Impact of cap-assisted colonoscopy on detection of proximal colon adenomas: systematic review and meta-analysis

Use of a Novel Artificial Intelligence System Leads to the Detection of Significantly Higher Number of Adenomas During Screening and Surveillance Colonoscopy: Results From a Large, Prospective, US Multicenter, Randomized Clinical Trial

INTRODUCTION

Adenoma per colonoscopy (APC) has recently been proposed as a quality measure for colonoscopy. We evaluated the impact of a novel artificial intelligence (AI) system, compared with standard high-definition colonoscopy, for APC measurement.

METHODS

This was a US-based, multicenter, prospective randomized trial examining a novel AI detection system (EW10-EC02) that enables a real-time colorectal polyp detection enabled with the colonoscope (CAD-EYE). Eligible average-risk subjects (45 years or older) undergoing screening or surveillance colonoscopy were randomized to undergo either CAD-EYE-assisted colonoscopy (CAC) or conventional colonoscopy (CC). Modified intention-to-treat analysis was performed for all patients who completed colonoscopy with the primary outcome of APC. Secondary outcomes included positive predictive value (total number of adenomas divided by total polyps removed) and adenoma detection rate.

RESULTS

In modified intention-to-treat analysis, of 1,031 subjects (age: 59.1 ± 9.8 years; 49.9% male), 510 underwent CAC vs 523 underwent CC with no significant differences in age, gender, ethnicity, or colonoscopy indication between the 2 groups. CAC led to a significantly higher APC compared with CC: 0.99 ± 1.6 vs 0.85 ± 1.5, P = 0.02, incidence rate ratio 1.17 (1.03-1.33, P = 0.02) with no significant difference in the withdrawal time: 11.28 ± 4.59 minutes vs 10.8 ± 4.81 minutes; P = 0.11 between the 2 groups. Difference in positive predictive value of a polyp being an adenoma among CAC and CC was less than 10% threshold established: 48.6% vs 54%, 95% CI -9.56% to -1.48%. There were no significant differences in adenoma detection rate (46.9% vs 42.8%), advanced adenoma (6.5% vs 6.3%), sessile serrated lesion detection rate (12.9% vs 10.1%), and polyp detection rate (63.9% vs 59.3%) between the 2 groups. There was a higher polyp per colonoscopy with CAC compared with CC: 1.68 ± 2.1 vs 1.33 ± 1.8 (incidence rate ratio 1.27; 1.15-1.4; P < 0.01).

DISCUSSION

Use of a novel AI detection system showed to a significantly higher number of adenomas per colonoscopy compared with conventional high-definition colonoscopy without any increase in colonoscopy withdrawal time, thus supporting the use of AI-assisted colonoscopy to improve colonoscopy quality ( ClinicalTrials.gov NCT04979962).

The role of cap-assisted endoscopy and its future implications

Cap-assisted endoscopy refers to a procedure in which a short tube made of a polymer (mostly transparent) is attached to the distal tip of the endoscope to enhance its diagnostic and therapeutic capabilities. It is reported to be particularly useful in: (1) minimizing blind spots during screening colonoscopy, (2) providing a constant distance from a lesion for clear visualization during magnifying endoscopy, (3) accurately assessing the size of various gastrointestinal lesions, (4) preventing mucosal injury during foreign body removal, (5) securing adequate workspace in the submucosal space during endoscopic submucosal dissection or third space endoscopy, (6) providing an optimal approach angle to a target, and (7) suctioning mucosal and submucosal tissue with negative pressure for resection or approximation. Here, we review various applications of attachable caps in diagnostic and therapeutic endoscopy and their future implications.

Colonoscopy vs the Fecal Immunochemical Test: Which is Best?

Although there is no debate around the effectiveness of colorectal cancer screening in reducing disease burden, there remains a question regarding the most effective and cost-effective screening modality. Current United States guidelines present a panel of options that include the 2 most commonly used modalities, colonoscopy and stool testing with the fecal immunochemical test (FIT). Large-scale comparative effectiveness trials comparing colonoscopy and FIT for colorectal cancer outcomes are underway, but results are not yet available. This review will separately state the "best case" for FIT and colonoscopy as the screening tool of first choice. In addition, the review will examine these modalities from a health economics perspective to provide the reader further context about the relative advantages of these commonly used tests.

Linked color imaging versus white light imaging in the diagnosis of colorectal lesions: a meta-analysis of randomized controlled trials

Background

Miss rate of colorectal neoplasia is associated with lesion histology, size, morphology, or location.

Objectives

We aim to compare the efficacy of Linked color imaging (LCI) versus white light imaging (WLI) for adenoma detection rate (ADR), the detection of sessile serrated lesions (SSLs), serrated lesions (SLs), advanced adenomas (AAs), diminutive lesions (DLs), and flat lesions (FLs) by using per-patient and per-lesion analysis based on randomized controlled trials (RCTs).

Design

Systematic review and meta-analysis.

Data sources and methods

PubMed, Embase, and Cochrane databases were searched through May 1st, 2023. We calculated risk ratio for dichotomous outcomes and mean difference for continuous outcomes, and performed sensitivity analyses and subgroup analyses.

Results

Overall, 17 RCTs (10,624 patients) were included. In per-patient analysis, ADR was higher in the LCI group versus the WLI group (p < 0.00001). This effect was consistent for SSL (p = 0.005), SLs (p = 0.01), AAs (p = 0.04), DLs (p < 0.00001), and FLs (p < 0.0001). In per-lesion analysis, LCI showed a significant superiority over WLI with regard to the mean number of adenomas per patient (p < 0.00001). This effect was in accordance with mean SSL (p = 0.001), mean SLs (p < 0.00001), and mean DLs (p < 0.0001) per patient. A subgroup analysis showed that the beneficial effect of the LCI group on the detection of AAs, SSL, and FLs was maintained only for studies when experts and trainees were included but not for experts only.

Conclusions

Meta-analyses of RCTs data support the use of LCI in clinical practice, especially for trainees.

Multicenter propensity score-matched analysis comparing short versus long cap-assisted colonoscopy for acute hematochezia

Background and Aim

While short and long attachment caps are available for colonoscopy, it is unclear which type is more appropriate for stigmata of recent hemorrhage (SRH) identification in acute hematochezia. This study aimed to compare the performance of short versus long caps in acute hematochezia diagnoses and outcomes.

Methods

We selected 6460 patients who underwent colonoscopy with attachment caps from 10 342 acute hematochezia cases in the CODE BLUE-J study. We performed propensity score matching (PSM) to balance baseline characteristics between short and long cap users. Then, the proportion of definitive or presumptive bleeding etiologies found on the initial colonoscopy and SRH identification rates were compared. We also evaluated rates of blood transfusions, interventional radiology, or surgery, as well as the rate of rebleeding and mortality within 30 days after the initial colonoscopy.

Results

A total of 3098 patients with acute hematochezia (1549 short cap and 1549 long cap users) were selected for PSM. The rate of colonic diverticular bleeding (CDB) diagnosis was significantly higher in long cap users (P = 0.006). While the two groups had similar rates of the other bleeding etiologies, the frequency of unknown etiologies was significantly lower in long cap users (P < 0.001). The rate of SRH with active bleeding was significantly higher in long cap users (P < 0.001). Other clinical outcomes did not differ significantly.

Conclusion

Compared to that with short caps, long cap-assisted colonoscopy is superior for the diagnosis of acute hematochezia, especially CDB, and the identification of active bleeding.

Adenoma detection rate in colonoscopy: how can it be improved?

INTRODUCTION

The introduction of widespread colonoscopy screening programs has helped in decreasing the incidence of Colorectal Cancer (CRC). However, 'back-to-back' colonoscopies revealed relevant percentage of missed adenomas. Quality indicators were created to further homogenize detection performances and decrease the incidence of post-colonoscopy CRC. Among them, the Adenoma Detection Rate (ADR), defined as the percentage obtained by dividing the number of endoscopic procedures in which at least one adenoma was resected, by the total number of procedures, was found to be inversely associated with the risks of interval colorectal cancer, advanced-stage interval cancer, and fatal interval cancer.

AREAS COVERED

In this paper, we performed a comprehensive review of the literature focusing on promising new devices and technologies, which are meant to positively affect the endoscopist performance in detecting adenomas, therefore increasing ADR.

EXPERT OPINION

Considering the current knowledge, although several devices and technologies have been proposed with this intent, the recent implementation of AI ranked over all of the other strategies and it is likely to become the new standard within few years. However, the combination of different device/technologies need to be investigated in the future aiming at even further increasing of endoscopist detection performances.

Impact of withdrawal time on adenoma detection rate: results from a prospective multicenter trial

BACKGROUND AND AIMS

Performing a high-quality colonoscopy is critical for optimizing the adenoma detection rate (ADR). Colonoscopy withdrawal time (a surrogate measure) of ≥6 minutes is recommended; however, a threshold of a high-quality withdrawal and its impact on ADR are not known.

METHODS

We examined withdrawal time (excluding polyp resection and bowel cleaning time) of subjects undergoing screening and/or surveillance colonoscopy in a prospective, multicenter, randomized controlled trial. We examined the relationship of withdrawal time in 1-minute increments on ADR and reported odds ratio (OR) with 95% confidence intervals. Linear regression analysis was performed to assess the maximal inspection time threshold that impacts the ADR.

RESULTS

A total of 1142 subjects (age, 62.3 ± 8.9 years; 80.5% men) underwent screening (45.9%) or surveillance (53.6%) colonoscopy. The screening group had a median withdrawal time of 9.0 minutes (interquartile range [IQR], 3.3) with an ADR of 49.6%, whereas the surveillance group had a median withdrawal time of 9.3 minutes (IQR, 4.3) with an ADR of 63.9%. ADR correspondingly increased for a withdrawal time of 6 minutes to 13 minutes, beyond which ADR did not increase (50.4% vs 76.6%, P < .01). For every 1-minute increase in withdrawal time, there was 6% higher odds of detecting an additional subject with an adenoma (OR, 1.06; 95% confidence interval, 1.02-1.10; P = .004).

CONCLUSIONS

Results from this multicenter, randomized controlled trial underscore the importance of a high-quality examination and efforts required to achieve this with an incremental yield in ADR based on withdrawal time. (Clinical trial registration number: NCT03952611.).

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.

High-Definition Colonoscopy Compared With Cuff- and Cap-Assisted Colonoscopy: Results From a Multicenter, Prospective, Randomized Controlled Trial

BACKGROUND AND AIMS

Mucosal exposure devices including distal attachments such as the cuff and cap have shown variable results in improving adenoma detection rate (ADR) compared with high-definition white light colonoscopy (HDWLE).

METHODS

We performed a prospective, multicenter randomized controlled trial in patients undergoing screening or surveillance colonoscopy comparing HDWLE to 2 different types of distal attachments: cuff (CF) (Endocuff Vision) or cap (CP) (Reveal). The primary outcome was ADR. Secondary outcomes included adenomas per colonoscopy, advanced adenoma and sessile serrated lesion detection rate, right-sided ADR, withdrawal time, and adverse events. Continuous variables were compared using Student's t test and categorical variables were compared using chi-square or Fisher's exact test using statistical software Stata version16. A P value <.05 was considered significant.

RESULTS

A total of 1203 subjects were randomized to either HDWLE (n = 384; mean 62 years of age; 81.3% males), CF (n = 379; mean 62.7 years of age; 79.9% males) or CP (n = 379; mean age 62.1 years of age; 80.5% males). No significant differences were found among 3 groups for ADR (57.3%, 59.1%, and 55.7%; P = .6), adenomas per colonoscopy (1.4 ± 1.9, 1.6 ± 2.4, and 1.4 ± 2; P = .3), advanced adenoma (7.6%, 9.2%, and 8.2%; P = .7), sessile serrated lesion (6.8%, 6.3%, and 5.5%; P = .8), or right ADR (48.2%, 49.3%, and 46.2%; P = .7). The number of polyps per colonoscopy were significantly higher in the CF group compared with HDWLE and CP group (2.7 ± 3.4, 2.3 ± 2.5, and 2.2 ± 2.3; P = .013). In a multivariable model, after adjusting for age, sex, body mass index, withdrawal time, and Boston Bowel Preparation Scale score, there was no impact of device type on the primary outcome of ADR (P = .77). In screening patients, CF resulted in more neoplasms per colonoscopy (CF: 1.7 ± 2.6, HDWLE: 1.3 ± 1.7, and CP: 1.2 ± 1.8; P = .047) with a shorter withdrawal time.

CONCLUSIONS

Results from this multicenter randomized controlled trial do not show any significant benefit of using either distal attachment devices (CF or CP) over HDWLE, at least in high-detector endoscopists. The Endocuff may have an advantage in the screening population. (ClinicalTrials.gov, Number: NCT03952611).

Quality Indicators for the Detection and Removal of Colorectal Polyps and Interventions to Improve Them

Modifiable risk factors for postcolonoscopy colorectal cancer include suboptimal lesion detection (missed neoplasms) and inadequate lesion removal (incomplete polypectomy) during colonoscopy. Competent detection and removal of colorectal polyps are thus fundamental to ensuring adequate colonoscopy quality. Several well-researched quality metrics for polyp detection have been implemented into clinical practice, chief among these the adenoma detection rate. Less data are available on quality indicators for polyp removal, which currently include complete resection rates and skills assessment tools. This review summarizes the available literature on quality indicators for the detection and removal of colorectal polyps, as well as interventions to improve them.

Irrigating Acetic Acid Solution During Colonoscopy for the Detection of Sessile Serrated Neoplasia: A Randomized Controlled Trial

BACKGROUND

Misdiagnosed sessile serrated lesions (SSLs) are important precursors for interval colorectal cancers.

AIMS

We investigated the usage of acetic acid (AA) solution for improving the detection of SSLs in the right colon in a randomized controlled trial.

METHODS

A tandem observation of the right colon was performed in 412 consecutive patients. A first inspection was performed under white light high-definition endoscopy. In the AA group, a low concentration vinegar solution (AA: 0.005%) irrigated by a water pump in the right colon was compared with a plain solution of normal saline (NS) in the diagnostic yield of SSLs during the second inspection. Secondary outcomes in overall polyp detection were measured.

RESULTS

Qualitative comparisons showed significant differences in the detection rates of all polyps except adenomas, with remarkable improvement in the demonstration of advanced (> 20 mm), SSLs, and hyperplastic polyps during the second inspection of the right colon using the AA solution. Significant improvement was also noted in the AA group, as far as the mean number of polyps/patient detected, not only in SSLs (AA group: 0.14 vs. NS group: 0.01, P < 0.001), but also in all histological types and all size-categories in the right colon. Small (≤ 9 mm) polyps were detected at a higher rate in the sigmoid colon expanding the effect of the method in the rest of the colon.

CONCLUSION

AA-assisted colonoscopy led to a significant increase in SSLs detection rate in the right colon in a safe, quick, and effective manner.

Sessile serrated adenoma/polyp detection rate of water exchange, Endocuff, and cap colonoscopy: A network meta-analysis

BACKGROUND AND AIM

Sessile serrated adenoma/polyp (SSA/P) may contribute to interval cancer. In a recent meta-analysis, water exchange (WE) was shown to be superior to Endocuff and cap colonoscopy at adenoma and advanced adenoma detection. The strong positive correlation between adenoma detection rate (ADR), advanced adenoma detection rate (AADR), and sessile serrated adenoma/polyp detection rate (SSA/PDR) prompted us to hypothesize that WE could significantly improve SSA/PDR compared with Endocuff and cap colonoscopy.

METHODS

The literature was searched for all randomized controlled trials (RCTs) that reported SSA/PDR as an outcome and included the keywords colonoscopy, and water exchange, Endocuff, or cap. We performed traditional network meta-analyses with random effect models comparing SSA/PDR of each method using air insufflation as the control and reported the odds ratios (ORs) with 95% confidence interval (CI). Performances were ranked based on P-score.

RESULTS

A total of 531 articles resulted from initial keywords search. Eleven RCTs were included in the analysis. A total of 7856 patients underwent air insufflation, WE, Endocuff, or cap colonoscopy. WE significantly increased SSA/PDR (OR 2.04; 95% CI 1.33-3.13). Endocuff (OR 1.15; 95% CI 0.94-1.41) and cap (OR 1.08; 95% CI 0.42-2.74) did not significantly impact SSA/P detection. P-scores for WE (0.96), Endocuff (0.49), cap (0.37), and air insufflation (0.17) suggested that WE had the highest SSA/PDR. The results did not change after adjusting for mean withdrawal time and indication for colonoscopy.

CONCLUSION

Water exchange significantly increases SSA/PDR and is superior to Endocuff and cap colonoscopy at detecting SSA/P.

Application of linked color imaging in the diagnosis of early gastrointestinal neoplasms and precancerous lesions: a review

INTRODUCTION

Minimally invasive endoscopic resection is often effective in the management of early gastrointestinal tumors. However, advanced and more effective methods of endoscopic examination are required to improve the rate of diagnosing early gastrointestinal tumors.

DISCUSSION

The development of dye-based image-enhanced endoscopy (d-IEE) and equipment-based image-enhanced endoscopy (e-IEE) has helped improve the diagnostic rate of early gastrointestinal tumor using endoscopy. In some special cases, these methods are still not accurate in diagnosing lesions. On the basis of these e-IEEs, a new endoscopic technique, linked color imaging (LCI), that combines a specific short wavelength narrow band of light with white light, has been developed.

CONCLUSION

In this article, we summarized the characteristics of LCI and the development of research regarding digestive tract examination.

PLAIN LANGUAGE SUMMARY

Application of linked color imaging in early gastrointestinal neoplasms At present, the complete diagnosis of early gastrointestinal tumors and precancerous lesions can be made by gastrointestinal endoscopy. With the improvement of therapeutic instruments and operators' experience, endoscopic therapy can often achieve significant effect in the treatment of early gastrointestinal tumors. The development and spread of equipment-based image-enhanced endoscopy (e-IEE) mode has helped improve the diagnosis rate of early gastrointestinal tumors under endoscopy. However, in some special cases, these methods are still not accurate for the diagnosis of lesions. On the basis of these E-IEEs, a new endoscopic technique, linked color imaging (LCI), has been developed, which combines a specific short wavelength narrow band of light with white light. LCI can significantly improve the diagnostic rate of all types of gastrointestinal mucosal lesions. Tumor lesions and inflammatory lesions can be distinguished by observing the mucosal microvascular structure and color difference. LCI helps detect early gastrointestinal mucosal lesions by taking advantage of the differences in light absorption of different wavelengths and contrast of enhanced colors in the later stage.

Colonoscopy screening and surveillance guidelines

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles.

Clear cap-assisted luminal stenting may improve technical success in gastroduodenal and colonic obstruction

Background  Luminal stenting is safe, effective, and at times the preferred method for relieving gastrointestinal obstruction. However, stent placement is not technically feasible when lesions cannot be traversed with a guidewire, resulting in the need for more invasive methods of palliation and urgent/emergent surgical intervention. In this series, we report our experience with cap-assisted stenting to improve lumen visualization in obstructed segments of the gastrointestinal tract and salvage cases that may have otherwise resulted in technical failure. Methods  A clear cap (i. e. distal attachment) was affixed to the scope tip to facilitate visualization and stenting in two cases of gastroduodenal obstruction and three cases of colonic obstruction. Indications for stent placement included malignant obstruction, diverticulitis-associated obstruction, and Crohn's disease-associated stricture. Results  In this report, we demonstrate that use of a clear cap facilitated endoscopic stenting in challenging cases of malignant and benign gastroduodenal and colonic obstruction. Conclusions  A clear cap for endoscopic stenting can be used in cases in which standard techniques are unsuccessful or those anticipated to be technically difficult at the outset. Cases with tortuous anatomy or particularly tight, friable, or exophytic obstructive lesions may benefit most from this novel technical modification.

Colon polyp detection using linked color imaging compared to white light imaging: Systematic review and meta-analysis

BACKGROUND AND AIM

Linked color imaging (LCI) is a novel image-enhancing technology which enhances color differences between a colorectal lesion and surrounding mucosa with enough brightness to illuminate the wide colorectal lumen. The aim of this study is to compare colorectal polyp detection using LCI with that using white light imaging (WLI).

METHODS

Randomized controlled trials and prospective studies comparing LCI with WLI for colorectal polyp detection were selected. Outcomes included overall polyp/adenoma detection and additional polyp detection at a second observation. Outcomes were documented by pooled risk ratios (RR) with 95% confidence interval (CI) using the Mantel-Haenszel random effect model.

RESULTS

Seven studies were included. LCI showed significant superiority for polyp and adenoma detection compared with WLI (RR 1.16, 95% CI 1.09-1.25, P < 0.001 for polyp detection; RR 1.26, 95% CI 1.14-1.39 P < 0.001 for adenoma detection). LCI significantly increased the number of polyps detected per patient compared with WLI (mean difference 0.27, 95% CI 0.01-0.53, P = 0.040). LCI significantly increased the number of adenomas detected per patient compared with WLI (mean difference 0.22, 95% CI 0.08-0.36, P = 0.002). LCI significantly increased the number of flat polyps detected per patient compared with WLI (mean difference 0.14, 95% CI 0.01-0.27, P = 0.040). LCI had a significantly higher rate of additional polyp detection compared with WLI in the right colon (RR 2.68, 95% CI 1.71-4.19, P < 0.001).

CONCLUSIONS

Linked color imaging has significantly greater polyp and adenoma detection rates and detection rate of previously missed polyps compared with WLI. We recommend the initial use of LCI for routine colonoscopy.

Cap-Assisted Chromoendoscopy Using a Mounted Cap Versus Standard Colonoscopy for Adenoma Detection

OBJECTIVES

Some neoplastic lesions remain undetected on colonoscopy. To date, no studies have investigated whether combining cap-assisted colonoscopy with chromoendoscopy increases the adenoma detection rate (ADR). This study aimed to compare cap-assisted chromoendoscopy (CAP/CHROMO) with standard colonoscopy (SC) with respect to their efficacy in detecting adenomas.

METHODS

This prospective, multicenter, randomized controlled trial included asymptomatic subjects aged 45-75 years who underwent colonoscopy for the first time at 14 university hospitals. Subjects were randomized to either the CAP/CHROMO group (with 0.09% indigo carmine spraying using a cap-mounted catheter at the tip of the colonoscope) or the SC group. All polyps were resected, but only histologically confirmed neoplastic lesions were considered for analysis. The primary outcome was ADR, defined as the proportion of subjects with at least 1 adenoma.

RESULTS

A total of 1,905 subjects were randomized to the CAP/CHROMO (n = 948) or SC (n = 957) group at 14 centers. Subjects' demographic characteristics were similar between both groups. The CAP/CHROMO group had significantly higher ADR than the SC group (54.4% vs 44.9%, P < 0.001). Significantly, more subjects with at least 1 proximal colon adenoma were identified by CAP/CHROMO (38.6%) than by SC (31.2%) (P = 0.001). The proximal serrated polyp detection rate by CAP/CHROMO was significantly higher in the female subgroup vs SC. However, advanced ADR was not different between the CAP/CHROMO and SC groups (9.3% vs 7.6%, P = 0.180).

DISCUSSION

CAP/CHROMO markedly improved the ADR and enhanced the detection of proximal adenoma. CAP/CHROMO is feasible for routine application and will allow for a more effective surveillance program.

How to increase proximal adenoma detection rate: a meta-analysis comparing water exchange, water immersion and air/CO2 insufflation methods for colonoscopy

Background

Recent meta-analyses have demonstrated a higher adenoma detection rate using the water exchange method (WE), compared to water immersion (WI) and air/CO₂ insufflation (ACI). Proximal adenomas have a high miss rate owing to their location and appearance. We performed a systematic review and meta-analysis of studies comparing the WE and WI methods to the ACI method, with a primary focus on proximal adenoma detection rate.

Methods

The following databases were searched for our systematic review: Medline, Embase, Cochrane Library, CINAHL, and Web of Sciences. We included both randomized controlled trials and cohort studies. The primary outcome was proximal adenoma detection rate, and secondary outcomes were right adenoma detection rate and cecal intubation rate.

Results

A total of 12 studies (17 arms) with 5660 patients (2260 ACI, 2281 WE, and 1119 WI) were included. A higher proximal adenoma detection rate (risk ratio [RR] 1.30, 95% confidence interval [CI] 1.11-1.53; P=0.001) and right adenoma detection rate (RR 1.43, 95%CI 1.19-1.71; P≤0.001; I²=0%) were noted for the WE group compared to the ACI group. The WI group did not demonstrate a better detection rate of proximal or right adenomas.

Conclusions

The water exchange method for colonoscopy holds promise and should be encouraged in the clinical setting to increase proximal and right adenoma detection rates. This will in turn decrease the incidence of colorectal cancer.

Comparison of colon adenoma detection rates using cap-assisted and Endocuff-assisted colonoscopy: a randomized controlled trial

Objectives and study aim  Colonoscopy prevents colorectal cancer by removing adenomatous polyps, but missed adenomas lead to interval cancers. Different devices have been used to increase adenoma detection rates (ADR). Two such devices of interest are the transparent cap (Olympus) and Endocuff (ARC Medical). Our study aimed to compare differences in ADR between Endocuff-assisted colonoscopy (EAC), cap-assisted colonoscopy (CAC) and standard colonoscopy (SC). Patients and methods  A sample size of 126 subjects was calculated to determine an effect size of 30 %. Patients undergoing screening or surveillance colonoscopy between March 2016 and January 2017 were randomized to SC, CAC or EAC groups. Three experienced endoscopists performed all colonoscopies. Patient demographics, procedure indication, Boston Bowel Prep Score (BBPS), withdrawal time, polyp size, location, histopathology, were analyzed. Results  There was no difference in ADR (52 %, 40 % and 54 %) in the SC, CAC and EAC groups respectively ( P  = 0.4). Similar findings were also observed for proximal ADR (45 %, 35 %, and 50 %, P  = 0.4) and SSA detection rate (16 %, 14 %, and 23 %, P  = 0.5). EAC detected higher mean ADR per colonoscopy compared to CAC (1.70 vs 0.76, P  = 0.01). However, there was no significant difference in mean ADR per positive colonoscopy (2.08, 1.63, and 2.59, P  = 0.21). Conclusion  In a randomized controlled trial comparing AC to CAC and SC, neither device conferred additional benefits in ADR among high detectors. When comparing each device, EAC may be better than CAC at detecting more total adenomas.

Ileal intubation is not associated with higher detection rate of right-sided conventional adenomas and serrated polyps compared to cecal intubation after adjustment for overall adenoma detection rate

Background

High cecal intubation rate (CIR) is associated with significant improved adenoma detection rate (ADR), however, self-reported CIR may be overestimated and inadequate documentation of cecal intubation is associated with a lower polyp detection rate compared to clear documentation. We aimed to investigate if ileal intubation may be associated with higher detection rates (DR) for right-sided conventional adenomas (cAD) and serrated polyps (SP) compared to cecal intubation in a large screening colonoscopy cohort.

Material and methods

Retrospective analysis of individuals ≥50 years with average risk for colorectal cancer (CRC) who underwent screening colonoscopy between 01/01/2012 and 14/12/2016 at a tertiary academic hospital and six community-based private practices. Exclusion criteria were conditions with increased risk for CRC (e.g. inflammatory bowel disease, history of CRC, hereditary cancer syndromes), previous colonoscopy at the same institution, and incomplete procedures. Right-sided colon was defined as caecum and ascending colon.

Results

4.138 individuals were analysed (mean age 62 years, 52.1% female). DR for right-sided cADs and SPs were significantly higher after ileal compared to cecal intubation in univariate (12.5% vs. 6.8%, p < 0.001, and 6.3% vs. 3.3%, p < 0.001), but not in multivariate analysis (OR 1.025, 95%-CI 0.639–1.646, p = 0.918, and OR 0.937, 95%-CI 0.671–1.309, p = 0.704). DRs did not differ between ileal and cecal intubation for endoscopists with ADR ≥25 and < 25%, respectively. ADR ≥25% was significantly associated with ileal intubation (OR 21.862, 95%-CI 18.049–26.481, p < 0.001).

Conclusion

Ileal intubation may not provide any benefit over cecal intubation concerning the detection of cADs and SPs in the right-sided colon.

Improving serrated adenoma detection rate in the colon by electronic chromoendoscopy and distal attachment: systematic review and meta-analysis

BACKGROUND AND AIMS

The evidence for modification of conventional colonoscopy using either "distal attachments" (DAs; endocap, endocuff, and endoring) or "electronic chromoendoscopy" (EC; narrow-band imaging [NBI], iScan, blue-light imaging, autofluorescence imaging, and linked-color imaging) to improve the detection of serrated adenomas during colonoscopy has shown conflicting results.

METHODS

A comprehensive literature search was performed using Medline, Google Scholar, Embase, and Cochrane Library based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials (RCTs) comparing any DA or EC with high-definition white-light colonoscopy for detection of serrated adenomas (sessile serrated adenoma/polyp and traditional serrated adenoma) were included. The primary outcome was serrated adenoma detection rate (SADR) defined as the number of patients with at least 1 serrated adenoma of total patients in that group. The secondary outcome was the number of serrated adenomas per subject. Pooled rates were reported using risk ratio (RR) with 95% confidence interval.

RESULTS

Seventeen studies with 13,631 patients (56% men; age range, 50-66 years) met the inclusion criteria. The use of DAs (RR, 1.21; P = .45) and EC (RR, 1.29; P = .09) during colonoscopy did not show a significant improvement in SADR. The SADR using EC was 6.9% (4 studies) and that with NBI alone was 3.7% (3 studies).

CONCLUSIONS

The results indicate that, except for NBI, the use of DAs or EC during colonoscopy does not improve detection of serrated adenomas in the colon. More RCTs evaluating NBI are needed to explore the effect.

Terminology, Molecular Features, Epidemiology, and Management of Serrated Colorectal Neoplasia

In addition to the adenoma to carcinoma sequence, colorectal carcinogenesis can occur via the serrated pathway. Studies have focused on clarification of categories and molecular features of serrated polyps, as well as endoscopic detection and risk assessment. Guidelines from the World Health Organization propose assigning serrated polyps to categories of hyperplastic polyps, traditional serrated adenomas, and sessile serrated lesions (SSLs). Traditional serrated adenomas and SSLs are precursors to colorectal cancer. The serrated pathway is characterized by mutations in RAS and RAF, disruptions to the Wnt signaling pathway, and widespread methylation of CpG islands. Epidemiology studies of serrated polyps have been hampered by inconsistencies in terminology and reporting, but the prevalence of serrated class polyps is 20%-40% in average-risk individuals; most serrated polyps detected are hyperplastic. SSLs, the most common premalignant serrated subtype, and are found in up to 15% of average-risk patients by high-detecting endoscopists. Variations in rate of endoscopic detection of serrated polyps indicate the need for careful examination, with adequate bowel preparation and sufficient withdrawal times. Risk factors for SSLs include white race, family history of colorectal cancer, smoking, and alcohol intake. Patients with serrated polyps, particularly SSLs and traditional serrated adenomas, have an increased risk of synchronous and metachronous advanced neoplasia. Surveillance guidelines vary among countries, but SSLs and proximal hyperplastic polyps require special attention in assignment of surveillance interval-especially in light of concerns regarding incomplete detection and resection.

To cap/cuff or ring: do distal attachment devices improve the adenoma detection?

Colonoscopy reduces the risk of colorectal cancer, by interrupting the adenoma-carcinoma sequence enabling the detection and removal of adenomas before they turn into colorectal cancer. Colonoscopy has its limitations as adenoma miss rates as high as 25% have been reported. The reasons for missed pathology are complicated and multi-factorial. The recent drive to improve adenoma detection rates has led to a plethora of new technologies. Areas covered: An increasing number of advanced endoscopes and distal attachment devices have appeared in the market. Advanced endoscopes aim to improve mucosal visualization by widening the field of view. Distal attachment devices aim to increase adenoma detection behind folds by flattening folds on withdrawal. In this review article, we discuss the three following distal attachment devices: the transparent cap, the Endocuff, and the Endoring. Expert commentary: The authors believe that the distal attachment devices will have a greater benefit for endoscopists with low baseline adenoma detection rates.

Colonoscopy attachments for the detection of precancerous lesions during colonoscopy: A review of the literature

Although colonoscopy has been proven effective in reducing the incidence of colorectal cancer through the detection and removal of precancerous lesions, it remains an imperfect examination, as it can fail in detecting up to almost one fourth of existing adenomas. Among reasons accounting for such failures, is the inability to meticulously visualize the colonic mucosa located either proximal to haustral folds or anatomic curves, including the hepatic and splenic flexures. In order to overcome these limitations, various colonoscope attachments aiming to improve mucosal visualization have been developed. All of them - transparent cap, Endocuff, Endocuff Vision and Endorings - are simply mounted onto the distal tip of the scope. In this review article, we introduce the rationale of their development, present their mode of action and discuss in detail the effect of their implementation in the detection of lesions during colonoscopy.

Comparative Efficacy of Colonoscope Distal Attachment Devices in Increasing Rates of Adenoma Detection: A Network Meta-analysis

BACKGROUND & AIMS

Several add-on devices have been developed to increase rates of colon adenoma detection (ADR). We assessed their overall and comparative efficacy, and estimated absolute magnitude of benefit through a network meta-analysis.

METHODS

We searched the PubMed/Medline and Embase database through March 2017 and identified 25 randomized controlled trials (comprising 16,103 patients) that compared the efficacy of add-on devices (cap; Endocuff; Arc Medical Design Ltd, Leeds, UK, and Endorings; Us Endoscopy, Mentor, OH) with each other or with standard colonoscopy. The primary outcome was ADR; secondary outcomes included rate of polyp detection, and rate of and time to cecal intubation. We performed pairwise and network meta-analyses, and appraised quality of evidence using Grading of Recommendations Assessment, Development and Evaluation. We estimated the magnitude of increase in ADR by low-performing endoscopists (baseline ADR, 10%) and high-performing endoscopists (baseline ADR, 40%) with use of these devices.

RESULTS

Overall, distal attachment devices increased ADR compared with standard colonoscopy (relative risk [RR], 1.13; 95% CI, 1.03-1.23; low-quality evidence), with potential absolute increases in ADR to 11.3% for low-performing endoscopists and to 45.2% for high-performing endoscopists. In a comparative evaluation, we found low-quality evidence that Endocuff increases ADR compared with standard colonoscopy (RR, 1.21; 95% CI, 1.03-1.41), with anticipated increases in ADR to 12% for low-performing endoscopists and to 48% for high-performing endoscopists. We found very low quality evidence to support the use of Endorings (RR, 1.70; 95% CI, 0.86-3.36) or caps (RR, 1.07; 95% CI, 0.96-1.19) vs standard colonoscopy for increasing ADR. The benefit of one distal attachment device over another was uncertain due to very low quality evidence.

CONCLUSIONS

Based on network meta-analysis, we anticipate only modest improvement in ADRs with use of distal attachment devices, especially in low-performing endoscopists.

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.

New endoscopy advances to refine adenoma detection rate for colorectal cancer screening: None is the winner

Colorectal cancer (CRC) is the third most common cancer in males and second in females, and globally the fourth cause for cancer death worldwide. Oncological screening of CRC has a major role in the management of the disease and it is mostly performed by colonoscopy. Anyway, effectiveness of endoscopic screening for CRC strictly depends on adequate detection and removal of potentially precancerous lesions, and accuracy of colonoscopy in detection of adenomas is still suboptimal. For this reason, several technological advances have been implemented in order to improve the diagnostic sensitivity of colonoscopy in adenoma detection. Among these: (1) Visual technologies such as chromoendoscopy and narrow band imaging; (2) optical innovation as high definition endoscopy, full-spectrum endoscopy or Third Eye Retroscope; and (3) mechanical advances as Cap assisted colonoscopy, Endocuff, Endoring and G-Eye endoscope. All these technologies advances have been tested over time by clinical studies with mixed results. Which of them is more likely to be successful in the next future?