Wallace, Michael B.

Abstract Background and study aims Adenoma recurrence is one of the key limitations of endoscopic mucosal resection (EMR), which occurs in 15 % to 30 % of cases during first surveillance colonoscopy. The main hypothesis behind adenoma recurrence is leftover micro-adenomas at the margins of post-EMR defects. In this systematic review and meta-analysis, we evaluated the efficacy of snare tip soft coagulation (STSC) at the margins of mucosal defects to reduce adenoma recurrence and bleeding complications. Methods Electronic databases such as PubMed and the Cochrane library were used for systematic literature search. Studies with polyps only resected by piecemeal EMR and active treatment: with STSC, comparator: non-STSC were included. A random effects model was used to calculate the summary of risk ratio and 95 % confidence intervals. The main outcome of the study was to compare the effect of STSC versus non-STSC with respect to adenoma recurrence at first surveillance colonoscopy after thermal ablation of post-EMR defects. Results Five studies were included in the systematic review and meta-analysis. The total number patients who completed first surveillance colonoscopy (SC1) in the STSC group was 534 and in the non-STSC group was 514. The pooled adenoma recurrence rate was 6 % (37 of 534 cases) in the STSC arm and 22 % (115 of 514 cases) in the non-STSC arm, (odds ratio [OR] 0.26, 95 % confidence interval [CI], 0.16–0.41, P = 0.001). The pooled delayed post-EMR bleeding rate 19 % (67 of 343) in the STSC arm and 22 % (78 of 341) in the non-STSC arm (OR 0.82, 95 %CI, 0.57–1.18). Conclusions Thermal ablation of post-EMR defects significantly reduces adenoma recurrence at first surveillance colonoscopy.

AbstractBackgroundIdentifying branch‐duct intraductal papillary mucinous neoplasms (BD‐IPMNs) at lowest risk of progression may allow for a reduced intensity of surveillance.ObjectiveWe aimed to externally validate the previously developed Dutch‐American Risk stratification Tool (DART‐1; https://rtools.mayo.edu/DART/), which identifies cysts at low risk of developing worrisome features (WFs) or high‐risk stigmata (HRS).MethodsThree prospective cohorts of individuals under surveillance for BD‐IPMNs were combined, independent from the original development cohort. We assessed the performance (discrimination and calibration) of DART‐1, a multivariable Cox‐proportional logistic regression model with five predictors for the development of WFs or HRS.ResultsOf 832 individuals (mean age 77 years, SD 11.5) under surveillance for a median of 40 months (IQR 44), 163 (20%) developed WFs or HRS. DART‐1's discriminative ability (C‐statistic 0.68) was similar to that in the development cohort (0.64–0.72) and showed moderate calibration. DART‐1 adequately estimated the risk for patients in the middle risk quintile, and slightly underestimated it in the lowest quintiles. Their range of predicted versus observed 3‐year risk was 0%–0% versus 0%–3.7% for Q1; 0.3%–0.4% versus 3%–11% for Q2; and 2.6%–3% versus 2.4%–9.8% for Q3. The development of WFs or HRS was associated with pancreatic cancer (p < 0.001). Vice versa, in absence of WFs or HRS, the risk of malignancy was low (0.3%).ConclusionsThe performance of DART‐1 to predict the development of WFs or HRS in BD‐IPMN was validated in an external international cohort, with a discriminative ability equal as in the development cohort. Risk estimations were most accurate for patients with BD‐IPMNs in the middle risk quintile and slightly underestimated in the lowest quintiles.

Abstract Background and study aims En bloc endoscopic mucosal resection (EMR) is preferred over piecemeal resection for polyps ≤ 20 mm. Data on colorectal EMR training are limited. We aimed to evaluate the en bloc EMR rate of polyps ≤ 20 mm among advanced endoscopy trainees and to identify predictors of failed en bloc EMR. Methods This was a multicenter prospective study evaluating trainee performance in EMR during advanced endoscopy fellowship. A logistic regression model was used to identify the number of procedures and lesion cut-off size associated with an en bloc EMR rate of ≥ 80 %. Multivariate analysis was performed to identify predictors of failed en bloc EMR. Results Six trainees from six centers performed 189 colorectal EMRs, of which 104 (55 %) were for polyps ≤ 20 mm. Of these, 57.7 % (60/104) were resected en bloc. Trainees with ≥ 30 EMRs (OR 6.80; 95 % CI: 2.80–16.50; P = 0.00001) and lesions ≤ 17 mm (OR 4.56;95 CI:1.23–16.88; P = 0.02) were more likely to be associated with an en bloc EMR rate of ≥ 80 %. Independent predictors of failed en bloc EMR on multivariate analysis included: larger polyp size (OR:6.83;95 % CI:2.55–18.4; P = 0.0001), right colon location (OR:7.15; 95 % CI:1.31–38.9; P = 0.02), increased procedural difficulty (OR 2.99; 95 % CI:1.13–7.91; P = 0.03), and having performed < 30 EMRs (OR: 4.87; 95 %CI: 1.05–22.61; P = 0.04). Conclusions In this pilot study, we demonstrated that a relatively low proportion of trainees achieved en bloc EMR for polyps ≤ 20 mm and identified procedure volume and lesion size thresholds for successful en bloc EMR and independent predictors for failed en bloc resection. These preliminary results support the need for future efforts to define EMR procedure competence thresholds during training.

LINKED CONTENTThis article is linked to Grover et al and Elwing & Sayuk papers. To view these articles, visit https://doi.org/10.1111/apt.16591 and https://doi.org/10.1111/apt.16603

Objectives Pancreatic acinar cell carcinoma (ACC) is a rare pancreatic cancer. The advancement of treatment is hampered because of the limited knowledge of its molecular mechanism. Methods Whole-exome sequencing was performed on DNA extracted from 11 pure ACC surgical samples. Potential germline variants were removed on the basis of polymorphic databases, alternative allele frequency, coverage depth, and Catalogue of Somatic Mutations in Cancer (COSMIC) annotations after variant calling procedure. Mutation profiles and signatures were assessed through the Mutational Patterns package. Results A median of 34 somatic mutations were detected (range, 19–60). Three novel recurrent small deletions were identified. Common pancreatic ductal adenocarcinoma mutations or neuroendocrine tumor mutants were not found. FAT atypical cadherin 4, mucin 5B, titin, and zinc finger homeobox 3 were consistently mutated across 4 independent ACC studies. A high contribution of COSMIC mutational signature 1 was seen in ACC, indicating deamination of 5-methylcytosine. The majority of the patients had COSMIC signatures 6, 15, or 20, relating to defective DNA mismatch repair. Six patients showed COSMIC mutational signature 10 because of the altered activity of DNA polymerase epsilon. Conclusions Distinct mutational signatures pathways were found in ACC and targeting them may improve clinical outcome.

SummaryBackgroundIrritable bowel syndrome (IBS) patients often experience meal‐associated symptoms. However, the underlying mechanisms are unclear.AimTo determine small intestinal mechanisms of lipid‐induced symptoms and rectal hypersensitivity in IBSMethodsWe recruited 26 IBS patients (12 IBS‐C, 14 IBS‐D) and 15 healthy volunteers (HV). In vivo permeability was assessed using saccharide excretion assay. Rectal sensitivity was assessed using a barostat before and after small bowel lipid infusion; symptoms were assessed throughout. Next, an extended upper endoscopy with probe‐based confocal laser endomicroscopy (pCLE) was performed with changes induced by lipids. Duodenal and jejunal mucosal biopsies were obtained for transcriptomics.ResultsFollowing lipid infusion, a higher proportion of HV than IBS patients reported no pain, no nausea, no fullness and no urgency (P < 0.05 for all). In a model adjusted for sex and anxiety, IBS‐C and IBS‐D patients had lower thresholds for first rectal sensation (P = 0.0007) and pain (P = 0.004) than HV. In vivo small intestinal permeability and mean pCLE scores were similar between IBS patients and HV. Post‐lipid, pCLE scores were higher than pre‐lipid but were not different between groups. Baseline duodenal transient receptor potential vanilloid (TRPV) 1 and 3 expression was increased in IBS‐D, and TRPV3 in IBS‐C. Duodenal TRPV1 expression correlated with abdominal pain (r = 0.51, FDR = 0.01), and inversely with first rectal sensation (r = −0.48, FDR = 0.01) and pain (r = −0.41, FDR = 0.02) thresholds.ConclusionLipid infusion elicits a greater symptom response in IBS patients than HV, which is associated with small intestinal expression of TRPV channels. TRPV‐mediated small intestinal chemosensitivity may mediate post‐meal symptoms in IBS.

Background and aims Artificial intelligence has been shown to increase adenoma detection rate (ADR) as the main surrogate outcome parameter of colonoscopy quality. To which extent this effect may be related to physician experience is not known. We performed a randomised trial with colonoscopists in their qualification period (AID-2) and compared these data with a previously published randomised trial in expert endoscopists (AID-1). Methods In this prospective, randomised controlled non-inferiority trial (AID-2), 10 non-expert endoscopists (<2000 colonoscopies) performed screening/surveillance/diagnostic colonoscopies in consecutive 40–80 year-old subjects using high-definition colonoscopy with or without a real-time deep-learning computer-aided detection (CADe) (GI Genius, Medtronic). The primary outcome was ADR in both groups with histology of resected lesions as reference. In a post-hoc analysis, data from this randomised controlled trial (RCT) were compared with data from the previous AID-1 RCT involving six experienced endoscopists in an otherwise similar setting. Results In 660 patients (62.3±10 years; men/women: 330/330) with equal distribution of study parameters, overall ADR was higher in the CADe than in the control group (53.3% vs 44.5%; relative risk (RR): 1.22; 95% CI: 1.04 to 1.40; p<0.01 for non-inferiority and p=0.02 for superiority). Similar increases were seen in adenoma numbers per colonoscopy and in small and distal lesions. No differences were observed with regards to detection of non-neoplastic lesions. When pooling these data with those from the AID-1 study, use of CADe (RR 1.29; 95% CI: 1.16 to 1.42) and colonoscopy indication, but not the level of examiner experience (RR 1.02; 95% CI: 0.89 to 1.16) were associated with ADR differences in a multivariate analysis. Conclusions In less experienced examiners, CADe assistance during colonoscopy increased ADR and a number of related polyp parameters as compared with the control group. Experience appears to play a minor role as determining factor for ADR. Trial registration number NCT:04260321.