to age, tumor differentiation, tumor stage, and other clinicopathological features (P<0.05). The diagnostic performance of the combination of four tumor markers for CRC was significantly better than when using a single marker (four-combined test: AUC (area under the curve) AUC=0.80), and the diagnostic performance was further improved after adding the fecal occult blood test test (FOBT) results (five-combined test: AUC=0.90). The combined detection of the five indexes was found to be effective for the early diagnosis of CRC (AUC=0.87). We concluded that the detection of serum tumor markers CEA, CA199, CA242, and CA50 combined with an FOBT could significantly improve the sensitivity and accuracy of a CRC diagnosis and contributed to an early diagnosis and appropriate treatment.