Vijay Kanakadandi

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 Barretts 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.

Inter-Observer Agreement among Pathologists Using Wide-Area Transepithelial Sampling With Computer-Assisted Analysis in Patients With Barrett's Esophagus.

OBJECTIVES:The histopathological diagnosis of Barrett’s esophagus (BE)-associated dysplasia has poor inter-observer agreement. The wide-area transepithelial sampling (WATS) procedure uses a minimally invasive brush biopsy technique for acquiring wide-area sampling of BE tissue followed by computer-assisted analysis. In this study, our aim was to assess inter-observer agreement among pathologists in the diagnosis of Barrett’s-associated dysplasia using the WATS computer-assisted analysis technique.METHODS:WATS slides with varying degrees of BE dysplasia were randomly selected and distributed to four pathologists. Each pathologist graded the slides as nondysplastic, low-grade dysplasia (LGD), or high-grade dysplasia/esophageal adenocarcinoma (HGD/EAC) and completed a standardized case report form (CRF) for each slide.RESULTS:In all, 149 BE slides were evaluated in a blinded manner by 4 pathologists. The slides included the following: no dysplasia (n=109), LGD, and HGD/EAC (n=40). The overall mean kappa value for all 3 diagnoses for the 4 observers was calculated at 0.86 (95% confidence interval (CI) 0.75–0.97). The kappa values (95% CI) for HGD/EAC, IND/LGD, and no dysplasia were 0.95 (0.88–0.99), 0.74 (0.61–0.85), and 0.88 (0.81–0.94), respectively.CONCLUSIONS:The diagnosis of BE and associated dysplasia using the WATS technique has very high inter-observer agreement. This appears to be significantly higher as compared with previously published data using standard histopathology.

Colonic polyps: are we ready to resect and discard?

Colorectal cancer represents a major cause of mortality in Western countries, and population-based colonoscopy screening is supported by official guidelines. A significant determinant of the cost of colonoscopy screening/surveillance is driven by polypectomy of diminutive (≤5 mm) lesions. When considering the low prevalence of advanced neoplasia within diminutive polyps, the additional cost of pathologic examination is mainly justified by the need to differentiate between precancerous adenomatous versus hyperplastic polyps. The aim of this review is to summarize the data supporting the clinical application of a resect and discard strategy, also addressing the potential pitfalls associated with this approach.

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 Barretts 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 Barretts 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.

Cigarette smoking is a modifiable risk factor for Barrett's oesophagus.

Background Cigarette smoking has been associated with an increased risk of oesophageal adenocarcinoma (OAC). However, the impact of smoking and more importantly smoking cessation on Barrett’s oesophagus (BO) is unclear. Objective The aim of the study is to evaluate the association between cigarette smoking and presence of BO in a large prospective cohort of patients with gastro-oesophageal reflux disease (GORD). Methods Patients presenting to the endoscopy unit for upper endoscopy completed a validated GORD questionnaire and information on demographics (age, gender, and ethnicity), cigarette smoking [status (current/past), amount (pack years) and duration of smoking cessation], clinical data [medication history, body mass index (BMI), and family history] and endoscopic findings [BO and hiatal hernia] were recorded. Cigarette smokers (current and past) and nonsmokers were compared using Fisher’s Exact test for categorical variables and Mann–Whitney test for continuous variables. Effects of cigarette smoking and smoking cessation on BO risk was assessed by stepwise logistic regression analysis. Results A total of 1056 patients were included in the analysis [mean age: 57.2 ± 12.7years, Caucasian 880 (83.3%), male 985 (93.3%), and mean BMI 29.6 (SD: ± 5.6)]. 827 (78.3%) were smokers and 229 (21.6%) were nonsmokers. 474 subjects (44.9%) had a previous history of smoking. Anytime smokers were more likely to have BO (adjusted OR: 3.3; 95 CI: 1.7–6.3; p < 0.01). Higher smoking burden (pack years) was associated with higher risk of BO in this GORD cohort (p for trend < 0.01). Duration of smoking cessation was inversely associated with risk of BO (p for trend: 0.01). Conclusion This study shows that smokers with reflux symptoms have about threefold higher risk of BO compared with nonsmokers, whereas discontinuing smoking is associated with a significant reduced risk. Smoking cessation appears to be a viable option to reduce BO risk in patients with reflux disease.

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.

Patterns of antiplatelet agent use in the US

Background: The American Society of Gastrointestinal Endoscopy (ASGE) published updated guidelines in 2009 to help endoscopists manage the treatment of their patients who have been prescribed antiplatelet therapy (APT). Study aim: To assess the use of APT among endoscopists, and to identify factors guiding their use of APT while treating their patients. Method: A survey questionnaire was distributed to endoscopists at two national meetings to assess their usage of APT while treating patients during the peri-endoscopic period. Results: The survey was provided to 400 attendees of whom 239 (60 %) responded. Only 30 % of respondents followed the ASGE guidelines for treating their patients and 26 % percent of respondents withheld all APT before engaging in any patient procedure. Endoscopists’ decisions appeared to be influenced by their own particular experiences rather than any specific APT usage guidelines (46 % vs 22 %; P < 0.05). As expected, more endoscopists (P < 0.05) continued APT for patients who underwent low risk procedures (90 %) than for patients who underwent high risk procedures (47 %). Approximately 50 % of the respondents did not perform high risk procedures for patients prescribed aspirin therapy. Conclusions: About one-fourth of endoscopists surveyed discontinued APT treatment of patients who underwent any endoscopic procedure, and one-half of them discontinued use of non-steroidal anti-inflammatory drug treatment of patients who underwent a high risk endoscopic procedure. Inappropriate withdrawal of APT medications may expose patients to unnecessary risks, and efforts to improve endoscopists’ application of ASGE guidelines for the use of APT to treat patients during the peri-endoscopic period are warranted.

Long-term results of the mucosal ablation of Barrett's esophagus: efficacy and recurrence.

Background and study aims: It has been postulated that the endoscopic ablation of Barrett’s esophagus can lead to complete eradication of the disease. This study was undertaken to evaluate the efficacy of endoscopic eradication therapy for Barrett’s esophagus and the rates of recurrence of intestinal metaplasia. Patients and methods: As part of an initial randomized controlled trial, patients with nondysplastic or low grade dysplastic Barrett’s esophagus underwent mucosal ablation. Following ablation, the patients had annual surveillance endoscopies. Recurrence was defined as the presence of intestinal metaplasia after initial complete eradication had been achieved. Results: A total of 28 patients with Barrett’s esophagus were followed for a mean of 6.4 years after ablation therapy. At baseline, the majority of the patients had nondysplastic Barrett’s esophagus (79 %). Initial complete eradication of intestinal metaplasia was achieved at a mean of 4.1 months. During long-term follow-up, initial recurrence of intestinal metaplasia was seen in 14 of the 28 of patients (50 %) at a mean of 40 months, and further maintenance ablation therapy was applied. At the final follow-up, 36 % of the patients had complete eradication of intestinal metaplasia, 18 % of the patients had intestinal metaplasia, and 21 % had died of unrelated causes; invasive esophageal adenocarcinoma had developed in 1 patient. Conclusions: The long-term results of this study demonstrate a recurrence rate of 50 % after complete eradication of Barrett’s esophagus with endoscopic eradication therapy. In addition, re-recurrence (in 36 %), even after further maintenance endoscopic eradication therapy, and deaths unrelated to the disease (21 %) occurred. Complete remission of Barrett’s esophagus appears to be a difficult goal to achieve. These results call into question the role of ablation in patients with low risk Barrett’s esophagus.

Cap-assisted colonoscopy: a meta-analysis of high-quality randomized controlled trials

Background and study aims  Standard colonoscopy (SC) is the preferred modality for screening for colon cancer; however, it carries a significant polyp/adenoma miss rate. Cap-assisted colonoscopy (CC) has been shown to improve polyp/adenoma detection rate, decrease cecal intubation time and increase cecal intubation rate when compared to standard colonoscopy (SC). However, data on adenoma detection rate (ADR) are conflicting. The aim of this meta-analysis was to compare the performance of CC with SC for ADR among high-quality randomized controlled trials. Patients and methods  We performed an extensive literature search using MEDLINE, EMBASE, Scopus, Cochrane and Web of Science databases and abstracts published at national meetings. Only comparative studies between CC and SC were included if they reported ADR, adenoma per person (APP), cecal intubation rate, and cecal intubation time. The exclusion criterion for comparing ADR was studies with Jadad score ≤ 2. The odds ratio (OR) was calculated using Mantel-Haenszel method. I 2 test was used to measure heterogeneity among studies. Results  Analysis of high-quality studies (Jadad score ≥ 3, total of 7 studies) showed that use of cap improved the ADR with the results being statistically significant (OR 1.18, 95 % CI 1.03 – 1.33) and detection of 0.16 (0.02 – 0.30) additional APP. The cecal intubation rate in the CC group was 96.3 % compared to 94.5 % with SC (total of 17 studies). Use of cap improved cecal intubation (OR 1.61, 95 % CI 1.33 – 1.95) when compared to SC ( P value < 0.001). Use of cap decreased cecal intubation time by an average of 0.88 minutes (95 % CI 0.37 – 1.39) or 53 seconds. Conclusions  Meta-analysis of high-quality studies showed that CC improved the ADR compared to SC.