Retrograde-viewing device improves adenoma detection rate in colonoscopies for surveillance and diagnostic workup

Efficacy of cecal retroflexion observed on adenoma missing of ascending colon during colonoscopy: A prospective, randomized, pilot trial

BACKGROUND

Although colonoscopic retroflexion has been proved effective in reducing missed adenomas, there is still a lack of comprehensive and in-depth research focused on the ascending colon. We aimed to conduct a randomized controlled trial and tandem colonoscopy to investigate whether cecal retroflexion observed during colonoscopy can reduce missed adenomas in the ascending colon.

METHODS

Men and women required to be between 45 and 80 years of age were screened for enrollment in the trial. Patients were randomly assigned according to a 1:1 ratio to either the trial group or control group. Patients in the trial group underwent 2 forward examination and a cecal retroflexion observed in the ascending colon, while patients in the control group underwent only 2 forward examinations in the ascending colon. The primary outcome was adenoma miss rate. The secondary outcomes contained adenoma detection rate, polyp miss rate, polyp detection rate, insertion time and withdrawal time. Differences between groups in the primary outcome and in the other categorical indicators were tested using chi-squared test and Fisher exact test. For the comparison of continuous outcomes, the Student t test was applied.

RESULTS

A total of 60 subjects were eligible for the study between April to June 2020, of which 55 were randomized and eligible for analysis (26 to the control group and 29 to the trial group). The characteristics of patients were no significant differences statistically between the trial group and the control group. Similarly, the characteristics of the colonoscopy procedures included cecal insertion distance, the length of cecum and ascending colon, insertion time, withdrawal time, quality of bowel preparation, numerical rating scale for pain, polyps detected, and adenomas detected, and there were no significant differences statistically between the 2 groups (P = .864, P = .754, P = .700, P = .974, P = .585, P = .835, P = .373, P = .489). The characteristics of the polyps were also no significant differences statistically between the 2 groups.

CONCLUSION

This pilot trial failed to show benefit of cecal retroflexion observed on adenoma missing of ascending colon during colonoscopy; however, further conclusions require a prospective study with a higher level of evidence. (NCT03355443).

Recent advances in devices and technologies that might prove revolutionary for colonoscopy procedures

INTRODUCTION

Colorectal cancer (CRC) is the third most common malignancy and second leading cause of cancer-related mortality in the world. Adenoma detection rate (ADR), a quality indicator for colonoscopy, has gained prominence as it is inversely related to CRC incidence and mortality. As such, recent efforts have focused on developing novel colonoscopy devices and technologies to improve ADR.

AREAS COVERED

The main objective of this paper is to provide an overview of advancements in the fields of colonoscopy mechanical attachments, artificial intelligence-assisted colonoscopy, and colonoscopy optical enhancements with respect to ADR. We accomplished this by performing a comprehensive search of multiple electronic databases from inception to September 2023. This review is intended to be an introduction to colonoscopy devices and technologies.

EXPERT OPINION

Numerous mechanical attachments and optical enhancements have been developed that have the potential to improve ADR and AI has gone from being an inaccessible concept to a feasible means for improving ADR. While these advances are exciting and portend a change in what will be considered standard colonoscopy, they continue to require refinement. Future studies should focus on combining modalities to further improve ADR and exploring the use of these technologies in other facets of colonoscopy.

Adoption of Optimal Small (6-9 mm) Colorectal Polyp Resection Technique Over Time

BACKGROUND

Cold snare polypectomy (CSP) is the preferred resection technique for small (6-9 mm) polyps due to lower rate of incomplete resection compared to cold forceps polypectomy (CFP) and improved safety profile over hot snare polypectomy (HSP).

AIMS

To describe resection techniques for small (6-9 mm) polyps and determine factors associated with sub-optimal technique.

METHODS

This was retrospective cohort study of colonoscopies performed by gastroenterological and surgical endoscopists from 2012 to 2019 where at least one 6-9 mm polyp was removed. Patient, provider, and procedure characteristics were collected. Univariate and multivariate regression analyses were performed to determine factors associated with sub-optimal technique.

RESULTS

In total, 773 colonoscopies where 1,360 6-9 mm polyps removed by 21 endoscopists were included. CSP was used for 1,122 (82.5%), CFP for 61 (4.5%), and HSP for 177 (13.0%). Surgeon specialty was associated with CFP use (aOR 7.81; 95% CI 3.02-20.16). Polyp location in left colon (aOR 1.65; 95% CI 1.17-2.33) and pedunculated morphology (aOR 12.76; 95% CI 7.24-22.50) were associated with HSP. There was a significant increase in overall CSP use from 30.4% in 2012 to 96.8% in 2019.

CONCLUSIONS

82.5% of all 6-9 mm polyps removed from 2012 to 2019 were removed using a cold snare with significant increase in CSP from 2012 to 2019. Differences in how optimal technique was adopted over time based on specialty highlight the need for standardized practice guidelines and quality monitoring.

Second exam of right colon improves adenoma detection rate: Systematic review and meta-analysis of randomized controlled trials

Background and study aims  A second examination of the right colon, either as a second forward view (SFV) or as retroflexion (RF) in the cecum, can increase adenoma detection rate (ADR) in the right colon. In this meta-analysis, we have evaluated the role of a second examination of the right colon in improving ADR. Methods  We reviewed several databases to identify randomized controlled trials that compared right colon SFV with no SFV, and RCTs that compared SFV with RF in the right colon, and reported data on ADR. Our outcomes of interest were ADR and polyp detection rate (PDR) with SFV vs no SFV, right colon and total withdrawal times, and additional ADR and PDR with SFV vs RF. For categorical variables, we calculated pooled risk ratios (RRs) with 95 % confidence intervals (CIs); for continuous variables, we calculated standardized mean difference (SMD) with 95 % CI. Data were analyzed using random effects model. Results  We included six studies with 3901 patients. Comparing SFV with no SFV, right colon ADR and PDR were significantly higher in the SFV group: ADR (RR [95 % CI] 1.39 [1.22,1.58]) and PDR (RR [95 % CI] 1.47 [1.30, 1.65]). We found no significant difference in right colon withdrawal time (SMD [95 % CI] 1.54 [-0.20,3.28]) or total withdrawal time (SMD (95 % CI) 0.37 [-0.39,1.13]) with and without SFV. We found no significant difference in additional ADR between SFV and RF. Conclusions  SFV of the right colon significantly increases right-sided and overall ADR.

Endoscopic cuff-assisted colonoscopy versus cap-assisted colonoscopy in adenoma detection: randomized tandem study-DEtection in Tandem Endocuff Cap Trial (DETECT)

BACKGROUND AND AIMS

Adenoma miss rate during colonoscopy is directly linked to risk of postcolonoscopy colorectal cancer. One of the reasons for missed adenomas is poor visualization of proximal folds during standard colonoscopy withdrawal. Disposable distal attachments such as the plastic cap and Endocuff (Arc Medical Design, Leeds, UK) that hold back folds appear to improve adenoma detection. The primary aim of this study was to compare adenoma detection rates between Endocuff-assisted colonoscopy (EAC) and cap-assisted colonoscopy (CAC).

METHODS

This is a randomized, single-center, tandem colonoscopy trial performed by the same endoscopists on the same day, first with Endocuff Vision (Arc Medical Design, Leeds, UK) followed by cap or vice versa. All procedures were performed by 3 experienced gastroenterology fellows.

RESULTS

One hundred fifty-four patients were recruited. Seventy-eight (50.6%) had CAC as their first procedure. Mean patient age was 61 years (male-to-female ratio, 1:1). Adenoma detection rate was significantly higher for EAC when compared to CAC (53% vs 26%, P = .001). Polyp miss rate was significantly lower in EAC (8.4%) compared with CAC (26.1%, P < .001) as was adenoma miss rate (EAC vs CAC, 6%, vs 19%; P = .002) and diminutive adenoma (<5 mm) miss rate in the EAC group (1.8% vs 19.6%, P < .001). However, there was no significant differences in the miss rates for small adenomas (5-9 mm) (3.7% vs 2.9%, P = .69) or adenomas 10 mm or larger (1.6% vs 2.6%, P = .98 ). The mean number of adenomas per procedure was significantly higher with EAC compared with CAC (1.5 vs .8, P < .001). Cecal intubation time was significantly shorter with EAC than CAC (median 6 vs 7 minutes, P = .01). Conversely, withdrawal time (median 10 vs 8 minutes, P = .01) was significantly longer in EAC.

CONCLUSIONS

This randomized, tandem study demonstrates that EAC has a significantly higher adenoma detection rate and lower adenoma miss rate than CAC. Although insertion times were shorter with EAC, procedures were slightly more uncomfortable, and the cuff had to be removed in a small number of cases. (Clinical trial registration number: NCT03254498.).

The Use of Attachment Devices to Aid in Adenoma Detection

PURPOSE OF REVIEW

With the intent of maximizing adenoma detection rate (ADR), different devices and colonoscopic innovations have been introduced over the past few years. There are a variety of attachment devices available for use in colonoscopy, all intended to improve ADR. In this review, we evaluate the evidence surrounding the available attachment devices and their impact on ADR.

RECENT FINDINGS

Endocuff, Endoring, Transparent cap, G-EYE balloon, and Third Eye Retroscope were all included in this review. Three of the devices, Endocuff, Endoring, and transparent hood or cap, have been shown to increase ADR without significantly altering the use of the colonoscope. Although balloon-assisted colonoscopy is not currently FDA-approved, it has the potential to increase ADR as well.

SUMMARY

Mechanical enhancement has been shown to complement the current forward-viewing colonoscope, and Endocuff appears to be the most beneficial attachment to improve ADR.

Advances in endoscopy for colorectal polyp detection and classification

While colonoscopy is considered the gold standard for colon cancer screening, recent advancements in endoscopes have allowed for improved visualization of the colonic mucosa and improved polyp detection rates. Newer technologies also allow for assessment of structural changes for polyp discrimination and determination of histologic type. Classification of polyps prevents the need for a histopathologic report, which requires the additional time and expertise of a pathologist and adds to the overall cost. This review considered advances in endoscopic technologies reported in PubMed over the past 12 years. Technologies that allow for increased visual field of colonic mucosa and may lead to improved colon polyp detection rates include cap-assisted colonoscopy, RetroView, extra-wide-angle view colonoscope, full-spectrum endoscopy, Third Eye Retroscope, NaviAid G-EYE balloon colonoscope, EndoRings, and Endocuff. Image-enhancing methods allow for pit pattern analysis of colorectal lesions, which enables the physician to classify colorectal polyps according to certain polyp characteristics. Image-enhancing methods include chromoendoscopy, autofluorescence, and virtual chromoendoscopy, including narrow band imaging, i-SCAN, flexible spectral imaging chromoendoscopy, and STORZ professional image enhancement systems. In addition, advancements have been made in in vivo microscopic evaluation of colonic epithelium, including confocal laser endomicroscopy, endocytoscopy, optical coherence tomography, spectroscopy, and autofluorescence spectroscopy. Colon capsule endoscopy also has a role in colon polyp detection and classification. The advancements in polyp detection and classification have great promise for earlier detection and removal of advanced adenomas before they advance to colorectal cancer.

Can technology increase adenoma detection rate?

Colorectal cancer is the third most common cancer worldwide and the second most common cause of cancer-related death in Europe and North America. Colonoscopy is the gold standard investigation for the colon but is not perfect, and small or flat adenomas can be missed which increases the risk of patients subsequently developing colorectal cancer. Adenoma detection rate is the most widely used marker of quality, and low rates are associated with increased rates of post-colonoscopy colorectal cancer. Standards of colonoscopy and adenoma detection vary widely between different endoscopists. Interventions to improve adenoma detection rate are therefore required. Many devices have been purported to increase adenoma detection rate. This review looks at current available evidence for device technology to improve adenoma detection rate during colonoscopy.

Impact of a new distal attachment on colonoscopy performance in an academic screening center

BACKGROUND AND AIMS

Distal attachments placed on the colonoscope tip may positively affect performance by assisting insertion and polyp detection. The original Endocuff (ARC Medical Design, Leeds, United Kingdom) appears to improve adenoma detection rate (ADR), but no data assess the performance of the second-generation Endocuff Vision.

METHODS

A pilot service evaluation study (April 2013 to September 2014) was conducted on patients with positive fecal occult blood tests within the National Bowel Cancer Programme during 3 consecutive periods: precuff/no device used, during-cuff/device used, and postcuff/no device used. During the middle period the use of the Endocuff Vision by the 4 screening-accredited colonoscopists was discretional (nonrandomized design). Data were analyzed using pairwise comparisons during the 3 designated periods to examine key performance indicators: adenoma detection, procedural time, sedation requirements, and patient comfort.

RESULTS

Four hundred ten complete colonoscopies were performed (137 precuff, 136 cuff, and 137 postcuff period). Overall, there was a notable increase in the mean ADR of 16% (P < .03) and in the mean number adenoma per procedure (MAP) of 83% (P = .007) from precuff to cuff period. The mean cecal intubation time was statistically lower during the cuff period (7 minutes) in relation to the precuff period (8 minutes; reduction of 12.5%, P = .002) and the postcuff period (9 minutes; increase of 28.6%, P = .002). The mean negative colonoscopy withdrawal time was also significantly lower during the cuff period (8 minutes, 30 seconds) when compared with the precuff (12 minutes) or postcuff period (9 minutes, 45 seconds; P ≤ .001). Multivariate regression analysis showed that the use of the Endocuff Vision was not associated with sedation requirements or patient discomfort scores. No adverse events were reported from the use of the Endocuff Vision, although it was electively removed in 6 patients where severe sigmoid colon diverticulosis was encountered and 2 patients because of discomfort during anal insertion.

CONCLUSIONS

In this pilot service evaluation study, the use of the Endocuff Vision appears to be associated with an improvement in overall colonoscopy operator performance. We found increased ADR and MAP as well as decreased time for colonoscope insertion and withdrawal time with no increase in sedation requirements or patient discomfort.

Use of warm carbon dioxide insufflators does not affect intra-colonic gas temperature and has no effect on polyp detection rate during colonoscopy - a randomized controlled trial

BACKGROUND AND STUDY AIMS

Methods to improve polyp detection during colonoscopy have been investigated, with conflicting results for warm water irrigation. Carbon Dioxide (CO ₂₎ warmed to 37 °C may have similar or more pronounced effects on bowel motility. This study aimed to assess whether warmed CO ₂ would improve polyp detection compared to room temperature air insufflation.

PATIENTS AND METHODS

 This was a double-blind, randomized controlled trial that enrolled 204 patients undergoing screening or surveillance outpatient colonoscopy. The primary outcome was polyp per patient detection rate. Secondary outcomes included adenoma per patient detection rates, bowel spasm, and patient comfort.

RESULTS

 The trial was terminated after an interim analysis determined futility. Between the warmed CO ₂ and room air groups, no significant differences were found in the per-colonoscopy polyp detection rate ( P  = 0.57); overall polyp detection rate ( P  = 0.69); or adenoma detection rates ( P  = 0.74). More patients in the room temperature group had lower spasm scores (p = 0.02); however, there was a trend towards greater patient comfort in the warmed CO ₂ group ( P  = 0.054). An ex-vivo study showed a significant difference between exiting CO ₂ temperature at the insufflator end vs. delivered CO ₂ temperature at the colonoscope tip end. The temperature of insufflation at the tip of the colonoscope was not different when using warmed vs. unwarmed insufflation ( P  = 0.62).

CONCLUSION

 When compared with room air insufflation, warmed CO ₂ insufflation did not affect polyp detection rates.

Endoscopic Improvement of the Adenoma Detection Rate during Colonoscopy - Where Do We Stand in 2015?

BACKGROUND

The presence of colorectal adenomas is considered a major risk factor for colorectal cancer development. The implementation of screening colonoscopy programs in the Western world has led to a substantial reduction of colorectal cancer death. Many efforts have been made to reduce the adenoma miss rates by the application of new endoscopic devices and techniques for better adenoma visualization.

SUMMARY

This special review gives the readership an overview of current endoscopic innovations that can aid in the increase of the adenoma detection rate (ADR) during colonoscopy. These innovations include the use of devices like EndoCuff® and EndoRings® as well as new technical equipment like third-eye endoscope® and full-spectrum endoscopy (FUSE®).

KEY MESSAGE

Technical improvements and newly developed accessories are able to improve the ADR. However, additional costs and a willingness to invest into potentially expensive equipment might be necessary. Investigator-dependent skills remain the backbone in the ADR detection.

Flexible Gastro-intestinal Endoscopy - Clinical Challenges and Technical Achievements

Flexible gastro-intestinal (GI) endoscopy is an integral diagnostic and therapeutic tool in clinical gastroenterology. High quality standards for safety, patients' comfort, and efficiency have already been achieved. Clinical challenges and technical approaches are discussed in this short review.

Image enhanced endoscopy for further characterization of mucosal and vascular patterns includes dye-spray or virtual chromoendoscopy. For confocal laser endoscopy, endocytoscopy, and autofluorescence clinical value has not yet been finally evaluated. An extended viewing field provided by additional cameras in new endoscopes can augment detection of polyps behind folds. Attachable caps, flaps, or balloons can be used to flatten colonic folds for better visualization and stable position.

Variable stiffness endoscopes, radiation-free visualization of endoscope position, and different overtube devices help reducing painful loop formation in clinical routine. Computer assisted and super flexible self-propelled colonoscopes for painless sedation-free endoscopy need further research. Single-use devices might minimize the risk of infection transmission in the future.

Various exchangeable accessories are available for resection, dissection, tunneling, hemostasis, treatment of stenosis and closure of defects, including dedicated suturing devices. Multiple arm flexible devices controlled via robotic platforms for complex intraluminal and transmural endoscopic procedures require further improvement.

Expert opinions and scientific evidence for colonoscopy key performance indicators

Colonoscopy is a widely performed procedure with procedural volumes increasing annually throughout the world. Many procedures are now performed as part of colorectal cancer screening programmes. Colonoscopy should be of high quality and measures of this quality should be evidence based. New UK key performance indicators and quality assurance standards have been developed by a working group with consensus agreement on each standard reached. This paper reviews the scientific basis for each of the quality measures published in the UK standards.

Chromoscopy versus conventional endoscopy for the detection of polyps in the colon and rectum

BACKGROUND

Although conventional colonoscopy is the most accurate test available for the investigation of the colorectum for polyps, data exist that raise concerns about its sensitivity. Chromoscopy (spraying dye onto the surface of the colon to make polyps more visible) may be one way of enhancing the ability of colonoscopy to detect polyps, particularly diminutive flat lesions, which otherwise may be difficult to detect.

OBJECTIVES

To determine whether the use of chromoscopy enhances the detection of polyps and neoplasia during endoscopic examination of the colon and rectum.

SEARCH METHODS

We searched the following databases: Cochrane Colorectal Cancer Group Specialised Register (October 2015), Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library; Issue 10, 2015), MEDLINE (January 1950 to October 2015), EMBASE (January 1974 to October 2015), and ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (both November 2015). We also handsearched abstracts from relevant meetings from 1980 to 2015. Search terms included 'randomised trials' containing combinations of the following: 'chromoscopy' 'colonoscopy' 'dye-spray' 'chromo-endoscopy' 'indigo-carmine' 'magnifying endoscopy'.

SELECTION CRITERIA

We included all prospective randomised trials comparing chromoscopic with conventional endoscopic examination of the whole of the colon and rectum. We excluded studies of people with inflammatory bowel disease or polyposis syndromes and any studies that combined chromoscopy with additional interventions (cap assistance, water-perfused, etc.).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of potentially eligible trials, and two review authors independently extracted data from the included trials. Outcome measures included the detection of polyps (neoplastic and non-neoplastic), the detection of diminutive lesions, the number of participants with multiple neoplastic lesions, and the extubation time.

MAIN RESULTS

We included seven trials (2727 participants) in this update. Five trials were of sufficiently similar design to allow for pooled results. Two trials differed substantially in design and were included in a subgroup analysis. All the trials had some methodological drawbacks. However, combining the results showed a significant difference in favour of chromoscopy for all detection outcomes. In particular, chromoscopy was likely to yield significantly more people with at least one neoplastic lesion (odds ratio (OR) 1.53, 95% confidence interval (CI) 1.31 to 1.79; 7 trials; 2727 participants), and at least one diminutive neoplastic lesion (OR 1.51, 95% CI 1.19 to 1.92; 4 trials; 1757 participants). Significantly more people with three or more neoplastic lesions were also detected, but only when studies that used high-definition colonoscopy in the control group were excluded (OR 4.63, 95% CI 1.99 to 10.80; 2 trials; 519 participants). None of the included studies reported any adverse events related to the use of the contrast dye.

AUTHORS' CONCLUSIONS

There is strong evidence that chromoscopy enhances the detection of neoplasia in the colon and rectum. People with neoplastic polyps, particularly those with multiple polyps, are at increased risk of developing colorectal cancer. Such lesions, which presumably would be missed with conventional colonoscopy, could contribute to the interval cancer numbers on any surveillance programme.

Recent advances in colonoscopy

Colonoscopy is an important and frequently performed procedure. It is effective in the prevention of colorectal cancer and is an important test in the investigation of many gastrointestinal symptoms. This review focuses on developments over the last 5 years that have led to changes in aspects of colonoscopy, including patient preparation, technical factors, therapeutic procedures, safety, and quality.

The ADENOMA Study. Accuracy of Detection using Endocuff Vision™ Optimization of Mucosal Abnormalities: study protocol for randomized controlled trial

BACKGROUND

Colonoscopy is the gold standard investigation for the diagnosis of bowel pathology and colorectal cancer screening. Adenoma detection rate is a marker of high quality colonoscopy and a high adenoma detection rate is associated with a lower incidence of interval cancers. Several technological advancements have been explored to improve adenoma detection rate. A new device called Endocuff Vision™ has been shown to improve adenoma detection rate in pilot studies.

METHODS/DESIGN

This is a prospective, multicenter, randomized controlled trial comparing the adenoma detection rate in patients undergoing Endocuff Vision™-assisted colonoscopy with standard colonoscopy. All patients above 18 years of age referred for screening, surveillance, or diagnostic colonoscopy who are able to consent are invited to the study. Patients with absolute contraindications to colonoscopy, large bowel obstruction or pseudo-obstruction, colon cancer or polyposis syndromes, colonic strictures, severe diverticular segments, active colitis, anticoagulant therapy, or pregnancy are excluded. Patients are randomized according to site, age, sex, and bowel cancer screening status to receive Endocuff Vision™-assisted colonoscopy or standard colonoscopy on the day of procedure. Baseline data, colonoscopy, and polyp data including histology are collected. Nurse assessment of patient comfort and patient comfort questionnaires are completed post procedure. Patients are followed up at 21 days and complete a patient experience questionnaire. This study will take place across seven NHS Hospital Trusts: one in London and six within the Northern Region Endoscopy Group. A maximum of 10 colonoscopists per site will recruit a total of 1772 patients, with a maximum of four bowel screening colonoscopists permitted per site.

DISCUSSION

This is the first trial to evaluate the adenoma detection rate of Endocuff Vision™ in all screening, surveillance, and diagnostic patient groups. This timely study will guide clinicians as to the role of Endocuff Vision™ in routine colonoscopy.

STUDY REGISTRATION

ISRCTN11821044.

Expanding the view of a standard colonoscope with the Third Eye® Panoramic™ cap

AIM: To evaluate a new imaging device for colonoscopy that adds two side viewing CMOS lenses, the Third Eye^® Panoramic™ cap.

METHODS: In this prospective observational feasibility study, 33 patients, 18 male and 15 female, underwent routine screening, surveillance or diagnostic colonoscopy with the new Third Eye^® Panoramic™ cap clipped on to the distal tip of a high definition Fuji EC530-LS Slim Colonoscope^®. All procedures were performed at the New York Presbyterian-Queens Endoscopy unit by two experienced endoscopists (Rubin M and Kim SH). Main outcome measurements included evaluation of the image quality of the Third Eye^® Panoramic™ cap, adenoma detection rate, cecal intubation rate, withdrawal time and total procedure time.

RESULTS: The Third Eye^® Panoramic™ cap enabled enhanced views without affecting the quality of the colonoscope’s image or its handling characteristics through the colon. Ileal intubation was accomplished in most cases, but was more challenging. The side view lenses detected polyps and diverticula hidden behind folds and in flexures not seen on the standard view. The side view lenses were easily cleaned utilizing an Endogator^® Irrigation Pump (Medivators, Minneapolis, MN, United States) by angling the scope tip against the mucosa while washing. The cecum was reached in all 33 patients. Mean cecal intubation time was 8.19 ± 2.17 min, mean withdrawal time was 10.15 ± 5.56 min and mean total procedure time was 20.31 ± 5.14 min. The overall adenoma detection rate was 44%.

CONCLUSION: The Third Eye^® Panoramic™ cap enables wide view colonoscopy with enhanced visualization utilizing standard forward view colonoscopes.

Developments in Screening Tests and Strategies for Colorectal Cancer

BACKGROUND

Worldwide, colorectal cancer (CRC) is the third most common cancer in men and second most common in women. It is the fourth most common cause of cancer mortality. In the United States, CRC is the third most common cause of cancer and second most common cause of cancer mortality. Incidence and mortality rates have steadily fallen, primarily due to widespread screening.

METHODS

We conducted keyword searches on PubMed in four categories of CRC screening: stool, endoscopic, radiologic, and serum, as well as news searches in Medscape and Google News.

RESULTS

Colonoscopy is the gold standard for CRC screening and the most common method in the United States. Technological improvements continue to be made, including the promising "third-eye retroscope." Fecal occult blood remains widely used, particularly outside the United States. The first at-home screen, a fecal DNA screen, has also recently been approved. Radiological methods are effective but seldom used due to cost and other factors. Serum tests are largely experimental, although at least one is moving closer to market.

CONCLUSIONS

Colonoscopy is likely to remain the most popular screening modality for the immediate future, although its shortcomings will continue to spur innovation in a variety of modalities.

Computer vision and augmented reality in gastrointestinal endoscopy

Augmented reality (AR) is an environment-enhancing technology, widely applied in the computer sciences, which has only recently begun to permeate the medical field. Gastrointestinal endoscopy—which relies on the integration of high-definition video data with pathologic correlates—requires endoscopists to assimilate and process a tremendous amount of data in real time. We believe that AR is well positioned to provide computer-guided assistance with a wide variety of endoscopic applications, beginning with polyp detection. In this article, we review the principles of AR, describe its potential integration into an endoscopy set-up, and envisage a series of novel uses. With close collaboration between physicians and computer scientists, AR promises to contribute significant improvements to the field of endoscopy.

The endoscopy evolution: 'the superscope era'

Developments to the design of the flexible endoscope are transforming the field of gastroenterology. There is a drive to improve colonic adenoma detection rates leading to advancements in the design of the colonoscope. Novel endoscopes now allow increased visualisation of colonic mucosa, including behind colonic folds, and aim to reduce pain associated with the procedure. In addition, a shift in surgical paradigm towards minimally invasive endoluminal surgery has meant innovations in flexible platforms are being sought. There are a number of limitations of the basic endoscope. These include a lack of stability and triangulation of instruments. Modifications to the flexible endoscope design form the basis of a number of newly developed and research platforms, some of which are discussed in this review.

Cap assisted colonoscopy for the detection of serrated polyps: a post-hoc analysis

Background

Colonoscopy offers limited protection against right-sided colon cancer, a significant proportion of which arise from the serrated pathway of carcinogenesis. The aim of this study was to compare cap-assisted colonoscopy and standard high-definition white light colonoscopy regarding serrated polyps’ detection.

Methods

Post hoc analysis was performed of a previously conducted randomized controlled trial comparing standard and cap-assisted colonoscopy for adenoma detection. Randomization was stratified based on the indication of colonoscopy and all procedures were performed by three experienced endoscopists. Following cecal intubation, the colonic mucosa was carefully inspected during withdrawal of colonoscope and all polyps detected were documented for their size, location, morphology and then removed and sent for histopathology. Detection rates of significant serrated polyps between both arms were compared using the Fisher’s exact test and Wilcoxon Rank Sum test.

Results

427 patients were enrolled (7 exclusions, 210 completed study in each arm, mean age of 61 years, 95% male, 75% Caucasian, 67% screening colonoscopies). There were no significant differences in baseline characteristics between both groups. Cap-assisted colonoscopy detected a significantly higher proportion of subjects with significant serrated polyps as well as a higher total number of significant serrated polyps compared to standard colonoscopy (12.8% vs. 6.6%, p =0.047 and 40 vs. 20,p = 0.03 respectively).

Conclusions

In this post-hoc analysis, Cap-assisted colonoscopy is a safe technique that offers a higher detection rate of significant serrated polyps when compared to standard colonoscopy. If confirmed in future trials, this simple technique has the potential to improve protection against interval colon cancers.

An updated Asia Pacific Consensus Recommendations on colorectal cancer screening

OBJECTIVE

Since the publication of the first Asia Pacific Consensus on Colorectal Cancer (CRC) in 2008, there are substantial advancements in the science and experience of implementing CRC screening. The Asia Pacific Working Group aimed to provide an updated set of consensus recommendations.

DESIGN

Members from 14 Asian regions gathered to seek consensus using other national and international guidelines, and recent relevant literature published from 2008 to 2013. A modified Delphi process was adopted to develop the statements.

RESULTS

Age range for CRC screening is defined as 50-75 years. Advancing age, male, family history of CRC, smoking and obesity are confirmed risk factors for CRC and advanced neoplasia. A risk-stratified scoring system is recommended for selecting high-risk patients for colonoscopy. Quantitative faecal immunochemical test (FIT) instead of guaiac-based faecal occult blood test (gFOBT) is preferred for average-risk subjects. Ancillary methods in colonoscopy, with the exception of chromoendoscopy, have not proven to be superior to high-definition white light endoscopy in identifying adenoma. Quality of colonoscopy should be upheld and quality assurance programme should be in place to audit every aspects of CRC screening. Serrated adenoma is recognised as a risk for interval cancer. There is no consensus on the recruitment of trained endoscopy nurses for CRC screening.

CONCLUSIONS

Based on recent data on CRC screening, an updated list of recommendations on CRC screening is prepared. These consensus statements will further enhance the implementation of CRC screening in the Asia Pacific region.

Diagnostic yield of third eye retroscope on adenoma detection during colonoscopy: A systematic review and meta-analysis

AIM: To determine the diagnostic yield of the “third eye retroscope”, on adenoma detection rate during screening colonoscopy.

METHODS: The “third eye retroscope” when used with standard colonoscopy provides an additional retrograde view to visualize lesions on the proximal aspects of folds and flexures. We searched MEDLINE (PubMed and Ovid), SCOPUS (including MEDLINE and EMBASE databases), Cochrane Database of Systemic Reviews, Google Scholar, and CINAHL Plus databases to identify studies that evaluated diagnostic yield of “third eye retroscope” during screening colonoscopy. DerSimonian Laird random effects model was used to generate the overall effect for each outcome. We evaluated statistical heterogeneity among the studies by using the Cochran Q statistic and quantified by I² statistics.

RESULTS: Four distinct studies with a total of 920 patients, mean age 59.83 (95%CI: 56.77-62.83) years, were included in the review. The additional adenoma detection rate (AADR) defined as the number of additional adenomas identified due to “third eye retroscope” device in comparison to standard colonoscopy alone was 19.9% (95%CI: 7.3-43.9). AADR for right and left colon were 13.9% (95%CI: 9.4-20) and 10.7 (95%CI: 1.9-42), respectively. AADR for polyps ≥ 6 mm and ≥ 10 mm were 24.6% (95%CI: 16.6-34.9) and 24.2% (95%CI: 12.9-40.8), respectively. The additional polyp detection rate defined as the number of additional polyps identified due to “third eye retroscope” device in comparison to standard colonoscopy alone was 19.8% (95%CI: 7.9-41.8). There were no complications reported with use of “third eye retroscope” device.

CONCLUSION: The “third eye retroscope” device when used with standard colonoscopy is safe and detects 19.9% additional adenomas, compared to standard colonoscopy alone.

Flexible and capsule endoscopy for screening, diagnosis and treatment

Endoscopy dates back to the 1860s, but many of the most significant advancements have been made within the past decade. With the integration of robotics, the ability to precisely steer and advance traditional flexible endoscopes has been realized, reducing patient pain and improving clinician ergonomics. Additionally, wireless capsule endoscopy, a revolutionary alternative to traditional scopes, enables inspection of the digestive system with minimal discomfort for the patient or the need for sedation, mitigating some of the risks of flexible endoscopy. This review presents a research update on robotic endoscopic systems, including both flexible scope and capsule technologies, detailing actuation methods and therapeutic capabilities. A future perspective on endoscopic potential for screening, diagnostic and therapeutic gastrointestinal procedures is also presented.

Fluorescence-based endoscopic imaging of Thomsen-Friedenreich antigen to improve early detection of colorectal cancer

Thomsen-Friedenreich (TF) antigen belongs to the mucin-type tumor-associated carbohydrate antigen. Notably, TF antigen is overexpressed in colorectal cancer (CRC) but is rarely expressed in normal colonic tissue. Increased TF antigen expression is associated with tumor invasion and metastasis. In this study, we sought to validate a novel nanobeacon for imaging TF-associated CRC in a preclinical animal model. We developed and characterized the nanobeacon for use with fluorescence colonoscopy. In vivo imaging was performed on an orthotopic rat model of CRC. Both white light and fluorescence colonoscopy methods were utilized to establish the ratio-imaging index for the probe. The nanobeacon exhibited specificity for TF-associated cancer. Fluorescence colonoscopy using the probe can detect lesions at the stage which is not readily confirmed by conventional visualization methods. Further, the probe can report the dynamic change of TF expression as tumor regresses during chemotherapy. Data from this study suggests that fluorescence colonoscopy can improve early CRC detection. Supplemented by the established ratio-imaging index, the probe can be used not only for early detection, but also for reporting tumor response during chemotherapy. Furthermore, since the data obtained through in vivo imaging confirmed that the probe was not absorbed by the colonic mucosa, no registered toxicity is associated with this nanobeacon. Taken together, these data demonstrate the potential of this novel probe for imaging TF antigen as a biomarker for the early detection and prediction of the progression of CRC at the molecular level.

One or two operator technique and quality performance of colonoscopy: a randomised controlled trial

BACKGROUND

The two-operator technique for colonoscopy, with the endoscopy assistant actively advancing and withdrawing the scope, is still commonly practiced in Europe. As uncontrolled data has suggested that the one-operator technique is associated with a higher adenoma detection rate, we tested the hypothesis that the two-operator-technique can achieve comparable performances in terms of adenoma detection.

METHODS

Non-inferiority trial in which consecutive adult outpatients were randomised to undergo colonoscopy by one (one-operator) or by four endoscopists. Each performed half the procedures by one-operator and half by two-operator technique independently of routine clinical practice. Main outcome measure was adenoma detection rate.

RESULTS

352 subjects (49% males, mean age 60 ± 12.1 years) were randomised to one (n=176) or to two-operator technique (n=176) colonoscopy. No significant differences were found in adenoma detection (33% vs. 30.7%, p=0.65), or cecal intubation rate, procedure times, and patient tolerability. No differences were found in the subgroup analysis according to routinely adopted colonoscopy technique.

CONCLUSIONS

This study does not confirm a higher adenoma detection rate for one-operator technique colonoscopy. Changing current practice to improve adenoma detection rate for endoscopists routinely using two-operator technique is not warranted.

Endoscopic innovations to increase the adenoma detection rate during colonoscopy

Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These numbers may however be conservative because they mainly come from back-to-back studies performed with standard colonoscopes, which are unable to visualize the entire mucosal surface. In the past several years, new endoscopic techniques have been introduced to improve the detection of polyps and adenomas. The introduction of high definition colonoscopes and visual image enhancement technologies have been suggested to lead to better recognition of flat and small lesions, but the absolute increase in diagnostic yield seems limited. Cap assisted colonoscopy and water-exchange colonoscopy are methods to facilitate cecal intubation and increase patients comfort, but show only a marginal or no benefit on polyp and adenoma detection. Retroflexion is routinely used in the rectum for the inspection of the dentate line, but withdrawal in retroflexion in the colon is in general not recommended due to the risk of perforation. In contrast, colonoscopy with the Third-Eye Retroscope^® may result in considerable lower miss rates compared to standard colonoscopy, but this technique is not practical in case of polypectomy and is more time consuming. The recently introduced Full Spectrum Endoscopy™ colonoscopes maintains the technical capabilities of standard colonoscopes and provides a much wider view of 330 degrees compared to the 170 degrees with standard colonoscopes. Remarkable lower adenoma miss rates with this new technique were recently demonstrated in the first randomized study. Nonetheless, more studies are required to determine the exact additional diagnostic yield in clinical practice. Optimizing the efficacy of colorectal cancer screening and surveillance requires high definition colonoscopes with improved virtual chromoendoscopy technology that visualize the whole colon mucosa while maintaining optimal washing, suction and therapeutic capabilities, and keeping the procedural time as low and patient discomfort as optimal as possible.

Prevention of interval colorectal cancers: what every clinician needs to know

Colonoscopic screening and surveillance have been very effective tools in the fight against colorectal cancer (CRC). Colonoscopy is more than a cancer screening test; it also can prevent CRC by detecting and removing precancerous lesions. Despite this potential, there has been increasing concern about CRCs that occur after a previous colonoscopy and before the next screening/surveillance examination (interval CRCs). The etiology of interval CRC is thought to be caused mostly by missed or incompletely resected lesions on index colonoscopy with some contribution of rapidly progressive new lesions. If this is true, many interval cancers should be preventable by improving colonoscopy technique. There are a variety of strategies to decrease interval CRC rates including use of a split-dosed bowel preparation, optimizing withdrawal technique, ensuring complete polypectomy, and careful pathologic examination of the tissue removed. Furthermore, there should be an increased emphasis on how endoscopists are trained to cultivate high-quality technique throughout their careers. It is important to inform patients that even high-quality colonoscopy is not perfectly sensitive for the detection of advanced neoplasia. Improving colonoscopy quality can decrease interval CRC rates and further decrease CRC incidence and mortality.

Retroview colonoscopy

A retroview in the colon permits an 11-25% increase in the adenoma detection rate when compared with a standard straight forward view during colonoscopy. This can often be accomplished in the rectum or the proximal colon by using dial controls and shaft manipulation to turn the tip of a standard colonoscope 180°. A special slim caliber instrument, the "Third Eye Retroscope" (a backward viewing device) has been developed which is inserted through the working channel of a colonoscope. New colonoscopes are being developed that have the capability of side vision with accompanying light illumination which, with wide angle lenses, provide an almost complete retroview of the colon.

Hyoscine N-butylbromide for adenoma detection during colonoscopy: a randomized, double-blind, placebo-controlled study

BACKGROUND

Hyoscine N-butylbromide (HBB), commonly used during colonoscopy to facilitate cecal intubation, has been proposed to increase the adenoma detection rate (ADR).

AIMS

To evaluate whether HBB administration increases the adenoma detection rate and influences patients' tolerance.

METHODS

Consecutive colonoscopy outpatients were randomized after cecal intubation to receive either 20mg HBB or placebo i.v. The number, size, histology and location of polyps were recorded. The air retained in the abdomen was either indirectly estimated by ΔAC (difference in the abdominal circumference measured before and after colonoscopy) or directly evaluated by patients' perception (visual analogic scale, range 0-100).

RESULTS

402 patients (44% male; mean age 57.7±12.5years) received either HBB or placebo. No differences in ADR (31.7% vs. 28%, p=0.48), advanced-ADR (7.4% vs. 10.5%, p=0.35) were observed between HBB and placebo group, respectively. A significantly lower detection rate of flat/depressed lesions was observed in the HBB group (0.5% vs. 5.5%, p=0.003). The ΔAC and the bloating perception were comparable between the two groups (p=0.22 and p=0.48, respectively).

CONCLUSIONS

HBB administered before colonoscope withdrawal does not increase adenoma detection rate and seems to hamper the visualization of flat/depressed lesions. This finding raises concerns on the indiscriminate use of HBB during colonoscopy.

The new view of colon cancer screening: forwards and backwards

Many different techniques for colon cancer screening are available. The fecal immunochemical test is best for fecal-based screening, although the DNA investigation may be more specific when further developed. Computed tomographic colonography is as good as colonoscopy for detecting colon cancer and is almost as good as colonoscopy for detecting advanced adenomas, but has limitations. The flexible sigmoidoscopic examination markedly decreases the incidence of cancer in the visualized segments, but colonoscopy is currently the best procedure for evaluating the large bowel. Techniques for retroflexion or backward view of the colon have been investigated, with all showing increased polyp detection.

Quality colonoscopy: A matter of time, technique or technology?

Quality colonoscopy is defined by the detection of adenomatous polyps at least 25% of the time in men and 15% of the time in women. Recent studies highlight the importance of key aspects of high quality colonoscopy. These include the amount of time spent examining the mucosa or withdrawal time, the quality of withdrawal technique and new technologies which seek to maximize the detection of colonic neoplasia. This review summarizes the latest evidence regarding the role of time, technique and technology in shaping the quality of colonoscopy.