Dye-based chromoendoscopy for the detection of colorectal neoplasia: meta-analysis of randomized controlled trials

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.

Quality of Colonoscopy Is Associated With Adenoma Detection and Postcolonoscopy Colorectal Cancer Prevention in Lynch Syndrome

BACKGROUND & AIMS

Colonoscopy reduces colorectal cancer (CRC) incidence and mortality in Lynch syndrome (LS) carriers. However, a high incidence of postcolonoscopy CRC (PCCRC) has been reported. Colonoscopy is highly dependent on endoscopist skill and is subject to quality variability. We aimed to evaluate the impact of key colonoscopy quality indicators on adenoma detection and prevention of PCCRC in LS.

METHODS

We conducted a multicenter study focused on LS carriers without previous CRC undergoing colonoscopy surveillance (n = 893). Incident colorectal neoplasia during surveillance and quality indicators of all colonoscopies were analyzed. We performed an emulated target trial comparing the results from the first and second surveillance colonoscopies to assess the effect of colonoscopy quality indicators on adenoma detection and PCCRC incidence. Risk analyses were conducted using a multivariable logistic regression model.

RESULTS

The 10-year cumulative incidence of adenoma and PCCRC was 60.6% (95% CI, 55.5%-65.2%) and 7.9% (95% CI, 5.2%-10.6%), respectively. Adequate bowel preparation (odds ratio [OR], 2.07; 95% CI, 1.06-4.3), complete colonoscopies (20% vs 0%; P = .01), and pan-chromoendoscopy use (OR, 2.14; 95% CI, 1.15-3.95) were associated with significant improvement in adenoma detection. PCCRC risk was significantly lower when colonoscopies were performed during a time interval of less than every 3 years (OR, 0.35; 95% CI, 0.14-0.97). We observed a consistent but not significant reduction in PCCRC risk for a previous complete examination (OR, 0.16; 95% CI, 0.03-1.28), adequate bowel preparation (OR, 0.64; 95% CI, 0.17-3.24), or previous use of high-definition colonoscopy (OR, 0.37; 95% CI, 0.02-2.33).

CONCLUSIONS

Complete colonoscopies with adequate bowel preparation and chromoendoscopy use are associated with improved adenoma detection, while surveillance intervals of less than 3 years are associated with a reduction of PCCRC incidence. In LS, high-quality colonoscopy surveillance is of utmost importance for CRC prevention.

Identification of Lynch Syndrome Carriers among Patients with Small Bowel Adenocarcinoma

Simple Summary

Small bowel adenocarcinoma (SBA) is associated with Lynch syndrome (LS). This is the first study to evaluate the identification of LS patients based on mismatch repair deficiency (MMRd) tumor among SBA. The authors found a 21.3% prevalence of MMRd tumors and a 10.1% prevalence of LS. A germline mutation was identified in 60% of patients with a MMRd tumor. This data suggests that universal tumor MMR testing among SBA patients should be implemented for the identification of LS.

Abstract

Background: Small bowel adenocarcinoma (SBA) is a rare disease which can be associated with Lynch syndrome (LS). LS tumors are characterized by the presence of microsatellite instability (MSI) and/or the loss of mismatch repair (MMR) protein expression. In SBA, the frequency of MMR deficient (MMRd) tumors varies from 5% to 35%. This study aims to describe the prevalence of LS carriers among patients with MMRd small bowel adenocarcinomas. Methods: A multicenter retrospective study with identification and MMR testing of all consecutive SBA between 2004 and 2020 in a multicenter Spanish study. Demographical data, tumor characteristics, follow-up and survival information were collected. Germline testing was driven by identification of MMRd tumors. Results: A total of 94 individuals diagnosed with SBA were recruited. We observed 20 (21.3%) MMRd tumors. In 9/15 (60%) patients with MMRd tumors, a pathogenic variant was identified (three MLH1, four MSH2, one MSH6 and one PMS2). Accordingly, the prevalence of LS among all SBA cases was 10.1%. Conclusions: More than one-fifth of SBA display MMRd and in more than a half is due to LS. Our data supports the implementation of universal MMR tumor testing among SBA for the identification of LS families.

A Liquid Biopsy Assay for Noninvasive Identification of Lymph Node Metastases in T1 Colorectal Cancer

BACKGROUND & AIMS

We recently reported use of tissue-based transcriptomic biomarkers (microRNA [miRNA] or messenger RNA [mRNA]) for identification of lymph node metastasis (LNM) in patients with invasive submucosal colorectal cancers (T1 CRC). In this study, we translated our tissue-based biomarkers into a blood-based liquid biopsy assay for noninvasive detection of LNM in patients with high-risk T1 CRC.

METHODS

We analyzed 330 specimens from patients with high-risk T1 CRC, which included 188 serum samples from 2 clinical cohorts-a training cohort (N = 46) and a validation cohort (N = 142)-and matched formalin-fixed paraffin-embedded samples (N = 142). We performed quantitative reverse-transcription polymerase chain reaction, followed by logistic regression analysis, to develop an integrated transcriptomic panel and establish a risk-stratification model combined with clinical risk factors.

RESULTS

We used comprehensive expression profiling of a training cohort of LNM-positive and LMN-negative serum specimens to identify an optimized transcriptomic panel of 4 miRNAs (miR-181b, miR-193b, miR-195, and miR-411) and 5 mRNAs (AMT, forkhead box A1 [FOXA1], polymeric immunoglobulin receptor [PIGR], matrix metalloproteinase 1 [MMP1], and matrix metalloproteinase 9 [MMP9]), which robustly identified patients with LNM (area under the curve [AUC], 0.86; 95% confidence interval [CI], 0.72-0.94). We validated panel performance in an independent validation cohort (AUC, 0.82; 95% CI, 0.74-0.88). Our risk-stratification model was more accurate than the panel and an independent predictor for identification of LNM (AUC, 0.90; univariate: odds ratio [OR], 37.17; 95% CI, 4.48-308.35; P < .001; multivariate: OR, 17.28; 95% CI, 1.82-164.07; P = .013). The model limited potential overtreatment to only 18% of all patients, which is dramatically superior to pathologic features that are currently used (92%).

CONCLUSIONS

A novel risk-stratification model for noninvasive identification of T1 CRC has the potential to avoid unnecessary operations for patients classified as high-risk by conventional risk-classification criteria.

Efficacy and Safety of Endoscopic Resection of Sessile Serrated Polyps 10 mm or Larger: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

The best method for endoscopic resection of sessile serrated polyps (SSP) 10 mm or larger is unclear; studies report variable outcomes in comparison to conventional adenomas. We performed a systematic review and meta-analysis to assess the efficacy and safety of resection of SSPs 10 mm or larger in size.

METHODS

We searched the PubMed/MEDLINE, Google Scholar, Embase, and Cochrane databases for studies reporting data on endoscopic resection of SSPs 10 mm or larger, through May 31st, 2019. The primary outcome was rate of residual SSP, which was the rate of residual SSP found at the polypectomy site during the first follow-up colonoscopy. Secondary outcomes were: technical success (rate of complete macroscopic resection), R0 resection rate (complete histological resection with absence of any polyp tissue at the lateral and deep margins after en-bloc resection), and adverse events (immediate or delayed bleeding and perforation). We performed IQR,group analyses for outcomes based on polyp size and resection techniques. Pooled proportion rates (%) or odds ratio with 95% CIs with heterogeneity (I²) and P < .05.

RESULTS

A total of 14 studies met the inclusion criteria: 911 patients (50.2% male; mean age, 62.8 ± 4.9 years) who underwent resection of 1137 SSPs (574 SSPs ≥ 20 mm) with a median polyp size of 19.4 mm (interquartile range, 15.9-29.6 mm). Follow-up information was available for 832 SSPs with a median follow-up duration of 12 months (interquartile range, 6-22.5 months). Piecemeal resection was performed in 58.5% SSPs. The pooled residual SSP rate was 4.3% (95% CI, 2%-6.5%). There was a higher residual SSP rate for polyps ≥ 20 mm compared to 10-19 mm (5.9% vs 1.2%; odds ratio, 3.02; 95% CI, 1-9.2; P = .049). Cold endoscopic mucosal resection (EMR) had significantly lower rates of delayed bleeding (0 vs 2.3%; P = .03) and residual polyp rate (0.9% vs 5%; P=.01) compared to hot EMR, based on univariate analysis. In multi-variate analysis there was no difference in residual polyp rate. There was no significant difference in other outcomes based on the size or method of resection.

CONCLUSIONS

In a systematic review and meta-analysis, we found that SSPs ≥ 10 mm can be safely resected with low residual polyp rates. Polyp size ≥ 20 mm is a significant factor for residual polyp. Compared to hot EMR, cold EMR is associated with a lower rate of delayed bleeding. Randomized controlled trials comparing hot and cold resection are needed to standardize techniques and optimize outcomes.

Effects of Blended (Yellow) vs Forced Coagulation (Blue) Currents on Adverse Events, Complete Resection, or Polyp Recurrence After Polypectomy in a Large Randomized Trial

BACKGROUND & AIMS

There is debate over the type of electrosurgical setting that should be used for polyp resection. Some endoscopists use a type of blended current (yellow), whereas others prefer coagulation (blue). We performed a single-blinded, randomized trial to determine whether type of electrosurgical setting affects risk of adverse events or recurrence.

METHODS

Patients undergoing endoscopic mucosal resection of nonpedunculated colorectal polyps 20 mm or larger (n = 928) were randomly assigned, in a 2 × 2 design, to groups that received clip closure or no clip closure of the resection defect (primary intervention) and then to either a blended current (Endocut Q) or coagulation current (forced coagulation) (Erbe Inc) (secondary intervention and focus of the study). The study was performed at multiple centers, from April 2013 through October 2017. Patients were evaluated 30 days after the procedure (n = 919), and 675 patients underwent a surveillance colonoscopy at a median of 6 months after the procedure. The primary outcome was any severe adverse event in a per patient analysis. Secondary outcomes were complete resection and recurrence at first surveillance colonoscopy in a per polyp analysis.

RESULTS

Serious adverse events occurred in 7.2% of patients in the Endocut group and 7.9% of patients in the forced coagulation group, with no significant differences in the occurrence of types of events. There were no significant differences between groups in proportions of polyps that were completely removed (96% in the Endocut group vs 95% in the forced coagulation group) or the proportion of polyps found to have recurred at surveillance colonoscopy (17% and 17%, respectively). Procedural characteristics were comparable, except that 17% of patients in the Endocut group had immediate bleeding that required an intervention, compared with 11% in the forced coagulation group (P = .006).

CONCLUSIONS

In a randomized trial to compare 2 commonly used electrosurgical settings for the resection of large colorectal polyps (Endocut vs forced coagulation), we found no difference in risk of serious adverse events, complete resection rate, or polyp recurrence. Electrosurgical settings can therefore be selected based on endoscopist expertise and preference. Clinicaltrials.gov ID NCT01936948.

Clip Closure Prevents Bleeding After Endoscopic Resection of Large Colon Polyps in a Randomized Trial

BACKGROUND & AIMS

Bleeding is the most common severe complication after endoscopic mucosal resection of large colon polyps and is associated with significant morbidity and cost. We examined whether prophylactic closure of the mucosal defect with hemoclips after polyp resection reduces the risk of bleeding.

METHODS

We performed a multicenter, randomized trial of patients with a large nonpedunculated colon polyp (≥20 mm) at 18 medical centers in North America and Spain from April 2013 through October 2017. Patients were randomly assigned to groups that underwent endoscopic closure with a clip (clip group) or no closure (control group) and followed. The primary outcome, postprocedure bleeding, was defined as a severe bleeding event that required hospitalization, a blood transfusion, colonoscopy, surgery, or another invasive intervention within 30 days after completion of the colonoscopy. Subgroup analyses included postprocedure bleeding with polyp location, polyp size, or use of periprocedural antithrombotic medications. We also examined the risk of any serious adverse event.

RESULTS

A total of 919 patients were randomly assigned to groups and completed follow-up. Postprocedure bleeding occurred in 3.5% of patients in the clip group and 7.1% in the control group (absolute risk difference [ARD] 3.6%; 95% confidence interval [CI] 0.7%-6.5%). Among 615 patients (66.9%) with a proximal large polyp, the risk of bleeding in the clip group was 3.3% and in the control group was 9.6% (ARD 6.3%; 95% CI 2.5%-10.1%); among patients with a distal large polyp, the risks were 4.0% in the clip group and 1.4% in the control group (ARD -2.6%; 95% CI -6.3% to -1.1%). The effect of clip closure was independent of antithrombotic medications or polyp size. Serious adverse events occurred in 4.8% of patients in the clip group and 9.5% of patients in the control group (ARD 4.6%; 95% CI 1.3%-8.0%).

CONCLUSIONS

In a randomized trial, we found that endoscopic clip closure of the mucosal defect following resection of large colon polyps reduces risk of postprocedure bleeding. The protective effect appeared to be restricted to large polyps located in the proximal colon. ClinicalTrials.gov no: NCT01936948.

Endoscopic surveillance after surgical or endoscopic resection for colorectal cancer: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Digestive Oncology (ESDO) Guideline

1:  We recommend post-surgery endoscopic surveillance for CRC patients after intent-to-cure surgery and appropriate oncological treatment for both local and distant disease.Strong recommendation, low quality evidence. 2:  We recommend a high quality perioperative colonoscopy before surgery for CRC or within 6 months following surgery.Strong recommendation, low quality evidence. 3:  We recommend performing surveillance colonoscopy 1 year after CRC surgery.Strong recommendation, moderate quality evidence. 4:  We do not recommend an intensive endoscopic surveillance strategy, e. g. annual colonoscopy, because of a lack of proven benefit.Strong recommendation, moderate quality evidence. 5:  After the first surveillance colonoscopy following CRC surgery, we suggest the second colonoscopy should be performed 3 years later, and the third 5 years after the second. If additional high risk neoplastic lesions are detected, subsequent surveillance examinations at shorter intervals may be considered.Weak recommendation, low quality evidence. 6:  After the initial surveillance colonoscopy, we suggest halting post-surgery endoscopic surveillance at the age of 80 years, or earlier if life-expectancy is thought to be limited by comorbidities.Weak recommendation, low quality evidence. 7:  In patients with a low risk pT1 CRC treated by endoscopy with an R0 resection, we suggest the same endoscopic surveillance schedule as for any CRC.Weak recommendation, low quality evidence.

Diminutive Polyps With Advanced Histologic Features Do Not Increase Risk for Metachronous Advanced Colon Neoplasia

BACKGROUND & AIMS

With advances in endoscopic imaging, it is possible to differentiate adenomatous from hyperplastic diminutive (1-5 mm) polyps during endoscopy. With the optical Resect-and-Discard strategy, these polyps are then removed and discarded without histopathology assessment. However, failure to recognize adenomas (vs hyperplastic polyps), or discarding a polyp with advanced histologic features, could result in a patient being considered at low risk for metachronous advanced neoplasia, resulting in an inappropriately long surveillance interval. We collected data from international cohorts of patients undergoing colonoscopy to determine what proportion of patients are high risk because of diminutive polyps advanced histologic features and their risk for metachronous advanced neoplasia.

METHODS

We collected data from 12 cohorts (in the United States or Europe) of patients undergoing colonoscopy after a positive result from a fecal immunochemical test (FIT cohort, n = 34,221) or undergoing colonoscopies for screening, surveillance, or evaluation of symptoms (colonoscopy cohort, n = 30,123). Patients at high risk for metachronous advanced neoplasia were defined as patients with polyps that had advanced histologic features (cancer, high-grade dysplasia, ≥25% villous features), 3 or more diminutive or small (6-9 mm) nonadvanced adenomas, or an adenoma or sessile serrated lesion ≥10 mm. Using an inverse variance random effects model, we calculated the proportion of diminutive polyps with advanced histologic features; the proportion of patients classified as high risk because their diminutive polyps had advanced histologic features; and the risk of these patients for metachronous advanced neoplasia.

RESULTS

In 51,510 diminutive polyps, advanced histologic features were observed in 7.1% of polyps from the FIT cohort and 1.5% polyps from the colonoscopy cohort (P = .044); however, this difference in prevalence did not produce a significant difference in the proportions of patients assigned to high-risk status (0.8% of patients in the FIT cohort and 0.4% of patients in the colonoscopy cohort) (P = .25). The proportions of high-risk patients because of diminutive polyps with advanced histologic features who were found to have metachronous advanced neoplasia (17.6%) did not differ significantly from the proportion of low-risk patients with metachronous advanced neoplasia (14.6%) (relative risk for high-risk categorization, 1.13; 95% confidence interval 0.79-1.61).

CONCLUSION

In a pooled analysis of data from 12 international cohorts of patients undergoing colonoscopy for screening, surveillance, or evaluation of symptoms, we found that diminutive polyps with advanced histologic features do not increase risk for metachronous advanced neoplasia.

Accuracy of the Narrow-Band Imaging International Colorectal Endoscopic Classification System in Identification of Deep Invasion in Colorectal Polyps

BACKGROUND & AIMS

T1 colorectal polyps with at least 1 risk factor for metastasis to lymph node should be treated surgically and are considered endoscopically unresectable. Optical analysis, based on the Narrow-Band Imaging International Colorectal Endoscopic (NICE) classification system, is used to identify neoplasias with invasion of the submucosa that require endoscopic treatment. We assessed the accuracy of the NICE classification, along with other morphologic characteristics, in identifying invasive polyps that are endoscopically unresectable (have at least 1 risk factor for metastasis to lymph node).

METHODS

We performed a multicenter, prospective study of data collected by 58 endoscopists, from 1634 consecutive patients (examining 2123 lesions) at 17 university and community hospitals in Spain from July 2014 through June 2016. All consecutive lesions >10 mm assessed with narrow-band imaging were included. The primary end point was the accuracy of the NICE classification for identifying lesions with deep invasion, using findings from histology analysis as the reference standard. Conditional inference trees were fitted for the analysis of diagnostic accuracy.

RESULTS

Of the 2123 lesions analyzed, 89 (4.2%) had features of deep invasion and 91 (4.3%) were endoscopically unresectable. The NICE classification system identified lesions with deep invasion with 58.4% sensitivity (95% CI, 47.5-68.8), 96.4% specificity (95% CI, 95.5-97.2), a positive-predictive value of 41.6% (95% CI, 32.9-50.8), and a negative-predictive value of 98.1% (95% CI, 97.5-98.7). A conditional inference tree that included all variables found the NICE classification to most accurately identify lesions with deep invasion (P < .001). However, pedunculated morphology (P < .007), ulceration (P = .026), depressed areas (P < .001), or nodular mixed type (P < .001) affected accuracy of identification. Results were comparable for identifying lesions that were endoscopically unresectable.

CONCLUSIONS

In an analysis of 2123 colon lesions >10 mm, we found the NICE classification and morphologic features identify those with deep lesions with >96% specificity-even in non-expert hands and without magnification. ClinicalTrials.gov number NCT02328066.

The clinical significance and synchronous polyp burden of large (≥ 20 mm) sessile serrated polyps in patients without serrated polyposis syndrome

BACKGROUND

Sessile serrated polyps (SSPs) are important precursors of colorectal carcinoma and interval cancer. Large SSPs (≥ 20 mm) outside the definition of serrated polyposis syndrome (SPS) have not been studied in comparison with SPS. We aimed to describe the characteristics of patients with large SSPs in this context.

METHODS

Patients with at least one SSP (≥ 20 mm) were eligible. Data from three consecutive colonoscopies were used to compare clinical and endoscopic characteristics in three patient groups: SPS, a solitary large SSP, and patients with at least two SSPs without fulfilling the criteria for SPS (oligo-SSP). Data on the diagnostic colonoscopy were collected retrospectively, whereas the remaining data was collected prospectively.

RESULTS

67/146 patients (45.9 %) had SPS, 53/146 (36.3 %) had a solitary SSP, and 26/146 (17.8 %) were categorized as oligo-SSP. Personal (16.4 %, 9.4 %, and 11.5 %, respectively) and family (17.9 %, 17.0 %, and 23.1 %, respectively) history of colorectal carcinoma did not differ significantly between groups. Polyp burden was greater in SPS compared with solitary SSP but was not different from oligo-SSP (advanced adenomas: SPS 32.8 % vs. solitary SSP 9.4 % [P = 0.002] vs. oligo-SSP 34.6 % [P = 0.87]; ≥ 10 conventional adenomas: 11.9 % vs. 0 % [P = 0.01] vs. 3.8 % [P = 0.44], respectively). Dysplasia in large SSPs was frequent in all groups (41.1 % overall). SPS was recognized by referring endoscopists in only 9.0 % of cases.

CONCLUSION

Patients with oligo-SSPs have similar synchronous polyp burden and clinical characteristics as patients with SPS and may require similar surveillance. Modification of the criteria for the diagnosis of SPS to include this group seems warranted. Patients with a solitary SSP have a lower risk of synchronous polyps, including advanced adenomas. Larger studies are warranted to determine whether these patients may return to standard surveillance following complete examination and clearance of the colon.

Colonoscopy quality requisites for selecting surveillance intervals: A World Endoscopy Organization Delphi Recommendation

BACKGROUND AND AIMS

Different post-polypectomy guidelines underscore the need for high-quality baseline colonoscopy before appropriate surveillance recommendations can be made. Standards for colonoscopy practice have been advocated by gastrointestinal societies. Our aims were to define standards for the procedural practice of colonoscopy in this particular setting of surveillance and to generate a colonoscopy procedural quality checklist that could be implemented in clinical practice.

METHODS

This study was based on the Delphi process methodology. The baseline questionnaire included 12 domains and 56 individual statements. A total of three rounds were carried out between September 2015 and March 2016 until consensus or lack of consensus was reached.

RESULTS

In total, consensus was reached on 27 statements in nine domains. High levels of agreement and consensus were reached that: (i) colonoscopy should be considered complete only if the whole cecum has been inspected, including the ileocecal valve and the appendiceal orifice (agreement score 4.63; degree of consensus 82%); (ii) quality of the bowel preparation should always be reported (agreement score 4.9, degree of consensus 94%); and (iii) it is preferable to use a segmental validated scale (agreement score 4.36, degree of consensus 86%). Consensus was also reached regarding multiple statements related to documentation of polyps and their resection. Finally, a colonoscopy quality checklist was drafted.

CONCLUSION

Consensus on different statements regarding quality of colonoscopy has been reached. Based on this consensus, we propose a colonoscopy quality checklist that would be helpful for post-polypectomy surveillance recommendations.

Endoscopic mucosal resection for large serrated lesions in comparison with adenomas: a prospective multicentre study of 2000 lesions

OBJECTIVE

Endoscopic mucosal resection (EMR) is effective for large laterally spreading flat and sessile lesions (LSLs). Sessile serrated adenomas/polyps (SSA/Ps) are linked to the relative failure of colonoscopy to prevent proximal colorectal cancer. We aimed to examine the technical success, adverse events and recurrence following EMR for large SSA/Ps in comparison with large conventional adenomas.

DESIGN

Over 74 months till August 2014, prospective multicentre data of LSLs ≥20 mm were analysed. A standardised dye-based conventional EMR technique followed by scheduled surveillance colonoscopy was used.

RESULTS

From a total of 2000 lesions, 323 SSA/Ps in 246 patients and 1527 adenomas in 1425 patients were included for analysis. Technical success for EMR was superior in SSA/Ps compared with adenomas (99.1% vs 94.5%, p<0.001). Significant bleeding and perforation were similar in both cohorts. The cumulative recurrence rates for adenomas after 6, 12, 18 and 24 months were 16.1%, 20.4%, 23.4% and 28.4%, respectively. For SSA/Ps, they were 6.3% at 6 months and 7.0% from 12 months onwards (p<0.001). Following multivariable adjustment, the HR of recurrence for adenomas versus SSA/Ps was 1.7 (95% CI 0.9 to 3.0, p=0.097). Subgroup analysis by lesion size revealed an eightfold increased risk of recurrence for 20-25 mm adenomas versus SSA/Ps, but no significantly different risk between lesion types in larger lesion groups.

CONCLUSION

Recurrence after EMR of 20-25 mm LSLs is significantly less frequent in SSA/Ps compared with adenomatous lesions. SSA/Ps can be more effectively removed than adenomatous LSLs with equivalent safety. Ensuring complete initial resection is imperative for avoiding recurrence.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT01368289.

Lymph node pooling: a feasible and efficient method of lymph node molecular staging in colorectal carcinoma

Background

Pathologic lymph node staging is becoming a deficient method in the demanding molecular era. Nevertheless, the use of more sensitive molecular analysis for nodal staging is hampered by its high costs and extensive time requirements. Our aim is to take a step forward in colon cancer (CC) lymph node (LN) pathology diagnosis by proposing a feasible and efficient molecular method in routine practice using reverse transcription loop-mediated isothermal amplification (RT-LAMP).

Results

Molecular detection of tumor cytokeratin 19 (CK19) mRNA with RT-LAMP was performed in 3206 LNs from 188 CC patients using two methods: individual analysis of 1449 LNs from 102 patients (individual cohort), and pooled LN analysis of 1757 LNs from 86 patients (pooling cohort). A median of 13 LNs (IQR 10–18) per patient were harvested in the individual cohort, and 18 LNs (IQR 13–25) per patient in the pooling cohort (p ≤ 0.001). The median of molecular assays performed in the pooling cohort was 2 per patient (IQR 1–3), saving a median of 16 assays/patient. The number of molecular assays performed in the individual cohort was 13 (IQR 10–18), corresponding to the number of LNs to be analyzed. The sensitivity and specificity of the pooling method for LN involvement (assessed by hematoxylin and eosin) were 88.9% (95% CI 56.5–98.0) and 79.2% (95% CI 68.9–86.8), respectively; concordance, 80.2%; PPV, 33.3%; NPV, 98.4%. The individual method had 100% sensitivity (95% CI 72.2–100), 44.6% specificity (95% CI 34.8–54.7), 50% concordance, 16.4% PPV, and 100% NPV. The amount of tumor burden detected in all LNs of a case, or total tumor load (TTL) was similar in both cohorts (p = 0.228).

Conclusions

LN pooling makes it possible to analyze a high number of LNs from surgical colectomies with few molecular tests per patient. This approach enables a feasible means to integrate LN molecular analysis from CC specimens into pathology diagnosis and provides a more accurate LN pathological staging with potential prognostic implications.

Endoscopic tattooing of early colon carcinoma enhances detection of lymph nodes most prone to harbor tumor burden

Background

Colorectal cancer (CRC) screening programs result in the detection of early-stage asymptomatic carcinomas suitable to be surgically cured. Lymph nodes (LN) from early CRC are usually small and may be difficult to collect. Still, at least 12 LNs should be analyzed from colectomies, to ensure a reliable pN0 stage. Presurgical endoscopic tattooing improves LN procurement. In addition, molecular detection of occult LN tumor burden in histologically pN0 CRC patients is associated with a decreased survival rate. We aimed to study the impact of presurgical endoscopic tattooing on the molecular detection of LN tumor burden in early colon neoplasms.

Methods

A prospective cohort study from a CRC screening-based population was performed at a tertiary academic hospital. LNs from colectomies with and without preoperative endoscopic tattooing were assessed by two methods, hematoxylin and eosin (HE), and RT-LAMP, to detect tumor cytokeratin 19 (CK19) mRNA. We compared the amount of tumor burden and LN yields from tattooed and non-tattooed specimens.

Results

HE and RT-LAMP analyses of 936 LNs were performed from 71 colectomies containing early carcinomas and endoscopically unresectable adenomas (8 pT0, 17 pTis, 27 pT1, 19 pT2); 47 out of 71 (66.2 %) were tattooed. Molecular positivity correlated with the presence of tattoo in LN [p < 0.001; OR 3.1 (95 % CI 1.7–5.5)]. A significantly higher number of LNs were obtained in tattooed specimens (median 17 LN vs. 14.5 LN; p = 0.019).

Conclusions

Endoscopic tattooing enables the analysis of those LNs most prone to harbor tumor cells and improves the number of LN harvested.

Electronic supplementary material

The online version of this article (doi:10.1007/s00464-016-5026-3) contains supplementary material, which is available to authorized users.

Clinical and endoscopic predictors of cytological dysplasia or cancer in a prospective multicentre study of large sessile serrated adenomas/polyps

OBJECTIVE

The serrated neoplasia pathway accounts for up to 30% of all sporadic colorectal cancers (CRCs). Sessile serrated adenomas/polyps (SSA/Ps) with cytological dysplasia (SSA/P-D) are a high-risk serrated CRC precursor with little existing data. We aimed to describe the clinical and endoscopic predictors of SSA/P-D and high grade dysplasia (HGD) or cancer.

DESIGN

Prospective multicentre data of SSA/Ps ≥20 mm referred for treatment by endoscopic mucosal resection (September 2008-July 2013) were analysed. Imaging and lesion assessment was standardised. Histological findings were correlated with clinical and endoscopic findings.

RESULTS

268 SSA/Ps were found in 207/1546 patients (13.4%). SSA/P-D comprised 32.4% of SSA/Ps ≥20 mm. Cancer occurred in 3.9%. On multivariable analysis, SSA/P-D was associated with increasing age (OR=1.69 per decade; 95% CI (1.19 to 2.40), p0.004) and increasing lesion size (OR=1.90 per 10 mm; 95% CI (1.30 to 2.78), p0.001), an 'adenomatous' pit pattern (Kudo III, IV or V) (OR=3.98; 95% CI (1.94 to 8.15), p<0.001) and any 0-Is component within a SSA/P (OR=3.10; 95% CI (1.19 to 8.12) p0.021). Conventional type dysplasia was more likely to exhibit an adenomatous pit pattern than serrated dysplasia. HGD or cancer was present in 7.2% and on multivariable analysis, was associated with increasing age (OR=2.0 per decade; 95% CI 1.13 to 3.56) p0.017) and any Paris 0-Is component (OR=10.2; 95% CI 3.18 to 32.4, p<0.001).

CONCLUSIONS

Simple assessment tools allow endoscopists to predict SSA/P-D or HGD/cancer in SSA/Ps ≥20 mm. Correct prediction is limited by failure to recognise SSA/P-D which may mimic conventional adenoma. Understanding the concept of SSA/P-D and the pitfalls of SSA/P assessment may improve detection, recognition and resection and potentially reduce interval cancer.

TRIAL REGISTRATION NUMBER

NCT01368289.

Comparison of the histopathological effects of two electrosurgical currents in an in vivo porcine model of esophageal endoscopic mucosal resection

BACKGROUND AND STUDY AIMS

Stricture formation is the main limitation of endoscopic resection in the esophagus. The optimal electrosurgical current (ESC) for endoscopic resection in the esophagus and other gastrointestinal sites is unknown. There may be a relationship between the type of ESC used and the development of post-procedure esophageal stricture. Unlike the low power coagulating current (LPCC), the microprocessor-controlled current (MCC), which alternates between short pulse cutting and coagulation, avoids high peak voltages that are thought to result in deep thermal injury. The aim of this study was to determine the histopathological variables associated with these two commonly employed ESCs used for esophageal endoscopic resection.

METHODS

Standardized endoscopic resection of normal mucosa by band mucosectomy was performed by a single endoscopist in 12 adult pigs. The procedures were randomized 1 : 1 to either LPCC (ERBE 100 C at 25 W) or MCC (ERBE Endocut Q, Effect 3). Necropsy and esophagectomy were performed at 72 hours after the procedure. Two histopathologists, who were blinded to the ESC allocation, independently assessed the presence and depth of ulceration, necrosis and inflammation.

RESULTS

A total of 45 resections were analyzed. In the LPCC and MCC groups, ulceration extending into the muscularis propria was present in 9/24 (37.5 %) and 1/21 (4.8 %) resected specimens, respectively (P = 0.04). Necrosis extending into the muscularis propria was present in 13/24 (54.1 %) and 1/21 (4.8 %) resected specimens, respectively (P = 0.002). One case of microperforation with muscularis propria injury was noted in the LPCC group compared with none in the MCC group. The quantified mean depth of ulceration, necrosis, and acute inflammation was significantly greater in the LPCC group. 

CONCLUSIONS

In an in vivo porcine survival model of esophageal endoscopic mucosal resection, the use of MCC resulted in significantly less deep thermal ulceration, necrosis, and acute inflammation compared with LPCC. MCC should be used in preference over LPCC for esophageal endoscopic resection.

Characterization and significance of protrusions in the mucosal defect after cold snare polypectomy

BACKGROUND

Cold snare polypectomy (CSP) is widely practiced; however, the endoscopic features of the CSP mucosal defect have not been studied. In particular, protrusions within the cold snare defect (CSDPs) may create concern for residual polyp. The frequency and constituents of this phenomenon are unknown.

OBJECTIVE

To describe the frequency, predictors, and histologic constituents of CSDPs.

DESIGN

Prospective observational study.

SETTING

Tertiary-care hospital endoscopy unit.

PATIENTS

Eighty-eight consecutive patients undergoing CSP for a polyp ≤ 10 mm in size.

INTERVENTION

Inspection of the cold snare mucosal defect with high-definition white light and biopsy sampling of CSDPs for separate histologic assessment, when present.

MAIN OUTCOME MEASUREMENT

Frequency and constituents of CSDPs.

RESULTS

Two hundred fifty-seven consecutive polyps ≤ 10 mm in size were removed in 88 patients (50 men [57%], mean age 63 years). Polyps were predominately adenomatous (162, 63%), located in the proximal colon (159, 62%) and flat (200, 78%). Mean lesion size was 5.5 mm (range, 2-10 mm). High-grade dysplasia was present in a single polyp for which the defect was bland. CSDPs occurred in 36 polypectomies (14%). CSDPs were associated with polyp size ≥ 6 mm (odds ratio, 3.7; P < .001 multivariable analysis) but not age, sex, lesion, histopathology, morphology, or location. Histopathologic examination of CSDPs revealed submucosa in 34 (94%) and muscularis mucosa in 29 (80%). No residual adenomatous or serrated polyp tissue was detected.

LIMITATIONS

Single-center study. Small number of polyps with high-grade dysplasia.

CONCLUSION

Protrusions are common within the CSP mucosal defect and are associated with polyp size ≥ 6 mm. CSDPs do not represent vascular structures, do not contain residual polyp, and are not associated with adverse outcomes in short-term follow-up. However, CSDPs represent incomplete mucosal layer resection.

Prevalence of somatic mutl homolog 1 promoter hypermethylation in Lynch syndrome colorectal cancer

BACKGROUND

Colorectal cancers (CRCs) that have microsatellite instability (MSI) and mutL homolog 1 (MLH1) immunoloss are observed in 3 clinical scenarios: Lynch syndrome (LS), sporadic MSI CRC, and Lynch-like syndrome (LLS). v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) mutational analysis is used to differentiate LS from sporadic MSI CRC. The role of MLH1 promoter methylation status for the differential diagnosis of these clinical forms is not well established. The objectives of this study were: 1) to analyze MLH1 promoter methylation in MLH1-deficient CRCs by pyrosequencing, and 2) to assess its role in the differential diagnosis of MLH1-deficient CRCs.

METHODS

In total, 165 CRCs were analyzed, including LS (n = 19), MSI BRAF-mutated CRC (n = 37), MSI BRAF wild-type CRC (n = 60), and a control group of CRCs without MSI (microsatellite stable [MSS] CRC; n = 49). MLH1 promoter methylation status was analyzed by pyrosequencing, and the ability of different strategies to identify LS was assessed.

RESULTS

The average ± standard deviation methylation in LS (9% ± 7%) was significantly lower than that in MSI BRAF-mutated CRC (42% ± 17%; P < .001) and in MSI BRAF wild-type CRC (25% ± 19%; P = .002). Somatic MLH1 hypermethylation was detected in 3 patients (15.8%) with LS, in 34 patients (91.9%) with MSI BRAF-mutated CRC, and in 37 patients (61.7%) with MSI BRAF wild-type tumors. Patients with MSI BRAF wild-type, unmethylated tumors (ie, LLS) had a stronger family history of CRC than those who had tumors with MLH1 methylation (P < .05). The sensitivity for ruling out LS was 100% for BRAF analysis, 84.2% for MLH1 methylation analysis, and 84.2% for the combination of both analyses.

CONCLUSIONS

Somatic MLH1 promoter methylation occurs in up to 15% of LS CRCs. Somatic BRAF analysis is the most sensitive strategy for ruling out LS. Patients who have CRCs with loss of MLH1 protein expression and neither BRAF mutation nor MLH1 methylation resemble patients with LS.

Risk stratification for advanced colorectal neoplasia according to fecal hemoglobin concentration in a colorectal cancer screening program

BACKGROUND & AIMS

The latest generation of fecal immunochemical tests (FIT) allows for quantitation of hemoglobin in feces, allowing for selection of optimal cut-off concentrations. We investigated whether individuals with positive results from quantitative FITs, in combination with other factors, could be identified as being at greatest risk for advanced colorectal neoplasia.

METHODS

In a retrospective study, we analyzed data from a consecutive series of 3109 participants with positive results from FITs (≥20 μg/g of feces) included in the first round of the Barcelona colorectal cancer screening program, from December 2009 through February 2012. All participants underwent colonoscopy and were assigned to groups with any advanced colorectal neoplasia or with nonadvanced colorectal neoplasia (but with another diagnosis or normal examination findings).

RESULTS

Median fecal hemoglobin concentrations were significantly higher in participants with advanced colorectal neoplasia (105 μg/g; interquartile range, 38-288 μg/g) compared with participants with nonadvanced colorectal neoplasia (47 μg/g; interquartile range, 23-119 μg/g) (P < .001). Positive predictive values for advanced colorectal neoplasia, determined using arbitrary fecal hemoglobin concentrations, differed with sex and age. Multivariate logistic regression analysis identified sex (men: odds ratio [OR], 2.07; 95% confidence interval, 1.78-2.41), age (60-69 y: OR, 1.24; 95% confidence interval, 1.07-1.44), and fecal hemoglobin concentration (>177 μg/g: OR, 3.80; 95% confidence interval, 3.07-4.71) as independent predictive factors for advanced colorectal neoplasia. Combining these factors, we identified 16 risk categories associated with different probabilities of identifying advanced colorectal neoplasia. Risk for advanced colorectal neoplasia increased 11.46-fold among individuals in the highest category compared with the lowest category; positive predictive values ranged from 21.3% to 75.6%.

CONCLUSIONS

Fecal hemoglobin concentration, in addition to sex and age, in individuals with positive results from FITs can be used to stratify probability for the detection of advanced colorectal neoplasia. These factors should be used to prioritize individuals for colonoscopy examination.

Colonic polyps: Is it useful to characterize them with advanced endoscopy?

There have been major developments in endoscopic imaging techniques in recent years. Endoscopes with high definition and magnification can provide high quality images that allow for the histological estimation of lesions in vivo and in situ when combined with ancillary enhancement techniques such as chromoendoscopy (CE) and virtual CE (narrow band imaging fujinon intelligent chromoendoscopy, or i-Scan). Despite the enormous potential for these advanced techniques, their value and feasibility in the clinic are still doubted, particularly in cases of colonic polyps that are slated for removal, where in vivo characterization may be deemed unnecessary. However, there are several advantages offered by such advanced endoscopic imaging. CE with or without magnification demonstrates highly accurate histology and invasion depth prediction, and virtual CE is a feasible and less cumbersome alternative to CE in terms of histological estimation, though not sufficiently accurate for depth invasion prediction. Furthermore, the supplementary information provided by advanced imaging systems can assist the endoscopist in the selection of a strategic approach, such as in deciding whether a colonic lesion should be resected, left in situ, or requires more intensive surgical treatment. Lastly, advanced high-resolution imaging techniques may be more cost effective, such that histopathology of low-risk lesions following resection can be eliminated. The results of these evaluations and comparisons with traditional CE are presented and discussed. Taken together, the benefits provided by these advanced capabilities justify their development, and advocates their use for the treatment and management of colonic polyps.

Colorectal cancer: serrated polyposis--should we screen first-degree relatives?

Serrated polyposis syndrome (SPS) is a condition characterized by multiple and/or proximal serrated polyps in the colorectum. Several features of SPS suggest there is an underlying genetic disorder that is yet to be identified. A new study provides insights on the diagnostic yield of screening colonoscopy in first-degree relatives of patients with SPS.

Analytical and clinical performance of Kroma iT, a compact fully-automated immunochemistry analyzer for fecal occult hemoglobin

BACKGROUND

We performed a laboratory and clinical evaluation of Kroma iT (Linear Chemicals S.L), an immunoturbidimetric analyzer for the detection of fecal occult blood.

MATERIALS AND METHODS

After a familiarization period, the imprecision, linearity of dilution and carry-over were determined and a clinical evaluation was performed on 210 patients.

RESULTS

Within-run imprecision ranged between 1.06% and 8.04%. Between-run imprecision ranged between 3.11% and 13.09%. Linearity of dilution revealed a mean recovery of all dilutions of 95.24%, with a standard deviation of 7.47%. No carry-over was detected. The clinical evaluation demonstrated that the mean hemoglobin levels of the fecal immunochemical test values from patients with advanced neoplasms (colorectal cancer plus advanced adenoma) were significantly higher than those of cases with a normal colonoscopy examination. Sensitivity for advanced neoplasms at cut-off values between 80 and 300 ng/ml (6.4-24 mg Hb/Kg feces) ranged from 45.5% to 36.4% and the specificity ranged from 86.8% to 92.3%. The positive predictive values for detecting colorectal cancer and advanced adenomas were 5.4-6.4% and 27-34% respectively and the negative predictive value ranged from 92.5% to 91.7%. Using two samples per patient, a substantial increase of sensitivity was observed, with only a slight decrease in specificity.

CONCLUSION

Kroma iT analyzer is easy to handle and safe for personnel to use. Its analytical and clinical performance makes it suitable for use in a clinical chemistry laboratory for the early detection of advanced neoplasms.

Biology and diagnosis of aberrant crypt foci

AIM

Aberrant crypt foci (ACFs) are clusters of colonic crypts that can be identified after staining and that have a different behaviour than the surrounding crypts. They have been hypothesized to be the potential precursors of colonic neoplastic lesions. Since they are detectable in vivo with endoscopic stains, they have been proposed as early biomarkers for colonic carcinogenesis. Our aim was to examine the literature regarding the role of ACFs in the pathogenesis of colorectal cancer (CRC).

METHOD

An intensive PubMed search was performed with the following terms: aberrant crypt foci, colorectal cancer, biomarker, carcinogenesis.

RESULTS

  Aberrant crypt foci have a variable prevalence and little is known about their natural history. They can be classified as hyperplastic or dysplastic. There is evidence that supports their role as preneoplastic lesions and features detectable by chromoendoscopy have been related to CRC risk. Moreover, ACFs have been shown to harbour genetic and epigenetic alterations common in adenomas and CRC. However, contradictory results have been obtained and difficulties in endoscopic detection and characterization have been described in large-scale studies.

CONCLUSION

  Despite the inconsistencies in ACF detection and characterization, several genetic and epigenetic changes common in both ACFs and CRC have been verified throughout the studies. This evidence is increasingly strong and it grows along with progress in the knowledge of carcinogenesis molecular pathways. Clinical application of ACFs as an intermediate endpoint for colorectal carcinogenesis is under development and a deeper knowledge of cancer mechanisms is needed before it can be applied or discarded.

Validation Microsatellite Path Score in a Population-Based Cohort of Patients With Colorectal Cancer

Purpose

Bethesda guidelines are used to recognize patients at risk for Lynch syndrome. However, obtaining personal and familial tumor data can sometimes be difficult. The Microsatellite Path Score (MsPath), a pathological score, based on age, tumor location, and pathologic features, has been developed to effectively predict colorectal cancer with DNA mismatch repair (MMR) deficiencies. However, the MsPath model's performance in an unselected, population-based colorectal cancer (CRC) population is unknown.

Patients and Methods

We analyzed all patients with CRC regardless of age, personal or family history, and tumor characteristics from the EPICOLON study, an independent, prospective, multicenter, population-based cohort (N = 1,222). All patients underwent tumor microsatellite instability (MSI) analysis and immunostaining for MLH1/MSH2, and those with MMR underwent tumor BRAF mutation analysis and MLH1/MSH2 germline testing. All the pathologic features were centralized and evaluated blinded to the MMR status.

Results

MsPath score for prediction of having MSI high, with the recommended MsPath cutoff score ≥1.0, had a sensitivity, specificity, and positive predictive value (PPV) of 92.8% (95% CI, 86.9 to 98.3), 64.1% (95% CI, 61.1 to 66.8), and 15.8% (95% CI, 12.2 to 18.6), respectively. MsPath score had a sensitivity, specificity, and PPV of 81.8% (95% CI, 59.0 to 99.8), 60.6% (95% CI, 57.8 to 63.4), and 1.9% (95% CI, 0.7 to 3.1), respectively, for the identification of MLH1/MSH2 gene carriers. Application of the MsPath score, resulted in two (18%) of 11 mutation carriers being missed, both pathogenic germline MSH2 mutations.

Conclusion

In the general nonselected population, the MsPath score accurately predicted the probability of bearing a MSI high CRC, but it was insufficiently accurate to use for the selection of patients warranting MLH1/MSH2 mutation testing in the setting of Lynch syndrome.

Endoscopic ultrasonography in patients with large gastric folds at endoscopy and biopsies negative for malignancy: predictors of malignant disease and clinical impact

OBJECTIVES

The aims of the study were to assess in patients with large gastric folds at endoscopy and endoscopic biopsies that tested negative for malignancy: (i) the predictive variables of malignancy in endoscopic ultrasonography (EUS), (ii) the impact of EUS.

METHODS

Patients with this condition evaluated with radial EUS (following the standard study protocol of our Unit in these patients) during a 5-yr period were included. Nine variables were evaluated as possible predictors of malignancy (chi2, t-test, and logistic regression procedure) using pathology results, or a minimum of 2 yr of follow-up as gold standard. Likelihood ratios (LR), pre-EUS, and post-EUS probabilities for the diagnosis of malignancy were used to assess the clinical impact of the technique.

RESULTS

Sixty-one patients were included (40 benign and 21 malignant). Predictive factors of malignancy were as follows: thickened gastric wall, thickened deep layers, impaired gastric distension, loss of the wall structure, and presence of ascites or lymph nodes, whereas the enlargement of superficial layers was a predictor of a benign condition. The enlargement of deep layers, as assessed by EUS was the only independent predictive factor for malignancy. When using this parameter, the pre-EUS probability of malignancy in our series (34%) increased up to 95% when EUS suggested malignancy (positive LR = 45), whereas it decreased to 4.7% when EUS precluded this diagnosis (negative LR = 0.102).

CONCLUSIONS

(i) The enlargement of deep layers is the only independent predictive factor for malignancy in patients with large gastric folds at endoscopy and biopsies testing negative for malignancy and (ii) EUS has a high clinical impact in these patients.