A resect and discard strategy would improve cost-effectiveness of colorectal cancer screening

Cost-effectiveness of "full spectrum endoscopy" colonoscopy for colorectal cancer screening

BACKGROUND

Compared to standard forward viewing colonoscopy, we aimed to assess the cost-effectiveness of full spectrum endoscopy colonoscopy in a population-based colorectal cancer screening and surveillance program.

METHODS

A Markov model was constructed to simulate the occurrence of colorectal neoplasia in a cohort of 100,000 subjects aged 50-100 years. The cost-effectiveness of full spectrum endoscopy was compared with that of standard forwarding viewing colonoscopy. Sensitivity for adenomatous and hyperplastic polyps <5mm, 6-9mm, and high-risk polyps were derived from the recent randomized tandem Fuse colonoscopy study.

RESULTS

The significantly higher sensitivity of full spectrum endoscopy in detecting additional adenomas resulted in an increase in cancer prevention from 58% to 74%, corresponding to a gain of 9 days per person. This 14% increase led to an absolute reduction in the cost of cancer care from $90 million to $57 million. This cost savings was only minimally impacted by the higher cost of more frequent post-polypectomy colonoscopy surveillance rates, leading to full spectrum endoscopy being associated with a savings of $145 per person. Thus, standard colonoscopy appeared to be "dominated" by the full spectrum endoscopy.

CONCLUSIONS

Compared to standard colonoscopy, full spectrum endoscopy appears to be more cost-effective for colon cancer screening and surveillance.

The addition of high magnifying endoscopy improves rates of high confidence optical diagnosis of colorectal polyps

BACKGROUND AND STUDY AIMS

The real-time optical diagnosis of colorectal polyps with high confidence predictions can achieve high levels of accuracy. Increasing the rates of high confidence optical diagnosis can improve the clinical application of real-time optical diagnosis in routine practice. The primary aim of this prospective study was to evaluate whether high magnifying endoscopy improves the rates of high confidence narrow-band imaging (NBI) - based optical diagnosis for differentiating between neoplastic and non-neoplastic colorectal lesions according to the NBI international colorectal endoscopic (NICE) classification.

PATIENTS AND METHODS

Consecutive adult patients undergoing colonoscopy with a high magnifying (maximum, × 80) colonoscope between April and August 2012 were recruited. The optical diagnosis for each polyp was evaluated during colonoscopy in two consecutive stages by the same endoscopist, who first used NBI with non-magnifying endoscopy (NBI-NME), then NBI with magnifying endoscopy (NBI-ME). A level of confidence was assigned to each prediction.

RESULTS

The analysis included 124 patients (mean age, 56.4 years; male-to-female ratio, 72:52) with 248 polyps smaller than 10 mm. Of the 248 polyps, 210 were 1 to 5 mm in size and 38 were 6 to 9 mm in size; 77 polyps were hyperplastic, 4 were sessile serrated adenomas/polyps, 160 were low grade adenomas, 5 were high grade adenomas, and 2 were deep submucosal invasive carcinomas. The rate of high confidence optical diagnosis when NBI-ME was used was significantly higher than the rate when NBI-NME was used for diminutive (1 - 5 mm) polyps (92.9 % vs 79.5 %, P < 0.001) and for small (6 - 9 mm) polyps (94.7 % vs 84.2 %, P = 0.048).

CONCLUSION

High magnifying endoscopy significantly improved the rates of high confidence NBI-based optical diagnosis of diminutive and small colorectal polyps.

STUDY REGISTRATION

UMIN 000007608.

Colorectal neoplasia pathways: state of the art

Colorectal cancer (CRC) is a heterogeneous disease and each CRC possesses a unique molecular tumor profile. The main pathways of oncogenesis are the chromosomal instability, microsatellite instability and serrated neoplasia pathway. Sessile serrated adenomas/polyps (SSA/Ps) may be the precursor lesions of CRC arising via the serrated neoplasia pathway. This has led to a paradigm shift because all SSA/Ps should be detected and resected during colonoscopy. The ability to accurately detect and resect only those polyps with a malignant potential could result in safer and cost-effective practice. Optimization of the endoscopic classification systems is however needed to implement targeted prevention methods.

New paradigms in polypectomy: resect and discard, diagnose and disregard

Polypectomy at colonoscopy has been shown to reduce the subsequent risk of colorectal cancer. With the advent of national screening programs, the number of colonoscopies performed has increased worldwide. In addition, the recent drive for quality improvement combined with advances in colonoscopic technology has resulted in increased numbers of polyps detected, resected, and sent for histopathology leading to spiraling costs associated with the procedure. Being able to diagnose small polyps in vivo (optical diagnosis) would allow for adenomas to be resected and discarded without the need to retrieve them or send them for formal histopathology.

Tools for polyp histology prediction

Although removal of adenomatous polyps has been shown to decrease the risk of colon cancer, distal hyperplastic polyps are thought to not have malignant potential. Most polyps detected during colonoscopy are diminutive (≤ 5 mm) and rarely harbor advanced histology, such as high-grade dysplasia or cancer. Therefore, predicting histology in real-time during colonoscopy can potentially decrease the enormous expenditure that ensues from universal histopathologic evaluation of polyps, and several novel imaging technologies have been developed and tested over the past decade for this purpose. Of these different technologies, electronic chromoendoscopy seems to strike a fair balance between accuracy, feasibility, and cost.

Endoscopic imaging

OPINION STATEMENT

The most important tools are the eye and the brain. A detailed white-light high-resolution examination and ability to recognize subtle lesions provide the foundation of the ability to detect lesions in the gastrointestinal tract. Novel technologies are now available to provide additional information with the goals of detection, delineation, or classification often with a focus on neoplasia in the gastrointestinal tract. The observer using these new tools must still recognize, interpret, and then make a clinically relevant conclusion. Therefore, the assessment of these tools may focus on both the technical feasibility to use the respective equipment to obtain an image and then also the associated cognitive-based criteria for image interpretation.

ASGE Technology Committee systematic review and meta-analysis assessing the ASGE PIVI thresholds for adopting real-time endoscopic assessment of the histology of diminutive colorectal polyps

In vivo real-time assessment of the histology of diminutive (≤5 mm) colorectal polyps detected at colonoscopy can be achieved by means of an "optical biopsy" by using currently available endoscopic technologies. This systematic review and meta-analysis was performed by the American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee to specifically assess whether acceptable performance thresholds outlined by an ASGE Preservation and Incorporation of Valuable endoscopic Innovations (PIVI) document for clinical adoption of these technologies have been met. We conducted direct meta-analyses calculating the pooled negative predictive value (NPV) for narrow-band imaging (NBI), i-SCAN, and Fujinon Intelligent Color Enhancement (FICE)-assisted optical biopsy for predicting adenomatous polyp histology of small/diminutive colorectal polyps. We also calculated the pooled percentage agreement with histopathology when assigning postpolypectomy surveillance intervals based on combining real-time optical biopsy of colorectal polyps 5 mm or smaller with histopathologic assessment of polyps larger than 5 mm. Random-effects meta-analysis models were used. Statistical heterogeneity was evaluated by means of I(2) statistics. Our meta-analyses indicate that optical biopsy with NBI, exceeds the NPV threshold for adenomatous polyp histology, supporting a "diagnose-and-leave" strategy for diminutive predicted nonneoplastic polyps in the rectosigmoid colon. The pooled NPV of NBI for adenomatous polyp histology by using the random-effects model was 91% (95% confidence interval [CI], 88-94). This finding was associated with a high degree of heterogeneity (I(2) = 89%). Subgroup analysis indicated that the pooled NPV was greater than 90% for academic medical centers (91.8%; 95% CI, 89-94), for experts (93%; 95% CI, 91-96), and when the optical biopsy assessment was made with high confidence (93%; 95% CI, 90-96). Our meta-analyses also indicate that the agreement in assignment of postpolypectomy surveillance intervals based on optical biopsy with NBI of diminutive colorectal polyps is 90% or greater in academic settings (91%; 95% CI, 86-95), with experienced endoscopists (92%; 95% CI, 88-96) and when optical biopsy assessments are made with high confidence (91%; 95% CI, 88-95). Our systematic review and meta-analysis confirms that the thresholds established by the ASGE PIVI for real-time endoscopic assessment of the histology of diminutive polyps have been met, at least with NBI optical biopsy, with endoscopists who are expert in using this advanced imaging technology and when assessments are made with high confidence.

Diminutive polyps among black and Latino populations undergoing screening colonoscopy: evidence supporting a resect and discard approach

BACKGROUND

A resect and discard strategy for diminutive (≤5 mm) colon polyps has been proposed to save costs of screening colonoscopy (SC). Prior studies on neoplasia prevalence based on polyp size have involved mostly white patients.

OBJECTIVE

To determine the prevalence of adenomas and advanced histologic features by size among primarily black and Latino patients enrolled in a prospective SC study.

DESIGN

Retrospective analysis of data from a prospective clinical trial.

SETTING

Urban academic medical center.

PATIENTS

Average risk, asymptomatic, minority patients aged ≥50 years undergoing SC.

INTERVENTIONS

Screening colonoscopy.

MAIN OUTCOME MEASUREMENTS

Rates of neoplasia and advanced histologic features (villous histology, high-grade dysplasia, or cancer) by polyp size and location.

RESULTS

A total of 566 polyps from 295 patients were analyzed. Diminutive polyps and small (6-9 mm) polyps had lower prevalence of ≥1 advanced feature compared with large (≥10 mm) polyps (0.9% and 2.7%, respectively, vs 13.6%; P < .001 for both comparisons). Distal polyps were less likely to be neoplastic (31.7% vs 61.4%; P < .001) than proximal polyps in all size categories (P < .001 for all comparisons). After adjusting for sex, ethnicity, age, and location, large polyps were more likely to have ≥1 advanced feature than diminutive polyps (adjusted odds ratio [OR] 19.5; 95% CI, 4.4-85.6) or small polyps (adjusted OR 6.1; 95% CI, 2.2-16.9).

LIMITATIONS

Use of pathology reports for polyp size.

CONCLUSION

Among a cohort of minority patients, advanced histologic features were very rare in diminutive polyps. Distal polyps were less likely to be neoplastic than proximal polyps in all size categories. This supports a resect and discard strategy for diminutive polyps, especially in the distal colon.

Resect and discard approach to colon polyps: real-world applicability among academic and community gastroenterologists

BACKGROUND

"Resect and discard" (RD) is a new paradigm for management of diminutive polyps.

AIM

To compare concordance of surveillance interval recommendations and diagnostic performance between RD and standard of care in a hospital outpatient department with both academic and community gastroenterologists.

METHODS

Prospective, observational study conducted at a single outpatient endoscopy center over 12 months. Patients with diminutive polyps on screening or surveillance colonoscopy were included. Histology predictions for all diminutive polyps (≤5 mm) were made based on endoscopic imaging. Concordance of recommended surveillance intervals and diagnostic performance of histology predictions were compared to histopathological review.

RESULTS

A total of 606 diminutive polyps were found in 315 patients (mean age 62.4 years, 49 % female). Histological prediction was made in 95.7 % of polyps (97.4 % of patients), with high confidence in 74.3 %. The concordance for surveillance intervals was 82.1 % compared to histopathological review and was similar between community and academic gastroenterologists (80.2 vs. 76.3 %, p = 0.38). Overall, sensitivity, specificity, and accuracy of histological predictions made with high confidence were 0.81, 0.36, and 77.1 %. Predictions made with narrow-band imaging (NBI) had lower accuracy (73.9 % with NBI vs. 82.5 % with high-definition white light (HWDL) only, p = 0.017) as well as lower prediction confidence (score of 7.6 with NBI vs. 8.6 with HDWL only, p < 0.001).

CONCLUSIONS

Our surveillance interval concordance was below the 90 % threshold deemed acceptable by the ASGE Preservation and Incorporation of Valuable Endoscopic Innovations statement. Diagnostic performance using optical imaging to predict histology was equal between community and academic endoscopists.

Advances in the removal of diminutive colorectal polyps

Diminutive polyps (<5 mm in diameter) represent the majority of polyps found during colonoscopy; about a half of them are adenomatous, with low risk of advanced neoplasia. Recent studies have demonstrated that cold polypectomy should be considered the recommended approach for resecting diminutive polyps and that cold snaring may be superior to cold forceps biopsy, at least for polyps of 4-5 mm. Recently, electronic chromoendoscopy has been applied to characterization of diminutive polyps to discriminate adenomatous from nonadenomatous lesions. Optical diagnosis of polyp histology could potentially exert huge cost savings by the 'resect and discard' strategy for diminutive polyps and 'leaving-in' for diminutive hyperplastic polyps in the recto-sigmoid colon. These policies represent the mainstay for adopting endoscopy-directed post-polypectomy surveillance strategies, endorsed by both American and European Endoscopy Societies. Accuracy of both histology and surveillance intervals predictions from academic centers have been encouraging, although the same performance has not been replicated in community practices.

Small colorectal polyps

Small (<10 mm) and diminutive (<6 mm) polyps harbour high-grade dysplasia or cancer in 0.3-5% of cases. The potential to grow and develop advanced histology is low. Traditional guidelines still recommend the removal of all polyps. Visual characterisation with modern endoscopic technology could enable us to leave diminutive hyperplastic polyps in situ and remove but discard small polyps. In expert hands, high-definition white-light endoscopy and virtual chromoendoscopy can reach an accuracy of more than 90% in distinguishing between hyperplastic and adenomatous pathology. For less experienced endoscopists the values are lower and therefore the concept is not yet fit for routine use. Polyps can be removed completely with snares but not with forceps. The cold snaring technique in particular has proved safe and effective for small polyps. With more experience in the future a 'cut and discard' strategy for small polyps and a 'do not resect' strategy for diminutive polyps will save money and time to deal with more advanced lesions.

Diminutive and Small Colorectal Polyps: The Pathologist's Perspective

Recent progress in advanced endoscopic imaging and electronic chromoendoscopy allows the real-time endoscopic estimation of the histologic type of polyps, mainly for the differentiation of adenomas from hyperplastic polyps. Accordingly, a "resect-and-discard" strategy applied to diminutive colorectal polyps is now one of the emerging issues among gastroenterologists. The strategy has a practical advantage in terms of the potential cost savings. However, it has a number of limitations in the medical, academic, and legal aspects. The major pitfalls include the endoscopic investigation of colorectal polyps with a wide variety of histogenetic origins, including serrated polyps, and the lack of a standardized method for polyp size measurement. Another issue is the importance of the pathologic diagnosis for legal purposes and medical research. Moreover, it is not certain whether the implementation of the strategy has economic benefit in countries with an undervalued reimbursement system for pathologic examination. There is no doubt that a highly confident optical diagnosis of polyp type is a novel valuable tool. It can provide a more steady symbiosis between gastroenterologists and pathologists to allow a more evident diagnosis and management of patients with colorectal polyps.

Advances, problems, and complications of polypectomy

The major role of colonoscopy with polypectomy in reducing the incidence of and mortality from colorectal cancer has been firmly established. Yet there is cause to be uneasy. One of the most striking recent findings is that there is an alarmingly high incomplete polyp removal rate. This phenomenon, together with missed polyps during screening colonoscopy, is thought to be responsible for the majority of interval cancers. Knowledge of serrated polyps needs to broaden as well, since they are quite often missed or incompletely removed. Removal of small and diminutive polyps is almost devoid of complications. Cold snare polypectomy seems to be the best approach for these lesions, with biopsy forcep removal reserved only for the tiniest of polyps. Hot snare or hot biopsy forcep removal of these lesions is no longer recommended. Endoscopic mucosal resection and endoscopic submucosal dissection have proven to be effective in the removal of large colorectal lesions, avoiding surgery in the majority of patients, with acceptably low complication rates. Variants of these approaches, as well as new hybrid techniques, are being currently tested. In this paper, we review the current status of the different approaches in removing polypoid and nonpolypoid lesions of the colon, their complications, and future directions in the prevention of colorectal cancer.

Usefulness of narrow-band imaging with dual-focus magnification for differential diagnosis of small colorectal polyps

BACKGROUND

Many authors have already reported the usefulness of narrow-band imaging (NBI) for the differential diagnosis of non-neoplastic and neoplastic colorectal lesions. However, it is not clear whether magnification is required for differential diagnosis. The aim of this prospective study was to clarify the clinical usefulness of a newly developed NBI system with a dual focus function (dual-focus NBI) compared with conventional white-light imaging (WLI) and NBI without magnification for distinguishing between non-neoplastic and neoplastic lesions.

PATIENTS AND METHODS

Thirty-seven consecutive patients who underwent screening colonoscopy with the novel system between July and December 2013 were analyzed. Patients with polyps >10 mm and those with polyps previously evaluated by histologic examination or colonoscopy were excluded. Lesions were diagnosed in real time with WLI, NBI without magnification, and dual-focus NBI, and then excised endoscopically. Each diagnosis was compared to that in the final histopathology reports. The primary endpoint was the diagnostic accuracy and the confidence level assigned to each modality by the endoscopists. The secondary endpoint was the differentiation ability according to the size of the lesion (≤5 and 6-10 mm).

RESULTS

In all, 100 lesions including 76 adenomatous polyps and 24 hyperplastic polyps were analyzed in 37 patients. The overall diagnostic accuracy, sensitivity, and specificity for differentiating adenomatous from hyperplastic polyps were 87.0, 89.5, and 79.2 % for WLI, 93.0, 94.7, and 87.5 % for NBI without magnification, and 94.0, 96.1, and 87.5 % for dual-focus NBI, respectively. The level of confidence was significantly different between dual-focus NBI and WLI and NBI without magnification for diminutive (≤5 mm) lesions (p < 0.001 and p < 0.01).

CONCLUSION

Dual-focus NBI is especially useful for differential diagnosis of diminutive colorectal lesions.

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.

High-definition vs. standard-definition endoscopy with indigo carmine for the in vivo diagnosis of colonic polyps

BACKGROUND

There is growing evidence that indigo carmine chromoendoscopy is effective for the in vivo diagnosis of colonic polyps. However, the impact of colonoscope resolution on diagnostic accuracy has not been investigated.

OBJECTIVE

We aimed to compare the effectiveness of in vivo diagnosis of small colonic polyps using indigo carmine dye spray with standard-definition and high-definition colonoscopes.

METHODS

Procedures were performed using Fujinon colonoscopes and EPX 4400 processor. Fujinon standard-definition (SD) and high-definition (HD) colonoscopes were used, with the endoscopist blinded to colonoscope definition. Polyps <10 mm were assessed using 0.2% indigo carmine dye spray, with the predicted diagnosis recorded. In each case the kind of colonoscope (SD or HD) was recorded. Polyps were removed and sent for histological analysis, with the pathologist blinded to the diagnosis made by the endoscopist. The predicted diagnosis was compared with the true histology to calculate the accuracy, sensitivity and specificity of in vivo assessment using either SD or HD scopes.

RESULTS

In total 237 polyps <10 mm in size were examined. There was no statistically significant difference for any of the measured parameters between SD and HD assessments, with an accuracy, sensitivity and specificity of 89%, 91% and 87% with SD colonoscopes and 92%, 96% and 84% with HD colonoscopes.

CONCLUSIONS

The accuracy of in vivo assessment of small colonic polyps with indigo carmine dye spray is excellent with standard-definition colonoscopes and is not improved with high-definition colonoscopes.

Current status and future perspectives of endoscopic diagnosis and treatment of diminutive colorectal polyps

During colonoscopy, small and diminutive colorectal polyps are commonly encountered. It is estimated that at least one adenomatous polyp is detected in almost half of all patients undergoing screening colonoscopy. In contrast, the 'predict, resect, and discard' strategy for diminutive and small colorectal polyps is a current topic especially in Western countries. 'Is this an acceptable policy in Japan?' Herein, we report the results of a questionnaire survey with regard to the management of diminutive colorectal polyps, including the thoughts of Japanese endoscopists regarding the 'predict, resect, and discard' strategy. At the moment, we propose that this strategy should be used by skilled endoscopists only.

Current management of diminutive colorectal polyps in Taiwan

The majority of polyps detected during colonoscopy are diminutive polyps, for which the cost of pathological analysis is substantial. In our analysis of a screening cohort of 10737 subjects undergoing screening colonoscopy, a total of 15877 neoplastic lesions were detected, of which 10816 (68.1%) were diminutive lesions. Of those diminutive lesions, 90 (0.83%) had a villous component, 14 (0.1%) had high-grade dysplasia, and none had invasive cancer. Only 1.3% of patients were advised to decrease their surveillance interval because of unfavorable histology. Laws regulating medical practice, uncertainty regarding the accuracy of endoscopic diagnosis of diminutive polyps outside of academic centers, and the relatively low cost of pathological analysis are among the barriers to adopting a 'resect and discard' practice in Taiwan.

Proposal of a new 'resect and discard' strategy using magnifying narrow band imaging: pilot study of diagnostic accuracy

BACKGROUND AND AIM

A 'resect and discard' strategy using non-magnifying narrow band imaging (N-NBI) has been proposed for reducing screening colonoscopy costs, but it does not take into consideration advanced histology and magnifying NBI (M-NBI) that can potentially further improve the 'resect and discard' strategy. We conducted a pilot study to investigate the feasibility of M-NBI for the new 'resect and discard' strategy with consideration for advanced histology.

METHODS

The present study involved 63 patients. For each polyp, optical diagnosis was independently made using N-NBI and M-NBI, a decision (discard or send for pathology) was made based on the M-NBI findings, and histological and optical diagnosis results were compared.

RESULTS

Sensitivity, specificity and accuracy (95% confidence interval) of M-NBI for lesions with advanced histology were 1.00 (0.36-1.00), 0.92 (0.91-0.92) and 0.92 (0.90-0.92), respectively. Whereas the management of 86% of small polyps could be decided without formal histopathology, lesions with advanced histology were not discarded using M-NBI. The diagnostic accuracy of M-NBI in distinguishing neoplastic from non-neoplastic lesions was higher than that of N-NBI.

CONCLUSIONS

We propose a new resect and discard strategy with advanced histology using M-NBI that is a promising strategy to reduce the costs of histopathology and to minimize the risk of discarding important lesions.

A review of image-enhanced endoscopy in the evaluation of colonic polyps

The practice of colonoscopy has changed considerably over the last decade. The growth of image-enhanced endoscopy have altered our concepts of how we perform colonoscopy. This article examines the evidence base behind these techniques and looks at where future research needs to be directed.

Endoscopic versus histological characterisation of polyps during screening colonoscopy

BACKGROUND

As screening colonoscopy becomes more widespread, the costs for histopathological assessment of resected polyps are rising correspondingly. Reference centres have published highly accurate results for endoscopic polyp classification. Therefore, it has been proposed that, for smaller polyps, the differential diagnosis that guides follow-up recommendations could be based on endoscopy alone.

OBJECTIVE

The aim was to prospectively assess whether the high accuracy for endoscopic polyp diagnosis as reported by reference centres can be reproduced in routine screening colonoscopy.

DESIGN

Ten experienced private practice endoscopists had initial training in pit patterns. Then they assessed all polyps detected during 1069 screening colonoscopies. Patients (46% men; mean age 63 years) were randomly assigned to colonoscopy with conventional or latest generation HDTV instruments. The main outcome measure was diagnostic accuracy of in vivo polyp assessment (adenomatous vs hyperplastic). Secondary outcome measures were differences between endoscopes and reliability of image-based follow-up recommendations; a blinded post hoc analysis of polyp photographs was also performed.

RESULTS

675 polyps were assessed (461 adenomatous, 214 hyperplastic). Accuracy, sensitivity and specificity of in vivo diagnoses were 76.6%, 78.1% and 73.4%; size of adenomas and endoscope withdrawal time significantly influenced accuracy. Image-based recommendations for post-polypectomy surveillance were correct in only 69.5% of cases. Post hoc analysis of polyp photographs did not improve accuracy.

CONCLUSIONS

In everyday practice, endoscopic classification of polyp type is not accurate enough to abandon histopathological assessment and use of latest generation colonoscopes does not improve this. Image-based surveillance recommendations after polypectomy would consequently not meet guideline requirements.

TRIALREGNO

NCT01297712.

Narrow band imaging to differentiate neoplastic and non-neoplastic colorectal polyps in real time: a meta-analysis of diagnostic operating characteristics

PURPOSE

Many studies have reported on the use of narrow band imaging (NBI) colonoscopy to differentiate neoplastic from non-neoplastic colorectal polyps. It has potential to replace pathological diagnosis of diminutive polyps. We aimed to perform a systematic review and meta-analysis on the real-time diagnostic operating characteristics of NBI colonoscopy.

METHODS

We searched PubMed, SCOPUS and Cochrane databases and abstracts. We used a two-level bivariate meta-analysis following a random effects model to summarise the data and fit hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve serves as an indicator of the diagnostic test strength. We calculated summary sensitivity, specificity and negative predictive value (NPV). We assessed agreement of surveillance interval recommendations based on endoscopic diagnosis compared to pathology.

RESULTS

For NBI diagnosis of colorectal polyps, the area under the HSROC curve was 0.92 (95% CI 0.90 to 0.94), based on 28 studies involving 6280 polyps in 4053 patients. The overall sensitivity was 91.0% (95% CI 87.6% to 93.5%) and specificity was 82.6% (95% CI 79.0% to 85.7%). In eight studies (n=2146 polyps) that used high-confidence diagnostic predictions, sensitivity was 93.8% and specificity was 83.3%. The NPVs exceeded 90% when 60% or less of all polyps were neoplastic. Surveillance intervals based on endoscopic diagnosis agreed with those based on pathology in 92.6% of patients (95% CI 87.9% to 96.3%).

CONCLUSIONS

NBI diagnosis of colorectal polyps is highly accurate--the area under the HSROC curve exceeds 0.90. High-confidence predictions provide >90% sensitivity and NPV. It shows high potential for real-time endoscopic diagnosis.

Optical biopsy of sessile serrated adenomas: do these lesions resemble hyperplastic polyps under narrow-band imaging?

BACKGROUND

Serrated colorectal lesions include hyperplastic polyps (HPs) and sessile serrated adenomas (SSAs). Optical biopsy could misclassify SSAs as unimportant if they resemble HPs.

OBJECTIVE

To explore the narrow-band imaging (NBI) features of SSAs. We hypothesized that SSAs resemble HPs under NBI.

DESIGN

Retrospective analysis of data from our prospective study of NBI in routine practice.

SETTING

Single specialty group.

PATIENTS

Patients undergoing colonoscopy.

INTERVENTION

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Polyp histology prediction by community gastroenterologists. Features of SSAs versus HPs and adenomas by using the Narrow-Band Imaging International Colorectal Endoscopic (NICE) Classification.

RESULTS

Among 2388 lesions, 141 were diagnosed on pathology as SSAs, 465 as HPs, and 1546 as adenomas. Each individual NICE feature of HPs was found in 38% to 42% of SSAs, 66% to 67% of HPs, and 15% to 20% of adenomas (P < .001 for each). Each individual NICE feature of adenomas was found in 57% to 62% of SSAs, 33% to 34% of HPs, and 80% to 84% of adenomas (P < .001 for each). Compared with HPs, SSAs were less likely (odds ratio [OR] 0.74; 95% confidence interval [CI], 0.69-0.79) and adenomas were even less likely (OR 0.62; 95% CI, 0.59-0.64) to have all 3 NICE features of HPs. SSAs >5 mm were more likely than smaller SSAs to have all 3 NICE features of adenomas. SSA location did not predict NBI features. Analyses restricted to high-confidence lesions showed similar results.

LIMITATIONS

The endoscopists were not NBI experts.

CONCLUSION

Community gastroenterologists observed a profile of NICE features among SSAs that was intermediate to the profiles observed for HPs and adenomas. These results require confirmation by NBI experts.

Review of economic evidence in the prevention and early detection of colorectal cancer

This paper aims to systematically review the cost-effectiveness evidence, and to provide a critical appraisal of the methods used in the model-based economic evaluation of CRC screening and subsequent surveillance. A search strategy was developed to capture relevant evidence published 1999-November 2012. Databases searched were MEDLINE, EMBASE, National Health Service Economic Evaluation (NHS EED), EconLit, and HTA. Full economic evaluations that considered costs and health outcomes of relevant intervention were included. Sixty-eight studies which used either cohort simulation or individual-level simulation were included. Follow-up strategies were mostly embedded in the screening model. Approximately 195 comparisons were made across different modalities; however, strategies modelled were often simplified due to insufficient evidence and comparators chosen insufficiently reflected current practice/recommendations. Studies used up-to-date evidence on the diagnostic test performance combined with outdated information on CRC treatments. Quality of life relating to follow-up surveillance is rare. Quality of life relating to CRC disease states was largely taken from a single study. Some studies omitted to say how identified adenomas or CRC were managed. Besides deterministic sensitivity analysis, probabilistic sensitivity analysis (PSA) was undertaken in some studies, but the distributions used for PSA were rarely reported or justified. The cost-effectiveness of follow-up strategies among people with confirmed adenomas are warranted in aiding evidence-informed decision making in response to the rapidly evolving technologies and rising expectations.

Gastroenterology trainees can easily learn histologic characterization of diminutive colorectal polyps with narrow band imaging

BACKGROUND & AIMS

Little is known about how teaching gastroenterology trainees polyp patterns by using narrow band imaging (NBI) affects their ability to characterize the histology of diminutive colorectal polyps. We developed and tested a tool to teach trainees to characterize the histology of diminutive polyps by using NBI.

METHODS

Twelve gastroenterology trainees with varying levels of colonoscopy experience watched a teaching tool that described the NBI criteria to distinguish polyp histology. The trainees then watched 80 videos of NBI examination of diminutive polyps, recording their predictions of polyp histology and their degree of confidence. After each video, an expert provided feedback about actual polyp histology and the NBI criteria that supported each diagnosis. Twelve weeks later, without training or feedback during the interval, the trainees watched the same videos and predicted histologies of the polyps. Performance was evaluated by comparing predicted classification with actual histologic findings. Cumulative sum analysis was used to determine the learning curve for each trainee.

RESULTS

Trainees made significant improvements in accuracy and the proportion of high-confidence predictions as they progressed through video blocks during the first session (P < .001). With active feedback, all trainees predicted polyp histologies with >90% accuracy, with a negative predictive value >90% for adenomatous histology. A median of 49 videos was required to achieve competency. For diagnoses made with high confidence, trainee performance exceeded 90% during the first and second sessions. Interobserver agreement was substantial (session 1, κ = 0.71; session 2, κ = 0.70).

CONCLUSIONS

We developed a computer-based tool, combined with short videos and active feedback, to train gastroenterologists to identify polyp histology by using NBI. After training, gastroenterology trainees characterized the histology of diminutive polyps with ≥ 90% accuracy.

Optical diagnosis of colorectal polyps using high-definition i-scan: An educational experience

AIM: To examine performances regarding prediction of polyp histology using high-definition (HD) i-scan in a group of endoscopists with varying levels of experience.

METHODS: We used a digital library of HD i-scan still images, comprising twin pictures (surface enhancement and tone enhancement), collected at our university hospital. We defined endoscopic features of adenomatous and non-adenomatous polyps, according to the following parameters: color, surface pattern and vascular pattern. We familiarized the participating endoscopists on optical diagnosis of colorectal polyps using a 20-min didactic training session. All endoscopists were asked to evaluate an image set of 50 colorectal polyps with regard to polyp histology. We classified the diagnoses into high confidence (i.e., cases in which the endoscopist could assign a diagnosis with certainty) and low confidence diagnoses (i.e., cases in which the endoscopist preferred to send the polyp for formal histology). Mean sensitivity, specificity and accuracy per endoscopist/image were computed and differences between groups tested using independent-samples t tests. High vs low confidence diagnoses were compared using the paired-samples t test.

RESULTS: Eleven endoscopists without previous experience on optical diagnosis evaluated a total of 550 images (396 adenomatous, 154 non-adenomatous). Mean sensitivity, specificity and accuracy for diagnosing adenomas were 79.3%, 85.7% and 81.1%, respectively. No significant differences were found between gastroenterologists and trainees regarding performances of optical diagnosis (mean accuracy 78.0% vs 82.9%, P = 0.098). Diminutive lesions were predicted with a lower mean accuracy as compared to non-diminutive lesions (74.2% vs 93.1%, P = 0.008). A total of 446 (81.1%) diagnoses were made with high confidence. High confidence diagnoses corresponded to a significantly higher mean accuracy than low confidence diagnoses (84.0% vs 64.3%, P = 0.008). A total of 319 (58.0%) images were evaluated as having excellent quality. Considering excellent quality images in conjunction with high confidence diagnosis, overall accuracy increased to 92.8%.

CONCLUSION: After a single training session, endoscopists with varying levels of experience can already provide optical diagnosis with an accuracy of 84.0%.

Colonic polyps: are we ready to resect and discard?

Colorectal cancer represents a major cause of mortality in Western countries, and population-based colonoscopy screening is supported by official guidelines. A significant determinant of the cost of colonoscopy screening/surveillance is driven by polypectomy of diminutive (≤5 mm) lesions. When considering the low prevalence of advanced neoplasia within diminutive polyps, the additional cost of pathologic examination is mainly justified by the need to differentiate between precancerous adenomatous versus hyperplastic polyps. The aim of this review is to summarize the data supporting the clinical application of a resect and discard strategy, also addressing the potential pitfalls associated with this approach.

Accuracy of narrow-band imaging in predicting colonoscopy surveillance intervals and histology of distal diminutive polyps: results from a multicenter, prospective trial

BACKGROUND

In vivo prediction of colorectal polyp histology by narrow-band imaging (NBI) could potentially avoid post-polypectomy histologic examination or resection of diminutive lesions, thereby reducing costs and risk.

OBJECTIVE

To assess whether NBI is able to predict colonoscopy surveillance intervals and histology of distal diminutive polyps according to American Society for Gastrointestinal Endoscopy (ASGE) criteria.

DESIGN

Prospective, multicenter study.

SETTING

Five endoscopic centers.

PATIENTS

Consecutive patients undergoing colonoscopy in 5 centers were included.

INTERVENTION

Participating endoscopists were required to pass a before-study qualifying examination. Histology of polyps that were <10 mm was predicted at NBI and assigned a designation of high or low confidence.

MAIN OUTCOME MEASUREMENTS

Accuracy of high-confidence NBI prediction for polyps ≤5 mm in predicting surveillance intervals and negative predictive value (NPV) for adenomatous histology in the rectosigmoid colon were compared with the ASGE thresholds (90% agreement, 90% NPV).

RESULTS

A total of 278 patients (mean age, 63 years; 58% male) were enrolled. At colonoscopy, 574 (97.3%) polyps <10 mm (429 ≤5 mm, 60% adenomatous) were retrieved for histologic analysis. Sensitivity, specificity, positive and negative predictive values, and accuracy of high confidence-NBI predictions for adenomatous histology in lesions ≤5 mm were 90%, 88%, 89%, 89%, and 89%, respectively. High-confidence characterization of polyps ≤5 mm predicted the correct surveillance interval in 92% to 99% of cases, according to the American and European guidelines. NPV of high-confidence NBI for adenomatous histology for the rectosigmoid colon lesions ≤5 mm was 92%.

LIMITATIONS

Only experienced endoscopists were included.

CONCLUSION

High-confidence prediction of histology for polyps ≤5 mm appears to be sufficiently accurate to avoid post-polypectomy histologic examination of the resected lesions as well as to allow rectosigmoid hyperplastic polyps to be left in place without resection. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01675752.).

Learning curve of virtual chromoendoscopy for the prediction of hyperplastic and adenomatous colorectal lesions: a prospective 2-center study

BACKGROUND

Computed virtual chromoendoscopy (CVC) enables high-definition imaging of mucosal lesions with improved tissue contrast. Previous studies have shown that CVC yields an improved detection rate of colorectal lesions. However, the learning curve for interpretation of CVC images is unknown.

OBJECTIVE

To examine the learning curve of correctly identifying hyperplastic and adenomatous colorectal lesions by using CVC.

DESIGN

Prospective, 2-center study.

PATIENTS

Consecutive patients undergoing screening colonoscopy were included. CVC images were analyzed by using corresponding polypectomies as the reference standard followed by a prospective, double-blind review of i-scan images.

METHODS

A training set containing 20 images with known histology was reviewed to standardize image interpretation, followed by a blind review of 110 unknown images. Overall, 4 endoscopists from 2 different endoscopy centers evaluated the images, which were obtained by 1 endoscopist using high-definition endoscopy with CVC.

RESULTS

Patients were included in a prospective fashion. Seventy-seven of 110 colorectal lesions were adenomas and 33 were hyperplastic lesions. Mean diameter of colonic polyps was 4 mm (range, 2-20 mm). Overall accuracy for the group was 73.9% for lesions 1 to 22, 79.6% for lesions 23 to 44, 84.1% for lesions 45 to 66, 87.5% for lesions 67 to 88, and 94.3% for lesions 89 to 110. Accuracy of i-scan for prediction of polyp histology was not dependent on polyp size (≤5 mm, 6-10 mm, or > 10 mm). The ability to obtain high-quality images was stable over time, and high-quality images were constantly produced.

LIMITATION

Post-hoc assessment.

CONCLUSION

Accurate interpretation of CVC images for prediction of hyperplastic and adenomatous colorectal lesions follows a learning curve but can be learned rapidly.

High-definition with i-Scan gives comparable accuracy for detecting colonic lesions by non-expert and expert endoscopists

BACKGROUND

Lesion detection rate during colonoscopy may be influenced by the endoscopist's experience. EPK-i system colonoscopy (i-Scan) can improve mucosal and vascular visualization for detecting lesions.

AIM

To compare mucosal lesions detection rate and the withdrawal time of the instrument among non-expert and expert endoscopists.

METHODS

Colonoscopy records of all consecutive patients undergoing first HD+ with i-Scan- or SWL-equipped colonoscopy for colorectal cancer screening over a twelve-month period were evaluated, in a "post hoc" analysis.

RESULTS

542 colonoscopies (389 HD+ with i-Scan; 153 SWL): expert and non-expert endoscopists did respectively 272 and 117 HD+ with i-Scan and 83 and 70 SWL colonoscopies. Expert endoscopists did more i-Scan colonoscopies than non-experts (p=0.006). In the SWL procedures, the experts detected mucosal lesions in more colonoscopies than non-experts (61/22 vs. 23/47, p=0.0001) and found a significantly higher mean number of lesions (1.34 vs. 0.47; p=0.0001). Experts detected more or less the same mean number of lesions with both imaging techniques, while among non-experts detection with HD+ with i-Scan was significantly better than with SWL imaging (1.39 vs. 0.47; p=0.0001).

CONCLUSIONS

HD+ with i-Scan imaging enables less skilled endoscopists to achieve results comparable to those of experienced ones in detecting mucosal lesions.

Clinicopathological features of colorectal polyps: evaluation of the 'predict, resect and discard' strategies

AIM

'Predict, resect and discard' strategies for diminutive and small colonic polyps are considered to be cost effective for treating colorectal cancers. The aim of this study was to determine, retrospectively, the histological features of colonic polyps resected by endoscopic procedures or surgery using an updated database.

METHOD

We retrospectively analysed the clinicopathological features of colorectal polyps, less than 20 mm in size, which were removed by endoscopy from January 2009 to November 2011 at the National Cancer Center Hospital (NCCH) in Tokyo, Japan.

RESULTS

Less than 1% of diminutive polyps (≤ 5 mm) were classified as mucosal high-grade neoplasia (Category 4), and no submucosal invasion by carcinoma (Category 5) lesions were noted. However, 3% of small polyps (6-9 mm) were classified as Category 5; of these, 6% were submucosal deep invasive cancers. Morphologically, depressed components were observed more frequently in carcinomas than in adenomas in both small and large polyps (10-20 mm).

CONCLUSION

In light of the 'predict, resect and discard' strategies for small polyps, we should pay attention to the possible clinical malignancy of small and large polyps. We recommend that these strategies should be applied selectively and that they should be informed by accurate endoscopic evaluations.

New paradigms for colonoscopic management of diminutive colorectal polyps: predict, resect, and discard or do not resect?

The possibility to predict in vivo the histology of colorectal polyps by advanced endoscopic imaging has resulted in the implementation of a more conservative management for diminutive lesions detected at colonoscopy. In detail, a predict-and-do-not-resect strategy has been proposed for diminutive lesions located in the rectosigmoid tract, whilst a predict-resect-and-discard policy has been advocated for nonrectosigmoid diminutive polyps. Recently, the American Society for Gastrointestinal Endoscopy set required thresholds to be met, before allowing the adoption of these policies in the clinical field. The ability of current endoscopic imaging in reaching these thresholds would depend on a complex interaction among the accuracy of advanced endoscopic imaging in differentiating between adenomatous and hyperplastic lesions, the prevalence of (advanced) neoplasia within diminutive lesions, and the type of surveillance intervals recommended. Aim of this review is to summarize the data supporting the application of both a predict-and-do-not-resect and a predict-resect-and-discard policies, also addressing the potential pitfalls associated with these strategies.

i-Scan high-definition white light endoscopy and colorectal polyps: prediction of histology, interobserver and intraobserver agreement

PURPOSE

Aim of the study was the evaluation of high-definition white light (HDWL) i-Scan endoscopy for diagnostic prediction of histology, inter- and intraobserver agreement for colorectal polyps.

METHODS

In this prospective single-center cohort study, a skilled endoscopist, with HDWL i-Scan, predicted on real-time the histology of 150 polyps from 78 patients undergoing colonoscopy. Subsequently, four endoscopists, not involved in the collection of cases, predicted the polyps' histology (neoplastic vs nonneoplastic) and repeated the assessment after 6 months.

RESULTS

Real-time assessment of the lesions predicted a correct histology in 138/150 cases with a sensitivity, specificity, and accuracy of 95, 82, and 92 %, respectively. Sensitivity, specificity, and accuracy of post-acquisition evaluation were 87.7, 61.7, and 82.2 %, respectively. The κ values of inter- and intraobserver agreement of prediction of histology were 0.462 (0.373-0.537) and 0.657 (0.523-0.917). Among the subset of polyps (n = 82) with good/excellent quality image, sensitivity and accuracy of HDWL i-Scan improved (97 %, p = 0.003 and 94 %, p = 0.002, respectively) as well as κ value of interobserver agreement (0.699).

CONCLUSIONS

HDWL i-Scan technology helps for characterization of polyps of the colon with good accuracy even if it cannot replace, at the moment, the histopathological examination. Reproducibility among operators is supported by a moderate substantial interobserver and intraobserver agreement.

Screening colonoscopy from a large single center of Thailand - something needs to be changed?

BACKGROUND

Results of screening colonoscopy from Western countries reported adenoma detection rates (ADRs) of 30-40% while those from Asia had ADR as low as 10%. There have been limited data regarding screening colonoscopy in Thailand. The objectives of this study were therefore to determine polyp and adenoma detection rates in Thai people, to evaluate the incidence of colorectal cancer detected during screening colonoscopy and to determine the endoscopic findings of the polyps which might have some impact on endoscopists to perform polypectomy.

MATERIALS AND METHODS

This study was a retrospective electronic chart review of asymptomatic Thai adults who underwent screening colonoscopy in our endoscopic center from June 2007 to October 2010.

RESULTS

A total of 1,594 cases were reviewed. The patients had an average age of 58.3 ± 10.5 years (range 27-82) and 55.5% were female. Most of the cases (83.8%) were handled by staff who were endoscopists. A total of 488 patients (30.6%) were reported to have colonic polyps. Left-sided colon was the most common site (45.1%), followed by right-sided colon (36.5%) and the rectum (18%). Those polyps were removed in 97.5% of cases and 88.5 % of the polyps were sent for histopathology (data lost 11.5%). Two hundred and sixty three cases had adenomatous polyps, accounting for 16.5 % ADR. Advanced adenomas were detected in 43 cases (2.6%). Hyperplastic polyps were mainly located distal to the splenic flexure of the colon whereas adenomas were found throughout the large intestine. Ten cases (0.6%) were found to have colorectal cancer. Four advanced adenomas and two malignant polyps were reported in lesions ≤ 5 mm.

CONCLUSION

The polyp detection rate, adenoma detection rate, advanced adenoma detection rate and colorectal cancer detection rate in the screening colonoscopy of Thai adults were 30.9%, 16.5%, 2.6% and 0.6% respectively. Malignant transformation was detected regardless of the size and location of the polyps. Therefore, new technology would play an important role indistinguishing polyps.

Real-time optical biopsy of colon polyps with narrow band imaging in community practice does not yet meet key thresholds for clinical decisions

BACKGROUND & AIMS

Accurate optical analysis of colorectal polyps (optical biopsy) could prevent unnecessary polypectomies or allow a "resect and discard" strategy with surveillance intervals determined based on the results of the optical biopsy; this could be less expensive than histopathologic analysis of polyps. We prospectively evaluated real-time optical biopsy analysis of polyps with narrow band imaging (NBI) by community-based gastroenterologists.

METHODS

We first analyzed a computerized module to train gastroenterologists (N = 13) in optical biopsy skills using photographs of polyps. Then we evaluated a practice-based learning program for these gastroenterologists (n = 12) that included real-time optical analysis of polyps in vivo, comparison of optical biopsy predictions to histopathologic analysis, and ongoing feedback on performance.

RESULTS

Twelve of 13 subjects identified adenomas with >90% accuracy at the end of the computer study, and 3 of 12 subjects did so with accuracy ≥90% in the in vivo study. Learning curves showed considerable variation among batches of polyps. For diminutive rectosigmoid polyps assessed with high confidence at the end of the study, adenomas were identified with mean (95% confidence interval [CI]) accuracy, sensitivity, specificity, and negative predictive values of 81% (73%-89%), 85% (74%-96%), 78% (66%-92%), and 91% (86%-97%), respectively. The adjusted odds ratio for high confidence as a predictor of accuracy was 1.8 (95% CI, 1.3-2.5). The agreement between surveillance recommendations informed by high-confidence NBI analysis of diminutive polyps and results from histopathologic analysis of all polyps was 80% (95% CI, 77%-82%).

CONCLUSIONS

In an evaluation of real-time optical biopsy analysis of polyps with NBI, only 25% of gastroenterologists assessed polyps with ≥90% accuracy. The negative predictive value for identification of adenomas, but not the surveillance interval agreement, met the American Society for Gastrointestinal Endoscopy-recommended thresholds for optical biopsy. Better results in community practice must be achieved before NBI-based optical biopsy methods can be used routinely to evaluate polyps; ClinicalTrials.gov number, NCT01638091.

Rationale for and clinical benefits of colonoscopy with narrow band imaging: pathological prediction and colorectal screening

INTRODUCTION

Narrow-band imaging (NBI), an emerging imaging technology, allows direct visualization of capillaries on the gastrointestinal mucosal surface. The combination of NBI and magnifying endoscopy can be used to identify morphological changes in these capillaries during the process of carcinogenesis.

FINDINGS AND CONCLUSIONS

Thus far, pathological predictions based on capillary pattern classifications have been reported to have good diagnostic accuracy. However, most of these studies have been single-center trials based on each institutional classification, and worldwide multicenter trials aimed at their standardization are needed to validate the clinical benefits of the various NBI classification systems.

Evolving role of computed tomographic colonography in colon cancer screening and diagnosis

Computed tomographic colonography (CTC) is a relatively new imaging modality for the examination of patients for colorectal polyps and cancer. It has been validated in its accuracy for the detection of colon cancer and larger polyps (more than likely premalignant). CTC, however, is not widely accepted as a primary screening modality in the United States at present by many third-party payers, including Medicare, and its exact role in screening is evolving. Moreover, there has been opposition to incorporating CTC as an accepted screening instrument, especially by gastroenterologists. Heretofore, optical colonoscopy has been the mainstay in this screening. We discuss these issues and the continuing controversies concerning CTC.

Comparative effectiveness of i-SCAN™ and high-definition white light characterizing small colonic polyps

AIM: To evaluate accuracy of in vivo diagnosis of adenomatous vs non-adenomatous polyps using i-SCAN digital chromoendoscopy compared with high-definition white light.

METHODS: This is a single-center comparative effectiveness pilot study. Polyps (n = 103) from 75 average-risk adult outpatients undergoing screening or surveillance colonoscopy between December 1, 2010 and April 1, 2011 were evaluated by two participating endoscopists in an academic outpatient endoscopy center. Polyps were evaluated both with high-definition white light and with i-SCAN to make an in vivo prediction of adenomatous vs non-adenomatous pathology. We determined diagnostic characteristics of i-SCAN and high-definition white light, including sensitivity, specificity, and accuracy, with regards to identifying adenomatous vs non-adenomatous polyps. Histopathologic diagnosis was the gold standard comparison.

RESULTS: One hundred and three small polyps, detected from forty-three patients, were included in the analysis. The average size of the polyps evaluated in the analysis was 3.7 mm (SD 1.3 mm, range 2 mm to 8 mm). Formal histopathology revealed that 54/103 (52.4%) were adenomas, 26/103 (25.2%) were hyperplastic, and 23/103 (22.3%) were other diagnoses include “lymphoid aggregates”, “non-specific colitis,” and “no pathologic diagnosis.” Overall, the combined accuracy of endoscopists for predicting adenomas was identical between i-SCAN (71.8%, 95%CI: 62.1%-80.3%) and high-definition white light (71.8%, 95%CI: 62.1%-80.3%). However, the accuracy of each endoscopist differed substantially, where endoscopist A demonstrated 63.0% overall accuracy (95%CI: 50.9%-74.0%) as compared with endoscopist B demonstrating 93.3% overall accuracy (95%CI: 77.9%-99.2%), irrespective of imaging modality. Neither endoscopist demonstrated a significant learning effect with i-SCAN during the study. Though endoscopist A increased accuracy using i-SCAN from 59% (95%CI: 42.1%-74.4%) in the first half to 67.6% (95%CI: 49.5%-82.6%) in the second half, and endoscopist B decreased accuracy using i-SCAN from 100% (95%CI: 80.5%-100.0%) in the first half to 84.6% (95%CI: 54.6%-98.1%) in the second half, neither of these differences were statistically significant.

CONCLUSION: i-SCAN and high-definition white light had similar efficacy predicting polyp histology. Endoscopist training likely plays a critical role in diagnostic test characteristics and deserves further study.

High-definition colonoscopy with i-Scan: Better diagnosis for small polyps and flat adenomas

AIM: To investigate if high-definition (HD) colonoscope with i-Scan gave a higher detection rate of mucosal lesions vs standard white-light instruments.

METHODS: Data were collected from the computerized database of the endoscopy unit of our tertiary referral center. We retrospectively analyzed 1101 consecutive colonoscopies that were performed over 1 year with standard white-light (n = 849) or HD+ with i-Scan (n = 252) instruments by four endoscopists, in an outpatient setting. Colonoscopy records included patients’ main details and family history for colorectal cancer, indication for colonoscopy (screening, diagnostic or surveillance), type of instrument used (standard white-light or HD+ plus i-Scan), name of endoscopist and bowel preparation. Records for each procedure included whether the cecum was reached or not and the reason for failure, complications during or immediately after the procedure, and number, size, location and characteristics of the lesions. Polyps or protruding lesions were defined as sessile or pedunculated, and nonprotruding lesions were defined according to Paris classification. For each lesion, histological diagnosis was recorded.

RESULTS: Eight hundred and forty-nine colonoscopies were carried with the standard white-light video colonoscope and 252 with the HD+ plus i-Scan video colonoscope. The four endoscopists did 264, 300, 276 and 261 procedures, respectively; 21.6%, 24.0%, 21.7% and 24.1% of them with the HD+ plus i-Scan technique. There were no significant differences between the four endoscopists in either the number of procedures done or the proportions of each imaging technique used. Both techniques detected one or more mucosal lesions in 522/1101 procedures (47.4%). The overall number of lesions recognized was 1266; 645 in the right colon and 621 in the left. A significantly higher number of colonoscopies recognized lesions in the HD+ plus i-Scan mode (171/252 = 67.9%) than with the standard white-light technique (408/849 = 48.1%) (P < 0.0001). HD+ with i-Scan colonoscopies identified more lesions than standard white-light imaging (459/252 and 807/849, P < 0.0001), in the right or left colon (mean ± SD, 1.62 ± 1.36 vs 1.33 ± 0.73, P < 0.003 and 1.55 ± 0.98 vs 1.17 ± 0.93, P = 0.033), more lesions < 10 mm (P < 0.0001) or nonprotruding (P < 0.022), and flat polyps (P = 0.04). The cumulative mean number of lesions per procedure detected by the four endoscopists was significantly higher with HD+ with i-Scan than with standard white-light imaging (1.82 ± 2.89 vs 0.95 ± 1.35, P < 0.0001).

CONCLUSION: HD imaging with i-Scan during the withdrawal phase of colonoscopy significantly increased the detection of colonic mucosal lesions, particularly small and nonprotruding polyps.

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.

Accuracy for optical diagnosis of small colorectal polyps in nonacademic settings

BACKGROUND & AIMS

When small colorectal lesions are accurately characterized, adenomas can be removed and discarded without formal histopathology analysis. Previous studies in an academic setting showed that many lesions can be managed accurately on the basis of their endoscopic image (optical diagnosis). We performed a prospective study to assess the accuracy of optical diagnosis of small colorectal polyps in a nonacademic setting (the DISCOUNT trial) by using high-resolution endoscopy (HRE) and narrow-band imaging (NBI).

METHODS

During colonoscopy, 1 of 3 nonacademic endoscopists characterized small lesions and declared whether this was done with low or high confidence. In cases of high confidence, the endoscopists decided whether lesions should be removed and discarded or whether they could be left in situ. A surveillance interval was then recommended on-site.

RESULTS

Of 215 patients in the study, 108 were found to have 281 small lesions. Of these lesions, 231 were characterized with high confidence by using HRE or NBI; the level of corresponding sensitivity was 77.0% (95% confidence interval, 68.4-83.8), and specificity was 78.8% (95% confidence interval, 70.6-85.2). Of these lesions, 164 were assigned for removal, and 67 were assigned to remain in situ, including 9 adenomas. In 54 patients, a surveillance interval could be recommended on-site that was in line with Dutch guidelines for 44 patients.

CONCLUSIONS

Even though many lesions were characterized by HRE or NBI with high confidence, optical diagnosis in a nonacademic setting proved to be disappointing, with a sensitivity of 77.0% and a specificity of 78.8%. Many lesions were accurately assigned to be removed or remain in situ, although few adenomas were assigned to remain in situ. Also, 19% of on-site recommendations for a surveillance interval proved to be inaccurate.

Difficult colon polypectomy

Colorectal cancer (CRC) is one of the leading causes of death from cancer in the world. We now know that 90% of CRC develop from adenomatous polyps. Polypectomy of colon adenomas leads to a significant reduction in the incidence of CRC. At present most of the polyps are removed endoscopically. The vast majority of colorectal polyps identified at colonoscopy are small and do not pose a significant challenge for resection to an appropriately trained and skilled endoscopist. Advanced polypectomy techniques are intended for the removal of difficult colon polyps. We have defined a “difficult polyp” as any lesion that due to its size, shape or location represents a challenge for the colonoscopist to remove. Although many “difficult polyps” will be an easy target for the advanced endoscopist, polyps that are larger than 15 mm, have a large pedicle, are flat and extended, are difficult to see or are located in the cecum or any angulated portion of the colon should be always considered difficult. Although very successful, advanced resection techniques can potentially cause serious, even life-threatening complications. Moreover, post polypectomy complications are more common in the presence of difficult polyps. Therefore, any endoscopist attempting advanced polypectomy techniques should be adequately supervised by an expert or have an excellent training in interventional endoscopy. This review describes several useful tips and tricks to deal with difficult polyps.

The future developments in endoscopy

Gastrointestinal endoscopy has seen great changes over recent years, and the future seems bright. Looking forward, some advances in technology can be predicted, but the current financial climate may limit their widespread adoption. Increasing subspecialisation with continuing service development and quality assurance are likely to form the basis of the major changes over the next 5 years. Increasing juxtaposition between laparoscopic and endoscopic procedures presents the most exciting opportunities over the 10-year timeframe. This article extrapolates current trends to try to predict the different possibilities for endoscopy over the next decade.

Prospective, randomized, back-to-back trial evaluating the usefulness of i-SCAN in screening colonoscopy

BACKGROUND

The newly developed i-SCAN application can theoretically maximize the effectiveness of colonoscopy. However, the practical usefulness of the i-SCAN application during screening colonoscopy has not been assessed.

OBJECTIVE

To assess the efficacy of the i-SCAN application during screening colonoscopy.

DESIGN

A prospective, randomized trial that used a modified, back-to-back colonoscopy.

SETTING

Academic hospital.

PATIENTS

This study involved 389 asymptomatic, consecutive, average-risk patients who underwent screening colonoscopy.

INTERVENTION

The patients were randomized to the first withdrawal with either conventional high-definition white light (HDWL group; n = 119), i-SCAN contrast/surface enhancement (CE/SE) mode (i-SCAN1 group; n = 115), or i-SCAN CE/SE/tone enhancement-colorectal mode (i-SCAN2 group; n = 118). All patients underwent a second examination with HDWL as the criterion standard.

MAIN OUTCOME MEASUREMENTS

The primary outcome measurement was the adenoma detection rate and adenoma miss rate. The secondary outcome measurement was the accuracy of the histologic prediction of neoplastic and nonneoplastic polyps.

RESULTS

The adenoma detection rates during the first withdrawal of HDWL, i-SCAN1, and i-SCAN2 were 31.9%, 36.5%, and 33.1%, respectively (P = .742), and the adenoma miss rates of each group were 22.9%, 19.3%, and 15.9%, respectively (P = .513). Based on the multivariate analysis, the application of i-SCAN was not associated with an improvement in adenoma detection and the prevention of missed polyps. However, the prediction of neoplastic and nonneoplastic colorectal lesions was more precise in the i-SCAN2 group compared with the HDWL group (accuracy 79.3% vs 75.5%, P = .029; sensitivity 86.5% vs 72.6%, P = .020; and specificity 91.4% vs 80.6%, P = .040).

LIMITATIONS

Single-center trial.

CONCLUSION

i-SCAN during the screening colonoscopy may fail to improve adenoma detection and the prevention of missed polyps, but i-SCAN appears to be effective for real-time histologic prediction of polyps compared with conventional HDWL colonoscopy. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01417611.).

Prevalence of advanced histological features in diminutive and small colon polyps

BACKGROUND

Investigators have proposed "predict, resect, and discard" strategies for diminutive (≤ 5 mm) or small (6-9 mm) polyps to reduce screening colonoscopy costs. Advanced histological features such as villous histology, high-grade dysplasia, and/or cancer in these polyps could deter adoption of these strategies.

OBJECTIVE

Determine the prevalence of advanced histological features in diminutive and small colon polyps.

DESIGN

Retrospective analysis of data from 3 prospective clinical trials.

SETTING

Two tertiary-care referral centers.

PATIENTS

This study involved patients undergoing screening or surveillance colonoscopy.

INTERVENTION

The location, size, and morphology of each polyp detected was documented. Each polyp was then resected, placed in a unique specimen jar, and sent for histopathological evaluation.

MAIN OUTCOME MEASUREMENTS

Rates of advanced histological features (villous histology, high-grade dysplasia, and cancer).

RESULTS

A total of 2361 polyps were detected, removed, and retrieved. Both diminutive and small polyps had a lower frequency of any advanced histological features compared with large polyps (0.5% and 1.5%, respectively vs 15.0%; P < .001 for both comparisons). Polyps <10 mm in size had a lower frequency of advanced histology compared with polyps ≥ 10 mm (0.8% vs 15.0%; P < .001). During sensitivity analysis, the frequency of advanced histological features varied from 0.2% to 0.7% within diminutive polyps, 1.5% to 3.6% within small polyps, and 0.8% to 1.2% within polyps <10 mm.

LIMITATIONS

Retrospective analysis from tertiary-care referral centers; predominantly white, male, veteran patient population resulting in limited generalizability of results.

CONCLUSION

The prevalence of advanced histological features in colon polyps ≤ 5 mm is very low (0.5%). This has important implications for the potential practice of "predicting, resecting, and discarding" diminutive colon polyps.