Performance of endoscopic submucosal dissection for undifferentiated early gastric cancer: a multicenter retrospective cohort.

Background and study aims Undifferentiated early gastric cancer (UD-EGC) represents an extended indication for endoscopic submucosal dissection (ESD) based on the existing guidelines. This study evaluated the prevalence of UD-EGC recurrence after ESD, and potentially implicated risk factors. Patients and methods Data from 17 centers were collected retrospectively including demographics, endoscopic and pathological findings, and follow-up data from UD-EGC cases treated by ESD. Patients with incomplete resection or advanced disease were excluded. Descriptive statistics quantified variables and calculated the incidence of recurrence. Chi-square test was applied to assess any link between independent variables and relapse; significantly associated variables were inserted to a multivariable regression model. Results Seventy-one patients were eligible, with 2:1 female to male ratio and age of 65.8 ± 11.8 years. Mean lesion size was 33.5 ± 18.8 mm and the most frequent histological subtype was signet ring-cells UGC (2:1). Patients were followed-up every 5.6 ± 3.7 months with a mean surveillance period of 29.3 ± 15.3 months until data collection. Four patients (5.6%) developed local recurrence 8.8 ± 6.5 months post-ESD, with no lymph node or distal metastases been reported. Lesion size was not associated with recurrence ( P = 0.32), in contrast to lymphovascular and perineural invasion which were independently associated with local recurrence ( P = 0.006 and P < 0.001, respectively). Conclusions ESD could be considered as the initial step to manage UD-EGC, providing at least an "entire-lesion" biopsy to guide therapeutic strategy. When histology confirms absence of lymphovascular and perineural invasion, this modality could be therapeutic, providing low recurrence rates.

Predicting residual neoplasia after a non-curative gastric ESD: validation and modification of the eCura system in the Western setting: the W-eCura score.

OBJECTIVE: To evaluate the risk factors for lymph node metastasis (LNM) after a non-curative (NC) gastric endoscopic submucosal dissection (ESD) and to validate and eventually refine the eCura scoring system in the Western setting. Also, to assess the rate and risk factors for parietal residual disease. DESIGN: Retrospective multicentre multinational study of prospectively collected registries from 19 Western centres. Patients who had been submitted to surgery or had at least one follow-up endoscopy were included. The eCura system was applied to assess its accuracy in the Western setting, and a modified version was created according to the results (W-eCura score). The discriminative capacities of the eCura and W-eCura scores to predict LNM were assessed and compared. RESULTS: A total of 314 NC gastric ESDs were analysed (72% high-risk resection (HRR); 28% local-risk resection). Among HRR patients submitted to surgery, 25% had parietal disease and 15% had LNM in the surgical specimen. The risk of LNM was significantly different across the eCura groups (areas under the receiver operating characteristic curve (AUC-ROC) of 0.900 (95% CI 0.852 to 0.949)). The AUC-ROC of the W-eCura for LNM (0.916, 95% CI 0.870 to 0.961; p=0.012) was significantly higher compared with the original eCura. Positive vertical margin, lymphatic invasion and younger age were associated with a higher risk of parietal residual lesion in the surgical specimen. CONCLUSION: The eCura scoring system may be applied in Western countries to stratify the risk of LNM after a gastric HRR. A new score is proposed that may further decrease the number of unnecessary surgeries.

Risk of Residual Neoplasia after a Local-Risk Resection of Colorectal Lesions by Endoscopic Submucosal Dissection: A Multinational Study.

Endoscopic submucosal dissection (ESD) in colorectal lesions is demanding, and a significant rate of non-curative procedures is expected. We aimed to assess the rate of residual lesion after a piecemeal ESD resection, or after an en bloc resection but with positive horizontal margins (local-risk resection-LocRR), for colorectal benign neoplasia. A retrospective multicenter analysis of consecutive colorectal ESDs was performed. Patients with LocRR ESDs for the treatment of benign colorectal lesions with at least one follow-up endoscopy were included. A cohort of en bloc resected lesions, with negative margins, was used as the control. A total of 2255 colorectal ESDs were reviewed; 352 of the ESDs were "non-curative". Among them, 209 were LocRR: 133 high-grade dysplasia and 76 low-grade dysplasia. Ten cases were excluded due to missing data. A total of 146 consecutive curative resections were retrieved for comparison. Compared to the "curative group", LocRRs were observed in lengthier procedures, with larger lesions, and in non-granular LSTs. Recurrence was higher in the LocRR group (16/199, 8% vs. 1/146, 0.7%; p = 0.002). However, statistical significance was lost when considering only en bloc resections with positive horizontal margins (p = 0.068). In conclusion, a higher rate of residual lesion was found after a piecemeal ESD resection, but not after an en bloc resection with positive horizontal margins.

Factors influencing the presence of potentially explosive gases during colonoscopy: Results of the SATISFACTION study.

This study tested the hypothesis that bowel preparation with mannitol should not affect the colonic concentration of H2 and CH4 . Therefore, the SATISFACTION study, an international, multicenter, randomized, parallel-group phase II-III study investigated this issue. The phase II dose-finding part of the study evaluated H2 , CH4 , and O2 concentrations in 179 patients randomized to treatment with 50 g, 100 g, or 150 g mannitol. Phase III of the study compared the presence of intestinal gases in 680 patients randomized (1:1) to receive mannitol 100 g in single dose or a standard split-dose 2 L polyethylene glycol (PEG)-Asc preparation (2 L PEG-Asc). Phase II results showed that mannitol did not influence the concentration of intestinal gases. During phase III, no patient in either group had H2 or CH4 concentrations above the critical thresholds. In patients with H2 and/or CH4 levels above detectable concentrations, the mean values were below the risk thresholds by at least one order of magnitude. The results also highlighted the effectiveness of standard washing and insufflation maneuvers in removing residual intestinal gases. In conclusion, bowel cleansing with mannitol was safe as the concentrations of H2 and CH4 were the same as those found in patients prepared with 2 L PEG-Asc. In both groups, the concentrations of gases were influenced more by the degree of cleansing achieved and the insufflation and washing maneuvers performed than by the preparation used for bowel cleansing. The trial protocol was registered with ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT04759885) and with EudraCT (eudract_number: 2019-002856-18).

Risk of residual neoplasia after a noncurative colorectal endoscopic submucosal dissection for malignant lesions: a multinational study.

BACKGROUND : Endoscopic submucosal dissection (ESD) in colorectal lesions is technically demanding and a significant rate of noncurative procedures is expected. We aimed to assess the rate of residual lesions after a noncurative ESD for colorectal cancer (CRC) and to establish predictive scores to be applied in the clinical setting. METHODS : Retrospective multicenter analysis of consecutive colorectal ESDs. Patients with noncurative ESDs performed for the treatment of CRC lesions submitted to complementary surgery or with at least one follow-up endoscopy were included. RESULTS : From 2255 colorectal ESDs, 381 (17 %) were noncurative, and 135 of these were performed in CRC lesions. A residual lesion was observed in 24 patients (18 %). Surgery was performed in 96 patients and 76 (79 %) had no residual lesion in the colorectal wall or in the lymph nodes. The residual lesion rate for sm1 cancers was 0 %, and for > sm1 cancers was also 0 % if no other risk factors were present. Independent risk factors for lymph node metastasis were poor differentiation and lymphatic permeation (NC-Lymph score). Risk factors for the presence of a residual lesion in the wall were piecemeal resection, poor differentiation, and positive/indeterminate vertical margin (NC-Wall score). CONCLUSIONS : Lymphatic permeation or poor differentiation warrant surgery owing to their high risk of lymph node metastasis, mainly in > sm1 cancers. In the remaining cases, en bloc and R0 resections resulted in a low risk of residual lesions in the wall. Our scores can be a useful tool for the management of patients who undergo noncurative colorectal ESDs.

Predictive Factors of Adequate Bowel Cleansing for Colonoscopy in the Elderly: A Retrospective Analysis of a Prospective Cohort.

Factors affecting the quality of bowel preparation for colonoscopy in the elderly are not fully known, and current guidelines provide no specific recommendations. This study aimed to assess the difference in bowel cleansing in young and elderly patients and evaluate predictors of bowel cleansing in the elderly. We retrospectively reviewed a prospective cohort of 1289 patients performing colonoscopy after a 1-, 2-, or 4-L PEG-based preparation. All 1289 were included in the analysis. Overall, 44.6% of patients were aged ≥65 years. Cleansing success (CS) was achieved in 77.3% and 70.3% of patients aged <65 years and ≥65 years, respectively. At multivariable analysis, split regimen (OR = 2.43, 95% CI = 1.34−4.38; p = 0.003), adequate cleansing at previous colonoscopy (OR = 2.29, 95% CI = 1.14−4.73; p = 0.02), tolerability score (OR = 1.29, 95% CI = 1.16−1.44; p < 0.001), a low-fiber diet for at least 3 days (OR = 2.45, 95% CI = 1.42−4.24; p = 0.001), and colonoscopy within 5 h after the end of preparation (OR = 2.67, 95% CI = 1.28−5.56; p = 0.008) were independently associated with CS in the elderly. Combining a low-fiber diet for at least 3 days, split preparation, and colonoscopy within 5 h allowed a CS rate above 90% and should always be encouraged. A 1-L PEG-ASC preparation was also associated with greater high-quality cleansing of the right colon and may be preferred.

From advanced diagnosis to advanced resection in early neoplastic colorectal lesions: Never-ending and trending topics in the 2020s.

Colonoscopy represents the most widespread and effective tool for the prevention and treatment of early stage preneoplastic and neoplastic lesions in the panorama of cancer screening. In the world there are different approaches to the topic of colorectal cancer prevention and screening: different starting ages (45-50 years); different initial screening tools such as fecal occult blood with immunohistochemical or immune-enzymatic tests; recto-sigmoidoscopy; and colonoscopy. The key aspects of this scenario are composed of a proper bowel preparation that ensures a valid diagnostic examination, experienced endoscopist in detection of preneoplastic and early neoplastic lesions and open-minded to upcoming artificial intelligence-aided examination, knowledge in the field of resection of these lesions (from cold-snaring, through endoscopic mucosal resection and endoscopic submucosal dissection, up to advanced tools), and management of complications.

Quality performance measures in upper gastrointestinal endoscopy for lesion detection: Italian AIGO-SIED-SIGE joint position statement.

Esophagogastroduodenoscopy (EGD) plays a crucial role in the management of gastroduodenal diseases by allowing a direct and accurate evaluation of the mucosa and the execution of several operative maneuvers. Despite a constant development of new imaging tools and operative devices, the widespread use of EGD has not resulted in a significant reduction of mortality for patients affected by esophageal/gastric cancer during the last three decades in Western countries. Evidence indicates that this disheartening scenario derives from a high variability of execution of EGD which determines its quality and diagnostic yield, delaying the diagnosis of neoplastic diseases. Based on this evidence, in recent years many scientific societies have produced different position papers aimed at defining quality performance measures in EGD. Thus, the Italian Association of Gastroenterologists and Endoscopists, the Italian Society of Digestive Endoscopy and the Italian Society of Gastroenterology have produced this joint document based on the review of ASGE, ACG, BSG, ESGE and Asian Consensus EGD position papers with the aim of indicating the quality standards of EGD (pre-, intra- and post-procedure) focused on lesion detection to be adopted in the Italian context.

Digital single-operator cholangioscopy in diagnostic and therapeutic bilio-pancreatic diseases: A prospective, multicenter study.

BACKGROUND AND AIM: Digital single-operator cholangioscopy (D-SOC) is an endoscopic procedure that is increasingly used for the management of bilio-pancreatic diseases. We aimed to investigate the efficacy and safety of D-SOC for diagnostic and therapeutic indications. METHODS: This is a multicenter, prospective study(January 2016-June 2019) across eighteen tertiary centers. The primary outcome was procedural success of D-SOC. Secondary outcomes were: D-SOC visual assessment and diagnostic yield of SpyBite biopsy in cases of biliary strictures, stone clearance rate in cases of difficult biliary stones, rate of adverse events(AEs) for all indications. RESULTS: D-SOC was performed in 369 patients (201(54,5%) diagnostic and 168(45,5%)therapeutic). Overall, procedural success rate was achieved in 360(97,6%) patients. The sensitivity, specificity, PPV, NPV and accuracy in biliary strictures were: 88,5%, 77,3%, 83,3%, 84,1% and 83,6% for D-SOC visual impression; 80,2%, 92,6%, 95,1%, 72,5% and 84,7% for the SpyBite biopsy, respectively. For difficult biliary stones, complete duct clearance was obtained in 92,1% patients (82,1% in a single session). Overall, AEs occurred in 37(10%) cases.The grade of AEs was mild or moderate for all cases, except one which was fatal. CONCLUSION: D-SOC is effective for diagnostic and therapeutic indications.Most of the AEs were minor and managed conservatively, even though a fatal event has happened that is not negligible and should be considered before using D-SOC.

Therapeutic strategies for gastroenteropancreatic neuroendocrine neoplasms: State-of-the-art and future perspectives.

Although gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have always been considered rare tumors, their incidence has risen over the past few decades. They represent a highly heterogeneous group of neoplasms with several prognostic factors, including disease stage, proliferative index (Ki67), and tumor differentiation. Most of these neoplasms express somatostatin receptors on the cell surface, a feature that has important implications in terms of prognosis, diagnosis, and therapy. Although International Guidelines propose algorithms aimed at guiding therapeutic strategies, GEP-NEN patients are still very different from one another, and the need for personalized treatment continues to increase. Radical surgery is always the best option when feasible; however, up to 80% of cases are metastatic upon diagnosis. Regarding medical treatments, as GEP-NENs are characterized by relatively long overall survival, multiple therapy lines are adopted during the lifetime of these patients, but the optimum sequence to be followed has never been clearly defined. Furthermore, although new molecular markers aimed at predicting the response to therapy, as well as prognostic scores, are currently being studied, their application is still far from being part of daily clinical practice. As they represent a complex disease, with therapeutic protocols that are not completely standardized, GEP-NENs require a multidisciplinary approach. This review will provide an overview of the available therapeutic options for GEP-NENs and attempts to clarify the possible approaches for the management of these patients and to discuss future perspectives in this field.

Clinical outcome of non-curative endoscopic submucosal dissection for early colorectal cancer.

OBJECTIVE: Endoscopic submucosal dissection (ESD) in a curative intent for submucosa-invasive early (T1) colorectal cancers (T1-CRCs) often leads to subsequent surgical resection in case of histologic parameters indicating higher risk of nodal involvement. In some cases, however, the expected benefit may be offset by the surgical risks, suggesting a more conservative approach. DESIGN: Retrospective analysis of consecutive patients with T1-CRC who underwent ESD at 13 centres ending inclusion in 2019 (n=3373). Cases with high risk of nodal involvement (non-curative ESD: G3, submucosal invasion>1000 µm, lymphovascular involvement, budding or incomplete resection/R1) were analysed if follow-up data (endoscopy/imaging) were available, regardless of the postendoscopic management (follow-up vs surgery) selected by the multidisciplinary teams in these institutions. Comorbidities were classified according to Charlson Comorbidity Index (CCI). Outcomes were disease recurrence, death and disease-related death rates in the two groups. Rate of residual disease (RD) at both the previous resection site and regional lymph nodes was assessed in the surgical cases as well as from follow-up in the follow-up group. RESULTS: Of 604 patients treated by colorectal ESD for submucosally invasive cancer, 207 non-curative resections (34.3%) were included (138 male; mean age 67.6±10.9 years); in 65.2% of cases, no complete resection was achieved (R1). Of the 207 cases, 60.9% (n=126; median CCI: 3; IQR: 2-4) underwent surgical treatment with RD in 19.8% (25/126), while 39.1% (n=81, median CCI: 5; IQR: 4-6) were followed up by endoscopy in all cases. Patients in the follow-up group had a higher overall mortality (HR=3.95) due to non-CRC causes (n=9, mean survival after ESD 23.7±13.7 months). During this follow-up time, tumour recurrence and disease-specific survival rates were not different between the groups (median follow-up 30 months; range: 6-105). CONCLUSION: Following ESD for a lesion at high risk of RD, follow-up only may be a reasonable choice in patients at high risk for surgery. Also, endoscopic resection quality should be improved. TRIAL REGISTRATION NUMBER: NCT03987828.

The unmet needs for identifying the ideal bowel preparation.

Colonoscopy, since it was first employed over 60 years ago, is now the gold standard method for visualizing the mucosa of the colon, but should be of good quality. Many factors affect quality, including the type of health service organization, type of facility, staff, equipment, patient characteristics, and bowel preparation (BP). The adequacy of bowel cleansing is critical, but, unfortunately, may be inadequate in up to one-third of procedures. The current article will present and discuss the main BPs and their drawbacks, which include patient-dependent and procedure-dependent factors. Cleansing quality depends on the ease/complexity of solution preparation, volume, taste, and timing of consumption. Consequently, important positive factors include simple instructions, easy preparation of the solution, low volume, pleasant taste, short drinking time (e.g. <30 min), and splitting the dose between the evening before and the morning of the colonoscopy (or even better, only one dose in the early morning to avoid night-time problems), and short onset of action. The BP solution must also be safe with negligible side effects. Furthermore, a positive experience supports patient willingness to repeat the procedure.

Effectiveness and safety of underwater techniques in gastrointestinal endoscopy: a comprehensive review of the literature.

BACKGROUND: Conventional endoscopic resection techniques such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), represent the standard of care for treatment of superficial gastrointestinal lesions. In 2012 a novel technique called underwater endoscopic mucosal resection (U-EMR) was described by Binmoeller and colleagues. This substantial variation from the standard procedure was afterwards applied at endoscopic submucosal dissection (U-ESD) and recently proposed also for peroral endoscopic myotomy (U-POEM) and endoscopic full-thickness resection (U-EFTR). METHODS: This paper aims to perform a comprehensive review of the current literature related to supporting the underwater resection techniques with the aim to evaluate their safety and efficacy. RESULTS: Based on the current literature U-EMR appears to be feasible and safe. Comparison studies showed that U-EMR is associated with higher "en-bloc" and R0 resection rates for colonic lesions, but lower "en-bloc" and R0 resection rates for duodenal non-ampullary lesions, compared to standard EMR. In contrast to U-EMR, little evidence supporting U-ESD are currently available. A single comparison study on gastric lesions showed that U-ESD had shorter procedural times and allowed a similar "en-bloc" resection rates compared to standard ESD. No comparison studies between U-ESD and ESD are available for colonic lesions. Finally, only some anecdotal experiences have been reported for U-POEM or U-EFTR, and the feasibility and effectiveness of these techniques need to be further investigated. CONCLUSIONS: Further prospective studies are necessary to better explore the advantages of underwater techniques compared to the respective standards of care, especially in the setting of U-ESD where consistent data are lacking and where standardization of the technique is needed.

Effectiveness and Tolerability of Very-low Volume Preparation for Colonoscopy: A Narrative Review.

An adequate bowel preparation is essential for a successful colonoscopy, in particular, in the setting of colorectal cancer screening. However, up to one-quarter of colonoscopies are associated with inadequate bowel preparation, which may result in reduced polyp and adenoma detection rates, prolonged procedural time, and an increased likelihood of repeat the procedure. The ideal intestinal preparation should provide an optimal observation of the mucosa (at least > 90% of the visible surface), with adequate acceptability and safety for the patient. With this premise, a very low-volume 1 L PEG-ASC solution (Plenvu; Norgine, Harefield, United Kingdom) has been recently introduced to improve patients' experience in colonoscopy by reducing the total intake of liquids to be consumed. This could represent a valid option for bowel cleansing, considering CRC screening and surveillance programs, improving both the quality of the examination and the patients' compliance. Nevertheless, it must be emphasized that a "one size fits all" preparation strategy is not feasible and that a bowel preparation regime must always be selected and tailored by the clinician for each patient, evaluating the best options on a case by case basis. This narrative review aims to sum up the evidence regarding new bowel preparation regimens in order to help clinicians to tailor the best choice for patients undergoing colonoscopy.

Gastrointestinal tract injuries after thermal ablative therapies for hepatocellular carcinoma: A case report and review of the literature.

BACKGROUND: Radiofrequency ablation (RFA) and microwave ablation (MWA) represent the standard of care for patients with early hepatocellular carcinoma (HCC) who are unfit for surgery. The incidence of reported adverse events is low, ranging from 2.4% to 13.1% for RFA and from 2.6% to 7.5% for MWA. Gastrointestinal tract (GIT) injury is even more infrequent (0.11%), but usually requires surgery with an unfavourable prognosis. Due to its low incidence and the retrospective nature of the studies, the literature reporting this feared complication is heterogeneous and in many cases lacks information on tumour characteristics, comorbidities and treatment approaches. CASE SUMMARY: A 77-year-old man who had undergone extended right hepatectomy for HCC was diagnosed with early disease recurrence with a small nodule compatible with HCC in the Sg4b segment of the liver with a subcapsular location. He was treated with percutaneous RFA and a few week later he was urgently admitted to the Surgery ward for abdominal pain and fever. A subcutaneous abscess was diagnosed and treated by percutaneous drainage. A fistulous tract was then documented by the passage of contrast material from the gastric antrum to the abdominal wall. The oesophagogastroduodenoscopy confirmed a circular wall defect at the lesser curvature of gastric antrum, leading directly to the purulent abdominal collection. An over-the-scope clip (OTSC) was used to successfully close the defect. CONCLUSION: This is the first reported case of RFA-related GIT injury to have been successfully treated with an OTSC, which highlights the role of this endoscopic treatment for the management of this complication.

Management of antiplatelet or anticoagulant therapy in endoscopy: A review of literature.

Endoscopic procedures hold a basal risk of bleeding that depends on the type of procedure and patients' comorbidities. Moreover, they are often performed in patients taking antiplatelet and anticoagulants agents, increasing the potential risk of intraprocedural and delayed bleeding. Even if the interruption of antithrombotic therapies is undoubtful effective in reducing the risk of bleeding, the thromboembolic risk that follows their suspension should not be underestimated. Therefore, it is fundamental for each endoscopist to be aware of the bleeding risk for every procedure, in order to measure the risk-benefit ratio for each patient. Moreover, knowledge of the proper management of antithrombotic agents before endoscopy, as well as the adequate timing for their resumption is essential. This review aims to analyze current evidence from literature assessing, for each procedure, the basal risk of bleeding and the risk of bleeding in patients taking antithrombotic therapy, as well as to review the recommendation of American society for gastrointestinal endoscopy, European society of gastrointestinal endoscopy, British society of gastroenterology, Asian pacific association of gastroenterology and Asian pacific society for digestive endoscopy guidelines for the management of antithrombotic agents in urgent and elective endoscopic procedures.

Effectiveness of very low-volume preparation for colonoscopy: A prospective, multicenter observational study.

BACKGROUND: The effectiveness of colonoscopy strictly depends on adequate bowel cleansing. Recently, a 1 L polyethylene glycol plus ascorbate (PEG-ASC) solution (Plenvu; Norgine, Harefield, United Kingdom) has been introduced on the evidence of three phase-3 randomized controlled trials, but it had never been tested in the real-life. AIM: To assess the effectiveness and tolerability of the 1 L preparation compared to 4 L and 2 L- PEG solutions in a real-life setting. METHODS: All patients undergoing a screening or diagnostic colonoscopy after a 4, 2 or 1 L PEG preparation, were consecutively enrolled in 5 Italian centers from September 2018 to February 2019. The primary endpoints of the study were the assessment of bowel cleansing success and high-quality cleansing of the right colon. The secondary endpoints were the evaluation of tolerability, adherence and safety of the different bowel preparations. Bowel cleansing was assessed through the Boston Bowel Preparation Scale. Adherence was defined as consumption of at least 75% of each dose, while tolerability was evaluated through a semi-quantitative scale. Safety was systematically monitored through adverse events reporting. RESULTS: Overall, 1289 met the inclusion criteria and were enrolled in the study. Of these, 490 patients performed a 4 L-PEG preparation (Selgesse®), 566 a 2 L-PEG cleansing (Moviprep® or Clensia®) and 233 a 1 L-PEG preparation (Plenvu®). Bowel cleansing by Boston Bowel Preparation Scale was 6.5 ± 1.5 overall and 6.3 ± 1.5, 6.2 ± 1.5, 7.3 ± 1.5 (P < 0.001) in the subgroups of 4 L, 2 L and 1 L-PEG preparation, respectively. Cleansing success was achieved in 72.4%, 74.1% and 90.1% (P < 0.001), while a high-quality cleansing of the right colon in 15.9%, 12.0% and 41.4% (P < 0.001) for 4 L, 2 L and 1 L-PEG preparation groups, respectively. The 1 L preparation was the most tolerated compared to the 2 and 4 L-PEG solutions in the absence of serious adverse events within any of the three groups. Multiple regression models confirmed 1 L PEG-ASC preparation as an independent predictor of overall cleansing success, high-quality cleansing of the right colon and of tolerability. CONCLUSION: This study supports the effectiveness and tolerability of 1 L PEG-ASC, also showing it is an independent predictor of overall cleansing success, high-quality cleansing of the right colon and of tolerability.