[Application study of stool-based methylated SDC2 test in the screening of colorectal neoplasms for physical examination population].

Objective: To investigate the value of stool-based methylated SDC2 test in physical examination population for the screening of colorectal neoplasms. Methods: Using the prospective cohort study method, from December 2020 to November 2021, 2 107 participants from the First People's Hospital of Xiushui County, Jiangxi Province were enrolled, consisted of 1 012 males and 1 094 females, aged 20-90 years with the median age of 49 years old. Fresh stool samples were collected and SDC2 DNA methylation tests were carried out as the primary screening method. The participants with positive results were recommended to undergo colonoscopy, and those who were negative were followed up by telephone. The positive rate of screening, the compliance of colonoscopy, and the detection of colorectal lesions were analyzed by chi-square test. Combined the follow-up results of negative subjects, the value of SDC2 DNA methylation test for the screening of colorectal neoplasms was evaluated. Results: Among the 2 107 participants, 2 106 completed the SDC2 methylation test. 113 participants (5.4%) were positive. The positive rate of primary screening increased with age significantly (χ2=32.135, P<0.001). Out of 113 cases, 72 (63.7%) underwent colonoscopy examinations. Finally, 3 (4.2%) cases of colorectal cancer, 12 (16.7%) cases of advanced adenoma, 31 (43.1%) cases of non-advanced adenoma, and 16 (22.2%) cases of non-adenomatous polyp were detected. The positive predictive value (PPV) of stool-based SDC2 DNA methylation test for intestinal lesions and colorectal neoplasms were 86.1% and 63.9%, respectively. Among the 1 374 follow-up participants, the negative predictive value (NPV) of this test for intestinal lesions and colorectal neoplasms were 97.7% and 99.4%, respectively. Conclusion: Primary stool-based SDC2 DNA methylation test and subsequent colonoscopy examination can effectively find colorectal neoplasms. This strategy may be a potential tool for the screening of colorectal neoplasms in general risk population.目的： 探讨采用粪便SDC2基因甲基化检测技术在体检人群中进行筛查，以评价此方法用于结直肠肿瘤筛查的应用价值。 方法： 采用前瞻性队列研究方法，2020年12月至2021年11月在江西省修水县第一人民医院，符合纳入及排除标准的2 107名常规体检人员被纳入本研究，包括男性1 012人，女性1 094人，年龄范围20~90岁，中位数年龄49岁。采集新鲜粪便样本，进行SDC2基因甲基化检测，报告结果为阳性或阴性，其中结果为阳性者建议接受肠镜检查，结果为阴性者进行电话随访。采用卡方检验分析初筛阳性率、肠镜依从性、以及肠道病变检出率，最后结合初筛阴性受检者的随访结果，评估SDC2甲基化检测技术对结直肠肿瘤的筛查效果。 结果： 采用粪便SDC2基因甲基化检测进行初筛2 107人，有效筛查2 106人，113人初筛阳性，阳性率5.4%（113/2 106），初筛阳性率随年龄增大而升高（χ2=32.135，P<0.001）；其中72名接受肠镜进一步检查，肠镜依从率63.7%（72/113）。在72名完成肠镜检查的人群中，检出结直肠癌3例（4.2%）、进展期腺瘤12例（16.7%）、非进展期腺瘤31例（43.1%）、非腺瘤性息肉16例（22.2%）。SDC2基因甲基化检测对所有肠道病变的阳性预测值为86.1%（62/72），其中对肠癌及癌前病变的阳性预测值为63.9%（46/72）。对初筛阴性且筛查时间超过6个月的人群进行电话随访，有效随访1 374名，SDC2基因甲基化检测对所有肠道病变的阴性预测值为97.7%（1 342/1 374），对肠癌及癌前病变的阴性预测值为99.4%（1 366/1 374）。 结论： 以粪便SDC2基因甲基化检测为初筛方法，结合肠镜检查，可有效发现肠癌及癌前病变，此策略可能是一般风险人群开展大规模结直肠肿瘤筛查的有效办法。.