A machine learning-based choledocholithiasis prediction tool to improve ERCP decision making: a proof-of-concept study.

BACKGROUND: Previous studies demonstrated limited accuracy of existing guidelines for predicting choledocholithiasis, leading to overutilization of endoscopic retrograde cholangiopancreatography (ERCP). More accurate stratification may improve patient selection for ERCP and allow use of lower-risk modalities. METHODS: A machine learning model was developed using patient information from two published cohort studies that evaluated performance of guidelines in predicting choledocholithiasis. Prediction models were developed using the gradient boosting model (GBM) machine learning method. GBM performance was evaluated using 10-fold cross-validation and area under the receiver operating characteristic curve (AUC). Important predictors of choledocholithiasis were identified based on relative importance in the GBM. RESULTS: 1378 patients (mean age 43.3 years; 61.2% female) were included in the GBM and 59.4% had choledocholithiasis. Eight variables were identified as predictors of choledocholithiasis. The GBM had accuracy of 71.5% (SD 2.5%) (AUC 0.79 [SD 0.06]) and performed better than the 2019 American Society for Gastrointestinal Endoscopy (ASGE) guidelines (accuracy 62.4% [SD 2.6%]; AUC 0.63 [SD 0.03]) and European Society of Gastrointestinal Endoscopy (ESGE) guidelines (accuracy 62.8% [SD 2.6%]; AUC 0.67 [SD 0.02]). The GBM correctly categorized 22% of patients directed to unnecessary ERCP by ASGE guidelines, and appropriately recommended as the next management step 48% of ERCPs incorrectly rejected by ESGE guidelines. CONCLUSIONS: A machine learning-based tool was created, providing real-time, personalized, objective probability of choledocholithiasis and ERCP recommendations. This more accurately directed ERCP use than existing ASGE and ESGE guidelines, and has the potential to reduce morbidity associated with ERCP or missed choledocholithiasis.

ASGE guideline on the role of endoscopy in the management of benign and malignant gastroduodenal obstruction.

This American Society for Gastrointestinal Endoscopy guideline provides evidence-based recommendations for the endoscopic management of gastric outlet obstruction (GOO). We applied the Grading of Recommendations, Assessment, Development and Evaluation methodology to address key clinical questions. These include the comparison of (1) surgical gastrojejunostomy to the placement of self-expandable metallic stents (SEMS) for malignant GOO, (2) covered versus uncovered SEMS for malignant GOO, and (3) endoscopic and surgical interventions for the management of benign GOO. Recommendations provided in this document were founded on the certainty of the evidence, balance of benefits and harms, considerations of patient and caregiver preferences, resource utilization, and cost-effectiveness.

Colonoscopy competence assessment tools: a systematic review of validity evidence.

BACKGROUND: Assessment tools are essential for endoscopy training, being required to support feedback provision, optimize learner capabilities, and document competence. We aimed to evaluate the strength of validity evidence that supports the available colonoscopy direct observation assessment tools using the unified framework of validity. METHODS: We systematically searched five databases for studies investigating colonoscopy direct observation assessment tools from inception until 8 April 2020. We extracted data outlining validity evidence (content, response process, internal structure, relations to other variables, and consequences) from the five sources and graded the degree of evidence, with a maximum score of 15. We assessed educational utility using an Accreditation Council for Graduate Medical Education framework and methodological quality using the Medical Education Research Quality Instrument (MERSQI). RESULTS: From 10 841 records, we identified 27 studies representing 13 assessment tools (10 adult, 2 pediatric, 1 both). All tools assessed technical skills, while 10 each assessed cognitive and integrative skills. Validity evidence scores ranged from 1-15. The Assessment of Competency in Endoscopy (ACE) tool, the Direct Observation of Procedural Skills (DOPS) tool, and the Gastrointestinal Endoscopy Competency Assessment Tool (GiECAT) had the strongest validity evidence, with scores of 13, 15, and 14, respectively. Most tools were easy to use and interpret, and required minimal resources. MERSQI scores ranged from 9.5-11.5 (maximum score 14.5). CONCLUSIONS: The ACE, DOPS, and GiECAT have strong validity evidence compared with other assessments. Future studies should identify barriers to widespread implementation and report on the use of these tools in credentialing examinations.

American Society for Gastrointestinal Endoscopy guideline on the role of endoscopy in the management of acute colonic pseudo-obstruction and colonic volvulus.

Colonic volvulus and acute colonic pseudo-obstruction (ACPO) are 2 causes of benign large-bowel obstruction. Colonic volvulus occurs most commonly in the sigmoid colon as a result of bowel twisting along its mesenteric axis. In contrast, the exact pathophysiology of ACPO is poorly understood, with the prevailing hypothesis being altered regulation of colonic function by the autonomic nervous system resulting in colonic distention in the absence of mechanical blockage. Prompt diagnosis and intervention leads to improved outcomes for both diagnoses. Endoscopy may play a role in the evaluation and management of both entities. The purpose of this document from the American Society for Gastrointestinal Endoscopy's Standards of Practice Committee is to provide an update on the evaluation and endoscopic management of sigmoid volvulus and ACPO.

American Society for Gastrointestinal Endoscopy guideline on the role of endoscopy in familial adenomatous polyposis syndromes.

Familial adenomatous polyposis (FAP) syndrome is a complex entity, which includes FAP, attenuated FAP, and MUTYH-associated polyposis. These patients are at significant risk for colorectal cancer and carry additional risks for extracolonic malignancies. In this guideline, we reviewed the most recent literature to formulate recommendations on the role of endoscopy in this patient population. Relevant clinical questions were how to identify high-risk individuals warranting genetic testing, when to start screening examinations, what are appropriate surveillance intervals, how to identify endoscopically high-risk features, and what is the role of chemoprevention. A systematic literature search from 2005 to 2018 was performed, in addition to the inclusion of seminal historical studies. Most studies were from worldwide registries, which have compiled years of data regarding the natural history and cancer risks in this cohort. Given that most studies were retrospective, recommendations were based on epidemiologic data and expert opinion. Management of colorectal polyps in FAP has not changed much in recent years, as colectomy in FAP is the standard of care. What is new, however, is the developing body of literature on the role of endoscopy in managing upper GI and small-bowel polyposis, as patients are living longer and improved endoscopic technologies have emerged.

ASGE guideline on minimum staffing requirements for the performance of GI endoscopy.

Efforts to increase patient safety and satisfaction, a critical concern for health providers, require periodic evaluation of all factors involved in the provision of GI endoscopy services. We aimed to develop guidelines on minimum staffing requirements and scope of practice of available staff for the safe and efficient performance of GI endoscopy. The recommendations in this guideline were based on a systematic review of published literature, results from a nationwide survey of endoscopy directors, along with the expert guidance of the American Society for Gastrointestinal Endoscopy (ASGE) Standards of Practice Committee members, ASGE Practice Operation Committee members, and the ASGE Governing Board.

ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis.

Each year choledocholithiasis results in biliary obstruction, cholangitis, and pancreatitis in a significant number of patients. The primary treatment, ERCP, is minimally invasive but associated with adverse events in 6% to 15%. This American Society for Gastrointestinal Endoscopy (ASGE) Standard of Practice (SOP) Guideline provides evidence-based recommendations for the endoscopic evaluation and treatment of choledocholithiasis. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to rigorously review and synthesize the contemporary literature regarding the following topics: EUS versus MRCP for diagnosis, the role of early ERCP in gallstone pancreatitis, endoscopic papillary dilation after sphincterotomy versus sphincterotomy alone for large bile duct stones, and impact of ERCP-guided intraductal therapy for large and difficult choledocholithiasis. Comprehensive systematic reviews were also performed to assess the following: same-admission cholecystectomy for gallstone pancreatitis, clinical predictors of choledocholithiasis, optimal timing of ERCP vis-à-vis cholecystectomy, management of Mirizzi syndrome and hepatolithiasis, and biliary stent therapy for choledocholithiasis. Core clinical questions were derived using an iterative process by the ASGE SOP Committee. This body developed all recommendations founded on the certainty of the evidence, balance of risks and harms, consideration of stakeholder preferences, resource utilization, and cost-effectiveness.

ASGE guideline on the role of endoscopy for bleeding from chronic radiation proctopathy.

Chronic radiation proctopathy is a common sequela of radiation therapy for malignancies in the pelvic region. A variety of medical and endoscopic therapies have been used for the management of bleeding from chronic radiation proctopathy. In this guideline, we reviewed the results of a systematic search of the literature from 1946 to 2017 to formulate clinical questions and recommendations on the role of endoscopy for bleeding from chronic radiation proctopathy. The following endoscopic modalities are discussed in our document: argon plasma coagulation, bipolar electrocoagulation, heater probe, radiofrequency ablation, and cryoablation. Most studies were small observational studies, and the evidence for effectiveness of endoscopic therapy for chronic radiation proctopathy was limited because of a lack of controlled trials and comparative studies. Despite this limitation, our systematic review found that argon plasma coagulation, bipolar electrocoagulation, heater probe, and radiofrequency ablation were effective in the treatment of rectal bleeding from chronic radiation proctopathy.

Prevalence of advanced histological features and synchronous neoplasia in patients with flat adenomas.

BACKGROUND AND AIMS: The prevalence of advanced histology in flat adenomas is uncertain. There are limited data on the prevalence of synchronous adenomas in patients with flat adenomas. The aims of this study were to determine whether the flat adenomas harbor advanced histology more than the polypoid adenomas and whether the presence of flat adenomas is an independent predictor of synchronous adenomas. METHODS: A retrospective analysis of data from 3 prospective clinical trials conducted at 2 tertiary care referral centers that included patients undergoing screening or surveillance colonoscopy was performed. The location, size, and morphology of each polyp resected was documented and sent for histopathological examination in a unique specimen jar. RESULTS: A total of 2931 polyps were removed in 1340 patients. Of the 1911 adenomas (65.2%), 293 (15.3%) were flat and 1618 (84.7%) were polypoid. The prevalence of advanced histology did not differ between flat and polypoid adenomas (1.4% vs 3.1%; P = .13). Multivariate analysis confirmed that the presence of at least 1 flat adenoma was a predictor of the presence of a large adenoma (P < .01; odds ratio [OR], 2.80; 95% CI, 1.86-4.22), advanced adenoma (P < .01; OR, 2.70; 95% CI, 1.80-4.06), and 3 or more adenomas (P < .01; OR, 2.44; 95% CI, 1.66-3.59). CONCLUSION: Although the prevalence of advanced histology in flat adenomas is similar to that of polypoid adenomas, flat adenomas are associated with increased prevalence of synchronous large and advanced adenomas. Whether these results imply shorter surveillance intervals in patients with flat adenomas needs to be explored in future studies.

Trainee participation and adenoma detection rates during screening colonoscopies.

GOAL: To evaluate whether participation of a gastroenterology trainee had an impact on adenoma detection rate (ADR) during screening colonoscopies performed with standard-definition colonoscopes (SD-C) versus high-definition colonoscopes (HD-C). BACKGROUND: ADR is an established quality indicator of colonoscopy and efforts to improve ADR have led to technological advancements including HD-C that have a greater angle of view and produce an image with higher pixel density compared with SD-C. Moreover, other factors like trainee participation have been shown to improve adenoma detection. METHODS: This is a retrospective review of screening colonoscopies performed during 2 different time periods by 4 experienced endoscopists with or without trainee participation. There are 2 arms of this study, based on whether screening colonoscopy was performed using SD-C or HD-C. Detailed review of endoscopy and histopathologic reports was conducted. Statistical analysis was performed and odds ratio and incidence rate ratios were calculated to adjust for numerous factors. RESULTS: No significant differences were seen with trainee participation in the SD-C arm of the study. In the HD-C arm, the total number, and the proportion of subjects with: adenomas, diminutive adenomas, and right-sided adenomas were significantly higher with trainee participation. CONCLUSIONS: Trainee participation significantly improved the overall adenoma detection, specifically diminutive adenoma and right-sided adenoma detection, but only when colonoscopies were performed with HD-C. The improved image quality and resolution provided by HD-C, coupled with enhanced visual scanning an additional pair of eyes provides, may account for the differential impact of trainee participation on ADR.

Standard endoscopy with random biopsies versus narrow band imaging targeted biopsies in Barrett's oesophagus: a prospective, international, randomised controlled trial.

BACKGROUND: White light endoscopy with random biopsies is the standard for detection of intestinal metaplasia (IM) and neoplasia in patients with Barrett's oesophagus (BO). Narrow band imaging (NBI) highlights surface patterns that correlate with IM and neoplasia in BO. OBJECTIVE: To compare high-definition white light (HD-WLE) and NBI for detection of IM and neoplasia in BO. DESIGN: International, randomised, crossover trial comparing HD-WLE and NBI. Patients referred for BO screening/surveillance at three tertiary referral centres were prospectively enrolled and randomised to HD-WLE or NBI followed by other procedures in 3-8 weeks. During HD-WLE, four quadrant biopsies every 2 cm, together with targeted biopsies of visible lesions (Seattle protocol), were obtained. During NBI examination, mucosal and vascular patterns were noted and targeted biopsies were obtained. All biopsies were read by a single expert gastrointestinal pathologist in a blinded fashion. RESULTS: 123 patients with BO (mean age 61; 93% male; 97% Caucasian) with mean circumferential and maximal extents of 1.8 and 3.6 cm, respectively, were enrolled. Both HD-WLE and NBI detected 104/113 (92%) patients with IM, but NBI required fewer biopsies per patient (3.6 vs 7.6, p<0.0001). NBI detected a higher proportion of areas with dysplasia (30% vs 21%, p=0.01). During examination with NBI, all areas of high-grade dysplasia and cancer had an irregular mucosal or vascular pattern. CONCLUSIONS: NBI targeted biopsies can have the same IM detection rate as an HD-WLE examination with the Seattle protocol while requiring fewer biopsies. In addition, NBI targeted biopsies can detect more areas with dysplasia. Regular appearing NBI surface patterns did not harbour high-grade dysplasia/cancer, suggesting that biopsies could be avoided in these areas.

Association between length of Barrett's esophagus and risk of high-grade dysplasia or adenocarcinoma in patients without dysplasia.

BACKGROUND & AIMS: It is not clear whether length of Barrett's esophagus (BE) is a risk factor for high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in patients with nondysplastic BE. We studied the risk of progression to HGD or EAC in patients with nondysplastic BE, based on segment length. METHODS: We analyzed data from a large cohort of patients participating in the BE Study-a multicenter outcomes project comprising 5 US tertiary care referral centers. Histologic changes were graded as low-grade dysplasia, HGD, or EAC. The study included patients with BE of documented length without dysplasia and at least 1 year of follow-up evaluation (n = 1175; 88% male), and excluded patients who developed HGD or EAC within 1 year of their BE diagnosis. The mean follow-up period was 5.5 y (6463 patient-years). The annual risk of HGD and EAC was plotted in 3-cm increments (≤3 cm, 4-6 cm, 7-9 cm, 10-12 cm, and ≥13 cm). We calculated the association between time to progression and length of BE. RESULTS: The mean BE length was 3.6 cm; 44 patients developed HGD or EAC, with an annual incidence rate of 0.67%/y. Compared with nonprogressors, patients who developed HGD or EAC had longer BE segments (6.1 vs 3.5 cm; P < .001). Logistic regression analysis showed a 28% increase in risk of HGD or EAC for every 1-cm increase in BE length (P = .01). Patients with BE segment lengths of 3 cm or shorter took longer to develop HGD or EAC than those with lengths longer than 4 cm (6 vs 4 y; P = nonsignificant). CONCLUSIONS: In patients with BE without dysplasia, length of BE was associated with progression to HGD or EAC. The results support the development of a risk stratification scheme for these patients based on length of BE segment.

Clinical utility and interobserver agreement of autofluorescence imaging and magnification narrow-band imaging for the evaluation of Barrett's esophagus: a prospective tandem study.

BACKGROUND: New endoscopic imaging techniques, such as autofluorescence imaging (AFI) and narrow-band imaging (NBI), have been developed to improve the detection of neoplastic lesions in Barrett's esophagus (BE). OBJECTIVE: To evaluate the clinical utility of AFI and magnification NBI to detect high-grade dysplasia (HGD) and early esophageal adenocarcinoma (EAC) and the interobserver agreement. DESIGN: Prospective tandem study of eligible patients. SETTING: Single, academic tertiary care center. PATIENTS: Forty-two patients with a history of confirmed BE were prospectively enrolled. INTERVENTIONS: The BE segment was examined under high-definition white-light endoscopy, and the presence of visible lesions was recorded. Subsequently, AFI and magnification NBI were performed in tandem on areas of the BE segment away from visible lesions; images obtained by these 2 systems were graded according to the color of reflected light and surface patterns, respectively. Biopsy specimens were obtained at the end of the procedure. MAIN OUTCOME MEASUREMENTS: The sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of the AFI and NBI patterns for the detection of HGD/EAC and interobserver agreement. RESULTS: Of the 42 patients enrolled, 14 (33%) had HGD/EAC. On patient-based analysis, AFI alone had a sensitivity, specificity, and NPV of 50%, 61%, and 71%, respectively, and the overall accuracy for the detection of HGD/EAC patients was 57%. By using magnification NBI in tandem fashion, the sensitivity and NPV improved to 71% and 76%, respectively, with a decrease in specificity to 46% and in overall accuracy to 55%. The 2 techniques had moderate interobserver agreement for both the patterns and prediction of histology. LIMITATIONS: Uncontrolled study performed at an academic center by expert endoscopists in a high-risk population. CONCLUSIONS: By using a multimodality endoscope, both AFI and magnification NBI had limited clinical accuracy and moderate overall interobserver agreement. AFI does not appear to be useful as a broad-based technique for the detection of neoplasia in patients with BE.

Higher adenoma detection rates with cap-assisted colonoscopy: a randomised controlled trial.

OBJECTIVE: Cap-assisted colonoscopy (CAC) uses a small plastic transparent cap attached to the tip of the colonoscope that can depress and flatten colonic folds and thus improve visualisation of their proximal aspects. The aim of this study was to compare CAC with standard colonoscopy (SC; high-definition white light) for adenoma detection rates. DESIGN: This is a prospective randomised controlled trial. SETTING: The study was performed in a tertiary-care Veterans Affairs Medical Center in the USA. PATIENTS: Subjects undergoing screening or surveillance colonoscopy were enrolled. INTERVENTIONS: Subjects were randomised to undergo either CAC or SC. MAIN OUTCOME MEASURES: The outcome measures were the proportion of subjects with at least one adenoma, the number of adenomas detected per subject, insertion time, caecal intubation rates and complications. RESULTS: 420 subjects were enrolled and included in the study (210 in each group). The proportion of subjects with at least one adenoma was higher with CAC compared to SC (69% vs 56%, p=0.009). CAC also detected a higher number of adenomas per subject (2.3 vs 1.4, p<0.001). The caecal intubation time was shorter with CAC (3.29 min vs 3.98 min, p<0.001). The caecal intubation rates were similar in the two groups (99% vs 98%, p=0.37). There were no complications associated with CAC or SC. CONCLUSIONS: CAC detected a 13% higher number of subjects with at least one adenoma and 59% higher adenomas per subject. CAC is a safe, effective and practical means to improve adenoma detection rates. CLINICAL TRIAL REGISTRATION: NCT 01211132.

Prevalence and predictors of columnar lined esophagus in gastroesophageal reflux disease (GERD) patients undergoing upper endoscopy.

OBJECTIVES: Chronic gastroesophageal reflux disease (GERD) is a risk factor for Barrett's esophagus (BE), the most important surrogate marker for the development of esophageal adenocarcinoma (EAC). The need to document the presence of intestinal metaplasia in esophageal biopsies from a columnar lined esophagus (CLE) to diagnose BE is debated. The objective of this study was to prospectively evaluate the prevalence and risk factors of CLE in a large cohort of GERD patients undergoing upper endoscopy. METHODS: Consecutive patients presenting to the endoscopy unit at a tertiary referral center for their index upper endoscopy for evaluation of GERD symptoms were enrolled in this prospective cohort study. Patients were asked to complete a validated GERD questionnaire that documents the onset of GERD symptoms (heartburn and acid regurgitation) and grades the frequency and severity of symptoms experienced over the past year. Demographic information, body mass index, and use of aspirin/nonsteroidal antiinflammatory drugs were recorded. Endoscopic details including length of CLE, presence and size of hiatal hernia were noted. Patients with CLE (cases) were compared with those without CLE (controls) using Fischer's exact test and t-test. All factors that were statistically significant (P<0.05) were then entered into stepwise logistic regression to evaluate for independent predictors of CLE. RESULTS: A total of 1058 patients with GERD symptoms were prospectively enrolled. On index endoscopy, the prevalence of CLE was 23.3%, whereas of CLE with documented intestinal metaplasia was 14.1%. On univariate analysis, male gender, Caucasian race, heartburn duration of >5 years, presence and size of hiatal hernia were significantly associated with the presence of CLE compared with controls (P<0.05). On multivariate analysis, heartburn duration >5 years (odds ratio (OR): 1.50, 95% confidence interval (CI): 1.07-2.09, P=0.01), Caucasian race (OR: 2.40, 95% CI: 1.42-4.03, P=0.001), and hiatal hernia (OR: 2.07, 95% CI: 1.50-2.87, P<0.01) were found to be independent predictors for CLE. CLE length was significantly associated with the presence of intestinal metaplasia (P<0.001). CONCLUSIONS: If BE is defined by the presence of CLE alone on upper endoscopy, up to 25% of GERD patients are diagnosed with this lesion. Enrolling all these patients in surveillance programs would have significant ramifications on health-care resources.

Longer inspection time is associated with increased detection of high-grade dysplasia and esophageal adenocarcinoma in Barrett's esophagus.

BACKGROUND: Current guidelines recommend that endoscopic surveillance of Barrett's esophagus (BE) be performed by using a strict biopsy protocol. However, novel methods to improve BE surveillance are still needed. OBJECTIVE: To evaluate the impact of Barrett's inspection time (BIT) on yield of surveillance. DESIGN: Post hoc analysis of data obtained from a clinical trial. SETTING: Five tertiary referral centers. PATIENTS: Patients undergoing BE surveillance. INTERVENTIONS: Coordinators prospectively recorded the time spent inspecting the BE mucosa with a stopwatch. MAIN OUTCOME MEASUREMENTS: Endoscopically suspicious lesions, high-grade dysplasia (HGD)/esophageal adenocarcinoma (EAC). RESULTS: A total of 112 patients underwent endoscopic surveillance by 11 individual endoscopists. Patients with longer BITs were more likely to have an endoscopically suspicious lesion (P < .001) and more endoscopically suspicious lesions (P = .0001) and receive a diagnosis of HGD/EAC (P = .001). There was a direct correlation between the endoscopist's mean BIT per centimeter of BE and the detection of patients with HGD/EAC (ρ = .63, P = .03). Endoscopists who had an average BIT longer than 1 minute per centimeter of BE detected more patients with endoscopically suspicious lesions (54.2% vs 13.3%, P = .04), and there was a trend toward a higher detection rate of HGD/EAC (40.2% vs 6.7%, P = .06). LIMITATIONS: Post hoc analysis of an enriched study population and experienced endoscopists at tertiary referral centers. CONCLUSIONS: Longer time spent inspecting the BE segment is associated with the increased detection of HGD/EAC. Taking additional time to perform a thorough examination of the BE mucosa may serve as an easy and widely available method to improve the yield of BE surveillance.

Prevalence of advanced histological features in diminutive and small colon polyps.

BACKGROUND: Investigators have proposed "predict, resect, and discard" strategies for diminutive (≤ 5 mm) or small (6-9 mm) polyps to reduce screening colonoscopy costs. Advanced histological features such as villous histology, high-grade dysplasia, and/or cancer in these polyps could deter adoption of these strategies. OBJECTIVE: Determine the prevalence of advanced histological features in diminutive and small colon polyps. DESIGN: Retrospective analysis of data from 3 prospective clinical trials. SETTING: Two tertiary-care referral centers. PATIENTS: This study involved patients undergoing screening or surveillance colonoscopy. INTERVENTION: The location, size, and morphology of each polyp detected was documented. Each polyp was then resected, placed in a unique specimen jar, and sent for histopathological evaluation. MAIN OUTCOME MEASUREMENTS: Rates of advanced histological features (villous histology, high-grade dysplasia, and cancer). RESULTS: A total of 2361 polyps were detected, removed, and retrieved. Both diminutive and small polyps had a lower frequency of any advanced histological features compared with large polyps (0.5% and 1.5%, respectively vs 15.0%; P < .001 for both comparisons). Polyps <10 mm in size had a lower frequency of advanced histology compared with polyps ≥ 10 mm (0.8% vs 15.0%; P < .001). During sensitivity analysis, the frequency of advanced histological features varied from 0.2% to 0.7% within diminutive polyps, 1.5% to 3.6% within small polyps, and 0.8% to 1.2% within polyps <10 mm. LIMITATIONS: Retrospective analysis from tertiary-care referral centers; predominantly white, male, veteran patient population resulting in limited generalizability of results. CONCLUSION: The prevalence of advanced histological features in colon polyps ≤ 5 mm is very low (0.5%). This has important implications for the potential practice of "predicting, resecting, and discarding" diminutive colon polyps.

Adequacy of esophageal squamous mucosa specimens obtained during endoscopy: are standard biopsies sufficient for postablation surveillance in Barrett's esophagus?

BACKGROUND: After endoscopic eradication therapy (EET) for Barrett's esophagus (BE), surveillance of residual/recurrent intestinal metaplasia/dysplasia including subsquamous tissue is performed by using biopsy forceps. OBJECTIVE: The goal of this study was to compare the adequacy of biopsy specimens obtained from neo-squamous (post-EET patients) and native (non-BE patients) squamous mucosa. DESIGN: A case-control study using squamous biopsy specimens obtained at 2 tertiary referral centers was conducted. INTERVENTIONS: Two experienced GI pathologists reviewed specimens from patients with neo- (post-EET patients) and native (non-BE patients) squamous mucosa in a blinded fashion after developing standardized criteria to assess tissue depth. MAIN OUTCOME MEASUREMENTS: The primary outcome was the proportion of biopsy specimens that contained any amount of lamina propria. RESULTS: A total of 193 biopsy specimens (1692 tissue pieces) from 104 patients were reviewed: 163 neo- and 30 native squamous. Of all biopsy specimens, only 37% contained any amount of lamina propria, and, furthermore, fewer than 4% of specimens had sufficient lamina propria (ie, more than two thirds of the entire squamous tissue present). When examining individual squamous tissue pieces, fewer than 11% contained lamina propria. No statistically significant differences in the presence of lamina propria were detected between neo- and native squamous mucosa. CONCLUSION: The majority of esophageal squamous biopsy specimens obtained during endoscopy do not demonstrate lamina propria and subepithelial structures. This is true for both neo- and native squamous mucosa. Biopsy specimens of neo-squamous mucosa obtained after EET appear to be inadequate to exclude subsquamous intestinal metaplasia/dysplasia because lamina propria is not present in more than 60% of specimens. This has larger implications in the clinical management of BE patients after EET.