The impact of endoscopic treatment on health-related quality of life in patients with Barrett's neoplasia: a scoping review.

PURPOSE: The objective of this scoping review is to understand the extent, type of evidence, and overall findings in relation to the impact of endoscopic treatment (ET) on health-related quality of life (HR-QoL) in patients with Barrett's dysplasia and early oesophageal cancer. METHODS: A comprehensive search was conducted for literature between 2001 and 2022 in computerised databases (PubMed, Embase, Cochrane Library, and CINAHL Complete). Additionally, sources of unpublished literature were searched in Google Advanced Search. After title and abstract checking, full-text papers were retrieved. Data were extracted, synthesised, key information tabulated, and a narrative synthesis completed. RESULTS: Six studies were included in the final analysis. Twelve different survey tools were utilised across all studies. Study designs included three randomised controlled studies, two prospective observational studies, and a single retrospective observational study. The average age of study participants ranged from 60.3 to 71.0 years. Two studies evaluated HR-QoL as primary outcome measures, but most research evaluated HR-QoL as a secondary outcome. Health domains evaluated in the studies focussed on the biophysical and psychosocial aspects of quality of life. CONCLUSION: A small number of research studies have been conducted in this area. Due to the heterogeneity and small number of included studies, it was difficult to draw conclusions about the impact of specific ET types on HR-QoL. Overall, there were perceived psychological benefits while undergoing ET. Future research could target specific ET subtypes and measure HR-QoL at baseline and post-procedures in the short and long term.

Effectiveness and safety of cold snare polypectomy and cold endoscopic mucosal resection for nonpedunculated colorectal polyps of 10-19 mm: a multicenter observational cohort study.

BACKGROUND : Cold snare polypectomy (CSP) is the standard of care for the resection of small (< 10 mm) colonic polyps. Limited data exist for its efficacy for medium-sized (10-19 mm) nonpedunculated polyps, especially conventional adenomas. This study evaluated the effectiveness and safety of CSP/cold endoscopic mucosal resection (C-EMR) for medium-sized nonpedunculated colonic polyps. METHODS : A prospective multicenter observational study was conducted of all morphologically suitable nonpedunculated colonic polyps of 10-19 mm removed by CSP/C-EMR between May 2018 and June 2021. Once resection was complete, multiple biopsies were taken of the margins circumferentially and centrally. The primary outcome was the incomplete resection rate (IRR), based on residual polyp in these biopsy specimens. Secondary outcomes were recurrence rate at first surveillance colonoscopy and rates of adverse events (AEs). RESULTS : CSP/C-EMR was performed for 350 polyps (median size 15 mm; 266 [76.0 %] Paris 0-IIa classification) in 295 patients. Submucosal injection was used for 87.1 % (n = 305) of polyps. Histology showed 68.6 % adenomas, 26.0 % sessile serrated lesions (SSLs) without dysplasia, 4.0 % SSL with dysplasia, and 1.4 % hyperplastic polyps. The IRRs based on margin or central biopsies being positive were 1.7 % (n = 6) and 0.3 % (n = 1), respectively. The polyp recurrence rate was 1.7 % (n = 4) at first surveillance colonoscopy - completed for 65.4 % (n = 229) of polyps at a median interval of 9.7 months. AEs occurred in 3.4 % (n = 10) of patients: four with post-polypectomy pain; three self-limiting post-polypectomy bleeds; two post-polypectomy-syndrome-like presentations; and one intraprocedural bleed treated with clips. There were no perforations. CONCLUSION : CSP/C-EMR for morphologically suitable nonpedunculated colonic polyps of 10-19 mm is effective and safe, including for conventional adenomas. Rates of incomplete resection and recurrence were low, with few AEs. Studies directly comparing this method with hot snare resection are required.

Post-colonoscopy cancer rate at a tertiary referral hospital in Australia: A data linkage analysis.

BACKGROUND AND AIM: Colorectal cancer (CRC) diagnosed following a cancer-negative colonoscopy is termed as post-colonoscopy CRC (PCCRC). The World Endoscopy Organization has recently standardized the definition of PCCRC-3Y (CRC developing within 3 years of a cancer-negative colonoscopy). In the present study, we sought to assess PCCRC-3Y rate, perform root-cause analyses, and identify factors associated with development of PCCRC at a tertiary referral hospital in Australia. METHODS: All patients undergoing colonoscopy from 2011 to 2018 were matched to a population-based cancer register. PCCRC-3Y rate was assessed for years 2011-2015. All PCCRC cases that developed within 6-48 months after a cancer-negative colonoscopy underwent root-cause analyses. Descriptive statistics were used to summarize data. RESULTS: Among 17 828 patients undergoing colonoscopy, 367 CRC cases were diagnosed during the study period. This included nine PCCRC cases, which developed at a median of 14 months (range 7-34 months) after cancer-negative colonoscopy. The PCCRC-3Y rate for years 2011-2015 was 2.16% (95% CI 0.91-5.15). All nine PCCRC cases were moderately or poorly differentiated adenocarcinomas; seven of nine were early-stage CRC (stages I and II) and six of nine probably represented missed lesions at index colonoscopy despite an apparently adequate examination. History of inflammatory bowel disease (IBD) (odds ratio [OR] 21.9, 95% confidence interval [CI] 4.6-103.7, P < 0.001) and diverticulosis (OR 5.4, 95% CI 1.4-20.5, P = 0.01) were significantly associated with development of missed CRC. CONCLUSIONS: In our tertiary referral colonoscopy cohort, PCCRC-3Y rate was 2.16% (95% CI 0.91-5.15). IBD and diverticulosis were significantly associated with risk of PCCRC. The majority of PCCRC lesions were likely missed at index colonoscopy, despite an apparently adequate examination.

Clinical significance of incidental 18 FDG PET uptake in the gastrointestinal tract: a retrospective cohort study.

BACKGROUND: Incidental gastrointestinal tract (GIT) uptake is found in up to 6.3% of patients undergoing positron emission tomography (PET). This may be physiologic or pathologic and requires endoscopic assessment. AIM: To determine the diagnostic yield of endoscopy in this setting and characterise PET avidity as a predictor of clinically significant findings. METHODS: We retrospectively reviewed all consecutive patients undergoing upper endoscopy or colonoscopy for incidental 18 FDG PET positivity in the GIT. RESULTS: A total of 255 patients (62% male, median age 67 years) underwent colonoscopy or sigmoidoscopy for 276 separate areas of PET avidity in the colon. Malignancy was found in 44 cases (16%), and a significant polyp was found in an additional 103 cases (37%). Neoplastic change was found more often in the case of intense compared with non-intense PET avidity (odds ratio (OR) 3.40, 95% confidence interval (CI) 1.95-5.93, P < 0.001), and in focal compared with diffuse uptake (OR 5.97, 95% CI 2.9-12.2, P < 0.001). Upper GIT endoscopy was performed in 75 patients (46 male, median age 63 years) for 77 isolated areas with PET avidity. Malignancy was found in 16 cases (21%), and all were new primary lesions. Numerically, malignant findings were more common in intense (29.7%) than non-intense (12.5%) PET avidity (OR 2.96, 95%, CI 0.92-9.57, P = 0.069). CONCLUSIONS: Both focal and intense colonic 18 FDG uptake correlate strongly with a high-risk polyp or malignant lesion. Up to 21% of all gastroscopies performed for evaluation of incidental PET uptake diagnosed a new primary malignancy. These referrals need appropriate triaging and timely endoscopic assessment.

Clinical utility of purgative bowel preparation before capsule endoscopy: a multicenter, blinded, randomized controlled trial.

BACKGROUND AND AIMS: Optimal bowel preparation before capsule endoscopy (CE) is currently unknown. In this multicenter, blinded, randomized controlled trial, we assessed clinical effectiveness of 2 types of purgative regimen and a control arm of clear fluid only. METHODS: Patients with suspected small intestinal bleeding were randomized into 3 arms: arm A, clear fluids only for 18 hours before CE and simethicone 200 mg in 150 mL water immediately before CE; arm B, same as A + 2 L of polyethylene glycol (PEG) 12 hours before CE; and arm C, same as A + 1 L PEG + sodium ascorbate 3 hours before CE. To assess diagnostic yield, lesions were classified either as highly relevant (P2) or less relevant (P0 or P1) lesions. Small-bowel visualization quality (SBVQ) was assessed using the Brotz score. Patient tolerability was assessed using the visual analog scale (0-10, with lower scores indicating better tolerability). RESULTS: Two hundred twenty-nine patients completed the study. The mean age was 58.7 years (95% confidence interval, 29.3-87.9), and 47.2% were men. There was no significant difference in diagnosis of P2 lesions in arms A, B, and C (48.7%, 48.0%, and 45.9%, respectively; P = .94). Overall SBVQ and distal SBVQ were similar across the 3 arms (P = .94 and P = .68, respectively). Patients reported better tolerability in arm A (mean score, 1.5) compared with arms B and C (mean score, 3.5 and 2.6, respectively; P < .001). CONCLUSIONS: The use of a purgative bowel preparation before CE does not improve diagnostic yield or small-bowel visualization and is associated with lower patient tolerance. (Clinical trial registration number: ACTRN 12614000883617.).

Comparison of Cap-Assisted vs Conventional Endoscopic Technique for Management of Food Bolus Impaction in the Esophagus: Results of a Multicenter Randomized Controlled Trial.

INTRODUCTION: "Push" or "pull" techniques with the use of snares, forceps, baskets, and grasping devices are conventionally used to manage esophageal food bolus impaction (FBI). A novel cap-assisted technique has recently been advocated to reduce time taken for food bolus (FB) removal. This study aimed to compare the effectiveness of the cap-assisted technique against conventional methods of esophageal FB removal in a randomized controlled trial. METHODS: Consecutive patients with esophageal FBI requiring endoscopic removal, from 3 Australian tertiary hospitals between 2017 and 2019, were randomized to either the cap-assisted technique or the conventional technique. Primary outcomes were technical success and FB retrieval time. Secondary outcomes were technical success rate, en bloc removal rate, procedure-related complication, length of hospital stay, and cost of consumables. RESULTS: Over 24 months, 342 patients with esophageal FBI were randomized to a cap-assisted (n = 171) or conventional (n = 171) technique. Compared with the conventional approach, the cap-assisted technique was associated with (i) shorter FB retrieval time (4.5 ± 0.5 minutes vs 21.7 ± 0.9 minutes, P < 0.001), (ii) shorter total procedure time (23.0 ± 0.6 minutes vs 47.0 ± 1.3 minutes, P < 0.0001), (iii) higher technical success rate (170/171 vs 160/171, P < 0.001), (iv) higher rate of en bloc removal (159/171 vs 48/171, P < 0.001), and (v) lower rate of procedure-related mucosal tear and bleeding (0/171 vs 13/171, P < 0.001). There were no major adverse events or deaths within 30 days in either group. The total cost of consumables was higher in the conventional group (A$19,644.90 vs A$6,239.90). DISCUSSION: This multicenter randomized controlled trial confirmed that the cap-assisted technique is more effective and less costly than the conventional approach and should be first-line treatment for esophageal FBI.

Point Mutations in Exon 1B of APC Reveal Gastric Adenocarcinoma and Proximal Polyposis of the Stomach as a Familial Adenomatous Polyposis Variant.

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is an autosomal-dominant cancer-predisposition syndrome with a significant risk of gastric, but not colorectal, adenocarcinoma. We mapped the gene to 5q22 and found loss of the wild-type allele on 5q in fundic gland polyps from affected individuals. Whole-exome and -genome sequencing failed to find causal mutations but, through Sanger sequencing, we identified point mutations in APC promoter 1B that co-segregated with disease in all six families. The mutations reduced binding of the YY1 transcription factor and impaired activity of the APC promoter 1B in luciferase assays. Analysis of blood and saliva from carriers showed allelic imbalance of APC, suggesting that these mutations lead to decreased allele-specific expression in vivo. Similar mutations in APC promoter 1B occur in rare families with familial adenomatous polyposis (FAP). Promoter 1A is methylated in GAPPS and sporadic FGPs and in normal stomach, which suggests that 1B transcripts are more important than 1A in gastric mucosa. This might explain why all known GAPPS-affected families carry promoter 1B point mutations but only rare FAP-affected families carry similar mutations, the colonic cells usually being protected by the expression of the 1A isoform. Gastric polyposis and cancer have been previously described in some FAP-affected individuals with large deletions around promoter 1B. Our finding that GAPPS is caused by point mutations in the same promoter suggests that families with mutations affecting the promoter 1B are at risk of gastric adenocarcinoma, regardless of whether or not colorectal polyps are present.

Australian clinical practice guidelines for the diagnosis and management of Barrett's esophagus and early esophageal adenocarcinoma.

Barrett's esophagus (BE), a common condition, is the only known precursor to esophageal adenocarcinoma (EAC). There is uncertainty about the best way to manage BE as most people with BE never develop EAC and most patients diagnosed with EAC have no preceding diagnosis of BE. Moreover, there have been recent advances in knowledge and practice about the management of BE and early EAC. To aid clinical decision making in this rapidly moving field, Cancer Council Australia convened an expert working party to identify pertinent clinical questions. The questions covered a wide range of topics including endoscopic and histological definitions of BE and early EAC; prevalence, incidence, natural history, and risk factors for BE; and methods for managing BE and early EAC. The latter considered modification of lifestyle factors; screening and surveillance strategies; and medical, endoscopic, and surgical interventions. To answer each question, the working party systematically reviewed the literature and developed a set of recommendations through consensus. Evidence underpinning each recommendation was rated according to quality and applicability.

Spontaneous remission of Cronkhite-Canada syndrome without immunosuppressive medication in the context of decompensated cirrhosis: A case report.

We present a case of Cronkhite-Canada syndrome in a patient with decompensated cirrhosis who had successful induction of remission with nutritional supplementation alone. We propose that early institution of high-protein, high-energy enteral supplementation should be offered to all patients, especially those with compelling contraindications to immunosuppression.

Repeated intentional foreign body ingestion, what can be done?

Repeated intentional foreign body ingestion (RIFBI) in patients with Emotionally Unstable Personality Disorder (EUPD) is a common clinical presentation to the emergency department. The relationship between repeated foreign body ingestion and a co-existent personality disorder diagnosis is complex, making it challenging to manage. Our institution implemented a novel interdisciplinary model of care for RIFBI as a way of improving health outcomes in this cohort of patients. Our observations following the model of care are presented herein. We encourage other health networks to adopt this model of care for managing RIBFI in EUPD.

Evaluation of the Australian Triage Scale in patients who present to the emergency department with upper gastrointestinal bleeding.

Evaluation of the Australian Triage Scale in patients who present to the emergency department with upper gastrointestinal bleeding BACKGROUND: Upper gastrointestinal bleeding (UGIB) is a common presentation to the emergency department (ED). Study aims were to evaluate the utility of the Australasian Triage Score (ATS) in patients presenting to the ED with UGIB. METHODS: This retrospective observational study included 356 patients over a 2-year period who presented to a metropolitan hospital ED. The ATS was categorised into three groups, ATS 1/2, ATS 3 and ATS 4/5. Primary outcomes explored the relationship between ATS and haemodynamic parameters. Secondary outcomes evaluated the proportion of patients with suspected variceal bleeding and allocated a non-life-threatening ATS category. RESULTS: The study population were distributed by ATS 1/2 (28.7 %), ATS 3 (46.6 %) and ATS 4/5 (24.7 %). Over half of patients with some haemodynamic compromise were allocated an ATS 3 or 4/5. Additionally, 56 % with suspected variceal bleeding and 51 % with syncope were also allocated an ATS category (3 or 4/5). CONCLUSIONS: The utility of the ATS recognises most patients presenting with UGIB at high-risk of adverse outcomes. Additional screening at triage maybe beneficial for those patients with a history of cirrhosis or varices, and UGIB-related syncope. Consideration of an ATS category of 2 for these patients may enable them to access earlier time-critical therapies.

Post-Endoscopy Upper Gastrointestinal Cancer Rate in a Tertiary Referral Centre: An Australian Data Linkage Analysis.

OBJECTIVE: High-quality gastroscopy is critical for early diagnosis of upper gastrointestinal cancers (UGCs), and assessment of missed cancers may serve as a key quality metric. Using a prospective gastroscopy database and data linkage with the Queensland Cancer Registry, we assessed the risk of developing UGC within 3 years of a cancer-negative gastroscopy at an Australian tertiary centre. Additional aims were to identify factors predictive of missed cancer, perform root cause analyses for missed cancers and assess overall survival. DESIGN/METHOD: We identified patients who were diagnosed with UGC within 3 years of undergoing gastroscopy between 2011 and 2016. Non-mucosal cancers, cancers distal to duodenum and patients undergoing surveillance were excluded. Cases diagnosed within 6 months of gastroscopy were defined as detected cancers, while those developing within 6-36 months were defined as missed cancers. Post-endoscopy UGC rate (PEUGIC-3Y) was calculated as ratio of missed over total cancers detected. Demographic, clinical, endoscopic and histologic variables were analysed. RESULTS: A total of 17,131 gastroscopies were performed for 10,393 patients during the study period. One hundred and twenty-six UGCs were diagnosed, including 120 detected UGCs and 6 missed UGCs. The overall PEUGIC-3Y rate was 4.8% (95% CI 2.1-10.4). The missed UGCs included 3 gastric adenocarcinomas, 2 gastro-oesophageal junction adenocarcinomas and 1 oesophageal squamous cell carcinoma. At the preceding 'cancer-negative gastroscopy', no macroscopic abnormalities were detected at the site of future UGC in 5/6 patients. A UGC developed in 2/6 patients despite an apparent adequate examination at index gastroscopy. Age, sex, indication for endoscopy and cancer location or histology were not predictive of missed cases, and survival was comparable between groups. CONCLUSION: We demonstrate that the PEUGIC-3Y rate was 4.8% (95% CI 2.1-10.4). The majority of missed cases were adenocarcinomas of the gastro-oesophageal junction or stomach and developed in segments which were found to be normal at index gastroscopy, highlighting the challenges in detecting subtle mucosal lesions in the upper gastrointestinal tract. While overall survival between patients with detected and post-gastroscopy cancers was comparable, these ultimately represent potential missed opportunities for diagnosing an early cancer and underscore the need for quality improvement in gastroscopy.

Clinicopathological Correlates of Dysplastic Sessile Serrated Lesion: A Prospective Cohort Study With a High Detection Rate.

Background and Aims: Sessile serrated lesions (SSLs) develop colorectal cancer (CRC), through a critical intermediary stage of SSL with dysplasia (SSLd). In this prospective observational study, we aimed to assess clinicopathological correlates of SSLd in the setting of a high lesion-detection rate. Methods: Patients diagnosed with SSL and SSLd from February 2018 until January 2020 were prospectively recruited, and SSLd specimens were re-evaluated by 2 expert pathologists in a blinded manner. Associations were analyzed using multivariate logistic regression models. Results: A total of 6425 patients underwent 7423 colonoscopies, and 2671 SSLs were resected from 1047 patients. The overall SSL detection rate per colonoscopy was 15.9%. The median age of patients with SSL was 54 years (interquartile range, 39-66), and 43.3% were male. After pathologist review, 24 SSLds were confirmed in 20 patients. The median size of SSLd was 8 mm (interquartile range, 5.75-15.25), and 13 of 24 SSLds were <10 mm in size. After multivariate analysis, older age (odds ratio = 1.07, 95% confidence interval = 1.03-1.1) and higher number of synchronous SSLs (odds ratio = 1.12, 95% confidence interval = 1.02-1.23) were associated with the presence of dysplasia. Patient sex and number and size of synchronous adenomas were not associated with the presence of SSLd. Seven of 20 patients with SSLd had synchronous or metachronous SSLd. Six of 20 patients with SSLd met the diagnostic criteria for serrated polyposis syndrome. Conclusion: The overall SSL detection rate was 15.9%, and 0.9% of SSLs were dysplastic. Older age and higher number of synchronous SSL were risk factors for the presence of dysplasia in SSLs. Thirty percent of patients with SSLd had serrated polyposis syndrome, and 35% had multiple SSLd.

Clinical utility of the Glasgow Blatchford Score in patients presenting to the emergency department with upper gastrointestinal bleeding: A retrospective cohort study.

OBJECTIVE: Upper gastrointestinal bleeding (UGIB) is a common presentation to EDs. Limited Australian data are available. Study aims were to assess mortality and re-bleeding rates in patients presenting with UGIB as risk-stratified by the Glasgow Blatchford Score (GBS). METHODS: We conducted a retrospective medical chart review of all patients presenting with UGIB to a Brisbane tertiary hospital ED over a 12-month period. This descriptive study summarised the medical characteristics related to UGIB as risk-stratified by the GBS. Non-variceal bleeding was categorised as low-risk (GBS 0-2) or high-risk (GBS 3+). Variceal bleeding was not risk stratified. RESULTS: A total of 211 patients presented with UGIB to the ED. The median age was 57 years, 67% were male. Mortality rates at 30 days were: 0% for GBS 0-2, 3% (95% confidence interval [CI] 0-6) for GBS 3+ and 10% (95% CI 0-21) for variceal groups. The overall 30-day re-bleeding rate was 4.3% (95% CI 2-7). High-risk patients accessed endoscopy according to international best practice of less than 24 h (GBS 3+, 23.7 h; variceal bleeding, 7.3 h). CONCLUSIONS: Mortality and re-bleeding outcomes are similar to other international UGIB cohorts. Patients with a low-risk bleed were appropriately identified and discharged home. Those at higher risk were correctly identified and accessed timely endoscopy. The GBS demonstrated clinical utility in an Australian ED cohort of UGIB bleeding patients.

Learning colon centreline from optical colonoscopy, a new way to generate a map of the internal colon surface.

Optical colonoscopy is known as a gold standard screening method in detecting and removing cancerous polyps. During this procedure, some polyps may be undetected due to their positions, not being covered by the camera or missed by the surgeon. In this Letter, the authors introduce a novel convolutional neural network (ConvNet) algorithm to map the internal colon surface to a 2D map (visibility map), which can be used to increase the awareness of clinicians about areas they might miss. This was achieved by leveraging a colonoscopy simulator to generate a dataset consisting of colonoscopy video frames and their corresponding colon centreline (CCL) points in 3D camera coordinates. A pair of video frames were used as input to a ConvNet, whereas the output was a point on the CCL and its direction vector. By knowing CCL for each frame and roughly modelling the colon as a cylinder, frames could be unrolled to build a visibility map. They validated their results using both simulated and real colonoscopy frames. Their results showed that using consecutive simulated frames to learn the CCL can be generalised to real colonoscopy video frames to generate a visibility map.

Rational investigation of upper abdominal pain.

BACKGROUND: Upper abdominal pain is a common problem with an extraordinary diversity of possible causes. Many patients have no structural disease, and making the correct diagnosis can be a challenge. The roles of endoscopy, testing for Helicobacter pylori, and imaging techniques have been debated widely and continue to be a matter for discussion. OBJECTIVE: This article details the value of various investigations in the setting of specific presentations of upper abdominal pain. DISCUSSION: Functional dyspepsia is a common cause of upper abdominal pain but the diagnosis should only be made after consideration of more serious pathology. The various organic causes of upper abdominal pain and the appropriate investigations are discussed. Early endoscopy is advisable in the presence of alarm symptoms and in patients over 55 years of age.

Automated visibility map of the internal colon surface from colonoscopy video.

PURPOSE: Optical colonoscopy is a prominent procedure by which clinicians examine the surface of the colon for cancerous polyps using a flexible colonoscope. One of the main concerns regarding the quality of the colonoscopy is to ensure that the whole colonic surface has been inspected for abnormalities. In this paper, we aim at estimating areas that have not been covered thoroughly by providing a map from the internal colon surface. METHODS: Camera parameters were estimated using optical flow between consecutive colonoscopy frames. A cylinder model was fitted to the colon structure using 3D pseudo stereo vision and projected into each frame. A circumferential band from the cylinder was extracted to unroll the internal colon surface (band image). By registering these band images, drift in estimating camera motion could be reduced, and a visibility map of the colon surface could be generated, revealing uncovered areas by the colonoscope. Hidden areas behind haustral folds were ignored in this study. The method was validated on simulated and actual colonoscopy videos. The realistic simulated videos were generated using a colonoscopy simulator with known ground truth, and the actual colonoscopy videos were manually assessed by a clinical expert. RESULTS: The proposed method obtained a sensitivity and precision of 98 and 96 % for detecting the number of uncovered areas on simulated data, whereas validation on real videos showed a sensitivity and precision of 96 and 78 %, respectively. Error in camera motion drift could be reduced by almost 50 % using results from band image registration. CONCLUSION: Using a simple cylindrical model for the colon and reducing drift by registering band images allows for the generation of visibility maps. The current results also suggest that the provided feedback through the visibility map could enhance clinicians' awareness of uncovered areas, which in return could reduce the probability of missing polyps.

Impact of colonoscopy bowel preparation on intestinal microbiota.

The gut microbiota is important in maintaining human health, but numerous factors have the potential to alter its composition. Our aim was to examine the impact of a standard bowel preparation on the intestinal microbiota using two different techniques. Fifteen subjects undergoing colonoscopy consumed a bowel preparation comprised of 10 mg bisacodyl and 2 L polyethylene glycol. The microbiota of stool samples, collected one month before, one week before (pre-colonoscopy), and one week, one month, and three to six months after colonoscopy (post-colonoscopy) was evaluated. Two samples were taken three to six months apart from five healthy subjects who did not undergo colonoscopy. Universal primers targeting the V2-V3 region of the 16S rRNA gene were used to PCR amplify all samples for denaturing gradient gel electrophoresis (PCR-DGGE). Pre- and post-colonoscopy samples were compared using Dice's similarity coefficients. Three samples from ten subjects who underwent colonoscopy, and both samples from the five subjects who didn't, were used for high-throughput sequencing of the V1-V3 region of the 16S rRNA gene. Samples were curated and analysed in Mothur. Results of the DGGE analyses show that the fecal microbiota of a small number of subjects had short-term changes. High-throughput sequencing results indicated that the variation between the samples of subjects who underwent colonoscopy was no greater than the variation observed between samples from subjects who did not. We conclude that bowel preparation does not have a lasting effect on the composition of the intestinal microbiota for the majority of subjects.