BACKGROUND Despite reports indicating that polyps proximal to the splenic flexure have higher rates of metachronous colorectal adenocarcinoma (CRC), the role of adenoma location on surveillance recommendations remains unclear. This study aimed to analyze the association between index polyp location and post-colonoscopy CRC among participants of the Minnesota Colon Cancer Control Study (MCCCS). METHODS The MCCCS randomized 46,551 patients 50-80 years to usual care, annual, or biennial screening with fecal occult-blood testing (FOBT). Screening was performed between 1976-1992. Positive FOBT was followed by colonoscopy. We analyzed participants whose colonoscopy revealed at least one adenoma. Patients were divided into those with at least one lesion proximal to the splenic flexure and those without. RESULTS Of 2,295 patients, 815 had proximal adenomas. The majority were men; mean age =62 years at randomization, and 69 years at index polyp. There was a high rate of advanced adenomas: 44% ≥1 polyp ≥1 cm, 35% with villous histology, and 5% high grade dysplasia. At 20 years, 87 patients had a CRC diagnosis, and the estimated cumulative incidence of CRC was 4.3%. Proximal adenomas had a higher risk of developing a post-colonoscopy CRC (SHR=1.63, 95% CI=1.05-2.53, P=0.03), which was attenuated after adjusting for polyp multiplicity in sensitivity analyses (SHR=1.56, 95% CI=0.96-2.53, P=0.07). CONCLUSION Although patients with proximal adenomas were found to have higher hazards of post-colonoscopy CRC, adjusting for polyp multiplicity attenuated the strength of association. Further research is warranted to determine whether polyp location should be factored in the determination of appropriate surveillance intervals.

中文翻译：

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近端息肉与结直肠癌发病率较高相关：明尼苏达结肠癌控制研究分析：息肉位置和癌症发病率。


背景 尽管有报告表明脾曲近端的息肉发生异时性结直肠腺癌 （CRC） 的几率较高，但腺瘤位置在监测建议中的作用仍不清楚。本研究旨在分析明尼苏达结肠癌控制研究 （MCCCS） 参与者指示息肉位置与结肠镜检查 CRC 后之间的关联。方法 MCCCS 将 46,551 名 50-80 岁的患者随机分配到常规护理、年度或两年一次的粪便潜血检测 （FOBT） 筛查组。筛选在 1976-1992 年间进行。FOBT 阳性后进行结肠镜检查。我们分析了结肠镜检查显示至少一个腺瘤的参与者。将患者分为脾曲近端至少有一个病灶的患者和无脾曲患者。结果 在 2,295 例患者中，815 例患有近端腺瘤。大多数是男性;随机分组时平均年龄 = 62 岁，指数息肉时为 69 岁。晚期腺瘤的发生率很高： 44% ≥1 息肉 ≥ cm ，35% 有绒毛组织学，5% 有高度异型增生。在 20 岁时，87 例患者被诊断为 CRC，估计 CRC 的累积发病率为 4.3%。近端腺瘤发生结肠镜术后 CRC 的风险更高 （SHR=1.63,95% CI=1.05-2.53，P=0.03），在敏感性分析中调整息肉多重性后减弱 （SHR=1.56,95% CI=0.96-2.53，P=0.07）。结论 尽管发现近端腺瘤患者发生结肠镜术后 CRC 的风险更高，但调整息肉多样性减弱了关联强度。有必要进行进一步的研究，以确定在确定适当的监测间隔时是否应考虑息肉的位置。