Colon adenoma features and their impact on risk of future advanced adenomas and colorectal cancer

AIM To review the evidence on the association between specific colon adenoma features and the risk of future colonic neoplasia [adenomas and colorectal cancer(CRC)]. METHODS We performed a literature search using the National Library of Medicine through Pub Med from 1/1/2003 to 5/30/2015. Specific Medical Subject Headings terms(colon, colon polyps, adenomatous polyps, epidemiology, natural history, growth, cancer screening, colonoscopy, CRC) were used in conjunction with subject headings/key words(surveillance, adenoma surveillance, polypectomy surveillance, and serrated adenoma). We defined nonadvanced adenomas as 1-2 adenomas each < 10 mm in size and advanced adenomas as any adenoma ≥ 10 mm size or with > 25% villous histology or high-grade dysplasia. A combined endpoint of advanced neoplasia included advanced adenomas and invasive CRC.RESULTS Our search strategy identified 592 candidate articlesof which 8 met inclusion criteria and were relevant for assessment of histology(low grade vs high grade dysplasia, villous features) and adenoma size. Six of these studies met the accepted quality indicator threshold for overall adenoma detection rate > 25% among study patients. We found 254 articles of which 7 met inclusion criteria for the evaluation of multiple adenomas. Lastly, our search revealed 222 candidate articles of which 6 met inclusion criteria for evaluation of serrated polyps. Our review found that villous features, high grade dysplasia, larger adenoma size, and having ≥ 3 adenomas at baseline are associated with an increased risk of future colonic neoplasia in some but not all studies. Serrated polyps in the proximal colon are associated with an increased risk of future colonic neoplasia, comparable to having a baseline advanced adenoma.CONCLUSION Data on adenoma features and risk of future adenomas and CRC are compelling yet modest in absolute effect size. Future research should refine this risk stratification.

Metabolic syndrome, lifestyle risk factors, and distal colon adenoma: A retrospective cohort study

AIM: To investigate relationships between colorectal adenoma incidence, metabolic syndrome (MS) components and lifestyle factors. METHODS: We conducted a retrospective cohort study using data from individuals who had multiple sigmoidoscopies for colon cancer at the Health Promotion Center of Ulsan University Hospital in Korea from 1998 to 2007. RESULTS: By multivariate analysis, the incidence of distal colon adenoma was increased by more than 1.76 times in individuals with at least one component of MS compared to those without a component of MS. After adjustment for age, gender, smoking, drinking, and physical exercise, only high body mass index (BMI) was significantly associated with the incidence of distal colon adenoma (Hazard ratio 1.66, 95% confidence interval 1.05-2.62). CONCLUSION: Our results suggest that high BMI may increase the risk of colorectal adenoma in Korean adults.

Differential expression of nucleolin in colon adenoma and adenocarcinoma

Objective The aim of the study was to investigate the discrepancy in nucleolin expression between colon adenoma and colon adenocarcinoma,explore the role of nucleolin expression in the carcinogenesis of colon adenocarcinoma,and determine the correlation of the nucleolin expression level with histological grade in colon adenocarcinoma.Methods In total,80 cases of colon adenocarcinoma with cancer-adjacent colon mucosa and 60 cases of colon adenomas were examined by immunohistochemistry using an antibody against nucleolin.Nucleolin expression levels in these groups were compared.The correlation between the nucleolin expression level and grade of colon adenocarcinoma was analyzed.Results Nucleolin expression is located in the nuclei of colon adenocarcinoma,colon adenoma,and cancer-adjacent colon mucosa tissues with different intensities.A semiquantitative evaluation using the Allred scoring system showed that the nucleolin immunostaining score in colon adenocarcinoma(7.8 ± 0.1) was significantly higher than those in colon adenoma(6.3 ± 0.2) and cancer-adjacent colon mucosa(5.4 ± 0.1;P < 0.01).The nucleolin immunostaining score in colon adenoma was significantly higher than that in cancer-adjacent colon mucosa(P < 0.01).Nucleolin expression levels in well-differentiated and moderately differentiated adenocarcinoma(6.8 ± 0.2) were significantly lower than those in poorly differentiated adenocarcinoma(8.0 ± 0.1;P < 0.01).Conclusion Increased nucleolin expression may play an important role in the process of malignant transformation of colon adenocarcinoma and predicts a poor prognosis.

Effect of a high-fat diet in development of colonic adenoma in an animal model

AIM: To investigate the effect of a high-fat diet in the formation of the precursors of colorectal cancer using an animal model.METHODS: Wistar rats were divided into two groups that were fed either a high-fat diet(HFD) or a normalfat diet(ND), and 1,2-dimethylhydrazine was administered at a dose of 40 mg/kg for 10 wk. The body weight/liver weight/epididymal fat weight were recorded after rats were sacrificed, and the formation of colonic adenoma was also observed. The levels of insulin, leptin, tumor necrosis factor(TNF)-α, insulinlike growth factor(IGF)-1 and triglycerides were determined by enzyme-linked immunosorbent assay in order to compare the altered levels of biochemical indices and inflammatory cytokines in the serum between rats fed an ND and HFD. Cell proliferation activity(Ki-67) was determined by immunohistochemical analysis. Western blot and immunofluorescence staining were used to examine the expression of pro-liferating cell nuclear antigen(PCNA), cyclooxygenase(COX)-2, cyclin D1, β-catenin and nuclear factor(NF)-κB proteins in the adenoma and comparative control tissues.RESULTS: The number of colonic adenomas and the colonic epithelial Ki-67 were significantly higher in the HFD group than in the ND group. The HFD group also had increased body weight, liver weight and epididymal fat weight, which were associated with increased levels of serum insulin, leptin, TNF-α, IGF-1 and triglycerides. HFD induced upregulation of PCNA, COX-2, cyclin D1, β-catenin and NF-κB proteins, as revealed by Western blot and immunofluorescence staining.CONCLUSION: HFD promotes the formation of colonic adenoma through inflammation, metabolic abnormalities, and increases cell cycle progression.

Disparities of conjugating protective enzyme activities in the colon of patients with adenomas and carcinomas

AIM:To investigate the metabolic enzymatic capacity of the colon mucosa to detoxify noxious carcinogenic compounds.METHODS:We investigated the activity of 2 conjugating enzymes-the microsomal uridine glucuronosyltransferase(UGT)and the cytosomal glutathione S-transferase(GST)in the uninvolved mucosa of the colon transversum and sigmoideum in patients with adenomatous polyps and colorectal cancer.Biopsies were taken from the mucosa during colonoscopies which were done for clinical(diagnostic)reasons.After storage,the biopsy material was homogenized and after differential centrifugation the enzyme assays were performed with 4-nitrophenol(UGT)and 1-chloro 2,4-dinitrobenzene(GST)as substrates.RESULTS:About 48 patients were included of which28 had adenomas and 20 had colorectal carcinomas confirmed by histopathology.Enzyme activities were expressed as nmol/mg per minute protein for the GST and as pmol/mg per minute protein for the UGT.Analysis of variance(F-test)indicated that both enzymes were more widely distributed in adenoma than in cancer patients.The means±SD were smaller for cancer patients:GST for adenomas 268±152 vs 241±69 for carcinomas and UGT for adenomas 197±200 vs 150±86 for carcinomas.CONCLUSION:Compared to patients with adenomatous colon polyps those with colorectal carcinoma exhibited a lower capacity of detoxifying enzyme metabolism and their activities clustered over a smaller range.

Pyogenic liver abscess associated with large colonic tubulovillous adenoma

生脓肝脓肿通常与许多疾病联合发生。很少，肝脓肿作为结肠的 tubulovillous 腺瘤的介绍表明被报导了。除了一个人有糖尿病(DM ) 的历史之外，没有肝胆管疾病或另外的明显的病原学，我们报导生脓肝脓肿的二个案例。在有 DM 的病人的病原体是克雷白氏杆菌属肺病(KP ) 。在两个，病人，，肠塞痛大约二～三个星期在肝脓肿的诊断以后发展了。结肠镜检查在两个盒子中与 tubulovillous 腺瘤的病理检查所见揭示了大息肉样瘤。二个教训从这二个案例被接受：(1 ) 一个内在的原因应该好攻击地与起因不明的肝脓肿在病人被调查；(2 ) DM 能是病原学然而并非 KP 肝脓肿的必然唯一的原因之一。

High-definition colonoscopy with i-Scan:Better diagnosis for small polyps and flat adenomas

AIM:To investigate if high-definition (HD) colonoscope with i-Scan gave a higher detection rate of mucosal lesions vs standard white-light instruments. METHODS:Data were collected from the computerized database of the endoscopy unit of our tertiary referral center. We retrospectively analyzed 1101 consecutive colonoscopies that were performed over 1 year with standard white-light (n = 849) or HD+ with i-Scan (n = 252) instruments by four endoscopists, in an outpatient setting. Colonoscopy records included patients' main details and family history for colorectal cancer, indication for colonoscopy (screening, diagnostic or surveillance), type of instrument used (standard white-light or HD+ plus i-Scan), name of endoscopist and bowel preparation. Records for each procedure included whether the cecum was reached or not and the reason for failure, complications during or immediately after the procedure, and number, size, location and characteristics of the lesions. Polyps or protrudinglesions were defined as sessile or pedunculated, and nonprotruding lesions were defined according to Paris classification. For each lesion, histological diagnosis was recorded. RESULTS:Eight hundred and forty-nine colonoscopies were carried with the standard white-light video colonoscope and 252 with the HD+ plus i-Scan video colonoscope. The four endoscopists did 264, 300, 276 and 261 procedures, respectively; 21.6%, 24.0%, 21.7% and 24.1% of them with the HD+ plus i-Scan technique. There were no significant differences between the four endoscopists in either the number of procedures done or the proportions of each imaging technique used. Both techniques detected one or more mucosal lesions in 522/1101 procedures (47.4%). The overall number of lesions recognized was 1266; 645 in the right colon and 621 in the left. A significantly higher number of colonoscopies recognized lesions in the HD+ plus i-Scan mode (171/252 = 67.9%) than with the standard white-light technique (408/849 = 48.1%) (P < 0.0001). HD+ with i-Scan colonoscopies identified more lesions than standard white-light imaging (459/252 and 807/849, P < 0.0001), in the right or left colon (mean ± SD, 1.62 ± 1.36 vs 1.33 ± 0.73, P < 0.003 and 1.55 ± 0.98 vs 1.17 ± 0.93, P = 0.033), more lesions < 10 mm (P < 0.0001) or nonprotruding (P < 0.022), and flat polyps (P = 0.04). The cumulative mean number of lesions per procedure detected by the four endoscopists was significantly higher with HD+ with i-Scan than with standard white-light imaging (1.82 ± 2.89vs 0.95 ± 1.35,P < 0.0001). CONCLUSION:HD imaging with i-Scan during the withdrawal phase of colonoscopy significantly increased the detection of colonic mucosal lesions, particularly small and nonprotruding polyps.

Significance of EZH2 and BMI-1 Protein Expression in Carcinogenesis of Colon Serrated Adenoma

Objective:To observe the significance of EZH2 and BMI-1 protein expression in the carcinogenesis process of colon serrated adenoma(SSA/P).Methods:Hematoxylin-eosin(HE)staining was used to observe the morphological characteristics of normal tissues,hyperplastic polyp(HP),SSA/P and colon cancer.Immunohistochemical staining was used to detect the expression of EZH2 and BMI-1 protein.The relative expression of EZH2 and BMI-1 was detected by qRT-PCR.Results:Compared with normal tissues,HP and colon cancer tissues,SSA/P showed serrated glandular hyperplasia,glandular dilatation,and deep nuclear staining,which had certain atypia.The positive expression rates of EZH2 and BMI-1 protein were 53.3%and 56%,which were close to those of colon cancer(66.7% and 76.6%)and higher than those of normal group and HP(16% and 8%,P<0.05).The relative expression of EZH2 and BMI-1 in SSA/P tissue was significantly higher than that in normal group and HP,but lower than that in carcinogenesis group(P<0.05).Conclusion:EZH2 and BMI-1 play an important role in the carcinogenesis of colon serrated adenoma,and can be used as the primary screening index before carcinogenesis.

基于“痰浊内阻”与“脂代谢紊乱”的联系论治结肠腺瘤复发与恶变

结直肠腺瘤作为结直肠癌的重要癌前病变,内镜下切除虽作为首要治疗手段,但腺瘤复发率较高,如何预防腺瘤的发生,阻断腺瘤癌序列的进展是我们的研究方向。中医理论中“痰浊内阻”是结肠腺瘤发生与复发的主要原因,并且“痰浊”与“脂代谢”二者联系密切,因此本文将就“痰浊内阻”与“脂代谢紊乱”在结肠腺瘤中的联系进行讨论,探讨结肠腺瘤“痰浊内阻”的现代生物学内涵。通过探讨二者之间的联系可为临床治疗结肠腺瘤提供思路,同时还可将其运用到其他有关痰浊内阻、脂代谢紊乱的疾病中,以扩展临床诊治思维。

高通量RNA测序技术分析结肠腺瘤转变为结肠癌的关键基因

目的:通过RNA测序技术分析比较正常结肠组织、结肠腺瘤及癌组织中基因表达谱的差异,识别从结肠腺瘤发展为结肠癌过程中的关键基因,并探究其潜在机制。方法:对同一患者的正常结肠组织、腺瘤及癌组织进行RNA测序分析,识别在结肠癌中显著表达、腺瘤组织中不显著表达的差异基因并进行GO和KEGG功能富集分析。结果:在结肠癌中显著表达、腺瘤组织中不显著表达的差异基因有4307个,其中5个差异最大的基因是EPYC、LINC01614、MCEMP1、NOX4、CLEC5A。对这些基因进行GO和KEGG功能富集分析发现,主要富集于生物过程调节、细胞过程调节、蛋白质结合等生物学过程和癌症通路、PI3K-Akt信号通路、MAPK信号通路等。结论:EPYC、LINC01614、MCEMP1、NOX4、CLEC5A等多个基因参与结肠腺瘤到结肠癌发展的过程,这些基因有望成为结直肠癌的治疗靶点。

Expression And Clinical Significance of Glucose Regulated Proteins GRP78 And GRP94 in Human Colon Cancer

Objective： To investigate the expression of glucose regulated proteins GRP78 and GRP94 in human colon cancer. Methods： Tissues of resected primary colon cancer, colon adenoma and normal tissue were investigated. Protein expression was detected with immunohistochemical staining, mRNA expression levels of GRP78 and GRP94 were determined by semiquantitative reverse transcriptase polymerase chain reaction （RT-PCR） after mRNA extraction. Results： The expression of GRP94 and GRP78 was significantly higher in colon cancer when compared to those in colon adenoma and normal tissue （P〈0.01）. GRP94 mRNA and protein expression was found to be in close relationship with the grade of differentiation, Dukes stages, lymph node involvement and remote metastasis in colon cancer （P〈0.01）, but no relationship with gender and age （P〉0.05）. GRP78 mRNA and protein expression increased with cancer progression along the normal tissue-adenoma-cancer sequence, but showed no association with grade of differentiation, Dukes stages, lymph node involvement, remote metastasis, gender and age （P〉0.05）. The mRNA expression of GRP78 and GRP94 was consistent with the proteins （P〈0.01）, but there is no correlation between overexpression of GRP78 and GRP94 （P〉0.05）, and the patients with both strong GRP78 and GRP94 protein expression did not show advanced tumor stages （P〉0.05）. Conclusion： Overexpression of GRP78 and GRP94 was found in colon cancer. Overexpression of GRP94 was closely related to cellular differentiation, Dukes stages, invasion and metastasis.

外周血相关指标在结肠癌和结肠腺瘤鉴别诊断中的临床价值研究

目的 探讨外周血中性粒细胞与白细胞比值(NWR)、淋巴细胞与白细胞比值(LWR)、癌胚抗原、糖类抗原125(CA125)在结肠癌和结肠腺瘤鉴别诊断中的临床价值。方法 收集2015年4月至2022年8月于山东第一医科大学附属省立医院确诊为结肠癌并行结肠癌根治术的129例结肠癌患者作为结肠癌组,随机收集同期结肠腺瘤患者129例作为结肠腺瘤组,回顾性分析比较2组患者的临床资料和外周血NWR、LWR、癌胚抗原、CA125水平,分析外周血4项指标与结肠癌病理特征的关系;绘制受试者工作特征(ROC)曲线,分析NWR、LWR、癌胚抗原、CA125单独及联合检测在结肠癌和结肠腺瘤鉴别诊断中的临床价值。结果 结肠癌组NWR、癌胚抗原、CA125水平均高于结肠腺瘤组,LWR低于结肠腺瘤组,差异均有统计学意义(均P<0.05)。浸润深度超过肌层的结肠癌患者癌胚抗原高于未超过肌层的患者,肿瘤直径≥7 cm患者外周血LMR低于肿瘤直径<7 cm的患者,而NWR、CA125水平高于肿瘤直径<7 cm的患者,差异均有统计学意义(均P<0.05)。ROC曲线分析结果显示,与单独检测[NWR曲线下面积(AUC)=0.746,95%置信区间:0.707~0.814;LWR AUC=0.739,95%置信区间:0.681~0.792;癌胚抗原AUC=0.572,95%置信区间:0.509~0.633;CA125 AUC=0.635,95%置信区间:0.573~0.694]相比,NWR、LWR、癌胚抗原和CA125联合检测可以提高对结肠癌与结肠腺瘤患者鉴别诊断的效能(AUC=0.799,95%置信区间:0.745~0.846)。结论 NWR、LWR、癌胚抗原和CA125联合检测对鉴别诊断结肠癌与结肠腺瘤患者具有一定的预测价值,可以辅助结肠癌诊断。

结肠腺瘤内镜切除术后复发的影响因素分析

目的 分析结肠腺瘤内镜切除术后复发的影响因素。方法 收集2020年7月至2022年8月在桂林市人民医院消化内科住院,行结肠腺瘤内镜切除术并经病理确诊为结肠腺瘤的182例患者的临床资料。所有患者均行内镜下切除术治疗,根据术后是否复发分为复发组和未复发组,记录患者的一般临床特征及腺瘤特征,分析结肠腺瘤术后复发的影响因素。结果 182例患者中,复发43例,未复发139例,复发率为23.6%。两组的年龄、吸烟、糖尿病史、非酒精性脂肪性肝病(NAFLD)史比较,差异具有统计学意义(P<0.05)。两组的腺瘤直径、腺瘤数量、腺瘤病理类型比较,差异具有统计学意义(P<0.05)。多因素Logistic回归分析结果显示,年龄≥60岁、吸烟、腺瘤数量≥3个、腺瘤病理类型为管状绒毛状腺瘤是术后结肠腺瘤复发的独立危险因素(P<0.05)。结论 结肠腺瘤内镜切除术后存在一定复发率,年龄≥60岁、吸烟、腺瘤数量≥3个、病理类型为管状绒毛状腺瘤是术后结肠腺瘤复发的独立危险因素。

Efficacy of cap-assisted colonoscopy according to lesion location and endoscopist training level

AIM: To evaluate the efficacy of cap-assisted colonoscopy(CAC) for detection of colorectal polyps and adenomas according to the lesion location and endoscopist training level.METHODS: Patients 20 years or older, who underwent their first screening colonoscopy in a single tertiary center from May 2011 to December 2012 were enrolled in this study. All patients underwent either CAC or standard colonoscopy(SC), and all of the procedures were performed by 11 endoscopists(8 trainees and 3 experts). All procedures were performed with highdefinition colonoscopes and narrow band imaging. The eight trainees had experiences of performing 150 to 500 colonoscopies, and the three experts had experiences of performing more than 3000 colonoscopies. A 4-mmlong transparent cap was attached to the end of a colonoscope in the CAC group. We retrospectively evaluated the number of polyps and adenomas, polyp detection rate(PDR), and the number of adenomas and adenoma detection rate(ADR) according to the lesion location and endoscopist training level between CAC and SC. We also evaluated the number of polyps and adenomas according to their size between CAC and SC.RESULTS: Overall, PDR and ADR using CAC were significantly higher than those using SC for both whole colon(48.5% vs 40.7%, P = 0.012; 35.7% vs 28.3%, P = 0.012) and right-side colon(35.3% vs 26.6%, P = 0.002; 27.0% vs 16.9%, P < 0.001). The number of polyps and adenomas per patient using CAC was significantly higher than that using SC for both the whole colon(1.07 ± 1.59 vs 0.82 ± 1.31, P = 0.008; 0.72 ± 1.32 vs 0.50 ± 1.01, P = 0.003) and right-side colon(0.66 ± 1.18 vs 0.41 ± 0.83, P < 0.001; 0.46 ± 0.97 vs 0.25 ± 0.67, P < 0.001). In the trainee group, the PDR and ADR using CAC were significantly higher than those using SC for both the whole colon(46.7% vs 39.7%, P = 0.040; 33.9% vs 26.0%, P =0.012) and right-side colon(34.2% vs 26.5%, P = 0.015; 25.3% vs 15.9%, P = 0.001). In the expert group, the PDR and ADR using CAC were significantly higher than those using SC only for the right-side colon(42.1% vs 27.0%, P =0.035; 36.8% vs 21.0%, P = 0.020).CONCLUSION: CAC is more effective than SC for detection of colorectal polyps and adenomas, especially when performed by trainees and when the lesions are located in the right-side colon.

Clear cell adenocarcinoma of the colon:A case report and review of literature

A primary clear cell adenocarcinoma of the colon is a rare oncologic entity. We herein report a case of such a tumor of the sigmoid colon in a 71-year-old woman who was successfully treated by an endoscopic polypectomy in our hospital. We also reviewed the published reports regarding cases of primary clear cell tumors in the colon.

Rectosigmoid findings are not associated with proximal colon cancer: Analysis of 6 196 consecutive cases undergoing total colonoscopy

AIM: To review the risk of proximal colon cancer in patients undergoing colonoscopy.METHODS: We estimated the risk of advanced proximal adenomas and cancers in 6 196 consecutive patients that underwent colonoscopy (mean age 60 years, 65% males,without prior history of colorectal examination). Neoplasms were classified as diminutive adenoma (5 mm or less),small adenoma (6-9 mm), advanced adenoma (10 mm or more, with villous component or high-grade dysplasia)and cancer (invasive adenocarcinoma). The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal colon (from cecum to descending colon).RESULTS: The trend of the prevalence of advanced proximal adenoma was to increase with severe rectosigmoid findings, while the prevalence of proximal colon cancer did not increase with severe rectosigmoid findings. Among the 157 patients with proximal colon cancer, 74% had no neoplasm in the rectosigmoid colon. Multivariate logisticregression analysis revealed that age was the main predictor of proximal colon cancer and existence of rectosigmoid adenoma was not a predictor of proximal colon cancer.CONCLUSION: Sigmoidoscopy is inadequate for colorectal cancer screening, especially in older populations.

Comparative effectiveness of i-SCAN^(TM) and high-definition white light characterizing small colonic polyps

AIM:To evaluate accuracy of in vivo diagnosis of adenomatous vs non-adenomatous polyps using i-SCAN digital chromoendoscopy compared with high-definition white light.METHODS:This is a single-center comparative effectiveness pilot study.Polyps(n = 103) from 75 averagerisk adult outpatients undergoing screening or surveillance colonoscopy between December 1,2010 and April 1,2011 were evaluated by two participating endoscopists in an academic outpatient endoscopy center.Polyps were evaluated both with high-definition white light and with i-SCAN to make an in vivo prediction of adenomatous vs non-adenomatous pathology.We determined diagnostic characteristics of i-SCAN and highdefinition white light,including sensitivity,specificity,and accuracy,with regards to identifying adenomatous vs non-adenomatous polyps.Histopathologic diagnosis was the gold standard comparison.RESULTS:One hundred and three small polyps,detected from forty-three patients,were included in the analysis.The average size of the polyps evaluated in the analysis was 3.7 mm(SD 1.3 mm,range 2 mm to 8 mm).Formal histopathology revealed that 54/103(52.4%) were adenomas,26/103(25.2%) were hyperplastic,and 23/103(22.3%) were other diagnoses include "lymphoid aggregates","non-specific colitis," and "no pathologic diagnosis." Overall,the combined accuracy of endoscopists for predicting adenomas was identical between i-SCAN(71.8%,95%CI:62.1%-80.3%) and high-definition white light(71.8%,95%CI:62.1%-80.3%).However,the accuracy of each endoscopist differed substantially,where endoscopist A demonstrated 63.0% overall accuracy(95%CI:50.9%-74.0%) as compared with endoscopist B demonstrating 93.3% overall accuracy(95%CI:77.9%-99.2%),irrespective of imaging modality.Neither endoscopist demonstrated a significant learning effect with i-SCAN during the study.Though endoscopist A increased accuracy using i-SCAN from 59%(95%CI:42.1%-74.4%) in the first half to 67.6%(95%CI:49.5%-82.6%) in the second half,and endoscopist B decreased accuracy using i-SCAN from 100%(95%CI:80.5%-100.0%) in the first half to 84.6%(95%CI:54.6%-98.1%) in the second half,neither of these differences were statistically significant.CONCLUSION:i-SCAN and high-definition white light had similar efficacy predicting polyp histology.Endoscopist training likely plays a critical role in diagnostic test characteristics and deserves further study.

Serrated polyps of the colon and rectum: Endoscopic features including image enhanced endoscopy

In this review, I outline the characteristic endoscopic findings of serrated lesions of the colorectum based on image enhanced endoscopy(IEE). Histopathologically, lesions with serrated structures are typically classified into the following three types based: hyperplastic polyps(HPs), traditional serrated adenomas(TSAs), and sessile serrated adenoma/polyps(SSA/Ps). Both HP and SSA/P often present as dark-green colors on auto fluorescence imaging(AFI) colonoscopy that are similar to the normal surrounding mucosa. In contrast, TSAs often have elevated shapes and present as magenta colors that are similar to the tubular adenomas. The superficial type of TSA also includes many lesions that present as magenta colors. When SSA/Ps are associated with cytological dysplasia, many lesions present with magenta colors, whereas lesions that are not associated with cytological dysplasia present with dark-green colors. When observed via narrow band imaging(NBI), many SSA/P include lesions with strong mucous adhesions. Because these lesions are observed with reddish mucous adhesions, we refer to them as "red cap sign" and place such signs among the typical findings of SSA/P. Because the dilatation of the pit in SSA/P is observed as a round/oval black dot on magnified observations, we refer to this finding as Ⅱ-dilatation pit(Ⅱ-D pit) and also positioned it as a characteristic finding of SSA/P. In contrast, dilatations of the capillary vessels surrounding the glands, such as those that occur in tubular adenoma, are not considered to be useful for differentiating HPs from SSA/Ps. However, in cases in which SSA/P is associated with cytological dysplasia, the dilatation of capillary vessels is observed in the same area. When submucosal layer invasion occurs in the same area, the blood flow presents with irregularities that are similar to those of common colorectal cancer at an early stage and disappears as the invasion proceeds deeply. The surface pattern of invasive cancer that is observed at the tumor surface is also likely to disappear. Based on the above results, we considered that the differentiations between HP and TSA, between TSA and SSA/P, and between HP and SSA/P might become easier due to the concomitant use of white light observation and IEE. We also concluded that AFI and NBI can be useful modalities for SSA/P lesions associated with cytological dysplasia.

Laterally spreading tumors:Limitations of computed tomography colonography

AIM:To prospectively investigate the detection rate of laterally spreading tumors(LSTs)of the colorectum by computed tomography(CT)colonography(CTC).METHODS:Patients with LSTs measuring≥20 mm detected during colonoscopy were prospectively enrolled in the study.All patients underwent colonoscopy and subsequent CTC on the same day.CTC was performed using multi-detector CT without contrast in the prone and supine positions.Two radiologists blinded to the existence of LSTs read the virtual endoscopic images as well as 2-D images.LSTs were classified into granular and non-granular types based on colonoscopic appearance.RESULTS:Forty-seven pathologically proven LSTs were evaluated prospectively.Histology included adenomas in 19,mucosal cancers in 19 and T1 cancers in 9.The mean diameter of the LSTs was 35.1 mm.Twenty-eight(60%)LSTs were correctly identified by CTC,and the configuration was similar to the colonoscopic appearance in most cases.Detection rate for the granular type was significantly higher than that for the nongranular type(71%vs 31%,P=0.013).Detection rate of adenomas was significantly lower than mucosal cancers(32%vs 79%,P=0.008)and T1 cancers(32%vs 78%,P=0.042).CONCLUSION:The detection rate of LSTs by CTC,particularly the non-granular type was not acceptable.Practitioners should be aware of the relatively low detection rate when using CTC.

Colonoscopy surveillance for high risk polyps does not always prevent colorectal cancer

AIM To determine the frequency and risk factors for colorectal cancer(CRC) development among individuals with resected advanced adenoma(AA)/traditional serrated adenoma(TSA)/advanced sessile serrated adenoma(ASSA). METHODS Data was collected from medical records of 14663 subjects found to have AA, TSA, or ASSA at screening or surveillance colonoscopy. Patients with inflammatory bowel disease or known genetic predisposition for CRC were excluded from the study. Factors associated with CRC developing after endoscopic management of high risk polyps were calculated in 4610 such patients who had at least one surveillance colonoscopy within 10 years following the original polypectomy of the incident advanced polyp. RESULTS84/4610(1.8%) patients developed CRC at the polypectomy site within a median of 4.2 years(mean 4.89 years), and 1.2%(54/4610) developed CRC in a region distinct from the AA/TSA/ASSA resection site within a median of 5.1 years(mean 6.67 years). Approximately, 30%(25/84) of patients who developed CRC at the AA/TSA/ASSA site and 27.8%(15/54) of patients who developed CRC at another site had colonoscopy at recommended surveillance intervals. Increasing age; polyp size; male sex; right-sided location; high degree of dysplasia; higher number of polyps resected; and piecemeal removal were associated with an increased risk for CRC developmentat the same site as the index polyp. Increasing age; right-sided location; higher number of polyps resected and sessile endoscopic appearance of the index AA/TSA/ASSA were significantly associated with an increased risk for CRC development at a different site. CONCLUSION Recognition that CRC may develop following AA/TSA/ASSA removal is one step toward improving our practice efficiency and preventing a portion of CRC related morbidity and mortality.