Academic Department of Surgery, School of Medicine, Royal Infirmary, University of Glasgow, Glasgow, UK.
Colorectal Dis. 2013 Nov;15(11):1375-81. doi: 10.1111/codi.12377.
Colorectal cancer screening using the faecal occult blood test (FOBt) detects a disproportionate number of left-sided tumours. This study aims to examine the theoretical impact on neoplasia detection rates of a sigmoidoscopy-first protocol in FOBt-positive patients undergoing colonoscopy.
From retrieved endoscopy/pathology reports, pathology up to and including the splenic flexure was assumed detectable by sigmoidoscopy. High-risk polyps prompting subsequent colonoscopy were classed as three or more polyps, one polyp of ≥ 1 cm, villous or tubulovillous components or the presence of high-grade dysplasia.
Between April 2009 and April 2011, 4631 patients underwent colonoscopy as a result of a positive FOBt in Greater Glasgow and Clyde. Cancer was detected in 398 (9%) and adenomas were detected in 1985 (47%) of which 1323 (67%) were deemed significant according to British Society of Gastroenterology guidelines. Applying the flexible sigmoidoscopy-first model, cancer would have been detected in 329 (8%) patients and adenomas in 1640 (39%), of which 1140 (70%) would have been significant. In total, 1546 (37%) patients would have required subsequent colonoscopy, following which 21 patients would have a new diagnosis of cancer. The positive predictive values (PPVs) for neoplasia (47 vs 57%, P < 0.001), significant neoplasia (35 vs 41%, P < 0.001) and cancer (8 vs 9%, P = 0.007) were all lower in the sigmoidoscopy-first model.
A significant reduction in the detection of both adenomas and cancers would be seen if the sigmoidoscopy-first protocol were to be used following a positive FOBt. Furthermore, a significant proportion of patients would be subjected to two procedures, with considerable implications for both the patient and cost.
粪便潜血试验（FOBt）筛查结直肠癌时会检测出大量左侧肿瘤。本研究旨在探讨 FOBt 阳性患者行结肠镜检查时采用乙状结肠镜优先方案对肿瘤检出率的理论影响。
根据检索到的内镜/病理报告，假设乙状结肠镜可检测到脾曲及以下的病理。需要进一步行结肠镜检查的高危息肉被归类为三个或更多息肉、一个 1cm 或以上的息肉、绒毛状或管状绒毛状成分或高级别异型增生。
2009 年 4 月至 2011 年 4 月，大格拉斯哥和克莱德地区 4631 例 FOBt 阳性患者行结肠镜检查。共检出 398 例（9%）癌症和 1985 例（47%）腺瘤，其中 1323 例（67%）符合英国胃肠病学会指南的标准。采用乙状结肠镜优先模式，将检出 329 例（8%）癌症和 1640 例（39%）腺瘤，其中 1140 例（70%）为显著病变。共 1546 例（37%）患者需要进一步行结肠镜检查，其中 21 例患者新诊断为癌症。乙状结肠镜优先模式下，肿瘤（47%比 57%，P < 0.001）、显著肿瘤（35%比 41%，P < 0.001）和癌症（8%比 9%，P = 0.007）的阳性预测值均较低。
如果采用 FOBt 阳性后的乙状结肠镜优先方案，腺瘤和癌症的检出率均会显著降低。此外，相当一部分患者需要接受两种检查，这对患者和成本都有重大影响。
