Clinical application and effectiveness analysis of modified Asia-Pacific colorectal cancer screening score combined with fecal occult blood test for colorectal cancer screening in asymptomatic population.

Aims: To evaluate the value of the modified Asia-Pacific colorectal cancer screening (APCS) scoring system combined with fecal occult blood test (FOBT) for colorectal cancer (CRC) screening in asymptomatic population of Wannan region.

Methods: We prospectively collected and investigated asymptomatic individuals attending Yijishan Hospital (the first affiliated hospital of Wannan Medical College) from January 1, 2021 to December 31, 2022. All enrolled patients received modified APCS scores and FOBT before colonoscopy. We used receiver operating characteristic (ROC) curves to estimate the screening value of the modified APCS score combined with FOBT. We also retrospectively collected patients with stage T1 CRC to explore the independent risk factors for lymph node metastasis (LNM) of CRC.

Results: 513 participants were finally included in the study. The combined detection of modified APCS score and FOBT can be divided into 5 groups [modified APCS high risk &FOBT + (T1 group), modified APCS high risk &FOBT- (T2 group), modified APCS medium risk &FOBT + (T3 group), modified APCS medium risk &FOBT- (T4 group), and modified APCS low risk &FOBT- (T5 group)], the detection rates of CRC were 9.09%, 1.67%, 5.77%, 0.92% and 0%, respectively. The detection rate of advanced adenoma was 25.76%, 35.00%, 21.15%, 2.75% and 1.96%, respectively. The detection rate of CRC in T1 group was 9.88 times that in T4 group, and the detection rate of advanced adenoma was 9.36 times that in T4 group. The high-risk group and positive rate of modified APCS were indicators for further colonoscopy. Tumor gross morphology, tumor differentiation degree, and nerve infiltration were independent risk factors for T1 CRC LNM.

Conclusions: The combination of modified APCS score and FOBT test has important clinical application value in the preliminary screening of colorectal tumors in asymptomatic population. For selected T1 CRC patients, if the lesion is ulcerative and the pathology indicates low differentiation, endoscopic submucosal dissection (ESD) treatment should be carefully selected to prevent the risk of LNM.