Risk factors for bleeding after endoscopic mucosal resection

AIM: To clarify the risk factors for bleeding after endoscopic mucosal resection (EMR). METHODS: A total of 297 consecutive patients who underwent EMR were enrolled. Some of the patients had multiple lesions. Bleeding requiring endoscopic treatment was defined as bleeding after EMR. Odds ratios (OR) with 95% confidence intervals (CI), calculated by logistic regression with multivariate adjustments for covariates, were the measures of association. RESULTS: Of the 297 patients, 57 (19.2%) patients with bleeding after EMR were confirmed. With multivariate adjustment, the cutting method of EMR, diameter, and endoscopic pattern of the tumor were associated with the risk of bleeding after EMR. The multivariate-adjusted OR for bleeding after EMR using endoscopic aspiration mucosectomy was 3.07 (95%CI, 1.59-5.92) compared with strip biopsy. The multiple-adjusted OR for bleeding after EMR for the highest quartile (16-50 mm) of tumor diameter was 5.63 (95%CI, 1.84-17.23) compared with that for the lowest (4-7 mm). The multiple-adjusted OR for bleeding after EMR for depressed type of tumor was 4.21 (95%CI, 1.75-10.10) compared with elevated type. CONCLUSION: It is important to take tumor characteristics (tumor size and endoscopic pattern) and cutting method of EMR into consideration in predicting bleeding after EMR.     

Effect of prophylactic clip placement following endoscopic mucosal resection of large colorectal lesions on delayed polypectomy bleeding: A meta-analysis

BACKGROUND The role of prophylactic clipping for the prevention of delayed polypectomy bleeding(DPB) remains unclear and conclusions from prior meta-analyses are limited due to the inclusion of variety of resection techniques and polyp sizes.AIM To conduct a meta-analysis on the effect of clipping on DPB following endoscopic mucosal resection(EMR) of colorectal lesions ≥ 20 mm.METHODS We performed a search of PubMed and the Cochrane library for studies comparing the effect of clipping vs no clipping on DPB following endoscopic resection. The Cochran Q test and I^2 were used to test for heterogeneity. Pooling was conducted using a random-effects model.RESULTS Thirteen studies with a total of 7794 polyps were identified, of which data was available on 1701 cases of EMR of lesions ≥ 20 mm. Prophylactic clipping was associated with a lower rate of DPB(1.4%) when compared to no clipping(5.2%)(pooled OR: 0.24, 95%CI: 0.12-0.50, P < 0.001) following EMR of lesions ≥ 20 mm.There was no significant heterogeneity among the studies(I^2 = 0%, P = 0.67).CONLUSION Prophylactic clipping may reduce DPB following EMR of large colorectal lesions.Future trials are needed to further identify risk factors and stratify high risk cases in order to implement a cost-effective preventive strategy.     

Efficacy, risk factors and complications of endoscopic polypectomy： Ten year experience at a single center

AIM： To examine the efficacy and complications of colonoscopic resection of colorectal polypoid lesions. METHODS： We retrospectively reviewed 1354 polypectomies performed on 1038 patients over a ten- year period. One hundred and sixty of these were performed for large polyps, those measuring ≥ 20 mm. Size, shape, location, histology, the technique of polypectomy used, complications, drugs assumption and associated intestinal or extra intestinal diseases were analyzed. For statistical analysis, the Pearson χ2 test, NPC test and a Binary Logistic Regression were used. RESULTS： The mean patient age was 65.9 ± 12.4 years, with 671 men and 367 women. The mean size of polyps removed was 9.45 ± 9.56 mm while the size of large polyps was 31.5 ± 10.8 mm. There were 388 pedunculated and 966 sessile polyps and the most common location was the sigmoid colon （41.3%）. The most frequent histology was tubular adenoma （55.9%） while for the large polyps was villous （92/160 -57.5%）. Coexistent malignancy was observed in 28 polyps （2.1%） and of these, 20 were large polyps. There were 17 procedural bleeding （1.3%） and one perforation. The statistical analysis showed that cancer is correlated to polyp size （P 〈 0.0001）; sessile shape （P 〈 0.0001） and bleeding are correlated to cardiac disease （P = 0.034）, tubular adenoma （P = 0.016） and polyp size.CONCLUSION： The endoscopic resection is a simple and safe procedure for removing colon rectal neoplastic lesions and should be considered the treatment of choice for large colorectal polyps. The polyp size is an important risk factor for malignancy and for bleeding.     

Prevalence of advanced colonic polyps in asymptomatic Chinese

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon. METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon. RESULTS: Colon polyps were detected in 971 (16.3%) subjects (613 males and 358 females) with their mean age being 56.6±10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%), 56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon, and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening. CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.     

Feasibility of cold snare polypectomy in Japan: A pilot study

AIM: To investigate the feasibility of cold snare polypectomy(CSP) in Japan.METHODS: The outcomes of 234 non-pedunculated polyps smaller than 10 mm in 61 patients who underwent CSP in a Japanese referral center were retrospectively analyzed. The cold snare polypectomies were performed by nine endoscopists with no prior experience in CSP using an electrosurgical snare without electrocautery.RESULTS: CSPs were completed for 232 of the 234 polyps. Two(0.9%) polyps could not be removed without electrocautery. Immediate postpolypectomy bleeding requiring endoscopic hemostasis occurred in eight lesions(3.4%; 95%CI: 1.1%-5.8%), but all were easily managed. The incidence of immediate bleeding after CSP for small polyps(6-9 mm) was significantly higher than that of diminutive polyps(≤ 5 mm; 15% vs 1%, respectively). Three(5%) patients complained of minor bleeding after the procedure but required no intervention. The incidence of delayed bleeding requiringendoscopic intervention was 0.0%(95%CI: 0.0%-1.7%). In total, 12% of the resected lesions could not be retrieved for pathological examination. Tumor involvement in the lateral margin could not be histologically assessed in 70(40%) lesions.CONCLUSION: CSP is feasible in Japan. However, immediate bleeding, retrieval failure and uncertain assessment of the lateral tumor margin should not be underestimated. Careful endoscopic diagnosis before and evaluation of the tumor residue after CSP are recommended when implementing CSP in Japan.     

Risk factors for bleeding after endoscopic submucosal dissection of colorectal neoplasms

AIM:To investigate the risk factors for delayed bleeding following endoscopic submucosal dissection(ESD)treatment for colorectal neoplasms.METHODS:We retrospectively reviewed the medical records of 317 consecutive patients with 325 lesions who underwent ESD for superficial colorectal neoplasms at our hospital from January 2009 to June2013.Delayed post-ESD bleeding was defined as bleeding that resulted in overt hematochezia 6 h to 30d after ESD and the observation of bleeding spots as confirmed by repeat colonoscopy or a required blood transfusion.We analyzed the relationship between risk factors for delayed bleeding following ESD and the following factors using univariate and multivariate analyses:age,gender,presence of comorbidities,use of antithrombotic drugs,use of intravenous heparin,resected specimen size,lesion size,lesion location,lesion morphology,lesion histology,the device used,procedure time,and the presence of significant bleeding during ESD.RESULTS:Delayed post-ESD bleeding was found in14 lesions from 14 patients(4.3%of all specimens,4.4%patients).Patients with episodes of delayed postESD bleeding had a mean hemoglobin decrease of2.35 g/dL.All episodes were treated successfully using endoscopic hemostatic clips.Emergency surgery was not required in any of the cases.Blood transfusion was needed in 1 patient(0.3%).Univariate analysis revealed that lesions located in the cecum(P=0.012)and the presence of significant bleeding during ESD(P=0.024)were significantly associated with delayed post-ESD bleeding.The risk of delayed bleeding was higher for larger lesion sizes,but this trend was not statistically significant.Multivariate analysis revealed that lesions located in the cecum(OR=7.26,95%CI:1.99-26.55,P=0.003)and the presence of significant bleeding during ESD(OR=16.41,95%CI:2.60-103.68,P=0.003)were independent risk factors for delayed post-ESD bleeding.CONCLUSION:Location in the cecum and significant bleeding during ESD predispose patients to delayed post-procedural bleeding.Therefore,careful and additional management is recommended for these patients.     

Removal of diminutive colorectal polyps: A prospective randomized clinical trial between cold snare polypectomy and hot forceps biopsy

AIM To compare the efficacy and safety of cold snare polypectomy(CSP) and hot forceps biopsy(HFB) for diminutive colorectal polyps.METHODS This prospective, randomized single-center clinical trial included consecutive patients ≥ 20 years of age with diminutive colorectal polyps 3-5 mm from December 2014 to October 2015. The primary outcome measures were en-bloc resection(endoscopic evaluation) and complete resection rates(pathological evaluation). The secondary outcome measures were the immediate bleeding or immediate perforation rate after polypectomy, delayed bleeding or delayed perforation rate after polypectomy, use of clipping for bleeding or perforation, and polyp retrieval rate. Prophylactic clipping after polyp removal wasn't routinely performed.RESULTS Two hundred eight patients were randomized into the CSP(102), HFB(106) and 283 polyps were evaluated(CSP: 148, HFB: 135). The en-bloc resection rate was significantly higher with CSP than with HFB [99.3%(147/148) vs 80.0%(108/135), P 0.0001]. The complete resection rate was significantly higher with CSP than with HFB [80.4%(119/148) vs 47.4%(64/135), P 0.0001]. The immediate bleeding rate was similar between the groups [8.6%(13/148) vs 8.1%(11/135), P = 1.000], and endoscopic hemostasis with hemoclips was successful in all cases. No cases of perforation or delayed bleeding occurred. The rate of severe tissue injury to the pathological specimen was higher HFB than CSP [52.6%(71/135) vs 1.3%(2/148), P 0.0001]. Polyp retrieval failure was encountered CSP(7), HFB(2).CONCLUSION CSP is more effective than HFB for resecting diminutive polyps. Further long-term follow-up study is required.     

rate of adverse events of gastroduodenal snare polypectomy for non-flat polyp is low: A prospective and multicenter study

AIM To evaluate the rate of adverse events(AEs) during consecutive gastric and duodenal polypectomies in several Spanish centers. METHODS Polypectomies of protruded gastric or duodenal polyps ≥ 5 mm using hot snare were prospectively included. Prophylactic measures of hemorrhage were allowed in predefined cases. AEs were defined and graded according to the lexicon recommended by the American Society for Gastrointestinal Endoscopy. Patients were followed for 48 h, one week and 1 mo after theprocedure. RESULTS308 patients were included and a single polypectomy was performed in 205. Only 36(11.7%) were on prior anticoagulant therapy. Mean polyp size was 15 ± 8.9 mm(5-60) and in 294 cases(95.4%) were located in the stomach. Hemorrhage prophylaxis was performed in 219(71.1%) patients. Nine patients presented AEs(2.9%), and 6 of them were bleeding(n = 6, 1.9%)(in 5 out of 6 AE, different types of endoscopic treatment were performed). Other 24 hemorrhagic episodes could be managed without any change in the outcome of the endoscopy and, consequently, were considered incidents. We did not find any independent risk factor of bleeding.CONCLUSION Gastroduodenal polypectomy using prophylactic measures has a rate of AEs small enough to consider this procedure a safe and effective method for polyp resection independently of the polyp size and location.     

Ultrasound virtual endoscopy: Polyp detection and reliability of measurement in an in vitro study with pig intestine specimens

AIM: To present our initial experience regarding the feasibility of ultrasound virtual endoscopy(USVE) and its measurement reliability for polyp detection in an in vitro study using pig intestine specimens.METHODS: Six porcine intestine specimens containing 30 synthetic polyps underwent USVE, computed tomography colonography(CTC) and optical colonoscopy(OC) for polyp detection. The polyp measurement defined as the maximum polyp diameter on twodimensional(2D) multiplanar reformatted(MPR) planes was obtained by USVE, and the absolute measurement error was analyzed using the direct measurement as the reference standard.RESULTS: USVE detected 29(96.7%) of 30 polyps, remaining a 7-mm one missed. There was one falsepositive finding. Twenty-six(89.7%) of 29 reconstructedimages were clearly depicted, while 29(96.7%) of 30 polyps were displayed on CTC with one false-negative finding. In OC, all the polyps were detected. The intraclass correlation coefficient was 0.876(95%CI: 0.745-0.940) for measurements obtained with USVE. The pooled absolute measurement errors ± the standard deviations of the depicted polyps with actual sizes ≤ 5 mm, 6-9 mm, and ≥ 10 mm were 1.9 ± 0.8 mm, 0.9 ± 1.2 mm, and 1.0 ± 1.4 mm, respectively.CONCLUSION: USVE is reliable for polyp detection and measurement in in vitro study.     

Importance of the surrounding colonic mucosa in distinguishing between hyperplastic and adenomatous polyps during acetic acid chromoendoscopy

AIM： To examine the characteristics of colonic polyps, where it is difficult to distinguish adenomatous polyps from hyperplastic polyps, with the aid of acetic acid chromoendoscopy. METHODS： Acetic acid spray was applied to colonic polyps smaller than 10 mm before complete excision. Endoscopic images were taken before and 15-30 s after the acetic acid spray. Both pre- and post-sprayed images were shown to 16 examiners, who were asked to interpret the lesions as either hyperplastic or adenomatous polyps. Regression analysis was performed to determine which factors were most likely related to diagnostic accuracy. RESULTS： In 50 cases tested by the 16 examiners, the overall accuracy was 62.4% （499/800）. Regression analysis demonstrated that surrounding colonic mucosa was the only factor that was significantly related to accuracy in discriminating adenomatous from hyperplastic polyps （P 〈 0.001）. Accuracy was higher for polyps with linear surrounding colonic mucosa than for those with nodular surrounding colonic mucosa （P 〈 0.001）, but was not related to the shape, location, or size of the polyp. CONCLUSION： The accuracy of predicting histology is significantly related to the pattern of colonic mucosa surrounding the polyp. Making a histological diagnosis of colon polyps merely by acetic acid spray is helpful for colon polyps with linear, regularly patterned surrounding colonic mucosa, and less so for those with nodular, irregularly patterned surrounding colonic mucosa.     

Meta-analysis and systematic review of colorectal endoscopic mucosal resection

AIM： To evaluate the proportion of successful complete cure en-bloc resections of large colorectal polyps achieved by endoscopic mucosal resection （EMR）. METHODS： Studies using the EMR technique to resect large colorectal polyps were selected. Successful complete cure en-bloc resection was defined as one piece margin-free polyp resection. Articles were searched for in Medline, Pubmed, and the Cochrane Control Trial Registry, among other sources. RESULTS： An initial search identified 2620 reference articles, from which 429 relevant articles were selected and reviewed. Data was extracted from 25 studies （n = 5221） which met the inclusion criteria. All the studies used snares to perform EMR. Pooled proportion of en-bloc resections using a random effect model was 62.85% （95% CI： 51.50-73.52）. The pooled proportion for complete cure en-bloc resections using a random effect model was 58.66% （95% CI： 47.14-69.71）. With higher patient load （〉 200 patients）, this complete cure en-bloc resection rate improves from 44.19% （95% CI： 24.31-65.09） to 69.17% （95% CI： 51.11-84.61）. CONCLUSION： EMR is an effective technique for the resection of large colorectal polyps and offers an alternative to surgery.     

Gallbladder polyps: Factors affecting surgical decision

AIM: To determine the factors affecting the decision to perform surgery, and the efficiency of ultrasonography (USG) in detecting gallbladder polyps (GP). METHODS: Data for 138 patients who underwent cholecystectomy between 1996 and 2012 in our clinic with a diagnosis of GP were retrospectively analyzed. Demographic data, clinical presentation, principal symptoms, ultrasonographic and histopathological findings were evaluated. Patients were evaluated in individual groups according to the age of the patients (older or younger than 50 years old) and polyp size (bigger or smaller than 10 mm) and characteristics of the polyps (pseudopolyp or real polyps). χ 2 tests were used for the statistical evaluation of the data. RESULTS: The median age was 50 (26-85) years and 91 of patients were female. Of 138 patients who underwent cholecystectomy with GP diagnosis, only 99 had a histopathologically defined polyp; 77 of them had pseudopolyps and 22 had true polyps. Twenty-one patients had adenocarcinoma. Of these 21 patients, 11 were male, their median age was 61 (40-85) years and all malignant polyps had diameters > 10 mm (P< 0.0001). Of 138 patients in whom surgery were performed, 112 had ultrasonographic polyps with diameters < 10 mm. Of the other 26 patients who also had polyps with diameters > 10 mm, 22 had true polyps. The sensitivity of USG was 84.6% for polyps with diameters > 10 mm (P < 0.0001); however it was only 66% in polyps with diameters < 10 mm. CONCLUSION: The risk of malignancy was high in the patients over 50 years old who had single polyps with diameters > 10 mm.     

Colon mucosal neoplasia referred for endoscopic mucosal resection: Recurrence of adenomas and prediction of submucosal invasion

BACKGROUND Endoscopic mucosal resection(EMR) is an effective and minimally invasive alternative to surgery for large polyps and laterally spreading lesions. Gross morphology and surface characteristics may help predict submucosal invasion of the lesion(SMIL) during endoscopic evaluation. This is one of the largest singlecenter studies reporting endoscopic mucosal resection for larger(≥ 20 mm) colorectal lesions in the United States.AIM To determine the recurrence rate of adenomas and endoscopic features that may predict submucosal invasion of colonic mucosal neoplasia.METHODS This is a retrospective cohort study of all the patients referred for endoscopic mucosal resection for lesions ≥ 20 mm, spanning a period from January 2013 to February 2017. The main outcome measure was identifying features that may predict submucosal invasion of mucosal lesions and predict recurrence of adenomas on follow-up surveillance colonoscopy performed at 4-6 mo.RESULTS A total of 480 patients with 500 lesions were included in the study. The median age was 68(Inter quantile range: 14) with 52% males. The most common lesion location was ascending colon(161; 32%). Paris classification 0-IIa(Flat elevation of mucosa-316; 63.2%); Kudo Pit Pattern IIIs(192; 38%) and Granular surface morphology(260; 52%) were most prevalent. Submucosal invasion was present in 23(4.6%) out of 500 lesions. The independent risk factors for SMIL were Kudo Pit Pattern IIIL + IV and V(Odds ratio: 4.5; P value 0.004) and Paris classification 0-IIc(Odds ratio: 18.2; P value 0.01). Out of 500, 354 post-endoscopic mucosal resection scars were examined at surveillance colonoscopy. Recurrence was noted in 21.8%(77 cases).CONCLUSION There was overall low prevalence of SMIL in our study. Kudo pit pattern(IIIL + IV and V) and Paris classification 0-IIc were the only factors identified as an independent risk factor for submucosal invasion. The independent risk factor for recurrence was adenoma size( 40 mm). Almost all recurrences(98.8%) were treated endoscopically.     

Long-term survival after resection of pancreatic cancer:A single-center retrospective analysis

AIM: To retrospectively analyze factors affecting the long-term survival of patients with pancreatic cancer who underwent pancreatic resection.METHODS: From January 2000 to December 2011,195 patients underwent pancreatic resection in our hospital.The prognostic factors after pancreatic resection were analyzed in all 195 patients.After excluding the censored cases within an observational period,the clinicopathological characteristics of 20 patients who survived ≥ 5(n = 20) and 5(n = 76) years were compared.For this comparison,we analyzed the patients who underwent surgery before June 2008 and were observed for more than 5 years.For statistical analyses,the log-rank test was used to compare the cumulative survival rates,and the χ2 and Mann-Whitney tests were used to compare the two groups.The CoxHazard model was used for a multivariate analysis,and P values less than 0.05 were considered significant.A multivariate analysis was conducted on the factors that were significant in the univariate analysis.RESULTS: The median survival for all patients was 27.1 months,and the 5-year actuarial survival rate was 34.5%.The median observational period was 595 d.With the univariate analysis,the UICC stage was significantly associated with survival time,and the CA19-9 ≤ 200 U/m L,DUPAN-2 ≤ 180 U/m L,t u m o r s i ze ≤ 2 0 m m,R 0 re s e c t i o n,a b s e n c e o f lymph node metastasis,absence of extrapancreatic neural invasion,and absence of portal invasion were favorable prognostic factors.The multivariate analysis showed that tumor size ≤ 20 mm(HR = 0.40; 95%CI: 0.17-0.83,P = 0.012) and negative surgical margins(R0 resection)(HR = 0.48; 95%CI: 0.30-0.77,P = 0.003) were independent favorable prognostic factors.Among the 96 patients,20 patients survived for 5 years or more,and 76 patients died within 5 years after operation.Comparison of the 20 5-year survivors with the 76 non-survivors showed that lower concentrations of DUPAN-2(79.5 vs 312.5 U/mL,P = 0.032),tumor size ≤ 20 mm(35% vs 8%,P = 0.008),R0 resection(95% vs 61%,P = 0.004),and absence of lymph nodemetastases(60% vs 18%,P = 0.036) were significantly associated with the 5-year survival.CONCLUSION: Negative surgical margins and a tumor size ≤ 20 mm were independent favorable prognostic factors.Histologically curative resection and early tumor detection are important factors in achieving long-term survival.     

Single-center study comparing computed tomography colonography with conventional colonoscopy

AIM： To compare the results from computed tomography （CT） colonography with conventional colonoscopy in symptomatic patients referred for colonoscopy. METHODS： The study included 227 adult outpatients, mean age 60 years, with appropriate indications for colonoscopy. CT colonography and colonoscopy were performed on the same day in a metropolitan teaching hospital. Colonoscopists were initially blinded to the results of CT colonography but there was segmental unblinding during the procedure. The primary outcome measures were the sensitivity and specificity of CT colonography for the identification of polyps seen at colonoscopy （i.e. analysis by polyp）. Secondary outcome measures included an analysis by patient, extracolonic findings at CT colonography, adverse events with both procedures and patient acceptance and preference. RESULTS： Twenty-five patients （11%） were excluded from the analysis because of incomplete colonoscopy or poor bowel preparation that affected either CT colonography, colonoscopy or both procedures. Polyps and masses （usually cancers） were detected at colonoscopy and CT colonography in 35% and 42% of patients, respectively. Of nine patients with a final diagnosis of cancer, eight （89%） were identified by CT colonography as masses （5） or polyps （3）. For polyps analyzed according to polyp, the overall sensitivity of CT colonography was 50% （95% CI, 39%-61%） but this increased to 71% （95% CI, 52%-85%） for polyps ≥ 6 mm in size. Similarly, specificity for all polyps was 48% （95% CI, 39%-58%） increasing to 67% （95% CI, 56%-76%） for polyps ≥6 mm. Adverse events were uncommon but included one colonic perforation at colonoscopy, Patient acceptance was high for both procedures but preference favoured CT colonography. CONCLUSION： Although CT colonography was more sensitive in this study than in some previous studies, the procedure is not yet sensitive enough for widespread application in symptomatic patients.     

Improving quality measures in colonoscopy and its therapeutic intervention

Colonoscopy with polypectomy has been shown to re-duce the risk of colon cancer. The critical element in the quality of colonoscopy in terms of polyp detection and removal continues to be the performance of the endoscopist, independent of patient-related factors. Im-proved results in terms of polyp detection and complete removal have implications regarding the development of screening and surveillance intervals and the reduction of interval cancers after negative colonoscopy. Advances in colonoscopy techniques such as high-definition colonos-copy, hood-assisted colonoscopy and dye-based chro-moendoscopy have improved the detection of small and flat-type colorectal polyps. Virtual chromoendoscopy has not proven to improve polyp detection but may be use-ful to predict polyp pathology. The majority of polyps can be removed endoscopically. Available polypectomy techniques include cold forceps polypectomy, cold snare polypectomy, conventional polypectomy, endoscopic mu-cosal resection and endoscopic submucosal dissection. The preferred choice depends on the polyp size and characteristics. Other useful techniques include colono-scopic hemostasis for acute colonic diverticular bleeding, endoscopic decompression using colonoscopic stenting, and transanal tube placement for colorectal obstruction. Here we review the current knowledge concerning the improvement of quality measures in colonoscopy and colonoscopy-related therapeutic interventions.     

Role of computed tomographic colonoscopy of postoperative surveillance in patient with gastric cancer

AIM: To examine the diagnostic yield of colorectal neoplasia at computed tomographic colonoscopy (CTC) as well as the feasibility of contrast enhanced CTC in patients with gastric cancer. METHODS: To examine the incidence of colon polyp we selected postoperative 188 gastric cancer patients, which we refer to as the 'colon polyp survey group'. To examine the feasibility of CTC for early detection of colon cancer or advanced colon adenoma, we selected 47 gastric cancer patients (M:F 29:18, mean age 53.8 years), which we call the 'CT colonoscopy group'. All the 47 patients underwent successive CTC and colonoscopy on the same day. RESULTS: Totally 109 colon polyps were observed from 59 out of 188 gastric cancer patients, the incidence rate of colon polyps in gastric cancer patients being 31.4%. The sensitivity of CTC in detecting individuals with at least 1 lesion of any size was 57.1%, the specificity was 72.7%, the positive predictive value was 47.1%, and the negative predictive value was 71.9%. When the cutoff size was decreased to 6 mm, the sensitivity and specificity were 80.0% and 92.9%, respectively, with positive and negative predictive values of 57.1% and 97.5%, respectively. Only one patient was classified as false negative by virtual colonoscopy. CONCLUSION: The diagnostic yield of colorectal polyp was 31.4% in patients with gastric cancer, and contrast enhanced CTC is an acceptable tool for the detection of synchronous colorectal advanced adenoma andpostoperative surveillance of gastric cancer patients.     

Comparative effectiveness of i-SCANTM 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.     

Predictive factors for lymph node metastasis in poorly differentiated early gastric cancer and their impact on the surgical strategy

AIM： To identify the predictive clinicopathological factors for lymph node metastasis （LNM） in poorly differentiated early gastric cancer （EGC） and to further expand the possibility of using endoscopic mucosal resection （EMR） for the treatment of poorly differentiated EGC. METHODS： Data were collected from 85 poorly- differentiated EGC patients who were surgically treated. Association between the clinicopathological factors and the presence of LNM was retrospectively analyzed by univariate and multivariate logistic regression analyses. RESULTS： Univariate analysis showed that tumor size （OR = 5.814, 95% CI = 1.050 - 32.172, P = 0.044）, depth of invasion （OR = 10.763, 95% CI = 1.259 - 92.026, P = 0.030） and lymphatic vessel involvement （OR = 61.697, 95% CI = 2.144 - 175.485, P = 0.007） were the significant and independent risk factors for LNM. The LNM rate was 5.4%, 42.9% and 50%, respectively, in poorly differentiated EGC patients with one, two and three of the risk factors, respectively. No LNM was found in 25 patients without the three risk factors. Forty-four lymph nodes were found to have metastasis, 29 （65.9%） and 15 （34.1%） of the lymph nodes involved were within N1 and beyond N1, respectively, in 12 patients with LNM. CONCLUSION： Endoscopic mucosal resection alone may be sufficient to treat poorly differentiated intramucosal EGC （≤ 2.0 cm in diameter） with no histologically-confirmed lymphatic vessel involvement. When lymphatic vessels are involved, lymph node dissection beyond limited （D1） dissection or D1＋ lymph node dissection should be performed depending on the tumor location.     

Treatment for gastric ‘indefinite for neoplasm/dysplasia' lesions based on predictive factors

BACKGROUND Gastric ‘indefinite for neoplasm/dysplasia'(IFND) is a borderline lesion that is difficult to diagnose as either regenerative or neoplastic. There is a need for guidance in the identification of a subset of patients, who have an IFND lesion with a higher risk of malignant potential, to enable risk stratification and optimal management.AIM To determine the clinical and pathologic factors for the accurate diagnosis of gastric IFND lesions.METHODS In total, 461 gastric lesions diagnosed via biopsy as IFND lesions were retrospectively evaluated. Endoscopic resection(n = 134), surgery(n = 22), and follow-up endoscopic biopsy(n = 305) were performed to confirm the diagnosis.The time interval from initial biopsy to cancer diagnosis was measured, and diagnostic delays were categorized as > 2 wk, > 2 mo, > 6 mo, and > 1 year. The IFND lesions presenting as regenerating atypia(60%) or atypical epithelia(40%)at initial biopsy were adenocarcinomas in 22.6%, adenomas in 8.9%, and gastritis in 68.5% of the cases.RESULTS Four clinical factors [age ≥ 60 years(2.445, 95%CI: 1.305-4.580, P = 0.005),endoscopic size ≥ 10 mm(3.519, 95%CI: 1.891-6.548, P < 0.001), single lesion(5.702, 95%CI: 2.212-14.696, P < 0.001), and spontaneous bleeding(4.056, 95%CI:1.792-9.180, P = 0.001)], and two pathologic factors [atypical epithelium(25.575,95%CI: 11.537-56.695, P < 0.001], and repeated IFND diagnosis [6.022, 95%CI:1.822-19.909, P = 0.003)] were independent risk factors for gastric cancer. With two or more clinical factors, the sensitivity and specificity for carcinoma were91.3% and 54.9%, respectively. Ten undifferentiated carcinomas were initially diagnosed as IFND. In the subgroup analysis, fold change(5.594, 95%CI: 1.458-21.462, P = 0.012) predicted undifferentiated or invasive carcinoma in the submucosal layers or deeper. Diagnostic delays shorter than 1 year were not associated with worse prognoses. Extremely well-differentiated adenocarcinomas accounted for half of the repeated IFND cases and resulted in low diagnostic accuracy even on retrospective blinded review.CONCLUSION More than two clinical and pathologic factors each had significant cut-off values for gastric carcinoma diagnosis; in such cases, endoscopic resection should be considered.