Role of high definition colonoscopy in colorectal adenomatous polyp detection

AIM:To investigate the rates of polyp detection in a mixed risk population using standard definition (SDC) vs high definition colonoscopes (HDC).METHODS:This was a retrospective cohort comparative study of 3 colonoscopists who each consecutively performed 150 SDC (307,200 pixel) and 150 HDC (792,576 pixels) in a community teaching hospital.RESULTS:A total of 900 colonoscopies were evaluated (mean age 56,46.8% men),450 with each resolution.Polyps of any type were detected in 46.0% of patients using SDC and 43.3% with HDC (P=0.42).There was no significant difference between the overall number of polyps,HDC (397) and SDC (410),detected among all patients examined,(P=0.73).One or more adenomatous polyps were detected in 24.2% of patients with HDC and 24.9% of patients with SDC colonoscopy (P=0.82).There was no significant difference between HDC (M=0.41) and SDC (M=0.42) regarding adenomatous polyp (P=0.88) or advanced adenoma (P=0.56) detection rate among all patients examined.CONCLUSION:HDC did not improve yield of adenomatous polyp,advanced adenoma or overall polyp detection in a population of individuals with mixed risk for colorectal cancer.

Predicting the presence of adenomatous polyps during colonoscopy with National Cancer Institute Colorectal Cancer Risk-Assessment Tool

AIM To evaluate the National Cancer Institute(NCI)Colorectal Cancer(CRC)Risk Assessment Tool as a predictor for the presence of adenomatous polyps(AP) found during screening or surveillance colonoscopy.METHODS This is a retrospective single center observational study.We collected data of adenomatous polyps in each colonoscopy and then evaluated the lifetime CRC risk.We calculated the AP prevalence across risk score quintiles,odds ratios of the prevalence of AP across risk score quintiles,area under curves(AUCs)and Youden’s indexes to assess the optimal risk score cut off value for AP prevalence status.RESULTS The prevalence of AP gradually increased throughout the five risk score quintiles:i.e.,27.63%in the first and 51.35%in the fifth quintile.The odd ratios of AP prevalence in the fifth quintile compared to the first and second quintile were 2.76[confidence interval(CI):1.71-4.47]and 2.09(CI:1.32-3.30).The AUC for all patients was 0.62(CI:0.58-0.66).Youden’s Index indicated the optimal risk score cutoff value discriminating AP prevalence status was 3.60.CONCLUSION Patients with the higher NCI risk score have higher risk of AP and subsequent CRC;therefore,measures to increase the effectiveness of CRC detection in these patients include longer withdrawal time,early surveillance colonoscopy,and choosing flexible colonoscopy over other CRC screening modalities.

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.

DISTINGUISHING BETWEEN HYPERPLASTIC AND ADENOMATOUS POLYPS AND NORMAL COLONIC MUCOSA BY USING MULTIPHOTON LASER SCANNING MICROSCOPY

Precisely distinguishing between hyperplastic and adenomatous polyps and normal human colonic mucosa at the cellular level is of great medical significance.In this work,multiphoton laserscarming microscopy(MPLSM)was used to obtain the high.-contrast images and the morpho-logical characteristics from normal colonic mucosa,hyperplastic polyps and tubular adenoma.Byintegrating the length and area measurement tools and computing tool,we quantified thedifference of crypt morphology and the alteration of nuclei in normal and diseased human colonicmucosa.Our results demonstrated that the morphology of crypts had an obvious tendency tocystic dilatation or elongated in hyperplastic polyps and tubular adenoma.The cont ent andnumber of mucin droplets of the scattered goblet cells had a piecemeal reduction in hyperplastic polyps and a large decrease in tubular adenoma The nuclei of epithelial cells might be elongated and pseudostratified,but overt dysplasia was absent in hyperplastic polyps.Nevertheless,thenuclei showed enlarged,crowded,stratified and a rod-like structure,with loss of polarity intubular adenoma.These results suggest that MPLSM has the capacity to distinguish betweenhyperplastic and adenomat ous polyps and normal human colonic mucosa at the celular level.

Predictive factors and model validation of post-colon polyp surgery Helicobacter pylori infection

BACKGROUND Recently,research has linked Helicobacter pylori(H.pylori)stomach infection to colonic inflammation,mediated by toxin production,potentially impacting colorectal cancer occurrence.AIM To investigate the risk factors for post-colon polyp surgery,H.pylori infection,and its correlation with pathologic type.METHODS Eighty patients who underwent colon polypectomy in our hospital between January 2019 and January 2023 were retrospectively chosen.They were then randomly split into modeling(n=56)and model validation(n=24)sets using R.The modeling cohort was divided into an H.pylori-infected group(n=37)and an H.pylori-uninfected group(n=19).Binary logistic regression analysis was used to analyze the factors influencing the occurrence of H.pylori infection after colon polyp surgery.A roadmap prediction model was established and validated.Finally,the correlation between the different pathological types of colon polyps and the occurrence of H.pylori infection was analyzed after colon polyp surgery.RESULTS Univariate results showed that age,body mass index(BMI),literacy,alcohol consumption,polyp pathology type,high-risk adenomas,and heavy diet were all influential factors in the development of H.pylori infection after intestinal polypectomy.Binary multifactorial logistic regression analysis showed that age,BMI,and type of polyp pathology were independent predictors of the occurrence of H.pylori infection after intestinal polypectomy.The area under the receiver operating characteristic curve was 0.969[95%confidence interval(95%CI):0.928–1.000]and 0.898(95%CI:0.773–1.000)in the modeling and validation sets,respectively.The slope of the calibration curve of the graph was close to 1,and the goodness-of-fit test was P>0.05 in the two sets.The decision analysis curve showed a high rate of return in both sets.The results of the correlation analysis between different pathological types and the occurrence of H.pylori infection after colon polyp surgery showed that hyperplastic polyps,inflammatory polyps,and the occurrence of H.pylori infection were not significantly correlated.In contrast,adenomatous polyps showed a significant positive correlation with the occurrence of H.pylori infection.CONCLUSION Age,BMI,and polyps of the adenomatous type were independent predictors of H.pylori infection after intestinal polypectomy.Moreover,the further constructed column-line graph prediction model of H.pylori infection after intestinal polypectomy showed good predictive ability.

Detection and analysis of serum bile acid profile in patients with colonic polyps

BACKGROUND Analyzing the variations in serum bile acid(BA)profile can provide a certain biological basis for early warning and prevention of various diseases.There is currently no comprehensive study on the relationship between the serum BA profile and colonic polyps.AIM To study the serum BA profile detection results of patients with colonic polyps,and analyze the correlation between BA and colonic polyps.METHODS From January 1,2022,to June 1,2023,204 patients with colonic polyps who were diagnosed and treated at Zhongda Hospital Southeast University were chosen as the study subjects,and 135 non-polyp people who underwent physical examination were chosen as the control group.Gathering all patients'clinical information,typical biochemical indicators,and BA profile.RESULTS Compared with the control group,the serum levels of taurocholic acid,glycocholic acid,glycochenodeoxycholic acid,and taurochenodeoxycholic acid in the colonic polyp group were significantly higher than those in the control group,while the content of deoxycholic acid(DCA)was lower than that in the control group(P<0.05).When colonic polyps were analyzed as subgroups,it was shown that there was a strong correlation between changes in the BA profile and polyp diameter,location,morphology,pathological kind,etc.CONCLUSION The serum BA profile showed significant changes in patients with colonic polyps,with a significant increase in primary conjugated BA content and a decrease in secondary free bile acid DCA content.There is a certain correlation between primary free BA and pathological parameters of polyps.

Colonic schistosomiasis mimicking cancer,polyp,and inflammatory bowel disease:Five case reports and review of literature

BACKGROUND Schistosomiasis,officially named as a neglected tropical disease by The World Health Organization,is a serious parasitic disease caused by trematode flukes of the genus Schistosoma.It is a common infectious disease,endemic in more than 78 countries.The disease can involve various organs and poses far-reaching public health challenges.CASE SUMMARY Here,we present a series of five patients with variable presentations:an asymptomatic patient who was diagnosed with colonic schistosomiasis upon screening colonoscopy;2 patients with clinical suspicion of colonic cancer;and 2 patients with a clinical diagnosis of inflammatory bowel disease.All patients were subsequently confirmed to have colonic schistosomiasis after colonoscopy and histopathologic examination.The clinical manifestations,colonoscopy features and histologic findings of the patients are described.Most of the patients showed significant clinical improvement following administration of oral praziquantel.CONCLUSION Intestinal schistosomiasis can present with features mimicking other gastrointestinal conditions.This disease should be a diagnostic consideration in patients who live in or have traveled to endemic areas.

Schistosomal(bilharzial)polyps:Travel through the colon and beyond

Schistosomiasis(bilharziasis)is a major neglected tropical disease.It is endemic in many tropical and subtropical communities.Schistosomal polyps(S.polyps)are not uncommon presentation of this infection.Although the colon is the most commonly affected organ,many other organs are affected.S.polyps are associated with a variable range of morbidity independent of the Schistosomal infection.S.polyps are frequently described in endemic areas and increasingly reported in non-endemic areas mainly among immigrants and visitors to the endemic areas.This review aimed to increase awareness of practitioners,especially gastroenterologists,for this peculiar type of polyps caused by this neglected infection hence improving patient outcomes.Web-based search of different databases was conducted for the literature focusing the development of S.polyps in the colon and other organs with analysis of the clinical manifestations,diagnosis and treatment.The following key words were used in the search,“Schistosomiasis”OR“Bilharziasis”AND“Polyps”OR“Polyp”AND“Colon”OR“Small intestine”OR“Duodenum”OR“Stomach”OR“Esophagus”OR”Gallbladder”OR”Pharynx”OR“Larynx”OR“Trachea”OR”Urinary bladder”OR“Ureter”OR“Renal Pelvis”OR“Urethra”.All publication types including case reports,case series,original research,and review articles were retrieved and analyzed.S.polyps are not infrequent presentation of acute or chronic Schistosomal infection.S.polyps are described in many organs including the bowel,genitourinary tract,skin,gallbladder and the larynx.Presentation of S.polyps is variable and depends on the site,number as well as the polyp size.The relationship of S.polyps to malignant transformation is a matter of discussion.Presence of S.polyps is sometimes the only manifestation of Schistosomiasis.Small polyps can be treated medically with praziquantel,while large accessible polyps are amendable for endoscopic excision through different polyp resection techniques.However,huge,complicated,non-accessible and suspicious polyps are indicated for surgical management or advanced endoscopic resection when appropriate.Clinicians and endoscopists should be aware about these facts when treating patients living in,immigrated from or visiting endemic areas.

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 le- sions vs standard white-light instruments. METHODS： Data were collected from the computer- ized database of the endoscopy unit of our tertiary referral center. We retrospectively analyzed 1101 con- secutive 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, diagnos- tic 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 imme- diately after the procedure, and number, size, location and characteristics of the lesions. Polyps or protruding lesions 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 colonosco- pies 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 be- tween 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 imag- ing （459/252 and 807/849, P 〈 0.0001）, in the right or left colon （mean ：1： 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 ± 2.89 vs 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.

Automated Colonic Polyp Detection and Classification Enabled Northern Goshawk Optimization with Deep Learning

The major mortality factor relevant to the intestinal tract is the growth of tumorous cells(polyps)in various parts.More specifically,colonic polyps have a high rate and are recognized as a precursor of colon cancer growth.Endoscopy is the conventional technique for detecting colon polyps,and considerable research has proved that automated diagnosis of image regions that might have polyps within the colon might be used to help experts for decreasing the polyp miss rate.The automated diagnosis of polyps in a computer-aided diagnosis(CAD)method is implemented using statistical analysis.Nowadays,Deep Learning,particularly throughConvolution Neural networks(CNN),is broadly employed to allowthe extraction of representative features.This manuscript devises a new Northern Goshawk Optimization with Transfer Learning Model for Colonic Polyp Detection and Classification(NGOTL-CPDC)model.The NGOTL-CPDC technique aims to investigate endoscopic images for automated colonic polyp detection.To accomplish this,the NGOTL-CPDC technique comprises of adaptive bilateral filtering(ABF)technique as a noise removal process and image pre-processing step.Besides,the NGOTL-CPDC model applies the Faster SqueezeNet model for feature extraction purposes in which the hyperparameter tuning process is performed using the NGO optimizer.Finally,the fuzzy Hopfield neural network(FHNN)method can be employed for colonic poly detection and classification.A widespread simulation analysis is carried out to ensure the improved outcomes of the NGOTL-CPDC model.The comparison study demonstrates the enhancements of the NGOTL-CPDC model on the colonic polyp classification process on medical test images.

Pleomorphic leiomyosarcoma of the maxilla with metastasis to the colon:A case report

BACKGROUND Pleomorphic leiomyosarcomas make up around 8.6%of all leiomyosarcomas.They behave aggressively and often have poor prognoses.They can affect the gastrointestinal tract and retroperitoneum.To date,pleomorphic leiomyosarcoma involving the mesocolon have been reported in nine patients.CASE SUMMARY The patient was a 44-year-old man with a history of pleomorphic leiomyosarcoma of the left maxilla with metastasis to the lung and liver.His most recent positron emission tomography-computed tomography(PET-CT)scan showed uptake in the ascending and transverse colons.A colonoscopy revealed a 5.0 cm×3.5 cm×3.0 cm pedunculated polyp in the ascending colon.The polyp was removed using hot snare polypectomy technique and retrieved with Rothnet.Histopathologic examination of the polyp showed a metastatic pleomorphic leiomyosarcoma.CONCLUSION Uptake(s)on PET-CT in a patient with pleomorphic leiomyosarcoma should raise suspicion for metastasis.

Mesh migration into the sigmoid colon after inguinal hernia repair presenting as a colonic polyp:A case report and review of literature

Mesh migration and penetration into abdominal visce-ra rarely occur after laparoscopic inguinal hernia repair. We present the first case of mesh migration into the sigmoid colon identified as a colonic polyp at initial co-lonoscopic examination. The patient complained of mild abdominal distention in the lower abdomen over the previous year without changes in bowel habits or stool appearance and without weight loss. By complement-ary endoscopic ultrasonography, a cavity--like structure beneath the suspected polyp was further confirmed. Enhanced abdominal computed tomography merely re-vealed local bowel wall thickening and inflammation of the colosigmoid junction. The migrating mesh, which was lodged in the sigmoid colon and caused intra--abdomi-nal adhesion in the lower abdominal cavity, was finally identified via exploratory surgery. The components of inflammatory granulation tissue around the mesh mate-rial were diagnosed based on histological examination of the surgical specimen after sigmoidectomy. In this patient, nonspecific endoscopic and imaging outcomes during clinical work--up led to the diagnostic dilemma of mesh migration. Therefore, the clinical, radiological and endoscopic challenges specific to this case as well as the underlying reasons for mesh migration are discussed in detail.

Colonoscopic polypectomy in anticoagulated patients

AIM:To review our experience performing polypectomy in anticoagulated patients without interruption of anticoagulation.METHODS: Retrospective chart review at the Veterans Affairs Palo Alto Health Care System. Two hundred and twenty five polypectomies were performed in 123 patients. Patients followed a standardized protocol that included stopping warfarin for 36 h to avoid supratherapeutic anticoagulation from the bowel preparation. Patients with lesions larger than 1 cm were generally rescheduled for polypectomy off warfarin. Endoscopic clips were routinely applied prophylactically. RESULTS: One patient (0.8%, 95% CI: 0.1%-4.5%) developed major post-polypectomy bleeding that required transfusion. Two others (1.6%, 95% CI: 0.5%-5.7%) had self-limited hematochezia at home and did not seek medical attention. The average polyp size was 5.1 ± 2.2 mm. CONCLUSION: Polypectomy can be performed in therapeutically anticoagulated patients with lesions up to 1 cm in size with an acceptable bleeding rate.

Association between colonic polyps and diverticular disease

AIM: To evaluate the association between colonic polyps and diverticular disease in Japan. METHODS: We retrospectively reviewed the medical records of 672 consecutive patients who underwent total colonoscopy between August 2006 and April 2007 at Nishinjo Hospital, Okinawa, Japan. Patients with a history of any of the following were excluded from the study: previous polypectomy, colonic resection, and inflammatory bowel diseases. The association between colonic polyps and diverticular disease was analyzed by logistic regression analysis, adjusted for age and sex. RESULTS: Prevalence of colonic polyps in all patients with diverticular disease was significantly higher than that in those without diverticular disease (adjusted odds ratio 1.7). CONCLUSION: Our data showed that patients with diverticular disease have a higher risk of colonic polyps compared to those without.

Colorectal cancer screening:The role of CT colonography

Computed tomography colonography(CTC) in colorectal cancer(CRC) screening has two roles:one present and the other potential.The present role is,without any further discussion,the integration into established screening programs as a replacement for barium enema in the case of incomplete colonoscopy.The potential role is the use of CTC as a first-line screening method together with Fecal Occult Blood Test,sigmoidoscopy and colonoscopy.However,despite the fact that CTC has been officially endorsed for CRC screening of average-risk individuals by different scientif ic societies including the American Cancer Society,the American College of Radiology,and the US Multisociety Task Force on Colorectal Cancer,other entities,such as the US Preventive Services Task Force,have considered the evidence insuff icient to justify its use as a mass screening method.Medicare has also recently denied reimbursement for CTC as a screening test.Nevertheless,multiple advantages exist for using CTC as a CRC screening test:high accuracy,full evaluation of the colon in virtually all patients,non-invasiveness,safety,patient comfort,detection of extracolonic findings and cost-effectiveness.The main potential drawback of a CTC screening is the exposure to ionizing radiation.However,this is not a major issue,since low-dose protocols are now routinely implemented,delivering a dose comparable or slightly superior to the annual radiation exposure of any individual.Indirect evidence exists that such a radiation exposure does not induce additional cancers.

Colonoscopic polypectomy and associated techniques

Polypectomy of colonic polyps has been shown to reduce the risk of colon cancer development and is considered a fundamental skill for all endoscopists who perform colonoscopy.A variety of polypectomy techniques and devices are available,and their use can vary greatly based on local availability and preferences.In general,cold forceps and cold snare have been the polypectomy methods of choice for smaller polyps,and hot snare has been the method of choice for larger polyps.The use of hot forceps has mostly fallen out of favor.Polypectomy for difficult to remove polyps may require the use of special devices and advanced techniques and has continued to evolve.As a result,the vast majority of polyps today can be removed endoscopically.Since electrocautery is frequently used for polypectomy,endoscopists should be thoroughly familiar with the basic principles of electrosurgery as it pertains to polypectomy.Tattooing of a polypectomy site is an important adjunct to polypectomy and can greatly facilitate future surgery or endoscopic surveillance.The two most common post-polypectomy complications are bleeding and perforation.Their incidence can be decreased with the use of meticulous polypectomy techniques and the application of some prophylactic maneuvers.This review will examine the technique of polypectomy and its complications from the perspective of the practicing gastroenterologist.

Association between CYP24A1 polymorphisms and the risk of colonic polyps and colon cancer in a Chinese population

AIM To determine the pathogenesis and potential single nucleotide polymorphisms(SNPs) as screening sites for colonic polyps,colon cancer and ulcerative colitis,and to analyze the possible association between these genetic polymorphisms and the three diseases. METHODS We evaluated genetic polymorphisms in 144 newly diagnosed colonic polyp patients,96 colon cancer patients and 44 ulcerative colitis patients. The four SNPs genotyped were rs4809957,rs6068816,rs6091822 and rs8124792. The control group consisted of 504 East Asians enrolled in the 1000 Genomes Project. Correlations between CYP24A1 SNPs and the diseases were analyzed by Fisher's exact probability test.RESULTS CYP24A1 polymorphisms rs4809957 A/G and rs6068816 C/T showed a statistically significant association with risk of the three diseases,when both the genotypes and allele frequencies were considered. With regard to rs6091822 G/T,all three diseases were related to risk allele carriers(GT + TT) vs wild-type(GG),but the associations between the allele frequencies and the diseases were not significant. The risk of colonic polyps and colon cancer was related to the allele frequencies of rs8124792 G/A,and this association remained for genotype frequencies of this SNP. CONCLUSION Four SNPs are related to the risk of colonic polyps and colon cancer. G allele in rs6091822 G/T may play an anti-cancer role only if it is homozygous. The A allele,which is a minor component of rs8124792,may be indicated in the diagnosis of colonic polyps or colon cancer rather than ulcerative colitis.

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 Taiwan Residents Chinese.

Colonic polyps: Is it useful to characterize them with advanced endoscopy?

There have been major developments in endoscopic imaging techniques in recent years.Endoscopes with high definition and magnification can provide high quality images that allow for the histological estimation of lesions in vivo and in situ when combined with ancillary enhancement techniques such as chromoendoscopy(CE)and virtual CE(narrow band imaging fujinon intelligent chromoendoscopy,or i-Scan).Despite the enormous potential for these advanced techniques,their value and feasibility in the clinic are still doubted,particularly in cases of colonic polyps that are slated for removal,where in vivo characterization may be deemed unnecessary.However,there are several advantages offered by such advanced endoscopic imaging.CE with or without magnification demonstrates highly accurate histology and invasion depth prediction,and virtual CE is a feasible and less cumbersome alternative to CE in terms of histological estimation,though not sufficiently accurate for depth invasion prediction.Furthermore,the supplementary information provided by advanced imaging systems can assist the endoscopist in the selection of a strategic approach,such as in deciding whether a colonic lesion should be resected,left in situ,or requires more intensive surgical treatment.Lastly,advanced high-resolution imaging techniques may be more cost effective,such that histopathology of lowrisk lesions following resection can be eliminated.The results of these evaluations and comparisons with traditional CE are presented and discussed.Taken together,the benefits provided by these advanced capabilities justify their development,and advocates their use for the treatment and management of colonic polyps.

Absence of MutY homologue mutation in patients with multiple sporadic adenomatous polyps in Korea

AIM： Recently, germ-line mutation in the base excision repair gene MYH has been identified to cause a novel autosomal recessive form of familial adenomatous polyposis （FAP）. Interestingly, a striking evidence for MYH mutations within different ethnic groups has been demonstrated. In this study, we screened 30 patients with multiple adenomatous polyps for MYH mutations to assess its prevalence and ethnic specificity in Korea. METHODS： Thirty patients （21 men and 9 women; mean age 62.3 years） with multiple adenomatous polyps were examined for MYH mutations. The mean number of adenomas per patient was 10.0. Sixteen exonic regions and their intronic sequences were amplified by PCR and subjected to SSCP and DNA sequencing analyses. RESULTS： None of the patients was identified to carry any truncating or sequence alterations in MYH. Our screening for the mutational regions, which were recognized from Caucasian patients or affected Indian families, also failed to detect sequence substitutions. CONCLUSION： Mutation in MYHmay be rarely involved in the pathogenesis of multiple sporadic colorectal adenomas in Korean population, although a large-scale analysis will be required to clarify the presence of specific MYH variants in a subset of patients and their role in the predisposition of multiple colorectal adenomas in Korean population.