Proficiency in the diagnosis of nonpolypoid colorectal neoplasm yields high adenoma detection rates

Dye-based chromoendoscopy following polypectomy reduces incomplete polyp resection

Background and study aims  The completeness of a polyp resection is an important determinant of quality in colonoscopy, and may reduce incidence of interval cancers. Incomplete resection rates (IRR) vary widely and range from 6.5 % to 22.7 %. Residual disease is more likely with larger polyps, for sessile serrated adenomas, and with more proximal lesions. Chromoendoscopy is increasingly employed in lesion detection. The aims of this study were to assess local IRR, and to determine whether chromoendoscopy could correctly identify residual disease post polypectomy. Patients and methods  This was a prospective study examining post polypectomy sites. Chromoendoscopy (0.13 % indigo carmine) was applied to resection bases to identify residual disease. Targeted base biopsies were taken from identified residual disease (positive group) or random base biopsies were taken when a clear base was visualised (negative group). Overall rates of incomplete resection were documented. Reported rates post chromoendoscopy and actual histological rates were documented and compared. Results  A total of 102 polyps were identified for inclusion, of which 15 % (n = 16) were excluded. Resection quality was evaluated in 86 polyps of 61 patients (female n = 33 54 %; mean Age 62.3 years). Polyps were mainly removed by cold snare (n = 71, 82.5 %). Most polyps (n = 58, 67 %) measured between 5 to 10 mm. Polyps were largely located in the right colon (n = 57, 66 %). Overall histological residual disease occurred in 17 /86 (19.6 %). Chromoendoscopy correctly identified residual disease in 13 of 17 bases (76.5 %). Only four of /86 (4.6 %) of polyp bases were missclassified post-chromoendoscopy (odds ratio 0.284 (95 % CI 0.0857-0.9409), P  = 0.03). Conclusion  Indigo carmine chromoendoscopy improves early detection of residual disease post polypectomy, reducing incomplete resection rates.

Risk factors associated with the detection and missed diagnosis of colorectal flat adenoma: a Chinese multicenter observational study

OBJECTIVES

Flat colorectal adenomas have a high risk of malignancy; however, their detection is often difficult due to their flat morphology. In this retrospective, large-scale study, we investigated the prevalence and characteristics of flat adenomas in a population in China.

METHODS

We analyzed the data collected for 16951 consecutive patients who underwent colonoscopy at four participating hospitals between September 2013 and September 2015. All colonoscopies were performed without magnification.

RESULTS

Among the 1,6951 patients, 2938 (17.3%) had adenoma and 796 (4.7%) had flat adenomas. The detection of flat adenoma showed a weak correlation with the detection of adenoma (r = 0.666). Multivariable logistic regression analysis revealed the following independent factors influencing the detection of flat adenomas: patient-related factors of age, presence of warning symptoms, history of adenomas and bowel preparation as well as endoscopist-related factors of endoscopist's level of proficiency, number of colonoscopy operators and withdrawal time.

CONCLUSIONS

The prevalence of flat adenomas in our study on Chinese patients was consistent with that reported from other countries. Factors conducive to the detection of flat adenomas were patient age of > 60 years, warning symptoms, history of adenoma, good bowel preparation, experienced endoscopist, single-operator colonoscopy and colonoscopy withdrawal time of >6 min.

Update on the role of chromoendoscopy in colonoscopic surveillance of patients with Lynch syndrome

(Virtual) chromoendoscopy (CE) improves the detection of small or flat colorectal polyps; however, the evidence in high-risk groups, such as patients of Lynch syndrome (LS), is low. Our aim was to identify and update the evidence for the recommendations regarding surveillance of LS patients, for which the current underlying evidence for use of (virtual) CE was explored. A systematic literature search in PubMed, EMBASE, and Cochrane library was conducted, for all studies comparing (virtual) CE with white-light endoscopy in LS patients. Studies are explained in detail, with special attention to study design, type of (virtual) CE, and timing of polypectomy. Eight studies (409 patients) were included. Five were nonrandomized back-to-back studies and three were randomized back-to-back studies (one parallel and two cross-over design). In six studies the polyps were directly removed, while in two studies polyps were removed only during the second caecal withdrawal. Five studies researched CE with indigo carmine and three studies investigated virtual CE. Due to the heterogeneity between studies, no statistical analysis could be performed. There was a large variety in study design, timing of polypectomy, different (virtual) CE techniques and the patients that were included. Based on current literature, no firm conclusions can be drawn with respect to the additional value of (virtual) CE in the surveillance of patients with LS. However, training of endoscopists in detection and removal of nonpolypoid colorectal neoplasms is crucial, as well as stricter adherence to LS surveillance guidelines in daily clinical practice. For future research, standardization in study designs is needed.

Distribution, size and shape of colorectal adenomas as determined by a colonoscopist with a high lesion detection rate: Influence of age, sex and colonoscopy indication

BACKGROUND

Increasing attention is focused on polyp-related features that may contribute to the operator-dependent nature of colonoscopy. Few data on polyps are available from high-yield colonoscopies, which may serve as a benchmark for quality control.

OBJECTIVES

Describe regional distribution, histology, size and shape of polyps, and the influence of patient age and gender, in colonoscopies performed by a colonoscopist with high lesion detection rate.

METHODS

Analysis of 698 consecutive patients with diagnostic, screening or surveillance colonoscopies.

RESULTS

In 704 colonoscopies, 1908 polyps were removed (360 were protruded and 1548 flat; 1313 were hyperplastic, 562 adenomas, 5 serrated adenomas and 8 mixed). There were 232 adenomas in female patients and 343 in male patients; 39% of the adenomas were protruded and 61% were flat. The peak adenoma detection rate (ADR) was 51% in patients beyond age 79 years. Men older than 49 years had a higher ADR than women. In men and women, respectively: 40% and 32% of adenomas were in the right colon, 31% and 22% were in the transverse colon, and 30% and 47% were in the left colon. Beyond age 59 years, the majority of adenomas were in the proximal colon.

CONCLUSIONS

An excess of adenomas in the proximal colon started at age 60 and this was more pronounced in men than in women. In all colonic regions, the majority of adenomas had a shape that was flat and smaller than 6 mm.

Detection rates of premalignant polyps during screening colonoscopy: time to revise quality standards?

BACKGROUND

Standards for the detection of adenomas during screening colonoscopy are widely used to measure examination quality. No such standards exist for sessile serrated adenomas (SSAs).

OBJECTIVE

To measure both the adenoma detection rate (ADR) and SSA detection rate (SSADR) during screening colonoscopy before and after quality improvement/financial incentive measures.

DESIGN

Retrospective determination of baseline ADR/SSADR by the endoscopist, followed by prospective collection of data after informing physicians of baseline detection rates.

SETTING

Tertiary cancer center with a large cancer screening program.

PATIENTS

A total of 2833 average-risk colorectal cancer screening patients 50 to 75 years of age undergoing initial colonoscopy.

DATA COLLECTION

Electronic medical records for indication and demographics, endoscopy report, and pathology report.

MAIN OUTCOME MEASUREMENTS

Detection rates of adenomas and SSAs by sex.

RESULTS

The overall ADR in male and female patients was 50.6% and 36.6%, respectively. The overall detection rate of advanced adenomas in male and female patients was 12.4% and 6.5%, respectively. The overall SSADR in male and female patients was 10.1% and 7.1%, respectively. In 108 patients (3.8% of entire group), SSAs were the only premalignant lesions found. Detection rates of both types of premalignant polyps improved over time but did not reach statistical significance.

LIMITATIONS

Single-center experience with limited sample size and small group of endoscopists.

CONCLUSION

ADRs far in excess of current standards are achievable. Cecal withdrawal time is associated with the ADR. Prevalence of SSA rivals that of advanced adenomas and is greater than current medical literature suggests. The combination of monitoring and financial incentives did not result in statistically significant improvement in ADRs.

Trouble in Paris (classification): polyp morphology is in the eye of the beholder

Key challenges to colonoscopy outcomes include polyp detection, appropriate polyp resection, and prediction of recurrent polyps. The Paris classification of gastrointestinal neoplasia has been used to attempt to address these challenges based on the hypothesis that the visual appearance of a polyp (e.g., sessile, flat, depressed) has an impact on these outcomes. Although the Paris classification has been widely used as a measurement tool in research, and reported to predict outcomes such as risk for high-grade dysplasia and invasive carcinoma, interobserver variability associated with this classification scheme has not been studied. In the current issue of the Red Journal, van Doorn et al. studied the interobserver variation of Paris classification in 85 colorectal polyps assessed by seven expert colonoscopists. They found that interobserver variation measured by kappa was only moderate (kappa=0.42; 95% confidence interval: 0.39-0.45). These findings suggest that without methods to improve interobserver variability, the Paris classification cannot routinely be used for research or routine practice. New approaches to characterizing polyp appearance may be required to use morphology as a predictor of clinical outcomes.

Polyp morphology: an interobserver evaluation for the Paris classification among international experts

OBJECTIVES

The Paris classification is an international classification system for describing polyp morphology. Thus far, the validity and reproducibility of this classification have not been assessed. We aimed to determine the interobserver agreement for the Paris classification among seven Western expert endoscopists.

METHODS

A total of 85 short endoscopic video clips depicting polyps were created and assessed by seven expert endoscopists according to the Paris classification. After a digital training module, the same 85 polyps were assessed again. We calculated the interobserver agreement with a Fleiss kappa and as the proportion of pairwise agreement.

RESULTS

The interobserver agreement of the Paris classification among seven experts was moderate with a Fleiss kappa of 0.42 and a mean pairwise agreement of 67%. The proportion of lesions assessed as "flat" by the experts ranged between 13 and 40% (P<0.001). After the digital training, the interobserver agreement did not change (kappa 0.38, pairwise agreement 60%).

CONCLUSIONS

Our study is the first to validate the Paris classification for polyp morphology. We demonstrated only a moderate interobserver agreement among international Western experts for this classification system. Our data suggest that, in its current version, the use of this classification system in daily practice is questionable and it is unsuitable for comparative endoscopic research. We therefore suggest introduction of a simplification of the classification system.

Tracking the molecular features of nonpolypoid colorectal neoplasms: a systematic review and meta-analysis

OBJECTIVES

Nonpolypoid colorectal neoplasms (NP-CRNs) are proposed as a major contributor to the occurrence of interval cancers, but their underlying biology remains controversial. We conducted a systematic review and meta-analysis to clarify the major biological events in NP-CRNs.

METHODS

We systematically searched for studies examining molecular characteristics of NP-CRNs. We performed random effect meta-analyses. We measured the heterogeneity among studies using I(2) and possible publication bias using funnel plots.

RESULTS

Fifty-three studies on KRAS, APC, or BRAF mutations, microsatellite instability (MSI), CpG island methylator phenotype (CIMP), or DNA promoter hypermethylation were included. We observed less KRAS mutations (summary odds ratio (OR) 0.30, confidence interval (CI)=0.19-0.46, I(2)=77.4%, CI=70.1-82.9) and APC mutations (summary OR 0.42, CI=0.24-0.72, I(2)=22.6%, CI=0.0-66.7) in NP-CRNs vs. protruded CRNs, whereas BRAF mutations were more frequent (summary OR 2.20, CI=1.01-4.81, I(2)=0%, CI=0-70.8), albeit all with large heterogeneity. Less KRAS mutations were especially found in NP-CRNs subtypes: depressed CRNs (summary OR 0.12, CI=0.05-0.29, I(2)=0%, CI=0-67.6), non-granular lateral spreading tumors (LSTs-NG) (summary OR 0.61, CI=0.37-1.0, I(2)=0%, CI=0-74.6), and early nonpolypoid carcinomas (summary OR 0.11, CI=0.06-0.19, I(2)=0%, CI=0-58.3). MSI frequency was similar in NP-CRNs and protruded CRNs (summary OR 0.99, CI=0.21-4.71, I(2)=70.3%, CI=38.4-85.7). Data for promoter hypermethylation and CIMP were inconsistent, precluding meaningful conclusions.

CONCLUSIONS

This meta-analysis provides indications that NP-CRNs are molecularly different from protruded CRNs. In particular, some subtypes of NP-CRNs, the depressed and LST-NG, are featured by less KRAS mutations than polypoid CRNs. Prospective, multicenter studies are needed to clarify the molecular pathways underlying nonpolypoid colorectal carcinogenesis and potential implications for surveillance intervals.

Adenoma detection in patients undergoing a comprehensive colonoscopy screening

Measures shown to improve the adenoma detection during colonoscopy (excellent bowel preparation, cecal intubation, cap fitted colonoscope to examine behind folds, patient position change to optimize colon distention, trained endoscopy team focusing on detection of subtle flat lesions, and incorporation of optimum endoscopic examination with adequate withdrawal time) are applicable to clinical practice and, if incorporated are projected to facilitate comprehensive colonoscopy screening program for colon cancer prevention. To determine adenoma and serrated polyp detection rate under conditions designed to optimize quality parameters for comprehensive screening colonoscopy. Retrospective analysis of data obtained from a comprehensive colon cancer screening program designed to optimize quality parameters. Academic medical center. Three hundred and forty-three patients between the ages of 50 years and 75 years who underwent first screening colonoscopy between 2009 and 2011 among 535 consecutive patients undergoing colonoscopy. Comprehensive colonoscopy screening program was utilized to screen all patients. Cecal intubation was successful in 98.8% of patients. The Boston Bowel Preparation Scale for quality of colonoscopy was 8.97 (95% confidence interval [CI]; 8.94, 9.00). The rate of adenoma detection was 60% and serrated lesion (defined as serrated adenomas or hyperplastic polyps proximal to the splenic flexure) detection was 23%. The rate of precancerous lesion detection (adenomas and serrated lesions) was 66%. The mean number of adenomas per screening procedure was 1.4 (1.2, 1.6) and the mean number of precancerous lesions (adenomas or serrated lesions) per screening procedure was 1.6 (1.4, 1.8). Retrospective study and single endoscopist experience. A comprehensive colonoscopy screening program results in high-quality screening with high detection of adenomas, advanced adenomas, serrated adenomas, and multiple adenomas.

Risk factors associated with colorectal flat adenoma detection

OBJECTIVES

Colorectal flat adenomas have been associated with a higher risk of colorectal malignancy. We describe demographic characteristics and endoscopic findings in patients with colorectal flat adenomas.

METHODS

In total, 1934 consecutive patients undergoing colonoscopy were prospectively included. Polyp shape was classified according to the Japanese classification. Chromoendoscopy was applied whenever a flat lesion was suspected. Indications for colonoscopy, demographic data, and characteristics of neoplastic lesions were recorded. Patients were classified as follows: group 1, no adenomas (n=1250); group 2, only protruding adenomas (n=427); group 3, protruding and flat adenomas (n=118); and group 4, only flat adenomas (n=139).

RESULTS

Approximately one in every 10 patients (13.2%) had flat adenomas. Among them, concomitant protruding adenomas were identified in approximately half of the cases. In multivariate analysis, age older than 50 years [odds ratio (OR)=1.62; 95% confidence interval (CI)=1.08-2.43, P=0.02], protruding adenomas (OR=2.17; 95% CI=1.65-2.87, P<0.001), follow-up colonoscopy for polyps or cancer (OR=2.22; 95% CI=1.59-3.10, P<0.001), screening colonoscopy (OR=1.60, 95% CI=1.15-2.22, P=0.005), and specifically trained endoscopist (OR=2.02, 95% CI=1.53-2.68, P<0.001) were associated independently with flat adenoma detection.

CONCLUSION

Flat adenomas have specific demographic factors that might help to improve detection. Particularly, age older than 50 years, colorectal neoplasia surveillance, and the presence of protruding adenomas should alert endoscopists to the possible presence of these lesions. Trained endoscopists may offer a greater chance of detecting these lesions.