结直肠锯齿状腺瘤的临床特征及恶变影响因素分析

目的锯齿状腺瘤被公认为结直肠癌的癌前病变,锯齿状通路被认为是可以独立发展成结直肠癌的重要通路,但目前对于锯齿状腺瘤恶变的相关危险因素还知之甚少。本文旨在分析锯齿状腺瘤在结直肠中的分布特点及潜在恶变因素。方法采用病例对照研究方法,回顾性收集2017年4月至2019年7月期间在中国医学科学院肿瘤医院行肠镜检查并经病理诊断为锯齿状腺瘤患者的临床资料,排除同时具有两种及以上病理类型病变的患者。总结锯齿状腺瘤的临床特征,并进行单因素和Logistic多因素回归分析,探讨锯齿状腺瘤发生恶变的影响因素。结果共在28730例行肠镜检查患者中,发现311例(1.08%)锯齿状腺瘤患者,共发现锯齿状腺瘤372枚。按WHO分类,无蒂锯齿状腺瘤/息肉22枚(5.9%),传统锯齿状腺瘤84枚(22.6%),未分类锯齿状腺瘤266枚(71.5%)。病理结果显示:无异型增生病变106枚(28.5%),低级别上皮内瘤变病变228枚(61.3%),高级别上皮内瘤变或癌变38枚(10.2%)。病变长径<10 mm有204枚(54.8%),≥10 mm有168枚(45.2%);病变位于左半结直肠238枚(64.0%),右半结肠134枚(36.0%)。内镜下大体分型:扁平型16枚(4.3%),无蒂型174枚(46.8%),亚蒂型117枚(31.5%),带蒂型59枚(15.9%)。窄带成像国际结直肠内镜(NICE)分型:Ⅰ型85枚(22.8%),Ⅱ型280枚(75.3%),Ⅲ型4枚(1.1%)。单因素分析显示,病变大小、病变位置、病变部位及不同WHO分类与结直肠锯齿状腺瘤发生恶变有关(均P<0.05);不同NICE分型的锯齿状腺瘤,其恶变率的差异亦有统计学差异(P=0.001)。多因素分析结果显示,病变长径≥10 mm(OR=6.699,95%CI:2.843~15.786)以及病变位于左半结直肠(OR=2.657,95%CI:1.042~6.775)是结直肠锯齿状腺瘤发生恶变的独立危险因素。结论锯齿状腺瘤主要位于左半结直肠,当病变长径≥10 mm或病变位于左半结直肠时,易发生恶变。

Clinicopathological features of the colorectal serrated adenoma and analysis on influencing factors of malignancy

Objective Serrated adenoma is recognized as a precancerous lesion of colorectal cancer,and the serrated pathway is considered as an important pathway that can independently develop into colorectal cancer.However,little is known about the related risk factors of carcinogenesis of serrated adenoma.The purpose of this study was to analyze the distribution characteristics and potential malignant factors of serrated adenoma in the colon and rectum.Methods A retrospective case-control study was conducted to collect the clinical data of patients with serrated adenoma who underwent colonoscopy and were pathologically diagnosed in the Cancer Hospital of Chinese Academy of Medical Sciences from April 2017 to July 2019,and exclude patients with two or more pathological types of lesions.The clinical characteristics of serrated adenoma were summarized,and univariate and logistic multivariate regression analysis was conducted to explore the influencing factors for serrated adenoma to develop malignant transformation.Results Among 28730 patients undergoing colonoscopy,311(1.08%)were found with 372 serrated adenomas,among which 22(5.9%)were sessile serrated adenomas/polyps,84(22.6%)were traditional serrated adenomas,and 266(71.5%)were unclassified serrated adenomas according to WHO classification.The pathological results showed that 106(28.5%)lesions were non-dysplasia,228(61.3%)lesions were low grade intraepithelial neoplasia,and 38(10.2%)lesions were high grade intraepithelial neoplasia or cancer.There were 204(54.8%)lesions with long-axis diameter<10 mm and 168(45.2%)lesions with length long-axis≥10 mm.238(64.0%)lesions were found in the left side colon and rectum and 134(36.0%)lesions in the right side colon.Gross classification under endoscopy:16 flat type lesions(4.3%),174 sessile lesions(46.8%),117 semi-pedunculated lesions(31.5%),59 pedunculated lesions(15.9%).Narrow-band imaging international colorectal endoscopic(NICE)classification:85(22.8%)type I lesions,280(75.3%)type II lesions,4(1.1%)type III lesions.Univariate analysis showed that lesion size,lesion location,lesion site and different WHO classifications were associated with malignant transformation of colorectal serrated adenoma(all P<0.05).For the serrated adenomas with different NICE classifications,there were statistically significant differences in the distribution of malignant lesions among groups(P=0.001).Multivariate analysis showed that the long-axis diameter of the lesion≥10 mm(OR=6.699,95%CI:2.843-15.786)and the lesion locating in the left side colorectum(OR=2.657,95%CI:1.042-6.775)were independent risk factors for malignant transformation.Conclusions Serrated adenomas mainly locate in the left side colon and rectum,and are prone to malignant transformation when the lesions are≥10 mm in long-axis diameter or left-sided.