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Despite regular need for colonoscopy in patients with Crohn's disease (CD), the efficacy and tolerability of bowel preparation (BP) agents is rarely assessed in this population. Assessing BP quality with existing scales may be challenging in CD due to presence of inflammation, bowel resection, and strictures.To provide recommendations for assessing BP quality in clinical trials for CD using a modified Research and Development/University of California, Los Angeles appropriateness process.Based on systematic reviews and a literature search, 110 statements relating to BP quality assessment in CD were developed. A panel of 15 gastroenterologists rated the statements as appropriate, uncertain, or inappropriate using a 9-point Likert scale.Panelists considered it appropriate that central readers, either alone or with local assessment, score BP quality in clinical trials. Central readers should be trained on scoring BP quality and local endoscopists on performing high-quality video recording. Both endoscope insertion and withdrawal phases should be reviewed to score BP quality in each colonic segment and segments should align with endoscopic disease activity indices. The Harefield Cleansing Scale and the Boston Bowel Preparation Scale were considered appropriate. The final score should be calculated as the average of all visualized segments. Both total and worst segment scores should also be assessed.We developed a framework for assessing BP quality in patients with CD based on expert feedback. This framework could support the development or refinement of BP quality scales and the integration of BP quality assessment in future CD studies.

Surveillance pouchoscopy is recommended for patients with restorative proctocolectomy with ileal pouch-anal anastomosis in ulcerative colitis or familial adenomatous polyposis, with the surveillance interval depending on the risk of neoplasia. Neoplasia in patients with ileal pouches mainly have a glandular source and less often are of squamous cell origin. Various grades of neoplasia can occur in the prepouch ileum, pouch body, rectal cuff, anal transition zone, anus, or perianal skin. The main treatment modalities are endoscopic polypectomy, endoscopic ablation, endoscopic mucosal resection, endoscopic submucosal dissection, surgical local excision, surgical circumferential resection and re-anastomosis, and pouch excision. The choice of the treatment modality is determined by the grade, location, size, and features of neoplastic lesions, along with patients' risk of neoplasia and comorbidities, and local endoscopic and surgical expertise.

Background and Aims: Dye-based chromoendoscopy (DBC) could be effective in increasing the adenoma detection rate (ADR) in patients undergoing colonoscopy, but the technique is time-consuming and its uptake is limited. We aimed to assess the effect of DBC on ADR based on available randomized controlled trials (RCTs). Methods: Four databases were searched up to April 2022 for RCTs comparing DBC with conventional colonoscopy (CC) in terms of ADR, advanced ADR, and sessile serrated adenoma detection rate as well as the mean adenomas per patient and non-neoplastic lesions. Relative risk (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes were calculated using random-effect models. The I2 test was used for quantifying heterogeneity. Risk of bias was evaluated with the Cochrane tool. Results: Overall, 10 RCTs (5334 patients) were included. Indication for colonoscopy was screening or surveillance (3 studies) and mixed (7 studies). Pooled ADR was higher in the DBC group versus the CC group (95% CI, 48.1% [41.4%-54.8%] vs 39.3% [33.5%-46.4%]; RR, 1.20 [1.11-1.29]), with low heterogeneity (I2 = 29%). This effect was consistent for advanced ADR (RR, 1.21 [1.03-1.42]; I2 = .0%), sessile serrated adenomas (6.1% vs 3.5%; RR, 1.68 [1.15-2.47]; I2 = 9.8%), and mean adenomas per patient (MD, .24 [.17-.31]) overall and in the right-sided colon (MD, .28 [.14-.43]). A subgroup analysis considering only trials using high-definition white-light endoscopy reduced the heterogeneity while still showing a significant increase in adenoma detection with DBC: 51.6% (95% confidence interval [CI], 47.1%-56.1%) and 59.1% (95% CI, 54.7-63.3%), RR = 1.14 (95% CI, 1.06-1.23), P = .0004, I2 = .0%, P = .50. Conclusions: Meta-analysis of RCTs showed that DBC increases key quality parameters in colonoscopy, supporting its use in everyday clinical practice.

Cold snare resection of colorectal lesions has been found to be safe and effective for an expanding set of colorectal lesions. In this study, we sought to understand the efficacy of simple cold snare resection and cold EMR versus hot snare resection and hot EMR for colorectal lesions 6 to 15 mm in size.At 3 U.S. centers, 235 patients with 286 colorectal lesions 6 to 15 mm in size were randomized to cold snaring, cold EMR, hot snaring, or hot EMR for nonpedunculated colorectal lesions 6 to 15 mm in size. The primary outcome was complete resection determined by 4 biopsy samples from the defect margin and 1 biopsy sample from the center of the resection defect.The overall incomplete resection rate was 2.4% (95% confidence interval [CI], .8%-7.5%). All 7 incompletely removed polyps were 10 to 15 mm in size and removed by hot EMR (n = 4, 6.2%), hot snare (n = 2, 2.2%), or cold EMR (n = 1, 1.8%). Cold snaring had no incomplete resections, required less procedural time than the other methods, and was not associated with serious adverse events.Cold snaring is a dominant resection technique for nonpedunculated colorectal lesions 6 to 15 mm in size. (Clinical trial registration number: NCT03462706.).

The impact of concomitant small serrated polyps (SPs) on the risk of subsequent neoplasia when small tubular adenomas (TAs) are found is uncertain.Patients who on index colonoscopy had ≤2 TAs of 10 mm in size in isolation were compared with those with concomitant ≤2 small-sized SPs. SP was inclusive of polyps described by pathology as sessile serrated lesions (SSLs) or proximal hyperplastic polyps (HPs) 10 mm in size. The primary endpoint was the rate of total metachronous advanced neoplasia (T-MAN) compared among the TAs in the isolation group and the groups inclusive of SPs (SSLs or proximal HPs).For patients with TAs and small SPs found concomitantly, the rate of T-MAN was 9.6% (24/251), which was significantly higher than the rate of T-MAN in patients with isolated small TAs (5.2% [59/1138], P = .011). Within the concomitant SP cohort, the rate of T-MAN in the proximal HP subgroup remained significantly increased (9% [19/212]) compared with the isolated small TA group (P = .037).When small TAs are found concomitantly with small SPs, there is an increase in the rate of T-MAN in comparison with isolated TAs. This increase in T-MAN also occurs when small TAs are found in conjunction with small proximal HPs. The presence of concomitant small SPs should be considered in determining surveillance intervals when small TAs are identified in colonoscopy screening programs.

Supplementary Figure 1. Gut microbial composition and diversity in patients with and without adenomas. A) Microbial composition was similar between groups across all taxonomic levels. The groups did not differ in terms of α-diversity: B) observed number of operational taxonomic units (OTUs) or C) the Shannon diversity index. The groups did not cluster by β-diversity: D) unweighted and E) weighted UniFrac distance metrics.

Background: Colorectal cancer is the second leading cause of cancer-related death, and most colorectal cancer usually arises from colorectal adenomas. Removal of polyps reduces mortality from colorectal cancer. Colorectal adenomas are known to aggregate in families; however, the genetic determinants for risk of polyps are largely unknown.Methods: In this study, we used data from the Tennessee Colorectal Polyp Study and the Tennessee-Indiana Adenoma Recurrence Study to conduct a GWAS of adenoma cases and controls. Our design consisted of discovery and replication phases for a total of 2,551 Caucasian adenoma cases and 3,285 Caucasian controls. We carried out logistic regression to test for association in both the discovery and replication phase and further examined the results with meta-analysis.Results: No single nucleotide polymorphism (SNP) achieved a genome-wide significant P value; however, the most significantly associated SNPs were either previously associated with colorectal cancer in GWAS, such as rs10505477 in the gene POU5F1 [odds ratio (OR) = 0.87; 95% confidence interval (CI) 0.81–0.94; P = 4.4 × 10−4), or have been biologically linked to benign growths in other tissues, such as rs1919314 in the gene histone deacetylase 9 (OR = 1.32; 95% CI, 1.18–1.47; P = 1.1 × 10−6).Conclusions: This study suggests that several SNPs may be related to adenoma risk and provides clues for future studies.Impact: These results suggest that some known genetic risk factors of colorectal cancer are necessary but not sufficient for carcinogenesis. Cancer Epidemiol Biomarkers Prev; 22(7); 1219–26. ©2013 AACR.

PDF file - 618K, Plot of the first two MDS axes generated in PLINK using 109,293 LD-pruned SNPs for the 11 Phase 3 HapMap populations.

PDF file - 244K, Concordance QC for the TCPS GWAS.

PDF file - 350K, GWAS sample QC.

Supplementary Table 1. MiRKAT association P values for various adenoma characteristics in individuals with adenomas

Supplementary Figure 2. Heat map of significantly predictive taxa. Hierarchical clustering is based on the Euclidean distance of log proportion, complete linkage. The left cluster is enriched in adenoma samples (P=0.1, Fisher's exact test).

PDF file - 379K, GWAS SNP QC.

Background: Adenomatous polyps are the most common precursor to colorectal cancer, the second leading cause of cancer-related death in the United States. We sought to learn more about early events of carcinogenesis by investigating shifts in the gut microbiota of patients with adenomas.Methods: We analyzed 16S rRNA gene sequences from the fecal microbiota of patients with adenomas (n = 233) and without (n = 547).Results: Multiple taxa were significantly more abundant in patients with adenomas, including Bilophila, Desulfovibrio, proinflammatory bacteria in the genus Mogibacterium, and multiple Bacteroidetes species. Patients without adenomas had greater abundances of Veillonella, Firmicutes (Order Clostridia), and Actinobacteria (family Bifidobacteriales). Our findings were consistent with previously reported shifts in the gut microbiota of colorectal cancer patients. Importantly, the altered adenoma profile is predicted to increase primary and secondary bile acid production, as well as starch, sucrose, lipid, and phenylpropanoid metabolism.Conclusions: These data hint that increased sugar, protein, and lipid metabolism along with increased bile acid production could promote a colonic environment that supports the growth of bile-tolerant microbes such as Bilophilia and Desulfovibrio. In turn, these microbes may produce genotoxic or inflammatory metabolites such as H2S and secondary bile acids, which could play a role in catalyzing adenoma development and eventually colorectal cancer.Impact: This study suggests a plausible biological mechanism to explain the links between shifts in the microbiota and colorectal cancer. This represents a first step toward resolving the complex interactions that shape the adenoma–carcinoma sequence of colorectal cancer and may facilitate personalized therapeutics focused on the microbiota. Cancer Epidemiol Biomarkers Prev; 26(1); 85–94. ©2016 AACR.

PDF file - 56K, Results from tests of association at all SNPs genotyped in replication experiments from the discovery, replication, and combined evidence from both phases using meta-analysis for adenoma and hyperplastic polyp-only cases.

PDF file - 56K, Results from tests of association at all SNPs genotyped in replication experiments from the discovery, replication, and combined evidence from both phases using meta-analysis after excluding 534 hyperplastic polyp-only cases.

PDF file - 171K

We sought to document patient perceptions in 2021 regarding colonoscopy experience and potential deterrents to repeat colonoscopy.Bowel preparation has been previously considered by patients to be the worst part of a colonoscopy.We conducted a prospective survey of consecutive patients age 18 years and older who had just completed colonoscopy at 2 outpatient endoscopy centers at a tertiary academic hospital. The short survey was conducted in the recovery area. The main outcome measure was patient perceptions of the worst part of their colonoscopy experience and which factor would most deter them from a future colonoscopy.Four hundred patients completed the survey of 405 approached. Average patient age was 64 years, and 48% were women. Seventy-five percent of patients used low-volume preparations. Bowel preparation was considered the worst part of colonoscopy by 71% of patients. Women were more likely to choose laxatives as the worst part of a colonoscopy. Bowel preparation was chosen most often (55%) as the most likely deterrent to a future colonoscopy. There were minimal differences in responses between those receiving low-volume versus high-volume (4 L) preparations.Bowel preparation remains the worst part of the colonoscopy experience for patients, and the most likely deterrent to future colonoscopy.

Background & Aims Nonpedunculated colorectal polyps are normally endoscopically removed to prevent neoplastic progression. Delayed bleeding is the most common major adverse event. Clipping the resection defect has been suggested to reduce delayed bleedings. Our aim was to determine if prophylactic clipping reduces delayed bleedings and to analyze the contribution of polyp characteristics, extent of defect closure, and antithrombotic use. Methods An individual patient data meta-analysis was performed. Studies on prophylactic clipping in nonpedunculated colorectal polyps were selected from PubMed, Embase, Web of Science, and Cochrane database (last selection, April 2020). Authors were invited to share original study data. The primary outcome was delayed bleeding ≤30 days. Multivariable mixed models were used to determine the efficacy of prophylactic clipping in various subgroups adjusted for confounders. Results Data of 5380 patients with 8948 resected polyps were included from 3 randomized controlled trials, 2 prospective, and 8 retrospective studies. Prophylactic clipping reduced delayed bleeding in proximal polyps ≥20 mm (odds ratio [OR], 0.62; 95% confidence interval [CI], 0.44–0.88; number needed to treat = 32), especially with antithrombotics (OR, 0.59; 95% CI, 0.35–0.99; number needed to treat = 23; subgroup of anticoagulants/double platelet inhibitors: n = 226; OR, 0.40; 95% CI, 0.16–1.01; number needed to treat = 12). Prophylactic clipping did not benefit distal polyps ≥20 mm with antithrombotics (OR, 1.41; 95% CI, 0.79–2.52). Conclusions Prophylactic clipping reduces delayed bleeding after resection of nonpedunculated, proximal colorectal polyps ≥20 mm, especially in patients using antithrombotics. No benefit was found for distal polyps. Based on this study, patients can be identified who may benefit from prophylactic clipping. (PROSPERO registration number CRD42020104317.)