High resolution colonoscopy with chromoscopy versus standard colonoscopy for the detection of colonic neoplasia: a randomized study

Colorectal Neoplasia in Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD), including ulcerative colitis and colonic Crohn's disease, are at an increased risk of developing colonic dysplasia and neoplasia. Multiple risk factors have been identified that increase the risk of colonic neoplasia in IBD, including but not limited to underlying disease extent, severity, duration, and concomitant primary sclerosing cholangitis. The overall risk of colonic neoplasia in IBD is decreasing but surveillance is still warranted in patients with high-risk features. In this review, we will discuss the epidemiology, pathogenesis, risk factors, approach to surveillance, and management of colonic neoplasia in IBD.

Chromoendoscopy and virtual chromoendoscopy for dysplasia screening in patients with ulcerative colitis (systematic review and meta-analysis)

AIM: to compare the diagnostic informativeness of mucosal dye spraying (chromoendoscopy) (CE) and virtual chromoendoscopy (VCE) in detecting dysplasia in patients with a long history ulcerative colitis (UC).MATERIALS AND METHODS: a systematic review and meta-analysis of studies comparing the results of the use of CE and VCE for the diagnosis of colitis-associated dysplasia was performed. The following indicators were evaluated: the frequency of patients with endoscopically detected colitis-associated dysplasia and the frequency of endoscopic diagnosis of colitis-associated dysplasia among the total number of identified lesions. The statistical analysis was carried out using the Review Manager software 5.3RESULTS: the systematic review included 4 studies, analyzing 364 patients in total. In the study groups, there were no statistical differences in patients with endoscopically detected colitis-associated dysplasia and in endoscopic diagnosis of colitis-associated dysplasia among total number of detected colorectal neoplasms (OR = 0.87; 95% CI 0.60–1.27; p = 0.47 and OR = 0.82; 95% CI 0.58–1.18; p = 0.29).CONCLUSION: meta-analysis could not demonstrate a significant difference between CE and VCE. However, additional studies are needed to recognize the role of VCE in the differentiation of neoplastic and non-neoplastic lesions in patients with UC

Dye-based chromoendoscopy for the detection of colorectal neoplasia: meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Dye-based chromoendoscopy (DBC) could be effective in increasing the adenoma detection rate (ADR) in patients undergoing colonoscopy, but the technique is time-consuming and its uptake is limited. We aimed to assess the effect of DBC on ADR based on available randomized controlled trials (RCTs).

METHODS

Four databases were searched up to April 2022 for RCTs comparing DBC with conventional colonoscopy (CC) in terms of ADR, advanced ADR, and sessile serrated adenoma detection rate as well as the mean adenomas per patient and non-neoplastic lesions. Relative risk (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes were calculated using random-effect models. The I² test was used for quantifying heterogeneity. Risk of bias was evaluated with the Cochrane tool.

RESULTS

Overall, 10 RCTs (5334 patients) were included. Indication for colonoscopy was screening or surveillance (3 studies) and mixed (7 studies). Pooled ADR was higher in the DBC group versus the CC group (95% CI, 48.1% [41.4%-54.8%] vs 39.3% [33.5%-46.4%]; RR, 1.20 [1.11-1.29]), with low heterogeneity (I² = 29%). This effect was consistent for advanced ADR (RR, 1.21 [1.03-1.42]; I² = .0%), sessile serrated adenomas (6.1% vs 3.5%; RR, 1.68 [1.15-2.47]; I² = 9.8%), and mean adenomas per patient (MD, .24 [.17-.31]) overall and in the right-sided colon (MD, .28 [.14-.43]). A subgroup analysis considering only trials using high-definition white-light endoscopy reduced the heterogeneity while still showing a significant increase in adenoma detection with DBC: 51.6% (95% confidence interval [CI], 47.1%-56.1%) and 59.1% (95% CI, 54.7-63.3%), RR = 1.14 (95% CI, 1.06-1.23), P = .0004, I² = .0%, P = .50.

CONCLUSIONS

Meta-analysis of RCTs showed that DBC increases key quality parameters in colonoscopy, supporting its use in everyday clinical practice.

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.

Evaluation of the impact of linked color imaging for improving the visibility of colonic polyp

Linked color imaging (LCI) is a novel endoscopic system used to increase color contrast. As LCI does not decrease luminal brightness, it may improve the detection of colonic neoplasms. However, the extent to which LCI improves the visibility of colonic polyps has not yet been determined. Between December 2016 and May 2017, patients who received total colonoscopy were consecutively recruited into this retrospective, single-center study. For each polyp identified, images obtained from white light (WL) imaging, blue laser imaging (BLI), and LCI of the same lesion and its surrounding mucosa were evaluated. The color differences (ΔE) between each lesion and its surrounding mucosa in non-magnified images were computed quantitatively using the CIELAB color space, which defines color perception according to colorimetric values, and compared among WL, BLI, LCI, and chromoendoscopy. The ΔE between the vessel and non-vessel areas in magnified images was also assessed. Of the 64 patients who were incorporated into this study, non-magnified and magnified (×80) images from 113 and 95 polyps, respectively, were assessed. The ΔE was intensified by LCI and chromoendoscopy compared with WL and BLI. The ΔE of neoplastic lesions was also intensified by LCI. In magnified images, BLI and LCI significantly increased the ΔE between the vessel and non-vessel areas compared with WL. Luminal brightness, indicated by L*, was not impaired by LCI; however, was reduced by BLI compared with WL and LCI. These results suggest that LCI enhanced the detection of colonic neoplasms without impairing luminal brightness. We propose the routine use of LCI for colonic polyp detection and BLI for magnifying observations of colonic polyps detected by LCI.

Comparison of the detection of colorectal lesions in different endoscopic modalities: A network meta-analysis and systematic review

A colonoscopy is considered to be the standard diagnostic test used to detect early colorectal lesions. Detection rates are expected to improve with optimised visualisation. A systematic review and network meta-analysis was conducted to evaluate detection efficiency in several colonoscopic modalities. Relevant articles were identified in searches of the PubMed, EMBASE and Cochrane Library databases. The modalities, comprising of standard-definition white light (SDWL), high-definition white light (HDWL), narrow-band imaging (NBI), autofluorescence imaging (AFI), PENTAX image enhanced technology (i-SCAN), Fuji Intelligent Color Enhancement (FICE), dye-based chromoendoscopy and novel image enhanced systems, including blue laser imaging (BLI) and linked color imaging (LCI), were compared to identify the most efficient modalities that could be used to detect colorectal lesions. Odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated. As a result, 40 studies fulfilled the inclusion criteria. Overall, in the network meta-analyses, NBI (OR, 1.29; 95% CI, 1.04-1.58), FICE (OR, 1.39; 95% CI, 1.11-1.77), chromoendoscopy (OR, 1.53; 95% CI, 1.22-1.93) and AFI (OR, 1.81; 95% CI, 1.07-2.87) were significantly better compared with SDWL at identifying adenoma in patients, and chromoendoscopy also proved significantly superior to HDWL (OR, 1.30; 95% CI, 1.06-1.60). In pairwise analyses, it was demonstrated that chromoendoscopy was significantly superior to HDWL at detecting the number of polyps (MD, -1.11; 95% CI, -1.46, -0.76) and flat lesions (MD, -0.30; 95% CI, -0.49, -0.10) per subject. Additionally, FICE detected a significantly greater number of subjects with polyps (OR, 0.78; 95% CI, 0.64-0.96) and NBI was significantly better at detecting the number of subjects with flat lesions (OR, 0.77; 95% CI, 0.60-0.99) compared with HDWL. Based on the meta-analysis, NBI, FICE and AFI were significantly better compared with SDWL at detecting patients with adenoma. Additionally, chromoendoscopy was significantly better than SDWL and HDWL at detecting the number of colorectal adenoma, however additional studies are needed to confirm these findings.

Molecular endoscopic imaging in cancer

Cancer is one of the major causes of death in both the USA and Europe. Molecular imaging is a novel field that is revolutionizing cancer management. It is based on the molecular signature of cells in order to study the human body both in normal and diseased conditions. The emergence of molecular imaging has been driven by the difficulties associated with cancer detection, particularly early-stage premalignant lesions which are often unnoticed as a result of minimal or no structural changes. Endoscopic surveillance is the standard method for early-stage cancer detection. In addition to recent major advancements in endoscopic instruments, significant progress has been achieved in the exploration of highly specific molecular probes and the combination of both will permit significant improvement of patient care. In this review, we provide an outline of the current status of endoscopic imaging and focus on recent applications of molecular imaging in gastrointestinal, hepatic and other cancers in the context of detection, targeted therapy and personalized medicine. As new imaging agents have the potential to broadly expand our cancer diagnostic capability, we will also present an overview of the main types of optical molecular probes with their pros and cons. We conclude by discussing the challenges and future prospects of the field.

Adenoma Detection is Increased in the Setting of Melanosis Coli

GOALS

To compare the adenoma detection rate (ADR) during colonoscopy in patients with melanosis coli against matched controls without melanosis.

BACKGROUND

Melanosis coli is a colonoscopic finding in which the colon wall appears darkly pigmented, most often due to extended laxative use, and is considered benign. The pigmentation spares adenomas, which should therefore be more readily detectable in melanosis coli.

STUDY

We identified all patients with melanosis on colonoscopy at our institution over a 5-year period. We matched each patient with 2 controls by age, gender, and endoscopist. We compared the prevalence of adenomas between groups, and used multivariable analysis, adjusting for procedure indication and bowel preparation quality, to determine the independent association of melanosis with adenoma detection.

RESULTS

At least 1 adenoma was detected in 34.7% of melanosis patients and 26.5% of controls [odds ratio (OR)=1.52; 95% confidence interval (CI), 1.04-2.24; P=0.03]. On multivariable analysis, the presence of melanosis remained associated with increased adenoma detection (OR=1.56; 95% CI, 1.05-2.33; P=0.03). Melanosis patients were more likely to have an adenoma ≤5 mm (OR=1.62; 95% CI, 1.04-2.51; P=0.03), but not adenomas 6 to 9 mm or ≥10 mm.

CONCLUSIONS

Melanosis coli is associated with a significant increase in ADR during colonoscopy compared with controls. The increased visibility of adenomas given their contrast with the pigmented background is a likely explanation. Future efforts to identify bowel preparation agents that can induce a similar effect could improve ADRs during colonoscopy.

Flat Serrated Polyps at CT Colonography: Relevance, Appearance, and Optimizing Interpretation

Serrated polyps are a recently recognized family of colonic polyps with subgroups that harbor future malignant potential. In the past, the significance of these lesions to the colorectal cancer carcinogenesis pathway was not recognized nor well understood. It is now known that serrated polyps account for approximately one-fourth of all sporadic colorectal cancers. The sessile serrated polyp (SSP) (also known as a sessile serrated adenoma [SSA]) is the main lesion of interest given its prevalence and subtle presentation. These lesions are often flat-only minimally raised from the colonic surface-and occur in the right colon. These lesions have been a likely common cause of screening failure at colonoscopy, although detection has improved with improved recognition over time. Although detection is difficult with image-based screening, serrated lesions can be detected at CT colonography. The prevalence in CT colonography screening populations mirrors the rates at colonoscopy for similar size categories. CT colonography allows identification of SSPs despite their minimally raised profile owing to the phenomenon of lesional contrast material coating. This contrast material coat aids in lesion detection by highlighting the subtle morphologic changes as well as increasing confidence that a true lesion exists despite a flat morphology. It is important to optimize contrast material coating with specific bowel preparations and other technical parameters. Radiologists should be aware of these technical and interpretation issues. Armed with this knowledge, radiologists should expect excellent results in detection of these subtle but important lesions. ^©RSNA, 2017.

Serrated lesions and serrated polyposis syndrome

The serrated pathway has been shown to be an alternative colorectal carcinogenetic route potentially accounting for up to one third of all CRCs. Serrated lesions, particularly SSPs, have been a focus of research during the past few years. They have well-established histological and molecular characteristics that account for their potential carcinogenetic risk through the accumulation BRAF, KRAS and methylator profile (CpG) mutations. Their endoscopic identification and resection represent a challenge because of their specific characteristics, and the need for an adequate specimen for histological diagnosis. Knowledge of these lesions is key, as is the adoption of established criteria for their endoscopic description and histological diagnosis. SPS is the maximum expression of involvement by serrated lesions, is associated with increased risk for CRC, and requires attentive endoscopic follow-up, as well as family screening. While the exact etiopathogenic mechanism remains unknown, current research will likely provide us with appropriate answers in the not too distant future.

Advances in image enhancement in colonoscopy for detection of adenomas

High-quality colonoscopy is mandatory to prevent adenoma recurrence and colorectal cancer. In the past few years, technical advances have been developed with the purpose of improving adenoma detection rate (ADR), one of the most important validated colonoscopy quality benchmarks. Several techniques or devices are used to optimize visualization: observation techniques; add-on devices; auxiliary imaging devices; colonoscopes with increased field of view; and colonoscopes with an integrated inflatable reusable balloon. Image-enhanced endoscopy (IEE) facilitates the detection and characterization of polyps and especially nonpolypoid colorectal neoplasms. Indigo carmine is the most frequently used dye in colonoscopy as it deposits in depressed areas, improving detection of flat and depressed lesions. Virtual chromoendoscopy has emerged as an effective contrast enhancement technology without the limitation of preparing dyes and applying them through the colonoscope working channel. Narrow-band imaging (NBI) enhances the capillary pattern and surface of the mucosa using optical filters, and second-generation NBI provides a twofold brighter image than the previous system, yielding promising ADR results. Moreover, a second-generation blue laser imaging system, LASEREO, has been reported to improve not only polyp detection rate but also ADR, becoming a promising IEE modality. Herein, we describe technical advances in colonoscopy imaging and their effect on ADR.

Enhanced flat adenoma detection rate with high definition colonoscopy plus i-scan for average-risk colorectal cancer screening

BACKGROUND AND AIM

The usefulness of high definition colonoscopy plus i-scan (HD+i-SCAN) for average-risk colorectal cancer screening has not been fully assessed. The detection rate of adenomas and other measurements such as the number of adenomas per colonoscopy and the flat adenoma detection rate have been recognized as markers of colonoscopy quality. The aim of the present study was to compare the diagnostic performance of an HD+i-SCAN with that of standard resolution white-light colonoscope.

METHODS

This is a retrospective analysis of a prospectively collected screening colonoscopy database. A comparative analysis of the diagnostic yield of an HD+i-SCAN or standard resolution colonoscopy for average-risk colorectal screening was conducted.

RESULTS

During the period of study, 155/163 (95.1%) patients met the inclusion criteria. The mean age was 56.9 years. Sixty of 155 (39%) colonoscopies were performed using a HD+i-SCAN. Adenoma-detection-rates during the withdrawal of the standard resolution versus HD+i-SCAN colonoscopies were 29.5% and 30% (p = n.s.). Adenoma/colonoscopy values for standard resolution versus HD+i-SCAN colonoscopies were 0.46 (SD = 0.9) and 0.72 (SD = 1.3) (p = n.s.). A greater number of flat adenomas were detected in the HD+i-SCAN group (6/60 versus 2/95) (p < .05). Likewise, serrated adenomas/polyps per colonoscopy were also higher in the HD+i-SCAN group.

CONCLUSIONS

A HD+i-SCAN colonoscopy increases the flat adenoma detection rate and serrated adenomas/polyps per colonoscopy compared to a standard colonoscopy in average-risk screening population. HD+i-SCAN is a simple, available procedure that can be helpful, even for experienced providers. The performance of HD+i-SCAN and substantial prevalence of flat lesions in our average-risk screening cohort support its usefulness in improving the efficacy of screening colonoscopies.

[Submucosal chromoendoscopy. A technique that highlights epithelia and differentiates histological components, and renders colon polypectomy easier and safer]

Submucosal chromoendoscopy involves the injection of a solution containing a vital stain, usually indigo carmine, into the intestinal wall submucosal layer. This allows to: Better delimit and characterize the various epithelia present (colonic mucosa, adenoma, hyperplastic polyp, serrated polyp, small bowel mucosa); expose and delimit lesion implantation areas; cooperate in the lifting of resectable lesions; ensure section across the submucosal plane; identify intestinal wall structures; render complex polypectomy feasible; and facilitate the identification of perforations.The present paper offers information on the endoscopic technique for submucosal injection, solution preparation and concentration, and on the potential benefits it may provide for polypectomy or endocopic mucosal resection whether en block or piecemeal. This endoscopic technique simultaneously combines a diagnostic and a therapeutic aspect, since lesion lifting in association with better delimited contours may improve not only accuracy but also endoscopic resection safety and feasibility.

Advances in endoscopic imaging in ulcerative colitis

Modern strategies for the treatment of ulcerative colitis require more accurate tools for gastrointestinal imaging to better assess mucosal disease activity and long-term prognostic clinical outcomes. Recent advances in gastrointestinal luminal endoscopy are radically changing the role of endoscopy in every-day clinical practice and research trials. Advanced endoscopic imaging techniques including high-definition endoscopes, optical magnification endoscopy, and various chromoendoscopy techniques have remarkably improved endoscopic assessment of ulcerative colitis. More recently, optical biopsy techniques with either endocytoscopy or confocal laser endomicroscopy have shown great potential in predicting several histological changes in real time during ongoing endoscopy. Here, we review current applications of advanced endoscopic imaging techniques in ulcerative colitis and present the most promising upcoming headways in this field.

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.

Role of magnifying colonoscopy for diagnosis of colorectal neoplasms: From the perspective of Japanese colonoscopists

Colorectal cancer is the third leading cause of cancer-related death. As the therapeutic strategy for colorectal cancer depends on the clinical stage of the tumor, precise and accurate staging is necessary prior to treatment decision-making. Colonoscopy is an essential tool for detection and prevention of colorectal cancer, as it also allows for removal of adenomatous lesions. Using conventional endoscopy, however, it is sometimes difficult to differentiate neoplastic lesions from non-neoplastic lesions. Several new endoscopic technologies have been developed to provide a more precise diagnosis. Magnifying chromoendoscopy and narrow-band imaging endoscopy with or without magnification are invaluable not only for distinction of colorectal neoplastic lesions from non-neoplastic lesions, but also for the accurate diagnosis of invasion depth in colorectal cancers. Based on an accumulation of a large number of clinical data, the use of magnifying colonoscopy has become inevitable for the prediction of histology and the diagnosis of invasion depth of colorectal neoplasms in Japan.

Overexpressed Claudin-1 Can Be Visualized Endoscopically in Colonic Adenomas In Vivo

BACKGROUND & AIMS

Conventional white-light colonoscopy aims to reduce the incidence and mortality of colorectal cancer (CRC). CRC has been found to arise from missed polypoid and flat precancerous lesions. We aimed to establish proof-of-concept for real-time endoscopic imaging of colonic adenomas using a near-infrared peptide that is specific for claudin-1.

METHODS

We used gene expression profiles to identify claudin-1 as a promising early CRC target, and performed phage display against the extracellular loop of claudin-1 (amino acids 53-80) to identify the peptide RTSPSSR. With a Cy5.5 label, we characterized binding parameters and showed specific binding to human CRC cells. We collected in vivo near-infrared fluorescence images endoscopically in the CPC;Apc mouse, which develops colonic adenomas spontaneously. With immunofluorescence, we validated specific peptide binding to adenomas from the proximal human colon.

RESULTS

We found a 2.5-fold increase in gene expression for claudin-1 in human colonic adenomas compared with normal. We showed specific binding of RTSPSSR to claudin-1 in knockdown and competition studies, and measured an affinity of 42 nmol/L and a time constant of 1.2 minutes to SW620 cells. In the mouse, we found a significantly higher target-to-background ratio for both polypoid and flat adenomas compared with normal by in vivo images. On immunofluorescence, we found significantly greater intensity for human adenomas (mean ± SD, 25.5 ± 14.0) vs normal (mean ± SD, 9.1 ± 6.0) and hyperplastic polyps (mean ± SD, 3.1 ± 3.7; P = 10-5 and 8 × 10-12, respectively), and for sessile serrated adenomas (mean ± SD, 20.1 ± 13.3) vs normal and hyperplastic polyps (P = .02 and 3 × 10-7, respectively).

CONCLUSIONS

Claudin-1 is overexpressed in premalignant colonic lesions, and can be detected endoscopically in vivo with a near-infrared, labeled peptide.

Design and Synthesis of Near-Infrared Peptide for in Vivo Molecular Imaging of HER2

We report the development, characterization, and validation of a peptide specific for the extracellular domain of HER2. This probe chemistry was developed for molecular imaging by using a structural model to select an optimal combination of amino acids that maximize the likelihood for unique hydrophobic and hydrophilic interactions with HER2 domain 3. The sequence KSPNPRF was identified and conjugated with either FITC or Cy5.5 via a GGGSK linker using Fmoc-mediated solid-phase synthesis to demonstrate flexibility for this chemical structure to be labeled with different fluorophores. A scrambled sequence was developed for control by altering the conformationally rigid spacer and moving both hydrophobic and hydrophilic amino acids on the C-terminus. We validated peptide specificity for HER2 in knockdown and competition experiments using human colorectal cancer cells in vitro, and measured a binding affinity of kd = 21 nM and time constant of k = 0.14 min(-1) (7.14 min). We used this peptide with either topical or intravenous administration in a preclinical model of colorectal cancer to demonstrate specific uptake in spontaneous adenomas and to show feasibility for real time in vivo imaging with near-infrared fluorescence. We used this peptide in immunofluorescence studies of human proximal colon specimens to evaluate specificity for sessile serrated and sporadic adenomas. Improved visualization can be used endoscopically to guide tissue biopsy and detect premalignant lesions that would otherwise be missed. Our peptide design for specificity to HER2 is promising for clinical translation in molecular imaging methods for early cancer detection.

Three Colon Adenocarcinomas Arising in a Patient with Serrated Polyposis Syndrome: Case Report and Review of the Literature

Background

Serrated polyposis syndrome (SPS) is a rare entity mainly concerning the 6th decade of life and which is characterized by the presence of multiple large hyperplastic polyps, sessile serrated adenomas, and adenomas within the colon.

Case Report

We describe the case of a SPS patient with 3 synchronous adenocarcinomas. The morphologic features of serrated colorectal lesions, their characteristic molecular alterations, and their role in colorectal cancer development are discussed herein.

Conclusion

Our findings suggest that SPS is a rare condition with an increased risk for colon cancer. Patients suffering from SPS should have regular colonoscopic surveillance, and perhaps those with numerous dysplastic hyperplastic polyps should be treated with colectomy.

Prospective evaluation of the proportion of sessile serrated adenoma/polyps in endoscopically diagnosed colorectal polyps with hyperplastic features

BACKGROUND AND STUDY AIMS

Sessile serrated adenoma/polyps (SSA/Ps) are considered precursors of colorectal cancers with microsatellite instability. However, it is still difficult to differentiate SSA/Ps from hyperplastic polyps endoscopically; therefore, the prevalence of SSA/Ps remains uncertain in clinical practice. This study aimed to clarify the proportion of SSA/Ps in endoscopically diagnosed colorectal polyps with hyperplastic features (E-HPs).

PATIENTS AND METHODS

Patients aged ≥ 40 years undergoing colonoscopy for standard clinical indications at our center were prospectively enrolled between June 2013 and May 2014. During colonoscopy, 0.05 % indigo carmine dye was sprayed throughout the colorectum to highlight lesions. All detected lesions were diagnosed by high definition magnifying narrow-band imaging and were resected endoscopically or surgically, apart from rectosigmoid E-HPs ≤ 5 mm. The number of rectosigmoid E-HPs ≤ 5 mm was recorded, and some were resected for use as tissue samples.

RESULTS

A total of 343 patients (male: 42.9 %; mean age: 61.5 years) were included. Among 3838 E-HPs (distal: 96.4 %) detected in 294 patients, 792 were resected and analyzed. All of 21 SSA/Ps identified in 17 patients were included in E-HPs, and the overall proportion of SSA/Ps in E-HPs was 2.7 %. However, this proportion increased with the size of E-HPs (≤ 5 mm: 0.7 %; 6 - 9 mm: 29.0 %; ≥ 10 mm: 70 %) and was higher in the proximal colon than in the distal colorectum (10.9 % vs. 0.9 %). In addition, no SSA/P was found in the rectum, and no SSA/P had cytological dysplasia.

CONCLUSIONS

The overall proportion of SSA/Ps in E-HPs was 2.7 %, although this proportion was higher in the proximal colon and increased with the size of E-HPs. SSA/Ps were common in routine colonoscopy, with a prevalence of at least 5.0 %.

STUDY REGISTRATION

UMIN000010832.

Chromocolonoscopy

Chromoendoscopy techniques improve the visualization of mucosal structures. This article reviews and summarizes key studies addressing the impact of chromoendoscopy on colonic neoplasia detection and differentiation of neoplastic from non-neoplastic polyps in average and high-risk populations, including patients with colonic inflammatory bowel disease (IBD). In this context, there are convincing data that chromoendoscopy differentiates neoplastic from non-neoplastic polyps in average-risk populations with high accuracy. Moreover, dye-based chromoendoscopy improves neoplasia detection in colonic IBD surveillance.

Adenoma detection at colonoscopy by polypectomy in withdrawal only versus both insertion and withdrawal: a randomized controlled trial

Colonic configuration during insertion phase (IP) and withdrawal phase (WP) is different and some polyps seen during IP are difficult to find during WP and vice versa. To determine if polypectomy performed during both IP and WP of colonoscopy (study arm) increases adenoma detection rate (ADR) compared to WP only (control arm). In this prospective randomized controlled trial, adults undergoing out-patient colonoscopy were enrolled. The primary outcome was mean number of adenomas detected per patient. Secondary outcomes were ADR, defined as the proportion of colonoscopies with at least one adenoma, polyp detection rates (PDR), number of patients classified as high-risk group (presence of ≥3 adenomas of any size, any adenoma ≥1 cm in size, or adenoma with villous component, or high grade dysplasia), procedural times, patients discomfort, and ease of procedure. Among 772 patients enrolled, 610 were included (329 in study arm and 281 in control arm). In both arms, mean number of adenomas detected per patient were similar, 0.78 ± 1.4 vs. 0.74 ± 1.5, P = 0.75. Also, ADR (39.2 vs. 38.1 %, P = 0.77) and PDR (57.1 and 54.1 %, P = 0.45) were similar. Mean insertion time was significantly higher in study arm (10.2 ± 5.8 vs. 9.3 ± 5.6 min, p = 0.046). Proportion of patients identified as high-risk group were significantly higher in study arm (18.8 vs. 11.7 %, P = 0.016).

CONCLUSIONS

Polypectomy performed during both IP and WP compared to the WP only, did not improve ADR or mean number of adenomas detected per patient.

TRIAL REGISTRATION

Clinicaltrials.gov, #NCT01025960.

Prevalence of serrated polyposis syndrome and its association with synchronous advanced adenoma and lifestyle

We assessed the clinicopathological characteristics of patients with serrated polyposis syndrome (SPS) and the incidence of advanced adenoma/colorectal cancer (CRC). We prospectively enrolled 249 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital over a 6-month period. All the polyps were diagnosed using magnification colonoscopy and resection/biopsy. The enrolled patients were divided into two groups, i) those with ≥5 histologically diagnosed hyperplastic polyps (HPs) proximal to the sigmoid colon, with at least 2 polyps >10 mm in diameter and ii) those with ≥20 HPs distributed throughout the colon. The clinical characteristics of the two groups were compared, including lifestyle, family history of CRC and colonoscopic findings. HPs were identified in 228 patients, of whom 21 (8.4%) had SPS. All 21 patients had ≥20 HPs distributed throughout the colon, with none having >2 HPs ≥1 cm in diameter in the right colon. Synchronous advanced adenoma/CRC was diagnosed in 76/249 (30.5%) patients. The prevalence of advanced adenoma/CRC was higher among patients with compared to those without SPS (P=0.075). SPS was also associated with older age and higher body mass index (BMI). Our results suggested that older age and higher BMI are independent risk factors for SPS. Advanced adenoma/CRC tended to occur more frequently among patients with compared to those without SPS, although the difference was not statistically significant.

Narrow band imaging vs. high definition colonoscopy for detection of colorectal adenomas in patients with positive faecal occult blood test: a randomised trial

BACKGROUND

The impact of narrow band imaging in improving the adenoma detection rate in a screening scenario is still unclear.

AIM

To evaluate whether narrow band imaging compared with high definition white light colonoscopy can enhance the adenoma detection rate during screening colonoscopy.

METHODS

Consecutive patients presenting for screening colonoscopy were included into this study and were randomly assigned to the narrow band imaging group (Group 1) or standard colonoscopy group (Group 2). Primary end point was the adenoma detection rate and secondary aim was the detection rate of advanced adenomas.

RESULTS

Overall, 117 patients were allocated to Group 1 and 120 to Group 2. Both the adenoma detection rate and the detection rate of advanced adenomas were not significantly different between the two groups (respectively, 52.1% vs. 55%, RR=0.95, 95% CI 0.75-1.20; 32.5% vs. 44.2%, RR=0.74, 95% CI 0.53-1.02). No significant difference between the proportions of polypoid and flat adenomas was found. Male gender, no prior history of screening, and endoscopist's adenoma detection rate were independent predictive factors of higher advanced adenoma detection rate.

CONCLUSIONS

In a screening scenario, narrow band imaging did not improve the adenoma nor advanced adenoma detection rates compared to high definition white light colonoscopy.

Endoscopists with low adenoma detection rates benefit from high-definition endoscopy

BACKGROUND

An endoscopists adenoma detection rate (ADR) of less than 20 % correlates with high risk for occurrence of interval cancer. The impact of high-definition (HD) imaging on the ADR is discussed controversially. We aimed to investigate whether detection rates of individual endoscopists increase within 1 year before and 1 year after the switch from standard to HD endoscopy.

METHODS

This cohort study analyzed 6,330 screening colonoscopies (2,968 with standard and 3,362 with HD) performed by 42 endoscopists between November 2007 and March 2013 within a nationwide quality assurance program for screening colonoscopy.

RESULTS

The ADR of endoscopists with a low ADR (<20 %) increased significantly higher (from 11.8 to 18.1 %, p = 0.003) than of those with a high ADR (≥ 20 %) (from 28.6 to 30.7 %, p = 0.439) after switch from standard to HD colonoscopes (p = 0.0076). The proportion of endoscopists with an ADR < 20 % decreased from 45 to 42.9 % (p = 0.593). There was no significant increase in age- and sex-adjusted detection rates of adenomas (20.2 vs 23.7 %; p = 0.089), advanced adenomas (4.7 vs 5.5 %; p = 0.479), flat adenomas (2.7 vs 3.1 %; p = 0.515), polyps (38.8 vs 41.5 %; p = 0.305), proximal polyps (18.5 vs 20 %; p = 0.469) and hyperplastic polyps (15 vs 17.2 %; p = 0.243) of endoscopists after switch to HD colonoscopes. There was no difference in detection rates of flat polyps (5.5 vs 5.5 %; p = 0.987).

CONCLUSIONS

The use of HD scopes is associated with marginal improvement in adenoma detection rates limited to those endoscopists with low adenoma detection rates prior to its introduction.

Image-enhanced endoscopy is critical in the surveillance of patients with colonic IBD

Cancer risk in patients with inflammatory bowel disease (IBD) involving the colon is high and increases with time. The quality and efficacy of colonoscopic surveillance is variable. Chromoendoscopy with targeted biopsies is superior to standard white light endoscopy with random biopsies. Although commonly practiced, the technique of random colonic biopsies has poor yield for dysplasia and has little clinical consequence. Studies have shown a limited role for electronic-based image-enhanced endoscopy, including narrow band imaging, in detecting IBD dysplasia. Efforts should focus on the dissemination of the technique of chromoendoscopy in routine clinical practice through training and quality metrics.

State of the art in advanced endoscopic imaging for the detection and evaluation of dysplasia and early cancer of the gastrointestinal tract

Ideally, endoscopists should be able to detect, characterize, and confirm the nature of a lesion at the bedside, minimizing uncertainties and targeting biopsies and resections only where necessary. However, under conventional white-light inspection – at present, the sole established technique available to most of humanity – premalignant conditions and early cancers can frequently escape detection. In recent years, a range of innovative techniques have entered the endoscopic arena due to their ability to enhance the contrast of diseased tissue regions beyond what is inherently possible with standard white-light endoscopy equipment. The aim of this review is to provide an overview of the state-of-the-art advanced endoscopic imaging techniques available for clinical use that are impacting the way precancerous and neoplastic lesions of the gastrointestinal tract are currently detected and characterized at endoscopy. The basic instrumentation and the physics behind each method, followed by the most influential clinical experience, are described. High-definition endoscopy, with or without optical magnification, has contributed to higher detection rates compared with white-light endoscopy alone and has now replaced ordinary equipment in daily practice. Contrast-enhancement techniques, whether dye-based or computed, have been combined with white-light endoscopy to further improve its accuracy, but histology is still required to clarify the diagnosis. Optical microscopy techniques such as confocal laser endomicroscopy and endocytoscopy enable in vivo histology during endoscopy; however, although of invaluable assistance for tissue characterization, they have not yet made transition between research and clinical use. It is still unknown which approach or combination of techniques offers the best potential. The optimal method will entail the ability to survey wide areas of tissue in concert with the ability to obtain the degree of detailed information provided by microscopic techniques. In this respect, the challenging combination of autofluorescence imaging and confocal endomicroscopy seems promising, and further research is awaited.

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

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

Image-enhanced, chromo, and cap-assisted colonoscopy for improving adenoma/neoplasia detection rate: a systematic review and meta-analysis

OBJECTIVE

The effectiveness of narrow band imaging (NBI), chromoendoscopy (CE), and cap-assisted colonoscopy (CAC) on adenoma detection rate (ADR) has been investigated in previous meta-analyses; however, there have been no meta-analyses of autofluorescence imaging (AFI) or flexible spectral imaging color enhancement (FICE) or i-scan. The aim of this study was to determine whether AFI and FICE/i-scan was more effective than standard/high-definition white light endoscopy to improve ADR and to update previous meta-analyses of NBI, CE, and CAC.

DESIGN

A systematic review and meta-analysis was conducted. Four investigators selected appropriate randomized controlled trials (RCT) using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline. All RCTs in which colonoscopy were performed with AFI, FICE, i-scan, NBI, CE, and CAC were included. The risk ratios (RRs) calculated from adenoma/neoplasia detection rate were used as the main outcome measurement.

RESULTS

A total of 42 studies were included in the analysis. Pooled estimates of RR (95%confidence interval [CI]) using AFI, FICE/i-scan, NBI, CE, and CAC were 1.04 (95% CI: 0.87-1.24) (I² = 0%) (fixed effects model [FEM]); 1.09 (95% CI: 0.97-1.23) (I² = 5%) (FEM); 1.03 (95% CI: 0.96-1.11) (I² = 0%) (FEM); 1.36 (95% CI: 1.23-1.51) (I² = 16%) (FEM); and 1.03 (95% CI: 0.93-1.14) (I² = 48%) (random effects model [REM]), respectively. The pooled estimate of RR (95%CI) using indigo carmine in non-ulcerative colitis (UC) patients and methylene blue in UC patients was 1.33 (95% CI: 1.20-1.48) (I² = 14%) (FEM) and 2.39 (95% CI: 1.18-4.84) (I² = 0%) (FEM), respectively.

CONCLUSION

In contrast to AFI, FICE/i-scan, NBI, and CAC, only CE improves ADR. CE with methylene blue, though not NBI, is effective for surveillance of neoplasia in chronic UC patients.

Chromocolonoscopy

Chromocolonoscopy is the process of endoscopically examining the colon mucosa after it has been stained with dye. The goal is to allow the endoscopist to identify subtle features in the mucosa, such as morphologically flat polyps or crypt patterns. Studies examining the efficacy of chromocolonoscopy to identify adenomas missed by conventional colonoscopy have shown that although chromocolonoscopy increases polyp yield, most additional lesions are small in size. Staining can also help in differentiating neoplastic from non-neoplastic polyps. Perhaps the most useful aspect of chromocolonoscopy is increasing the yield for dysplasia in patients undergoing colonoscopy for inflammatory bowel disease surveillance.

Near infrared optical visualization of epidermal growth factor receptors levels in COLO205 colorectal cell line, orthotopic tumor in mice and human biopsies

In this study, we present the applicability of imaging epidermal growth factor (EGF) receptor levels in preclinical models of COLO205 carcinoma cells in vitro, mice with orthotopic tumors and ex vivo colorectal tumor biopsies, using EGF-labeled with IRDye800CW (EGF-NIR). The near infrared (NIR) bio-imaging of COLO205 cultures indicated specific and selective binding, reflecting EGF receptors levels. In vivo imaging of tumors in mice showed that the highest signal/background ratio between tumor and adjacent tissue was achieved 48 hours post-injection. Dissected colorectal cancer tissues from different patients demonstrated ex vivo specific imaging using the NIR bio-imaging platform of the heterogeneous distributed EGF receptors. Moreover, in the adjacent gastrointestinal tissue of the same patients, which by Western blotting was demonstrated as EGF receptor negative, no labeling with EGF-NIR probe was detected. Present results support the concept of tumor imaging by measuring EGF receptor levels using EGF-NIR probe. This platform is advantageous for EGF receptor bio-imaging of the NCI-60 recommended panel of tumor cell lines including 6-9 colorectal cell lines, since it avoids radioactive probes and is appropriate for use in the clinical setting using NIR technologies in a real-time manner.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Adenoma detection in patients undergoing a comprehensive colonoscopy screening

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

Indications, stains and techniques in chromoendoscopy

Early detection of malignancies within the gastrointestinal tract is essential to improve the prognosis and outcome of affected patients. However, conventional white light endoscopy has a miss rate of up to 25% for gastrointestinal pathology, specifically in the context of small and flat lesions within the colon. Chromoendoscopy and other advanced imaging techniques aim at facilitating the visualization and detection of neoplastic lesions and have been applied throughout the gastrointestinal tract. Chromoendoscopy, particularly in combination with magnifying endoscopy has significantly improved means to detect neoplastic lesions in the gastrointestinal mucosa, particularly in ulcerative colitis and Crohn's colitis. In addition, chromoendoscopy is beneficial in the upper gastrointestinal tract, especially when evaluating Barrett's oesophagus (BO) for the presence of dysplasia. Furthermore, it also improves characterization, differentiation and diagnosis of endoscopically detected suspicious lesions, and helps to delineate the extent of neoplastic lesions that may be amenable to endoscopic resection. This review discusses the dyes, indications and advanced endoscopic imaging methods used in various chromoendoscopic techniques, and presents a critical overview of the existing evidence supporting their use in current practice with a particular emphasis on the role in inflammatory bowel disease and BO.

Comparison of high definition with standard white light endoscopy for detection of dysplastic lesions during surveillance colonoscopy in patients with colonic inflammatory bowel disease

BACKGROUND

Dysplasia in colonic inflammatory bowel disease (IBD) is often multifocal and flat. High-definition (HD) colonoscopy improves adenoma detection rates by improving the ability to detect subtle mucosal changes. The utility of HD colonoscopy in dysplasia detection in patients with IBD has not been reported so far. We aimed to compare the yield of dysplastic lesions detected by standard definition (SD) white light endoscopy with HD endoscopy.

METHODS

A retrospective cohort study of patients with long-standing (>7 years) colonic IBD undergoing surveillance colonoscopy at Nottingham University Hospital was studied between September 2008 and February 2010. Details of diagnosis, duration of disease, and outcomes of the colonoscopy were collected from the endoscopy database, electronic patient records, and patient notes.

RESULTS

There were 160 colonoscopies (101 ulcerative colitis [UC] and 59 Crohn's disease [CD]) in the SD group and 209 colonoscopies (147 UC and 62 CD) in the HD group. The groups were well matched for all demographic variables. Thirty-two dysplastic lesions (27 on targeted biopsy) were detected in 24 patients in the HD group and 11 dysplastic lesions (six on targeted biopsy) were detected in eight patients the SD group. The adjusted prevalence ratio of detecting any dysplastic lesion and dysplastic lesion on targeted biopsy was 2.21 (95% confidence interval [CI] 1.09-4.45) and 2.99 (95% CI 1.16-7.79), respectively, for HD colonoscopy.

CONCLUSIONS

HD colonoscopy improves targeted detection of dysplastic lesions during surveillance colonoscopy of patients with colonic IBD in routine clinical practice. Randomized controlled studies are required to confirm these findings.

Transparent cap colonoscopy versus standard colonoscopy to improve caecal intubation

BACKGROUND

Colonoscopy is considered the gold-standard investigation for screening and diagnosis of colorectal cancer. It is also becoming increasingly desirable for assessment, management, diagnosis and follow-up of other colorectal diseases, such as inflammatory bowel diseases and acute diverticulitis. Hence, due to the increasing demand for colonoscopy, devices to advance examination techniques are highly sought-after and the colonoscope with the transparent cap could be one of these.

OBJECTIVES

To identify and review all relevant data in order to determine whether colonoscopy with a transparent cap is a more effective diagnostic tool than colonoscopy.

SEARCH METHODS

We searched the MEDLINE, EMBASE and CINAHL databases, and the Cochrane Central Register of Controlled Trials for all randomised controlled trials (RCTs) comparing the use of colonoscopy with a transparent cap with standard colonoscopy.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials which compared the use of colonoscopy with a transparent cap with standard colonoscopy.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, interventions used and outcomes measured was extracted from each study. Data was entered into the Cochrane Review Manager software (RevMan 5.0, 2008) and analysed using Cochrane MetaView.

MAIN RESULTS

In the present meta-analysis, we considered 14 randomised controlled trials so far published. The findings of our work indicate that colonoscopy with transparent cap has a faster caecal intubation time when compared with standard colonoscopy. Reviewing studies individually would also seem to favour colonoscopy with transparent cap for polyp detection rate and pain during procedure but due to lack of comparable data meta-analysis was not feasible.

AUTHORS' CONCLUSIONS

This review suggests that a transparent cap on the end of the colonoscope may give a marginally faster caecal intubation time compared with standard colonoscopy. It also suggests that there is a better polyp detection rate and less pain with the cap. However, the authors feel that further randomised controlled trials in this area would provide more clinically significant information on this adjunct to colonoscopy.

A randomized, controlled trial of narrow-band imaging vs high-definition white light for adenoma detection in patients at high risk of adenomas

AIM

The study aimed to investigate whether narrow-band imaging (NBI) can enhance adenoma detection in patients at high risk for adenomas compared with high-definition white-light endoscopy (WLE). High risk was defined as three or more adenomas at last colonoscopy, history of colorectal cancer and positive faecal occult blood test.

METHOD

Two hundred and fourteen patients were randomized 1:1 to examination with NBI or WLE. The primary outcome measure was the proportion of patients with at least one adenoma detected. Secondary outcomes included total adenomas and polyps, flat adenomas, nonadenomatous polyps, advanced adenomas and patients with three or five or more adenomas. A post hoc analysis to examine the effect of endoscopist and bowel preparation was performed.

RESULTS

There was no significant difference in the proportion of patients with at least one adenoma: NBI 73%vs WLE 66%, odds ratio 1.40 (95% CI 0.78-2.52), P = 0.26. There was no significant difference for any secondary outcome measure except for the number of flat adenomas which was significantly greater with NBI [comparison ratio 2.66 (95% CI 1.52-4.63), P = 0.001]. Post hoc analysis indicated that one of three endoscopists performed significantly better for adenoma detection with NBI than WLE [comparison ratio 1.92 (95% CI 1.07-3.44), P = 0.03]. Good bowel preparation was associated with significantly improved adenoma detection with NBI [comparison ratio 1.55 (95% CI 1.01-2.22), P = 0.04] but not with fair preparation.

CONCLUSION

Overall NBI did not improve detection compared with WLE in a group of patients at high risk for colorectal adenomas, but specific subgroups might benefit.

The efficacy of cap-assisted colonoscopy in polyp detection and cecal intubation: a meta-analysis of randomized controlled trials

OBJECTIVES

The role of cap-assisted colonoscopy (CAC) in polyp detection and cecal intubation is unclear. We conducted a meta-analysis to compare the efficacy of CAC vs. standard colonoscopy (SC).

METHODS

Publications in English and non-English literatures (OVID, MEDLINE, and EMBASE) and abstracts in major international conferences were searched for controlled trials comparing CAC and SC. Outcome measures included the proportion of patients with polyps or adenomas detected, cecal intubation rate, cecal intubation time, and total colonoscopy time. The statistical heterogeneity of trials was examined and the effects were pooled by random-effects model. The risk of bias was evaluated by the assessment tool from the Cochrane Handbook. Subgroup analyses were performed for possible clinical and methodological heterogeneities.

RESULTS

From 2,358 citations, 16 randomized controlled clinical trials were included consisting of 8,991 subjects (CAC: 4,501; SC: 4,490). Mean age of subjects was 61.0 years old and 60% were males. CAC detected a higher proportion of patients with polyp(s) (relative risk (RR): 1.08; 95% confidence interval (CI): 1.00-1.17) and reduced the cecal intubation time (mean difference: -0.64 min; 95% CI: -1.19 to -0.10). Cecal intubation rate (RR: 1.00; 95% CI: 0.99-1.02) and total colonoscopy time (mean difference: -0.97 min; 95% CI: -2.33 to 0.40) were comparable between the two groups. In subgroup analyses, a short cap (≤4 mm) was associated with improved polyp detection, whereas a long cap (≥7 mm) was associated with a shorter cecal intubation time.

CONCLUSIONS

CAC demonstrated marginal benefit over SC for polyp detection and shortened the cecal intubation time.

Back-to-back comparison of auto-fluorescence imaging (AFI) versus high resolution white light colonoscopy for adenoma detection

Background

Some patients under close colonoscopic surveillance still develop colorectal cancer, thus suggesting the overlook of colorectal adenoma by endoscopists. AFI detects colorectal adenoma as a clear magenta, therefore the efficacy of AFI is expected to improve the detection ability of colorectal adenoma. The aim of this study is to determine the efficacy of AFI in detecting colorectal adenoma.

Methods

This study enrolled 88 patients who underwent colonoscopy at Asahikawa Medical University and Kushiro Medical Association Hospital. A randomly selected colonoscopist first observed the sigmoid colon and rectum with conventional high resolution endosopy (HRE). Then the colonoscopist changed the mode to AFI and handed to the scope to another colonoscopist who knew no information about the HRE. Then the second colonoscopist observed the sigmoid colon and rectum. Each colonoscopist separately recorded the findings. The detection rate, miss rate and procedural time were assessed in prospective manner.

Results

The detection rate of flat and depressed adenoma, but not elevated adenoma, by AFI is significantly higher than that by HRE. In less-experienced endoscopists, AFI dramatically increased the detection rate (30.3%) and reduced miss rate (0%) of colorectal adenoma in comparison to those of HRE (7.7%, 50.0%), but not for experienced endoscopists. The procedural time of HRE was significantly shorter than that of AFI.

Conclusions

AFI increased the detection rate and reduced the miss rate of flat and depressed adenomas. These advantages of AFI were limited to less-experienced endoscopists because experienced endoscopists exhibited a substantially high detection rate for colorectal adenoma with HRE.

Narrow band imaging for detection of dysplasia in colitis: a randomized controlled trial

OBJECTIVES

In ulcerative colitis surveillance, chromoendoscopy improves dysplasia detection 3 – 5-fold compared with white light endoscopy (WLE). The aim of this study was to investigate whether narrow band imaging (NBI) can improve dysplasia detection compared with WLE.

METHODS

This was a randomized, parallel-group trial. A total of 220 patients were needed to be recruited to detect a threefold increase in dysplasia detection. In all, 112 patients with long-standing ulcerative colitis were randomized to colonoscopic extubation with NBI (56) or WLE (56) (1:1 ratio) at two tertiary endoscopy units in the United Kingdom. Targeted biopsies of suspicious areas and quadrantic random biopsies every 10 cm were taken in both groups. The primary outcome measure was the proportion of patients with at least one area of dysplasia detected. In a prespecified mid-point analysis, the criteria for trial discontinuation were met and the trial was stopped and analyzed at this point.

RESULTS

There was no difference in the primary outcome between the two groups, with 5 patients having at least one dysplastic lesion in each group (odds ratio (OR) 1.00, 95 % confidence interval (95 % CI) 0.27 – 3.67, P = 1.00). This remained unchanged when adjusted for other variables (OR 0.69, 95 % CI 0.16 – 2.96, P = 0.62). Overall, dysplasia detection was 9 % in each arm. Yield of dysplasia from random nontargeted biopsies was 1 / 2,707 (0.04 % ).

CONCLUSIONS

Overall, in this multicenter parallel-group trial, there was no difference in dysplasia detection when using NBI compared with high-definition WLE colonoscopy. Random background biopsies were ineffective in detecting dysplasia.

Serrated polyposis syndrome: Molecular, pathological and clinical aspects

Hyperplastic polyps have traditionally been considered not to have malignant potential. New pathological classification of serrated polyps and recent discoveries about the serrated pathway of carcinogenesis have revolutionized the concepts and revitalized the research in this area. Until recently, it has been thought that most colorectal cancers arise from conventional adenomas via the traditional tumor suppressor pathway initiated by a mutation of the APC gene, but it has been found that this pathway accounts for only approximately 70%-80% of colorectal cancer (CRC) cases. The majority of the remaining colorectal cancer cases follow an alternative pathway leading to CpG island methylator phenotype carcinoma with BRAF mutation and with or without microsatellite instability. The mechanism of carcinomas arising from this alternative pathway seems to begin with an activating mutation of the BRAF oncogene. Serrated polyposis syndrome is a relatively rare condition characterized by multiple and/or large serrated polyps of the colon. Clinical characteristics, etiology and relationship of serrated polyposis syndrome to CRC have not been clarified yet. Patients with this syndrome show a high risk of CRC and both sporadic and hereditary cases have been described. Clinical criteria have been used for diagnosis and frequent colonoscopy surveillance should be performed in order to prevent colorectal cancer. In this review, we try to gather new insights into the molecular pathogenesis of serrated polyps in order to understand their possible clinical implications and to make an approach to the management of this syndrome.

Trimodal endoscopic imaging for the detection and differentiation of colorectal adenomas: a prospective single-centre clinical evaluation

PURPOSE

The purpose of this study is to evaluate an endoscopic trimodal imaging (ETMI) system (high resolution, autofluorescence, and NBI) in the detection and differentiation of colorectal adenomas.

METHODS

A prospective randomised trial of tandem colonoscopies was carried out using the Olympus XCF-FH260AZI system. Each colonic segment was examined twice for lesions, once with HRE and once with AFI, in random order per patient. All detected lesions were assessed with NBI for pit pattern and with AFI for colour. All lesions were removed and sent for histology. Any lesion identified on the second examination was considered as missed by the first examination. Outcome measures are adenoma miss rates of AFI and HRE, and diagnostic accuracy of NBI and AFI for differentiating neoplastic from non-neoplastic lesions.

RESULTS

Ninety-four patients underwent colonoscopy with ETMI (47 in each group). Among 47 patients examined with AFI first, 31 adenomas in 15 patients were detected initially [detection rate 0.66 (0.52-0.75)]. Subsequent HRE inspection identified six additional adenomas. Among 47 patients examined with HRE first, 29 adenomas in 14 patients were detected initially [detection rate 0.62 (0.53-0.79)]. Successive AFI yielded seven additional adenomas. Adenoma miss rates of AFI and HRE were 14% and 16.2%, respectively (p = 0.29). Accuracy of AFI alone for differentiation was lower than NBI (63% vs. 80%, p < 0.001). Combined use of AFI and NBI achieved improved accuracy for differentiation (84%), showing a trend for superiority compared with NBI alone (p = 0.064).

CONCLUSIONS

AFI did not significantly reduce the adenoma miss rate compared with HRE. AFI alone had a disappointing accuracy for adenoma differentiation, which could be improved by combination of AFI and NBI.

Serrated polyposis syndrome and the role of serrated polyps in colorectal cancer development

SUMMARY Serrated polyposis syndrome is characterized by the presence of multiple colorectal serrated polyps and is associated with an increased colorectal cancer risk. The mixture of distinct precursor lesion types and malignancies in serrated polyposis syndrome provides a unique model to study the recently proposed serrated neoplasia pathway. This pathway involves the progression of serrated polyps, that is, hyperplastic polyps, sessile serrated adenoma/polyps and/or traditional serrated adenomas, to colorectal cancer. The early genetic events of this route, as currently identified, are BRAF or KRAS mutations and an enhanced CPG island methylation status of multiple genes. There is evidence to suggest that a proportion of sporadic colorectal cancers originate from serrated polyps, which encompass molecular sequences of events such as hypermethylation of different genes and BRAF mutations. This review discusses the characteristics and clinical relevance of serrated polyps and provides an overview of the clinical aspects and treatment of serrated polyposis syndrome.

A morphologic analysis of sessile serrated polyps observed during routine colonoscopy (with video)

BACKGROUND

Proximal colorectal cancer may arise from sessile serrated polyps (SSPs), which are often inconspicuous during colonoscopy. The gross morphologic characteristics of SSPs have not been systematically described, and this omission may contribute to colonoscopists overlooking them.

OBJECTIVES

To analyze the gross morphologic characteristics of SSPs detected during routine colonoscopy.

DESIGN

Retrospective analysis of high-resolution endoscopic video clips depicting SSPs in situ.

SETTING

Outpatient gastroenterology practice.

PATIENTS

A total of 124 subjects undergoing surveillance or screening colonoscopy after split-dose bowel preparation.

INTERVENTIONS

Analysis of 158 SSPs performed by using validated descriptors.

MAIN OUTCOME MEASUREMENTS

The prevalence of morphologic characteristics related to polyp shape, color, and texture.

RESULTS

A total of 158 SSPs were studied. For 7 visual descriptors, a κ coefficient of ≥ 0.7 was achieved, indicating good to excellent intraobserver agreement. The most prevalent visual descriptors were the presence of a mucous cap (63.9%), rim of debris or bubbles (51.9%), alteration of the contour of a fold (37.3%), and interruption of the underlying mucosal vascular pattern (32.3%). The most common "sentinel signs" were the presence of a mucous cap and alteration of the contour of a mucosal fold (each 24.6%), rim of debris or bubbles (21.7%), and a dome-shaped protuberance (20.3%). When comparing SSPs with adenomatous polyps, the frequencies of 5 of 7 morphologic characteristics and the distribution of sentinel signs differed (P < .01).

LIMITATIONS

Single-site, retrospective analysis.

CONCLUSIONS

SSPs exhibit distinct, variable morphologic characteristics. Many do not display classic features such as a mucous cap. Enhanced appreciation of these morphologic characteristics may improve SSP detection and thereby colorectal cancer prevention.