David G. Hewett

Validation of a Simple Classification System for Endoscopic Diagnosis of Small Colorectal Polyps Using Narrow-Band Imaging

BACKGROUND & AIMS Almost all colorectal polyps ≤ 5 mm are benign, yet current practice requires costly pathologic analysis. We aimed to develop and evaluate the validity of a simple narrow-band imaging (NBI)-based classification system for differentiating hyperplastic from adenomatous polyps. METHODS The study was conducted in 4 phases: (1) evaluation of accuracy and reliability of histologic prediction by NBI-experienced colonoscopists; (2) development of a classification based on color, vessels, and surface pattern criteria, using a modified Delphi method; (3) validation of the component criteria by people not experienced in endoscopy or NBI analysis (25 medical students, 19 gastroenterology fellows) using 118 high-definition colorectal polyp images of known histology; and (4) validation of the classification system by NBI-trained gastroenterology fellows, using still images. We performed a pilot evaluation during real-time colonoscopy. RESULTS We developed a classification system for the endoscopic diagnosis of colorectal polyp histology and established its predictive validity. When all 3 criteria were used, the specificity ranged from 94.9% to 100% and the combined sensitivity ranged from 8.5% to 61.0%. The specificities of the individual criteria were lower although the sensitivities were higher. During real-time colonoscopy, endoscopists made diagnoses with high confidence for 75% of consecutive small colorectal polyps, with 89% accuracy, 98% sensitivity, and 95% negative predictive values. CONCLUSIONS We developed and established the validity of an NBI classification system that can be used to diagnose colorectal polyps. In preliminary real-time evaluation, the system allowed endoscopic diagnoses of colorectal polyp histology.

Endoscopic prediction of deep submucosal invasive carcinoma: validation of the Narrow-Band Imaging International Colorectal Endoscopic (NICE) classification

BACKGROUND A simple endoscopic classification to accurately predict deep submucosal invasive (SM-d) carcinoma would be clinically useful. OBJECTIVE To develop and assess the validity of the NBI international colorectal endoscopic (NICE) classification for the characterization of SM-d carcinoma. DESIGN The study was conducted in 4 phases: (1) evaluation of endoscopic differentiation by NBI-experienced colonoscopists; (2) extension of the NICE classification to incorporate SM-d (type 3) by using a modified Delphi method; (3) prospective validation of the individual criteria by inexperienced participants, by using high-definition still images without magnification of known histology; and (4) prospective validation of the individual criteria and overall classification by inexperienced participants after training. SETTING Japanese academic unit. MAIN OUTCOME MEASUREMENTS Performance characteristics of the NICE criteria (phase 3) and overall classification (phase 4) for SM-d carcinoma; sensitivity, specificity, predictive values, and accuracy. RESULTS We expanded the NICE classification for the endoscopic diagnosis of SM-d carcinoma (type 3) and established the predictive validity of its individual components. The negative predictive values of the individual criteria for diagnosis of SM-d carcinoma were 76.2% (color), 88.5% (vessels), and 79.1% (surface pattern). When any 1 of the 3 SM-d criteria was present, the sensitivity was 94.9%, and the negative predictive value was 95.9%. The overall sensitivity and negative predictive value of a global, high-confidence prediction of SM-d carcinoma was 92%. Interobserver agreement for an overall SM-d carcinoma prediction was substantial (kappa 0.70). LIMITATIONS Single Japanese center, use of still images without prospective clinical evaluation. CONCLUSION The NICE classification is a valid tool for predicting SM-d carcinomas in colorectal tumors.

Miss rate of right-sided colon examination during colonoscopy defined by retroflexion: an observational study

BACKGROUND Colonoscopy is less effective in the proximal compared with the distal colon. OBJECTIVE To describe the success rate, yield, and safety of retroflexion of the right side of the colon after a careful forward-viewing examination. DESIGN Prospective observational study. SETTING Tertiary-care hospital outpatient endoscopy center and associated ambulatory surgery center. PATIENTS A total of 1000 consecutive adults undergoing elective screening or surveillance colonoscopy, without previous bowel resection, inflammatory bowel disease, or polyposis syndromes. INTERVENTION After cecal intubation, a careful examination of the cecum to the hepatic flexure was performed in the forward view with removal of all identified polyps. The colonoscope was then reinserted to the cecum and retroflexed, and examination was performed to the hepatic flexure in retroflexion. MAIN OUTCOME MEASUREMENTS Success rate, per-polyp and per-patient miss rates, and adverse events rate of retroflexion. RESULTS Retroflexion was successful in 94.4% of patients. Looping in the insertion tube was the apparent cause of 89% of failed attempts. The forward view identified 634 proximal colon polyps and 497 adenomas, and retroflexion identified an additional 68 polyps and 54 adenomas, representing a per-adenoma miss rate of 9.8% and an intention-to-treat, per-patient adenoma miss rate of 4.4%. Older age, male sex, and polyps seen on the forward view predicted polyps seen on retroflexion. There were no adverse events. LIMITATIONS Single-center, uncontrolled study with only 2 endoscopists. CONCLUSIONS Right-sided colon retroflexion is generally achievable and safe in our hands. The yield is comparable to that expected from a second examination in the forward view.

Cap-fitted colonoscopy: a randomized, tandem colonoscopy study of adenoma miss rates

BACKGROUND Failures of adenoma detection diminish the effectiveness of colonoscopy. OBJECTIVE This study investigated the impact of cap-fitted colonoscopy (CFC) on the adenoma miss rate at colonoscopy. DESIGN Randomized, tandem colonoscopy study. SETTING University hospital. PATIENTS This study involved patients undergoing elective screening or surveillance colonoscopy. INTERVENTION Patients were randomized to undergo cap-fitted (n = 52) or regular, high-definition (n = 48) colonoscopy before undergoing a second colonoscopy by the alternate method. During CFC, a plastic cap or hood was attached to the tip of the colonoscope, which was used to flatten haustral folds and improve mucosal exposure. MAIN OUTCOME MEASUREMENTS The primary outcome measure was the miss rate for adenomas between patients who underwent CFC first and patients who underwent regular colonoscopy first. RESULTS A total of 238 adenomas were detected in 67 patients (67%), with a combined overall miss rate of 27.7%, comprising 66 missed adenomas in 38 patients. Patients undergoing initial CFC had a significantly lower miss rate for all adenomas compared with that of patients undergoing regular colonoscopy (21% vs 33%, P = .039). Miss rates with CFC were significantly lower for adenomas of ≤5 mm (22% vs 35%; P = .037). There was no significant difference in per-patient miss rates between the initial CFC group (51%, n = 18) and the initial regular colonoscopy group (63%, n = 20, P = .36). LIMITATIONS Single-center study with two endoscopists. CONCLUSION CFC reduces miss rates for all adenomas and specifically for small adenomas. ( CLINICAL TRIAL REGISTRATION NUMBER NCT00577083).

The impact of videorecording on the quality of colonoscopy performance: A pilot study

OBJECTIVES:Colonoscopy provides imperfect protection against colorectal cancer and is operator dependent. Colonoscopies typically are poorly documented. We aimed to determine whether videorecording impacts short-term performance of colonoscopy.METHODS:We videorecorded routine colonoscopies by seven colonoscopists, with and without their awareness. Colonoscopy quality was measured by blinded assessment of inspection time and technique.RESULTS:From pre- to post-awareness of videorecording, mean inspection time increased by 49% for all colonoscopies combined and increased significantly for four individual colonoscopists. The overall quality of mucosal inspection technique improved by 31% after awareness of videorecording.CONCLUSIONS:Awareness of videorecording improved physician performance of colonoscopy. Further investigation of the role of videorecording in achieving sustained improvements in the quality performance of colonoscopy, including increases in adenoma detection, is warranted.

Leaving distal colorectal hyperplastic polyps in place can be achieved with high accuracy by using narrow-band imaging: an observational study

BACKGROUND Accurate colonoscopic assessment of colorectal polyp histology could avoid resection of distal nonadenomatous polyps and reduce costs and risk. OBJECTIVE To assess the accuracy of predicting histology by using narrow-band imaging (NBI) in real time for distal colorectal polyps. DESIGN Prospective observational study. SETTING University hospital and ambulatory surgery center. PATIENTS This study involved 225 consecutive adults undergoing elective screening or surveillance colonoscopy. INTERVENTION We evaluated real-time histology of 235 distal (rectosigmoid) colorectal polyps from 31 patients by using high-definition colonoscopy and NBI without optical magnification. For each polyp, the endoscopist described size, Paris classification, and surface characteristics (vascular and pit pattern, color, pseudodepression). Before resection, histology was predicted, and a level of confidence (high or low) was assigned. MAIN OUTCOME MEASUREMENTS Sensitivity and negative predictive value of high-confidence endoscopic predictions of adenomatous versus hyperplastic histology for polyps ≤ 5 mm. RESULTS The accuracy of a high-confidence endoscopic prediction was 97.7%, sensitivity for adenomatous histology 93.9%, specificity 98.4%, negative predictive value 97.9%, and positive predictive value 75.6%. The performance characteristics for predicting diminutive distal polyps (≤ 5 mm) with high confidence were sensitivity 96.0%, specificity 99.4%, negative predictive value 99.4%, and positive predictive value 96.0%. LIMITATIONS Single-center study with a single endoscopist. CONCLUSION NBI without optical magnification is sufficiently accurate to allow distal hyperplastic polyps to be left in place without resection and small, distal adenomas to be discarded without pathologic assessment. These findings validate NBI criteria based on color, vessels, and pit characteristics for predicting real-time colorectal polyp histology.

Improving Colonoscopy Quality Through Health-Care Payment Reform

Problems with the quality of colonoscopy are well recognized. Variation in colonoscopist performance is compounded by payment structures that reward volume rather than quality. Payment reform has emerged as one strategy to address these and more systemic problems in the quality of health care. Various forms of value-based purchasing might encourage a realignment of incentives, and allow reimbursement to be directly linked with clinically important goals of colonoscopy. This paper proposes criteria for the selection of quality measures, and three candidate indicators to define quality for the purpose of payment reform in colonoscopy: cecal intubation rate, adenoma detection rate, and recommended post-polypectomy surveillance interval. These measures represent valid, credible, and reliable indicators of the quality of colonoscopy for colorectal cancer screening and surveillance. Payment reform should explicitly link public reporting and performance on these quality measures to payment for colonoscopy.

Editorial: Detection targets for colonoscopy: From variable detection to validation

Abstract: Variation in the detection of both adenomas and cancers at colonoscopy is well established, and adenoma detection is a valid indicator of the quality of colonoscopy. A study reported in this issue demonstrated variable detection of serrated lesions among endoscopists. It is possible that serrated lesions are a major key to the lower level of protection provided by colonoscopy for proximal compared with the distal colon cancer, and serrated lesions may be an appropriate detection target during colonoscopy.

Hyperplastic Polyposis Syndrome Is Associated With Cigarette Smoking, Which May Be a Modifiable Risk Factor

OBJECTIVES:Hyperplastic polyposis syndrome (HPS) confers an increased risk of colorectal cancer and is difficult to manage clinically. Because both polyps and resultant cancers display the CpG island methylator phenotype and mutation of the BRAF oncogene, and because sporadic cancers with these characteristics are associated with cigarette smoking, we hypothesized that cigarette smoking may predispose to the development of HPS.METHODS:This was a case–control study with two independent control series conducted at a tertiary hospital in Brisbane, Queensland, Australia. Cases comprised patients with HPS (n=32) recruited through the database of the Queensland Familial Bowel Registry, who satisfied the World Health Organization international classification for HPS. Cases were compared with colonoscopy controls (n=298) defined as consecutive patients undergoing colonoscopy for clinical indications, who were free from polyps. We also compared cases with a second set of population controls (n=645) selected at random from a population register serving the catchment area for cases. This was an observational study, and all participants completed a questionnaire to obtain a comprehensive smoking history.RESULTS:The prevalence rate of current smoking was 47% in HPS patients, 17% in colonoscopy controls, and 12% in population controls. HPS patients were significantly more likely to be current smokers than were either colonoscopy controls (odds ratio (OR)=8.3, 95% confidence interval (CI): 3.0–22.9) or population controls (OR=12.7, 95% CI: 4.9–33.1).CONCLUSIONS:Cigarette smoking is strongly associated with HPS, thus suggesting that smoking exposure may increase the expression of this condition. Further studies should examine the possible benefits of quitting smoking in HPS patients.

Colonoscopic Polypectomy: Current Techniques and Controversies

Colonoscopic polypectomy is fundamental to effective colonoscopy. Through its impact on the polyp-cancer sequence, colonoscopic polypectomy reduces colorectal cancer incidence and mortality. Because it eliminates electrosurgical risk, cold snaring has emerged as the preferred technique for most small and all diminutive polyps. Few clinical trial data are available on the effectiveness and safety of specific techniques. Polypectomy technique seems highly variable between endoscopists, with some techniques more effective than others are. Further research is needed to investigate operator variation in polypectomy outcomes and establish an evidence base for best practice.