Methylated SDC2 testing in stool DNA for early screening of colorectal cancer in Shipai Town, Dongguan City / 中华胃肠外科杂志

ABSTRACT

Objective: To explore the utility of stool-based DNA test of methylated SDC2 (mSDC2) for colorectal cancer (CRC) screening in residents of Shipai Town, Dongguan City. Methods: This was a cross-sectional study. Using a cluster sampling method, residents of 18 villages in Shipai Town, Dongguan City were screened for CRC from May 2021 to February 2022. In this study, mSDC2 testing was employed as a preliminary screening method. Colonoscopy examination was recommended for individuals identified as high-risk based on the positive mSDC2 tests. The final screening results, including the rate of positive mSDC2 tests, the rate of colonoscopy compliance, the rate of lesions detection, and the cost-effectiveness of screening, were analyzed to explore the benefits of this screening strategy. Results: A total of 10 708 residents were enrolled and completed mSDC2 testing, giving a participation rate of 54.99% (10 708/19 474) and a pass rate of 97.87% (10 708/10 941). These individuals included 4 713 men (44.01%) and 5 995 women (55.99%) with a mean age of (54.52±9.64) years. The participants were allocated to four age groups (40-49, 50-59, 60-69, and 70-74 years), comprising 35.21%(3770/10 708), 36.25% (3882/10 708), 18.84% (2017/10 708), and 9.70% (1039/10 708) of all participants, respectively. mSDC2 testing was positive in 821/10 708 (7.67%) participants, 521 of whom underwent colonoscopy, resulting in a compliance rate of 63.46% (521/821). After eliminating of 8 individuals without pathology results, data from 513 individuals were finally analyzed. Colonoscopy detection rate differed significantly between age groups (χ2=23.155, P<0.001),ranging from a low of 60.74% in the 40-49 year age group to a high of 86.11% in the 70-74 year age group. Colonoscopies resulted in the diagnosis of 25 (4.87%) CRCs, 192 (37.43%) advanced adenomas, 67 (13.06%) early adenomas, 15 (2.92%) serrated polyps, and 86 (16.76%) non- adenomatous polyps. The 25 CRCs were Stage 0 in 14 (56.0%) individuals, stage I in 4 (16.0%), and Stage II in 7(28.0%). Thus, 18 of the detected CRCs were at an early stage. The early detection rate of CRCs and advanced adenomas was 96.77% (210/217). The rate of mSDC2 testing for all intestinal lesions was 75.05% (385/513). In particular, the financial benefit of this screening was 32.64 million yuan, and the benefit-cost ratio was 6.0. Conclusion: Screening for CRCs using stool-based mSDC2 testing combined with colonoscopy has a high lesion detection rate and a high cost-effectiveness ratio. This is a CRC screening strategy that deserves to be promoted in China.