[Methylated SDC2 testing in stool DNA for early screening of colorectal cancer in Shipai Town, Dongguan City].

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.目的： 探讨粪便SDC2基因甲基化（mSDC2）检测在东莞市石排镇居民结直肠癌早期筛查的应用价值。 方法： 本研究采用横断面研究方法。2021年5月至2022年2月期间，东莞市石排镇政府采用整群抽样方法确定东莞市石排镇18个村的筛查范围，对符合初筛标准的居民由东莞市石排医院开展粪便mSDC2检测，确定高危人群，初筛阳性者建议其接受肠镜复查。观察mSDC2检测初筛的阳性率、肠镜依从率、肠镜检出率以及筛查成本-效益。 结果： 有效筛查人数共计10 708人，筛查参与率54.99%（10 708/19 474），合格率97.87%（10 708/10 941）。筛查对象中，男性4 713例（44.01%），女性5 995例（55.99%），年龄为（54.52±9.64）岁；以年龄段分组，40~49岁组3 770人（35.21%），50~59岁组3 882人（36.25%），60～69岁组2 017人（18.84%），70~74岁组1 039人（9.70%）。通过初筛检出mSDC2阳性结果的居民共计821人，初筛阳性率为7.67%（821/10 708），521人接受了肠镜检查，肠镜依从率为63.46%（521/821）。521例完成肠镜检查的居民中，有8例未能提供病理结果，可分析结果513例。各年龄组间肠道病变检出率的差异具有统计学意义（χ2=23.155，P<0.001）；肠镜病变检出率随年龄的增高而上升，40~49岁年龄组最低（60.74%），70~74岁年龄组最高（86.11%）。通过病理诊断发现，共检出结直肠癌25例（4.87%），进展期腺瘤192例（37.43%），非进展期腺瘤67例（13.06%），锯齿状腺瘤或息肉15例（2.92%），非腺瘤性息肉86例（16.76%）。检出的25例结直肠癌中，肿瘤分期0期14例（56.0%），Ⅰ期4例（16.0%），Ⅱ期7例（28.0%）。有18例为早期癌，早期癌和进展期腺瘤早诊率为96.77%（210/217）。粪便mSDC2检测对所有肠道病变的检出率为75.05%（385/513）。本次筛查效益为3 264.0万元，效益成本比为6.0。 结论： 粪便mSDC2检测初筛结合肠镜精筛的结直肠癌筛查模式，具有较高的肠道病变检出率和良好的成本-经济效益，是一种值得在国内社区推广的肠癌筛查策略。.