Diagnostic performance of volumetric laser endomicroscopy for Barrett's esophagus dysplasia amongst gastroenterology trainees.

BACKGROUND: Volumetric laser endomicroscopy (VLE) is an advanced imaging modality used in Barrett's esophagus (BE) surveillance. VLE image interpretation is challenged by subtle grayscale image variation across a large amount of data. Training in VLE interpretation is not standardized. This study aims to determine if VLE training can be incorporated into a gastroenterology (GI) fellowship curriculum with the use of a self-directed module. METHODS: A standardized, self-directed training module (30 min) was created explaining the background and established VLE criteria for the diagnosis of BE dysplasia. A VLE image dataset was generated from a multicenter VLE database of targeted biopsies. GI trainees were asked to grade each image for the presence or absence of the following criteria (I) increased surface optical frequency domain imaging (OFDI) signal intensity and (II) atypical glands and provide a final diagnosis (dysplastic vs. non-dysplastic). Diagnostic performance was calculated and results compared to VLE expert interpretation using histology as the gold-standard. RESULTS: The dataset included 50 VLE images (10 high-grade dysplasia, 40 non-dysplastic BE). VLE images were reviewed in a randomized and blinded fashion by 5 GI trainees with no prior VLE experience and 5 experienced VLE users. Sensitivity, specificity and accuracy of GI trainees was 83.3% (95% CI: 71.5-91.7%), 59.0% (95% CI: 51.6-66.0%), and 64.8% (95% CI: 58.5-70.7%) compared to 80.0% (95% CI: 67.7-89.2%), 79.5% (95% CI: 73.0-85.0%), and 79.6% (95% CI: 74.1-84.4%) for VLE experts respectively. The difference in specificity and accuracy between the two groups were statistically significant with P<0.001. CONCLUSIONS: A brief training session on VLE is inadequate to reach competency in interpretation of VLE by GI trainees. Additional experience is required to accurately interpret VLE images.

Randomized Controlled Trial of Self-directed Versus In-Classroom Education of Narrow Band Imaging in Diagnosing Colorectal Polyps Using the NICE Criteria.

BACKGROUND: The optimal method for teaching NBI International Colorectal Endoscopic (NICE) criteria to medical trainees is unknown. METHODS: Trainees (medical students, residents, and gastroenterology fellows) were randomized to 2 groups (in-classroom vs. self-directed training). Teaching phase: A standardized presentation was developed about narrow band imaging (NBI) and NICE criteria. The in-class teaching group attended a single live-teaching session (with NBI expert). The self-directed training group was provided with the same educational tool with recorded audio. Testing phase: All participants provided their predicted histology and their level of confidence. After completing initial 10 clips, the in-class teaching group received live feedback (NBI expert), whereas the self-teaching group received automated audio feedback. All participants then reviewed the next 30 NBI videos. The diagnostic performance of NBI in predicting histology was compared between the 2 groups. RESULTS: Twenty medical trainees (8 students, 8 residents, and 4 gastroenterology fellows) participated in the study. The overall accuracy, sensitivity, specificity, and negative predictive value in using NBI to predict histology were: 79.0% [95% confidence interval (CI), 76.2-81.8], 69.5% (95% CI, 65.0-74.0), 88.5% (95% CI, 85.3-91.6), and 74.4% (95% CI, 70.4-78.3). There were no significant differences in the performance characteristics between the in-classroom and self-directed groups for all responses including those answered with high confidence. CONCLUSIONS: Using a standardized educational tool, the accuracy of distinguishing adenomatous versus hyperplastic colon polyps using NBI between the in-class teaching and self-directed learning were similar. This suggests that both training methods can be utilized for the education of medical trainees in the use of NICE criteria.

Validation of Probe-based Confocal Laser Endomicroscopy (pCLE) Criteria for Diagnosing Colon Polyp Histology.

BACKGROUND: Validated probe-based confocal endomicroscopy (pCLE) criteria for distinguishing hyperplastic polyps (HPs) and tubular adenomas (TA) have not yet been developed. AIM: To develop pCLE criteria for distinguishing HP from TA and evaluate its performance characteristics among experts. METHODS: pCLE criteria for colon polyp histology were developed and tested in 2 phases prospectively. Phase I: 8 preliminary criteria were developed and tested internally. Criteria achieving an accuracy of >75% (epithelial surface: regular vs. irregular; goblet cells: increased vs. decreased; gland axis: horizontal vs. vertical; gland shape: slit/stellate vs. villiform; image scale: gray vs. dark) were evaluated in Phase II of study wherein external assessors evaluated these criteria in a separate set of pCLE videos. Accuracy and interobserver agreement (95% confidence intervals) were determined for colon histology prediction. RESULTS: Phase I (criteria development/internal testing): 8 criteria were assessed by 4 pCLE experts using 28 videos (14 HP/14 TA). Five of 8 pCLE criteria met selection for phase II (accuracy >75%). Phase II (external validation): 36 pCLE colon polyp videos (HP 16/TA 20) were evaluated by 8 external assessors. Overall accuracy in diagnosis of colon polyp histology was 84.9% (95% confidence interval, 81.7-87.7). Of predictions made with high confidence (75%), histology was predicted with an accuracy of 91%, sensitivity 83%, specificity 100%, negative predictive value 87% and positive predictive value 98%. Interobserver agreement was substantial (κ=0.73). CONCLUSIONS: We demonstrate the development and validation of pCLE criteria for prediction of colon polyp histology. Using these criteria, overall accuracy in differentiating TA from HP was high with substantial interobserver agreement.

Esophageal Cancer.

Esophageal cancer carries a poor prognosis among gastrointestinal malignancies. Although esophageal squamous cell carcinoma predominates worldwide, Western nations have seen a marked rise in the incidence of esophageal adenocarcinoma that parallels the obesity epidemic. Efforts directed toward early detection have been difficult, given that dysplasia and early cancer are generally asymptomatic. However, significant advances have been made in the past 10 to 15 years that allow for endoscopic management and often cure in early stage esophageal malignancy. New diagnostic imaging technologies may provide a means by which cost-effective, early diagnosis of dysplasia allows for definitive therapy and ultimately improves the overall survival among patients.

Effectiveness of focal vs. balloon radiofrequency ablation devices in the treatment of Barrett's esophagus.

BACKGROUND AND AIMS: The safety and efficacy of radiofrequency ablation (RFA) in treatment of Barrett's esophagus (BE)-associated dysplasia has been well established. The effectiveness of focal and balloon RFA devices has not been compared. Therefore, the aim of our study was to assess the effectiveness of focal and balloon RFA devices in the treatment of BE by calculating absolute and percentage change in BE length with RFA therapy by comparing pre- and post-treatment BE length. PATIENTS AND METHODS: This is a retrospective cross-sectional study of patients who underwent at least one treatment with either focal and/or balloon RFA devices who were identified from two tertiary centers. Patients' demographics, hiatal hernia, pre- and post-treatment BE length, prior use of endoscopic therapies and number of sessions were recorded. RESULTS: Sixty-one patients who had undergone 161 RFA treatment sessions met inclusion criteria. There was no significant difference in percentage change in BE length with greater number of RFA sessions. RFA with a focal device resulted in greater percentage reduction in BE length compared to the balloon system (73% vs. 39%, p < 0.01). After adjusting for initial BE length, pre-treatment BE length, hernia status, prior endoscopic mucosal resection (EMR), prior RFA, and prior EMR/RFA sessions, RFA with a focal device at each session remained an independent predictor for a significant reduction in BE extent as compared to the balloon system. CONCLUSION: The focal RFA device alone was more effective in treatment of BE compared to the balloon system, with a greater reduction in extent of BE. The focal RFA device for endoscopic eradication therapy of BE should be considered the preferred technique.

Maize hybrids derived from GM positive and negative segregant inbreds are compositionally equivalent: any observed differences are associated with conventional backcrossing practices.

In this study, we show that compositional differences in grain harvested from genetically modified (GM) maize hybrids derived from near-isogenic trait-positive and trait-negative segregant inbreds are more likely related to backcrossing practices than to the GM trait. To demonstrate this, four paired GM trait-positive (NK603: herbicide tolerance) and trait-negative near-isogenic inbred male lines were generated. These were crossed with two different females (testers) to create a series of trait-positive and trait-negative hybrid variants. The hypothesis was, that compositional variation within the hybrid variants would reflect differences associated with backcrossing practices and provide context to any observed differences between GM and non-GM hybrids. The F1 hybrids, as well as corresponding conventional comparator hybrids, were grown concurrently at four field sites across the United States during the 2013 season. Grain was harvested for compositional analysis; proximates (protein, starch, and oil), amino acids, fatty acids, minerals, tocopherols (α-, δ-, γ-), ß-carotene, phytic acid, and raffinose were measured. Statistical analysis showed that within each hybrid tester set, there were very few significant (p < 0.05) differences between the paired trait-positive and trait-negative hybrids or between the conventional comparators and the trait-positive or trait-negative hybrids. Assessments of the magnitudes of differences and variance component analysis highlighted that growing location, and the tester used in hybrid formation, had a markedly greater effect on composition than did the GM trait. Significantly, for each tester set, compositional differences within the trait-positive and trait-negative hybrid variants were greater than differences between the GM and non-GM comparators. Overall, GM trait insertion is not intrinsically a meaningful contributor to compositional variation, and observed differences between GM and non-GM comparators typically reflect incidental changes associated with conventional breeding practices. These results contribute to ongoing discussions on the relevance of negative segregants as comparators in GM assessments.

Development and Validation of a Classification System to Identify High-Grade Dysplasia and Esophageal Adenocarcinoma in Barrett's Esophagus Using Narrow-Band Imaging.

BACKGROUND & AIMS: Although several classification systems have been proposed for characterization of Barrett's esophagus (BE) surface patterns based on narrow-band imaging (NBI), none have been widely accepted. The Barrett's International NBI Group (BING) aimed to develop and validate an NBI classification system for identification of dysplasia and cancer in patients with BE. METHODS: The BING working group, composed of NBI experts from the United States, Europe, and Japan, met to develop a validated, consensus-driven NBI classification system for identifying dysplasia and cancer in BE. The group reviewed 60 NBI images of nondysplastic BE, high-grade dysplasia, and esophageal adenocarcinoma to characterize mucosal and vascular patterns visible by NBI; these features were used to develop the BING criteria. We then recruited adult patients undergoing surveillance or endoscopic treatment for BE at 4 institutions in the United States and Europe, obtaining high-quality NBI images and performing histologic analysis of biopsies. Experts individually reviewed 50 NBI images to validate the BING criteria, and then evaluated 120 additional NBI images (not previously viewed) to determine whether the criteria accurately predicted the histology results. RESULTS: The BING criteria identified patients with dysplasia with 85% overall accuracy, 80% sensitivity, 88% specificity, 81% positive predictive value, and 88% negative predictive value. When dysplasia was identified with a high level of confidence, these values were 92%, 91%, 93%, 89%, and 95%, respectively. The overall strength of inter-observer agreement was substantial (κ = 0.681). CONCLUSIONS: The BING working group developed a simple, internally validated system to identify dysplasia and EAC in patients with BE based on NBI results. When images are assessed with a high degree of confidence, the system can classify BE with >90% accuracy and a high level of inter-observer agreement.

In-class didactic versus self-directed teaching of the probe-based confocal laser endomicroscopy (pCLE) criteria for Barrett's esophagus.

BACKGROUND AND AIMS: Optimal teaching methods for disease recognition using probe-based confocal laser endomicroscopy (pCLE) have not been developed. Our aim was to compare in-class didactic teaching vs. self-directed teaching of Barrett's neoplasia diagnosis using pCLE. METHODS: This randomized controlled trial was conducted at a tertiary academic center. Study participants with no prior pCLE experience were randomized to in-class didactic (group 1) or self-directed teaching groups (group 2). For group 1, an expert conducted a classroom teaching session using standardized educational material. Participants in group 2 were provided with the same material on an audio PowerPoint. After initial training, all participants graded an initial set of 20 pCLE videos and reviewed correct responses with the expert (group 1) or on audio PowerPoint (group 2). Finally, all participants completed interpretations of a further 40 videos. RESULTS: Eighteen trainees (8 medical students, 10 gastroenterology trainees) participated in the study. Overall diagnostic accuracy for neoplasia prediction by pCLE was 77 % (95 % confidence interval [CI] 74.0 % - 79.2 %); of predictions made with high confidence (53 %), the accuracy was 85 % (95 %CI 81.8 % - 87.8 %). The overall accuracy and interobserver agreement was significantly higher in group 1 than in group 2 for all predictions (80.4 % vs. 73 %; P = 0.005) and for high confidence predictions (90 % vs. 80 %; P < 0.001). Following feedback (after the initial 20 videos), the overall accuracy improved from 73 % to 79 % (P = 0.04), mainly driven by a significant improvement in group 1 (74 % to 84 %; P < 0.01). Accuracy of prediction significantly improved with time in endoscopy training (72 % students, 77 % FY1, 82 % FY2, and 85 % FY3; P = 0.003). CONCLUSION: For novice trainees, in-class didactic teaching enables significantly better recognition of the pCLE features of Barrett's esophagus than self-directed teaching. The in-class didactic group had a shorter learning curve and were able to achieve 90 % accuracy for their high confidence predictions.

Limitations of endoscopic ablation in Barrett's esophagus.

In the last 5-10 years, endoscopic ablative therapies have been gaining ground as treatment for Barrett's esophagus associated with high-grade dysplasia and early cancer, and they are becoming the most preferred technique over surgery as the standard of care. These therapies are associated with a lower rate of complications and mortality than surgery; studies have found them to be safe, effective and tolerable. Endoscopic ablative therapies are not, however, without their drawbacks. There is a paucity of data on long-term efficacy, and direct comparisons of the different modalities are lacking. Unlike surgery, current data suggest that endoscopic ablation treatments may not be curative in all patients, so patients require ongoing surveillance and acid suppression. Questions remain regarding durability as well as factors promoting recurrence after endoscopic therapy. The authors conducted a systematic review of the literature on ablative therapies in Barrett's esophagus to describe the modalities currently available and to provide an understanding of their limitations.

Incidence of pancreatic fistula after distal pancreatectomy and efficacy of endoscopic therapy for its management: results from a tertiary care center.

Pancreatic fistula is a known complication of distal pancreatectomy. Endotherapy with pancreatic duct stent placement and pancreatic sphincterotomy has been shown to be effective in its management; however, experience of endotherapy in the management of this complication has not been extensively reported from the United States. Preoperative endoscopic retrograde cholangiopancreatography (ERCP) with pancreatic stent placement has also been proposed to prevent this complication after distal pancreatectomy. In our cohort of 59 patients who underwent distal pancreatectomy, 13 (22%) developed a pancreatic fistula in the immediate postoperative period, of whom 8 (14%) patients (5 female, mean age 52 years) were referred for an ERCP because of ongoing symptoms related to the pancreatic fistula. The pancreatic fistula resolved in all patients after a median duration of 62 days from the index ERCP. The median number of ERCPs required to document resolution of the pancreatic fistula was 2. Although a sizeable percentage of patients develop a pancreatic fistula after distal pancreatectomy, only a small percentage of patients require ERCP for management of this complication. Given the high success rate of endotherapy in resolving pancreatic fistula and the fact that the majority of patients who undergo distal pancreatectomy never require an ERCP, performing ERCP for prophylactic pancreatic duct stent prior to distal pancreatectomy might not be necessary.

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.