Recurrence following successful eradication of neoplasia with endoscopic mucosal resection compared with endoscopic submucosal dissection in Barrett's esophagus: a retrospective comparison.

BACKGROUND: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are effective treatments for Barrett's neoplasia. However, little is known about recurrence rates following these techniques. We compared long-term neoplasia recurrence rates following EMR and ESD. METHODS: This study included patients with Barrett's neoplasia (high grade dysplasia/adenocarcinoma) treated between July 2019 and December 2023 at a tertiary referral center in Canada. Outcomes were residual neoplasia at first follow-up, complete remission of neoplasia (CRN), and neoplasia recurrence following CRN. RESULTS: 157 patients were included (87 EMR, 70 ESD). Compared with EMR, the ESD group had larger lesions (median 2 vs. 3 cm, P<0.05), more adenocarcinoma (85.1% vs. 94.3%, P = 0.07), and deeper submucosal invasion (T1a: 71.6% vs. 75.8%; T1b-SM1: 25.7% vs. 6.1%; T1b≥SM2: 2.7% vs. 18.2%; P<0.05). Among 124 patients with follow-up (71 EMR, 53 ESD), 84.9% of ESD-treated patients had curative resections (i.e. R0 resection with low risk for lymph node metastasis), whereas 94.4% of EMR-treated patients had deep margin R0 resection of low risk lesions. At first follow-up, residual neoplasia (14.1% vs. 11.3%) and CRN (97.2% vs. 100%) were similar in the EMR and ESD groups, but neoplasia recurrence following CRN was significantly higher with EMR (13% vs. 1.9%, P<0.05), with cumulative probability of recurrence at 3 years of 18.3% vs. 4.2%, respectively. CONCLUSIONS: Neoplasia recurrence following CRN was significantly higher following EMR compared with ESD, suggesting that ESD may be superior to EMR in preventing neoplasia recurrence in Barrett's esophagus.

Unified Magnifying Endoscopic Classification (UMEC) of Gastrointestinal Lesions: A North American Validation Study.

Background and study aim: Magnifying endoscopy enables the diagnosis of advanced neoplasia throughout the gastrointestinal tract. The unified magnifying endoscopic classification (UMEC) framework unifies optical diagnosis criteria in the esophagus, stomach, and colon, dividing lesions into three categories: non-neoplastic, intramucosal neoplasia, and deep submucosal invasive cancer. This study aims to ascertain the performance of North American endoscopists when using the UMEC. Methods: In this retrospective cohort study, five North American endoscopists without prior training in magnifying endoscopy independently diagnosed images of gastrointestinal tract lesions using UMEC. All endoscopists were blinded to endoscopic findings and histopathological diagnosis. Using histopathology as the gold standard, the endoscopists' diagnostic performances using UMEC were evaluated. Results: A total of 299 lesions (77 esophagus, 92 stomach, and 130 colon) were assessed. For esophageal squamous cell carcinoma, the sensitivity, specificity, and accuracy ranged from 65.2% (95%CI: 50.9-77.9) to 87.0% (95%CI: 75.3-94.6), 77.4% (95%CI: 60.9-89.6) to 96.8% (95%CI: 86.8-99.8), and 75.3% to 87.0%, respectively. For gastric adenocarcinoma, the sensitivity, specificity, and accuracy ranged from 94.9% (95%CI: 85.0-99.1) to 100%, 52.9% (95%CI: 39.4-66.2) to 92.2% (95%CI: 82.7-97.5), and 73.3% to 93.3%. For colorectal adenocarcinoma, the sensitivity, specificity, and accuracy ranged from 76.2% (95%CI: 62.0-87.3) to 83.3% (95%CI: 70.3-92.5), 89.7% (95%CI: 82.1-94.9) to 97.7% (95%CI: 93.1-99.6), and 86.8% to 90.7%. Intraclass correlation coefficients indicated good to excellent reliability. Conclusion: UMEC is a simple classification that may be used to introduce endoscopists to magnifying narrow-band imaging and optical diagnosis, yielding satisfactory diagnostic accuracy.

Comparison of Endoscopic Mucosal Resection versus Endoscopic Submucosal Dissection for Barrett's Neoplasia and Esophageal Adenocarcinoma: A Systematic Review and Meta-Analysis.

BACKGROUND AND AIMS: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are both accepted resection strategies for Barrett's esophagus-related neoplasia and esophageal adenocarcinoma (EAC). However, a lack of consensus exists regarding which technique offers superior outcomes. This study aims to systematically review the evidence comparing EMR versus ESD in treating Barrett's neoplasia and EAC. METHODS: We searched three databases (Embase, MEDLINE, Cochrane Central) until October 2023. We included studies comparing the efficacy of EMR and ESD for Barrett's neoplasia and EAC. Primary outcomes include en bloc, R0, and curative resection, complete remission of dysplasia (CRD), and local recurrence. Secondary outcomes encompass adverse events. RESULTS: Our search identified 905 records. Eleven studies were included in the final analyses. Data showed significantly higher en bloc resection rates with ESD [odds ratio(OR)=27.36 (95% confidence intervals(CI):7.12-105.21), p<0.01, 6 studies]. R0 resection rates were significantly higher with ESD [OR=5.73 (95%CI:2.32-14.16), p<0.01, 7 studies]. Curative resection rates tended to be higher with ESD [OR=3.49 (95%CI:0.86-14.14), p=0.080, 4 studies]. There was no significant difference in CRD rates [OR=0.92 (95%CI:0.37-2.26),p=0.86, 3 studies]. Local recurrence rates tended to be lower with ESD [OR=0.35 (95%CI: 0.11-1.04), p=0.058, 10 studies]. As for adverse events, there was no significant difference in bleeding, perforation, and postoperative stricture rates. CONCLUSIONS: This systematic review and meta-analysis demonstrates that ESD achieves higher en bloc, R0 and curative resection rates, with a tendency toward lower recurrence rates. These results suggest that ESD may be a more effective option for managing Barrett's neoplasia and EAC.

Establishment of standards for the referral of large nonpedunculated colorectal polyps: an international expert consensus using a modified Delphi process.

BACKGROUND AND AIMS: Resection of colorectal polyps has been shown to decrease the incidence and mortality of colorectal cancer. Large nonpedunculated colorectal polyps are often referred to expert centers for endoscopic resection, which requires relevant information to be conveyed to the therapeutic endoscopist to allow for triage and planning of resection technique. The primary objective of this study was to establish minimum expected standards for the referral of large nonpedunculated colonic polyps for potential endoscopic resection. METHODS: A Delphi method was used to establish consensus on minimum expected standards for the referral of large colorectal polyps among a panel of international endoscopy experts. The expert panel was recruited through purposive sampling, and 3 rounds of surveys were conducted to achieve consensus. Quantitative and qualitative data were analyzed for each round. RESULTS: A total of 24 international experts from diverse continents participated in the Delphi study, resulting in consensus on 19 statements related to the referral of large colorectal polyps. The identified factors, including patient demographic characteristics, relevant medications, lesion factors, photodocumentation, and the presence of a tattoo, were deemed important for conveying the necessary information to therapeutic endoscopists. The mean scores for the statements, which were scored on a scale of 1 to 10, ranged from 7.04 to 9.29, with high percentages of experts considering most statements as a very high priority. Subgroup analysis according to continent revealed some variations in consensus rates among experts from different regions. CONCLUSIONS: The identified consensus statements can aid in improving the triage and planning of resection techniques for large colorectal polyps, ultimately contributing to the reduction of colorectal cancer incidence and mortality.

Aspirin exposure and its association with metal stent patency in malignant distal biliary obstruction: a large international multicenter propensity score-matched study.

BACKGROUND AND AIMS: Stent dysfunction is common after ERCP with self-expandable metal stent (SEMS) insertion for malignant distal biliary obstruction (MDBO). Chronic aspirin (acetylsalicylic acid; ASA) exposure has been previously shown to potentially decrease this risk. We aim to further ascertain the protective effect of ASA and to identify other predictors of stent dysfunction. METHODS: This multicenter retrospective cohort study was conducted at 9 sites in Canada and 1 in the United States. Patients with MDBO who underwent ERCP with SEMS placement between January 2014 and December 2019 were included and divided into 2 cohorts: ASA exposed (ASA-E) and ASA unexposed (ASA-U). Propensity-score matching (PSM) was performed to limit selection bias. Matched variables were age, sex, tumor stage, and type of metal stent. The primary outcome was the hazard rate of stent dysfunction. A multivariable Cox proportional hazards model was used to identify independent predictors of stent dysfunction. RESULTS: Of 1396 patients assessed, after PSM 496 patients were analyzed (248 ASA-E and 248 ASA-U). ERCP with SEMS placement was associated with a high clinical success of 82.2% in ASA-E and 81.2% in ASA-U cohorts (P = .80). One hundred eighty-four patients had stent dysfunction with a mean stent patency time of 229.9 ± 306.2 days and 245.4 ± 241.4 days in ASA-E and ASA-U groups, respectively (P = .52). On multivariable analysis, ASA exposure did not protect against stent dysfunction (hazard ratio [HR], 1.25; 95% confidence interval [CI], .96-1.63). An etiology of pancreatic cancer (HR, 1.36; 95% CI, 1.15-1.61) predicted stent dysfunction, whereas cancer therapy was protective (HR, .73; 95% CI, .55-.96). Chronic ASA use was not associated with an increased risk for adverse events including bleeding, post-ERCP pancreatitis, and perforation. CONCLUSIONS: In this large, multicenter study using PSM, chronic exposure to ASA did not protect against stent dysfunction in MDBO. Instead, the analysis revealed that the etiology of pancreatic cancer was an independent predictor of stent dysfunction and cancer therapy was protective.

Endoscopic Ultrasound-Guided Biliary Drainage of First Intent With a Lumen-Apposing Metal Stent vs Endoscopic Retrograde Cholangiopancreatography in Malignant Distal Biliary Obstruction: A Multicenter Randomized Controlled Study (ELEMENT Trial).

BACKGROUND & AIMS: Endoscopic ultrasound-guided choledochoduodenostomy with a lumen-apposing metal stent (EUS-CDS) is a promising modality for management of malignant distal biliary obstruction (MDBO) with potential for better stent patency. We compared its outcomes with endoscopic retrograde cholangiopancreatography with metal stenting (ERCP-M). METHODS: In this multicenter randomized controlled trial, we recruited patients with MDBO secondary to borderline resectable, locally advanced, or unresectable peri-ampullary cancers across 10 Canadian institutions and 1 French institution. This was a superiority trial with a noninferiority assessment of technical success. Patients were randomized to EUS-CDS or ERCP-M. The primary end point was the rate of stent dysfunction at 1 year, considering competing risks of death, clinical failure, and surgical resection. Analyses were performed according to intention-to-treat principles. RESULTS: From February 2019 to February 2022, 144 patients were recruited; 73 were randomized to EUS-CDS and 71 were randomized to ERCP-M. The mean (SD) procedure time was 14.0 (11.4) minutes for EUS-CDS and 23.1 (15.6) minutes for ERCP-M (P < .01); 40% of the former was performed without fluoroscopy. Technical success was achieved in 90.4% (95% CI, 81.5% to 95.3%) of EUS-CDS and 83.1% (95% CI, 72.7% to 90.1%) of ERCP-M with a risk difference of 7.3% (95% CI, -4.0% to 18.8%) indicating noninferiority. Stent dysfunction occurred in 9.6% vs 9.9% of EUS-CDS and ERCP-M cases, respectively (P = .96). No differences in adverse events, pancreaticoduodenectomy and oncologic outcomes, or quality of life were noted. CONCLUSIONS: Although not superior in stent function, EUS-CDS is an efficient and safe alternative to ERCP-M in patients with MDBO. These findings provide evidence for greater adoption of EUS-CDS in clinical practice as a complementary and exchangeable first-line modality to ERCP in patients with MDBO. CLINICALTRIALS: gov, Number: NCT03870386.

Predictors of recurrence of dysplasia or cancer in patients with dysplastic Barrett's esophagus following complete eradication of dysplasia: a single-center retrospective cohort study.

BACKGROUND AND AIMS: Endoscopic mucosal resection (EMR) and radiofrequency ablation (RFA) for Barrett's esophagus (BE)-related high-grade dysplasia (HGD) and early esophageal adenocarcinoma (EAC) are considered effective treatments for eradication of BE. Little is known about the impact of achieving complete eradication of intestinal metaplasia (CE-IM) following the complete eradication of neoplasia (CE-N), specifically if CE-IM reduces the risk of recurrent dysplasia. METHODS: Retrospective cohort study of consecutive patients with BE and HGD or intramucosal cancer (IMC)-treated endoscopically at a tertiary referral center between 2001 and 2019. Association between CE-IM and recurrent dysplasia after CE-N was evaluated. RESULTS: A total of 433 patients treated with EMR and/or RFA were included. Of these, 381 (88%) achieved CE-N, of which 345 (80%) had adequate follow-up for inclusion in the analysis. A total of 266 (77%) patients achieved CE-IM; with a median follow-up since initial treatment for HGD/IMC of 45.9 months (IQR 25.9, 93.1); 20 patients (5.8%) had recurrent dysplasia after achieving CE-N. Kaplan Meier survival curves revealed that time free of recurrence in those who achieved CE-IM was significantly higher (p = 0.002). In the multivariable analysis, CE-IM was associated with a significant lower hazard of recurrence (HR 0.2, 95% CI 0.1, 0.6), whereas the number of endoscopic treatments to achieve CE-N was associated with a significant higher hazard of recurrence (HR 1.1, 95% CI 1.0, 1.2). CONCLUSION: Achieving CE-IM following CE-N reduces the risk of recurrent dysplasia and should be considered a treatment target among patients with BE undergoing endoscopic therapies for HGD or EAC.

Psychological interventions for reducing anxiety in patients undergoing first-time colonoscopy: a pilot and feasibility study.

OBJECTIVES: To assess the feasibility of a randomized controlled trial (RCT), evaluating the efficacy and patients' perceptions of a psychological intervention aimed at reducing anxiety levels in adults undergoing first-time colonoscopy. METHODS: Adults undergoing first-time colonoscopy were randomized to a psychological intervention vs. sham intervention. The primary outcome was feasibility, defined as a recruitment rate of >50%. Patients' state anxiety was assessed before and after the intervention using the state-trait inventory for cognitive and somatic anxiety (STICSA) score. Follow-up interviews were performed within 1 week with a sample of patients and focus groups with clinical staff. RESULTS: A total of 130 patients were recruited from 180 eligible patients (72%). Eighty were randomized and completed the study (n = 39) in the psychological intervention group and (n = 41) in the sham. In the psychological intervention group, pre- and postmedian STICSA scores were 29 and 24 (P < 0.001), respectively. In the sham group, pre- and postmedian scores were 31 and 25 (P < 0.001), respectively. Follow-up interviews with patients (n = 13) suggested that 100% of patients perceived the psychological intervention as beneficial and would recommend it to others. CONCLUSION: The study was feasible. Patients in both groups improved their anxiety scores, but there were no significant differences between arms. Despite this, patients receiving psychological intervention perceived a benefit from the relaxation exercises.

Educational interventions are associated with improvements in colonoscopy quality indicators: a systematic review and meta-analysis.

Background and study aims The quality of screening-related colonoscopy depends on several physician- and patient-related factors. Adenoma detection rate (ADR) varies considerably between endoscopists. Educational interventions aim to improve endoscopists' ADRs, but their overall impact is uncertain. We aimed to assess whether there is an association between educational interventions and colonoscopy quality indicators. Methods A comprehensive search was performed through August 2019 for studies reporting any associations between educational interventions and any colonoscopy quality indicators. Our primary outcome of interest was ADR. Two authors assessed eligibility criteria and extracted data independently. Risk of bias was also assessed for included studies. Pooled rate ratios (RR) with 95 % confidence intervals (CI) were reported using DerSimonian and Laird random effects models. Results From 2,253 initial studies, eight were included in the meta-analysis for ADR, representing 86,008 colonoscopies. Educational interventions were associated with improvements in overall ADR (RR 1.29, 95 % CI 1.25 to 1.42, 95 % prediction interval 1.09 to 1.53) and proximal ADR (RR 1.39, 95 % CI 1.29 to 1.48), with borderline increases in withdrawal time, ([WT], mean difference 0.29 minutes, 95 % CI - 0.12 to 0.70 minutes). Educational interventions did not affect cecal intubation rate ([CIR], RR 1.01, 95 % CI 1.00 to 1.01). Heterogeneity was considerable across many of the analyses. Conclusions Educational interventions are associated with significant improvements in ADR, in particular, proximal ADR, and are not associated with improvements in WT or CIR. Educational interventions should be considered an important option in quality improvement programs aiming to optimize the performance of screening-related colonoscopy.

Association Between Age and Complications After Outpatient Colonoscopy.

Importance: There are insufficient data describing the incidence and risk factors of postcolonoscopy complications in older individuals. Objective: To assess the association between older age (≥75 years) and the risk of postcolonoscopy complications. Design, Setting, and Participants: This population-based retrospective cohort study included adults (≥50 years) undergoing outpatient colonoscopy between April 2008 and September 2017, identified from Ontario administrative databases. Individuals with inflammatory bowel disease and hereditary colorectal cancer syndromes were excluded. The study population was subdivided into a colorectal cancer screening-eligible cohort (patients aged 50-74 years) and an older cohort (patients aged ≥75 years). The statistical analysis was conducted from December 2018 to September 2019. Exposures: Older age (≥75 years). Main Outcomes and Measures: The primary outcome was postcolonoscopy complications, defined as the composite of hospitalization or emergency department visits in the 30-day period after the outpatient colonoscopy. Secondary outcomes included incidence of surgically treated colorectal cancer and all-cause mortality at 30 days. Independent variables associated with postcolonoscopy complications were also assessed. Results: The study sample included 38 069 patients; the mean (SD) age was 65.2 (10.1) years, there were 19 037 women (50.0%), and 27 831 patients (73.1%) underwent a first colonoscopy. The cumulative incidence of complications was 3.4% (1310 patients) in the overall population, and it was higher in individuals aged 75 years or older (515 of 7627 patients [6.8%]) than in screening-eligible cohort (795 of 30 443 patients [2.6%]) (P < .001). Independent risk factors for postcolonoscopy complications were age 75 years or older (odds ratio [OR], 2.3; 95% CI, 2.0-2.6), anemia (OR, 1.4; 95% CI, 1.2-1.7), cardiac arrhythmia (OR, 1.7; 95% CI, 1.2-2.2), congestive heart failure (OR, 3.4; 95% CI, 2.5-4.6), hypertension (OR, 1.2; 95% CI, 1.0-1.5), chronic kidney disease (OR, 1.8; 95% CI, 1.1-3.0), liver disease (OR, 4.7; 95% CI, 3.5-6.5), smoking history (OR, 3.2; 95% CI, 2.4-4.3), and obesity (OR, 2.3; 95% CI, 1.2-4.2). The number of previous colonoscopies was associated with a lower risk of complications (OR, 0.9; 95% CI, 0.7-1.0). The incidence of surgically treated colorectal cancer was higher in the older cohort than the screening-eligible cohort (119 patients [1.6%] vs 144 patients [0.5%]; P < .001). All-cause mortality rates were 0.1% overall (39 patients) and 0.1% (19 patients) for individuals aged 50 to 74 years and 0.2% (20 patients) for those aged 75 years and older (P < .001). Conclusions and Relevance: In this population-based cohort study of individuals living in southern Ontario, age of 75 years and older was associated with a higher risk of 30-day postprocedure complications after outpatient colonoscopy. These findings suggest that the decision to perform a colonoscopy should be carefully considered in patients older than 75 years, especially in the presence of comorbidities. Further studies are needed to better understand the benefits of invasive procedures as opposed to less invasive approaches for colorectal cancer screening and surveillance among older patients.

Associations between endoscopist feedback and improvements in colonoscopy quality indicators: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Colonoscopy quality indicators such as adenoma detection rate (ADR) are surrogates for the effectiveness of screening-related colonoscopy. It is unclear whether endoscopist feedback on these indicators improves performance. We performed a meta-analysis to determine whether associations exist between endoscopist feedback and colonoscopy performance. METHODS: We conducted a search through May 2019 for studies reporting on endoscopist feedback and associations with ADR or other colonoscopy quality indicators. Pooled rate ratios (RRs) and weighted mean differences were calculated using DerSimonian and Laird random effects models. Subgroup, sensitivity, and meta-regression analyses were performed to assess for potential methodological or clinical factors associated with outcomes. RESULTS: From 1326 initial studies, 12 studies were included in the meta-analysis for ADR, representing 33,184 colonoscopies. Endoscopist feedback was associated with an improvement in ADR (RR, 1.21; 95% confidence interval [CI], 1.09-1.34). Low performers derived a greater benefit from feedback (RR, 1.62; 95% CI, 1.18-2.23) compared with moderate performers (RR, 1.19; 95% CI, 1.11-1.29), whereas high performers did not derive a significant benefit (RR, 1.06; 95% CI, 0.99-1.13). Feedback was not associated with increases in withdrawal time (weighted mean difference, +0.43 minutes; 95% CI, -0.50 to +1.36 minutes) or improvements in cecal intubation rate (RR, 1.00; 95% CI, 0.99-1.01). CONCLUSION: Endoscopist feedback is associated with modest improvements in ADR. The implementation of routine endoscopist audit and feedback should be considered alongside other quality improvement interventions in institutions dedicated to the provision of high-quality screening-related colonoscopy.

Anxiety But Not Depression Predicts Poor Outcomes in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Patients with inflammatory bowel disease (IBD) have high rates of psychiatric comorbidities, but it is not clear whether those with comorbidities are at higher risk of poor outcomes. We aimed to determine whether patients with IBD who have co-existing anxiety and/or depression are more likely to have poor IBD-related outcomes compared with IBD patients without anxiety and/or depression. METHODS: This was a prospective longitudinal follow-up study in Ontario, Canada, from 2008 to 2016. Patients were asked to complete questionnaires at the time of initial assessment, including the Hospital Anxiety and Depression Scale (HADS). We selected a number of clinical variables at the time of presentation and tested their ability to predict subsequent poor IBD-related outcomes, such as IBD-related hospitalization, emergency room visits, and recurrent courses of corticosteroids over the duration of follow-up. Logistic regression was used for multivariate analysis. RESULTS: Four hundred fourteen IBD patients completed the baseline questionnaire. Among them, 125 had anxiety and/or depression at baseline. Factors that predicted poor IBD-related outcomes during longitudinal follow-up included increased severity of disease at initial presentation, prior IBD-related surgery, longer duration of follow-up, and elevated C-reactive protein at time of initial presentation. After adjustment for potential covariates, IBD patients with abnormal anxiety subscores had poor IBD-related outcomes compared with those without elevated anxiety subscores (odds ratio [OR] 3.36, 95% CI, 1.51-7.48). No difference in IBD-related outcomes were observed in those with abnormal depression subscores compared with those without elevated depression scores (OR 0.43, 95% CI, 0.14-1.32). CONCLUSIONS: Severe disease, anxiety, and previous IBD-related surgery predict poor IBD-related outcomes in patients in the future. Closer monitoring with regular follow-up may be appropriate for patients with these risk factors.

Universal determination of microsatellite instability using BAT26 as a single marker in an Argentine colorectal cancer cohort.

Microsatellite instability (MSI) is a hallmark tool for Lynch syndrome (LS) screening and a prognostic marker for sporadic colorectal cancer (CRC). In regions with limited resources and scarce CRC molecular characterization as South America, the implementation of universal MSI screening is under debate for both its purposes. We sought to estimate the frequency of BAT26 in colorectal adenocarcinomas and to determine associated clinical and histological features. Consecutive patients from a CRC registry were included. BAT26 determination was performed in all cases; if instability was found, immunohistochemistry (IHC) and BRAF mutation analyses were done, as appropriate. Differences were assessed by chi-squared or Fisher's exact test, or by T test or Mann-Whitney. Multiple logistic regression was used to identify factors independently associated with BAT26-unstable tumors. We included 155 patients; mean age was 65.6 (SD 14.4) and 56.1% were male. The frequency of BAT26-unstable tumors was 22% (95% CI 15.7-29.3). Factors independently associated with BAT26-unstable tumors were right colon localization (OR 3.4, 95% CI 1.3-8.7), histological MSI features (OR 5.1, 95% CI 1.9-13.6) and Amsterdam criteria (OR 23.2, 95% CI 1.9-286.7). IHC was altered in 85.3% BAT26-unstable tumors and 70.6% lacked MLH1 expression; 47.8% of these harbored BRAF V600E mutation. We provide evidence to link the frequency of BAT26 to an increased diagnostic yield (up to 1.4-folds) of suspected LS cases in comparison to the revised Bethesda guidelines alone. In regions with limited resources, clinical and histological features associated with BAT26-unstable status could be useful to direct MSI screening in sporadic CRCs and may help guide clinical care and future research.

Lynch syndrome in South America: past, present and future.

After decades of unawareness about Lynch syndrome, the medical community in South America is increasingly interested and informed. The visits and support of mentors like H. T. Lynch had been crucial to this awakening. Several countries have at least one registry with skilled personnel in genetic counseling and research. However, this only represents a very restricted resource for the region. According to the GETH, there are 27 hereditary cancer care centers in South America (21 in Brazil, 3 in Argentina, 1 in Uruguay, 1 in Chile and 1 in Peru). These registries differ in fundamental aspects of function, capabilities and funding, but are able to conduct high quality clinical, research and educational activities due to the dedication and personal effort of their members, and organizational support. More support from the governments as well as the participation of the community would boost the initiatives of people leading these groups. Meantime, the collaboration among the South American registries and the involvement of registries and leaders from developed countries will allow to maximize the efficiency in caring for affected patients and their families. The aim of this article is to describe how the knowledge of LS began to be spread in South America, how the first registries were organized and to summarize the current state of progress. In addition, we will provide an update of the clinical and molecular findings in the region.