COMPUTER-AIDED DIAGNOSIS IMPROVES CHARACTERIZATION OF BARRETT'S NEOPLASIA BY GENERAL ENDOSCOPISTS.

BACKGROUND & AIMS: Characterization of visible abnormalities in Barrett esophagus (BE) patients can be challenging, especially for unexperienced endoscopists. This results in suboptimal diagnostic accuracy and poor inter-observer agreement. Computer-aided diagnosis (CADx) systems may assist endoscopists. We aimed to develop, validate and benchmark a CADx system for BE neoplasia. METHODS: The CADx system received pretraining with ImageNet with consecutive domain-specific pretraining with GastroNet which includes 5 million endoscopic images. It was subsequently trained and internally validated using 1,758 narrow-band imaging (NBI) images of early BE neoplasia (352 patients) and 1,838 NBI images of non-dysplastic BE (173 patients) from 8 international centers. CADx was tested prospectively on corresponding image and video test sets with 30 cases (20 patients) of BE neoplasia and 60 cases (31 patients) of non-dysplastic BE. The test set was benchmarked by 44 general endoscopists in two phases (phase 1: no CADx assistance; phase 2: with CADx assistance). Ten international BE experts provided additional benchmark performance. RESULTS: Stand-alone sensitivity and specificity of the CADx system were 100% and 98% for images and 93% and 96% for videos, respectively. CADx outperformed general endoscopists without CADx assistance in terms of sensitivity (p=0.04). Sensitivity and specificity of general endoscopist increased from 84% to 96% and 90 to 98% with CAD assistance (p<0.001), respectively. CADx assistance increased endoscopists' confidence in characterization (p<0.001). CADx performance was similar to Barrett experts. CONCLUSION: CADx assistance significantly increased characterization performance of BE neoplasia by general endoscopists to the level of expert endoscopists. The use of this CADx system may thereby improve daily Barrett surveillance.

A new artificial intelligence system successfully detects and localises early neoplasia in Barrett's esophagus by using convolutional neural networks.

BACKGROUND AND AIMS: Seattle protocol biopsies for Barrett's Esophagus (BE) surveillance are labour intensive with low compliance. Dysplasia detection rates vary, leading to missed lesions. This can potentially be offset with computer aided detection. We have developed convolutional neural networks (CNNs) to identify areas of dysplasia and where to target biopsy. METHODS: 119 Videos were collected in high-definition white light and optical chromoendoscopy with i-scan (Pentax Hoya, Japan) imaging in patients with dysplastic and non-dysplastic BE (NDBE). We trained an indirectly supervised CNN to classify images as dysplastic/non-dysplastic using whole video annotations to minimise selection bias and maximise accuracy. The CNN was trained using 148,936 video frames (31 dysplastic patients, 31 NDBE, two normal esophagus), validated on 25,161 images from 11 patient videos and tested on 264 iscan-1 images from 28 dysplastic and 16 NDBE patients which included expert delineations. To localise targeted biopsies/delineations, a second directly supervised CNN was generated based on expert delineations of 94 dysplastic images from 30 patients. This was tested on 86 i-scan one images from 28 dysplastic patients. FINDINGS: The indirectly supervised CNN achieved a per image sensitivity in the test set of 91%, specificity 79%, area under receiver operator curve of 93% to detect dysplasia. Per-lesion sensitivity was 100%. Mean assessment speed was 48 frames per second (fps). 97% of targeted biopsy predictions matched expert and histological assessment at 56 fps. The artificial intelligence system performed better than six endoscopists. INTERPRETATION: Our CNNs classify and localise dysplastic Barrett's Esophagus potentially supporting endoscopists during surveillance.

Optimized Surveillance Intervals Following Endoscopic Eradication of Dysplastic Barrett's Esophagus: An International Cohort Study.

BACKGROUND & AIMS: Recommended surveillance intervals after complete eradication of intestinal metaplasia (CE-IM) after endoscopic eradication therapy (EET) are largely not evidence-based. Using recurrence rates in a multicenter international Barrett's esophagus (BE) CE-IM cohort, we aimed to generate optimal intervals for surveillance. METHODS: Patients with dysplastic BE undergoing EET and achieving CE-IM from prospectively maintained databases at 5 tertiary-care centers in the United States and the United Kingdom were included. The cumulative incidence of recurrence was estimated, accounting for the unknown date of actual recurrence that lies between the dates of current and previous endoscopy. This cumulative incidence of recurrence subsequently was used to estimate the proportion of patients with undetected recurrence for various surveillance intervals over 5 years. Intervals were selected that minimized recurrences remaining undetected for more than 6 months. Actual patterns of post-CE-IM follow-up evaluation are described. RESULTS: A total of 498 patients (with baseline low-grade dysplasia, 115 patients; high-grade dysplasia [HGD], 288 patients; and intramucosal adenocarcinoma [IMCa], 95 patients) were included. Any recurrence occurred in 27.1% and dysplastic recurrence occurred in 8.4% over a median of 2.6 years of follow-up evaluation. For pre-ablation HGD/IMCa, intervals of 6, 12, 18, and 24 months, and then annually, resulted in no patients with dysplastic recurrence undetected for more than 6 months, comparable with current guideline recommendations despite a 33% reduction in the number of surveillance endoscopies. For pre-ablation low-grade dysplasia, intervals of 1, 2, and 4 years balanced endoscopic burden and undetected recurrence risk. CONCLUSIONS: Lengthening post-CE-IM surveillance intervals would reduce the endoscopic burden after CE-IM with comparable rates of recurrent HGD/IMCa. Future guidelines should consider reduced surveillance frequency.

Radiofrequency ablation for low-grade dysplasia in Barrett's esophagus: long-term outcome of a randomized trial.

BACKGROUND AND AIMS: A prior randomized study (Surveillance versus Radiofrequency Ablation study [SURF study]) demonstrated that radiofrequency ablation (RFA) of Barrett's esophagus (BE) with confirmed low-grade dysplasia (LGD) significantly reduces the risk of esophageal adenocarcinoma. Our aim was to report the long-term outcomes of this study. METHODS: The SURF study randomized BE patients with confirmed LGD to RFA or surveillance. For this retrospective cohort study, all endoscopic and histologic data acquired at the end of the SURF study in May 2013 until December 2017 were collected. The primary outcome was rate of progression to high-grade dysplasia (HGD)/cancer. All 136 patients randomized to RFA (n = 68) or surveillance (n = 68) in the SURF study were included. After closure of the SURF study, 15 surveillance patients underwent RFA based on patient preference and study outcomes. RESULTS: With 40 additional months (interquartile range, 12-51), the total median follow-up from randomization to last endoscopy was 73 months (interquartile range, 46-85). HGD/cancer was diagnosed in 1 patient in the RFA group (1.5%) and in 23 in the surveillance group (33.8%) (P = .000), resulting in an absolute risk reduction of 32.4% (95% confidence interval [CI], 22.4%-44.2%) with a number needed to treat of 3.1 (95% CI, 2.3-4.5). Seventy-five of 83 patients (90%; 95% CI, 82.1%-95.0%) treated with RFA for BE reached complete clearance of BE and dysplasia. BE recurred in 7 of 75 patients (9%; 95% CI, 4.6%-18.0%), mostly minute islands or tongues, and LGD in 3 of 75 (4%; 95% CI, 1.4%-11.1%). CONCLUSIONS: RFA of BE with confirmed LGD significantly reduces the risk of malignant progression, with sustained clearance of BE in 91% and LGD in 96% of patients, after a median follow-up of 73 months. (Clinical trial registration number: NTR1198.).

Standard versus simplified radiofrequency ablation protocol for Barrett's esophagus: comparative analysis of the whole treatment pathway.

Background and study aims The standard radiofrequency ablation (RFA) protocol for Barrett's esophagus (BE) encompasses an intermediary cleaning phase between two ablation sessions. A simplified protocol omitting the cleaning phase is less labor-intensive but equally effective in studies based on single ablation procedures. The aim of this study was to compare efficacy and safety of the standard and simplified RFA protocols for the whole treatment pathway for BE, including both circumferential and focal devices. Patients and methods We performed a retrospective analysis of prospectively collected data on patients receiving RFA between January 2007 and August 2017 at two institutions. Outcomes assessed were: 1) complete remission of dysplasia (CR-D) and intestinal metaplasia (CR-IM) at 18 months; and 2) rate of esophageal strictures. Results One hundred forty-five patients were included of whom 73 patients received the standard and 72 patients received the simplified protocol. CR-D was achieved in 94.5 % and 95.8 % of patients receiving the standard and simplified protocol, respectively ( P  = 0.71). CR-IM was achieved in 84.9 % and 77.8 % of patients treated with the standard and simplified protocol, respectively ( P  = 0.27). Strictures were significantly more common among patients who received the simplified protocol (12.5 %) compared to the standard protocol (1.4 %; P  = 0.008). The median number of esophageal dilations was one. Conclusion The simplified RFA protocol is as effective as the standard protocol in eradicating BE but carries a higher risk of strictures. This needs to be taken into account, particularly in patients with higher pretreatment risk of strictures, such as those with esophageal narrowing from previous endoscopic mucosal resection (EMR).

Is Endoscopic Ultrasound (EUS) necessary in the pre-therapeutic assessment of Barrett's esophagus with early neoplasia?

Endoscopic ultrasound (EUS) is considered the most accurate tool for the TNM staging of esophageal cancer, but its role in early Barrett's neoplasia is still debatable. The aim was to evaluate the utility of EUS in Barrett's patients prior to therapy. Retrospective review of 109 patients enrolled in a treatment protocol for Barrett's neoplasia in our institution. EUS assessment was classified as suspicious for invasion in 19 patients; 84% of them had no evidence of invasion in final pathology. The assessment of depth of invasion of Barrett's neoplasia based solely on EUS findings leads to overstaging in most patients.

Usefulness of an intensive bowel cleansing strategy for repeat colonoscopy after preparation failure.

BACKGROUND: No consensus exists regarding the optimal bowel preparation regimen for patients with poor bowel cleansing at a previous colonoscopy. OBJECTIVE: We investigated the usefulness of an intensive cleansing regimen for repeat colonoscopy after previous failure of bowel preparation. DESIGN AND SETTING: A prospective observational study was performed in patients undergoing colonoscopy at a university-based, tertiary referral hospital. PATIENTS AND INTERVENTION: Outpatients with inadequate preparation at an index colonoscopy were offered a repeat colonoscopy and instructed to follow an intensive preparation regimen consisting of a low-fiber diet for 72 hours, liquid diet for 24 hours, bisacodyl (10 mg) in the evening of the day before the colonoscopy, and a split dose of polyethylene glycol (1.5 L in the evening before and 1.5 L in the morning on the day of the colonoscopy). MAIN OUTCOME MEASURES: The adequacy of bowel cleansing was assessed according to the Boston Bowel Preparation Scale (0 or 1 on any colon segment = inadequate bowel preparation). Procedural variables, detection rates for polyps and adenomas, compliance, and tolerability of the regimen were assessed. Satisfaction with the regimen was assessed with a 10-point visual analog scale. RESULTS: Of 83 patients with inadequate bowel preparation at colonoscopy, 51 underwent a second colonoscopy and were analyzed; 46 patients (90.2%) had adequate bowel cleansing at the second colonoscopy, with a mean (SD) total Boston Bowel Preparation Scale score of 7.43 (1.5) and scores of 2.31 (0.6) for the right colon, 2.49 (0.6) for the transverse colon, and 2.63 (0.6) for the left colon. Polyps, flat lesions, or flat lesions proximal to the splenic flexure were found in significantly more patients at the second colonoscopy than at the index colonoscopy. The global satisfaction score was 6.6 (2.7). LIMITATIONS: The study was limited because of its open observational design, possible patient learning effect for bowel preparation at the repeat colonoscopy, and the inclusion of only outpatients. CONCLUSIONS: An intensive regimen consisting of a low-fiber diet, bisacodyl, and a split dose of polyethylene glycol can achieve good colon preparation with an improved detection rate for polyps and adenomas in most patients who have had poor bowel cleansing at a previous colonoscopy.