Detecting diminutive colorectal lesions at colonoscopy: a randomised controlled trial of pan-colonic versus targeted chromoscopy

Clinical evaluation of endoscopic trimodal imaging for the detection and differentiation of colonic polyps

BACKGROUND & AIMS

Endoscopic trimodal imaging (ETMI) incorporates high-resolution endoscopy (HRE) and autofluorescence imaging (AFI) for adenoma detection, and narrow-band imaging (NBI) for differentiation of adenomas from nonneoplastic polyps. The aim of this study was to compare AFI with HRE for adenoma detection and to assess the diagnostic accuracy of NBI for differentiation of polyps. This was a randomized trial of tandem colonoscopies. The study was performed at the Academic Medical Center in Amsterdam.

METHODS

One hundred patients underwent colonoscopy with ETMI. Each colonic segment was examined twice for polyps, once with HRE and once with AFI, in random order per patient. All detected polyps were assessed with NBI for pit pattern and with AFI for color, and subsequently removed. Histopathology served as the gold standard for diagnosis. The main outcome measures of this study were adenoma miss-rates of AFI and HRE, and diagnostic accuracy of NBI and AFI for differentiating adenomas from nonneoplastic polyps.

RESULTS

Among 50 patients examined with AFI first, 32 adenomas were detected initially. Subsequent inspection with HRE identified 8 additional adenomas. Among 50 patients examined with HRE first, 35 adenomas were detected initially. Successive AFI yielded 14 additional adenomas. The adenoma miss-rates of AFI and HRE therefore were 20% and 29%, respectively (P = .351). The sensitivity, specificity, and overall accuracy of NBI for differentiation were 90%, 70%, and 79%, respectively; corresponding figures for AFI were 99%, 35%, and 63%, respectively.

CONCLUSIONS

The overall adenoma miss-rate was 25%; AFI did not significantly reduce the adenoma miss-rate compared with HRE. Both NBI and AFI had a disappointing diagnostic accuracy for polyp differentiation, although AFI had a high sensitivity.

Narrow-band imaging magnification predicts the histology and invasion depth of colorectal tumors

BACKGROUND

There are several reports concerning the differential diagnosis of non-neoplastic and neoplastic colorectal lesions by narrow-band imaging (NBI). However, there are only a few NBI articles that assessed invasion depth.

OBJECTIVE

To determine the clinical usefulness of NBI magnification for evaluating microvessel architecture in relation to pit appearances and in the qualitative diagnosis of colorectal tumors.

DESIGN

A retrospective study.

SETTING

Department of Endoscopy, Hiroshima University, Hiroshima, Japan.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 289 colorectal lesions were analyzed: 12 hyperplasias (HP), 165 tubular adenomas (TA), 65 carcinomas with intramucosal to scanty submucosal invasion (M-SM-s), and 47 carcinomas with massive submucosal invasion (SM-m). Lesions were observed by NBI magnifying endoscopy and were classified according to microvessel features and pit appearances: type A, type B, and type C. Type C was divided into 3 subtypes (C1, C2, and C3), according to the detailed NBI magnifying findings of pit visibility, vessel diameter, irregularity, and distribution. These were compared with histologic findings.

RESULTS

Histologic findings of HP and TA were seen in 80.0% and 20.0%, respectively, of type A lesions. TA and M-SM-s were found in 79.7% and 20.3%, respectively, of type B lesions. TA, M-SM-s, and SM-m were found in 21.6%, 29.9%, and 48.5, respectively, of type C lesions. HPs were observed significantly more often than TAs in type A lesions, TAs were observed significantly more often than carcinomas in type B lesions, carcinomas were observed significantly more often than TAs in type C (P < .01). TA, M-SM-s, and SM-m were found in 46.7%, 42.2%, and 11.1% of type C1 lesions, respectively. M-SM-s and SM-m were found in 45.5% and 54.5%, respectively, of type C2 lesions. SM-m was found in 100% of type C3 lesions. TAs and M-SM-s were observed significantly more often than SM-m in type C1 lesions, and SM-m were observed significantly more often than TAs and M-SM-s in type C3 lesions (P < .01).

CONCLUSIONS

NBI magnification findings of colorectal lesions were associated with histologic grade and invasion depth.

A comparison of conventional endoscopy, chromoendoscopy, and the optimal-band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps

BACKGROUND

The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye.

OBJECTIVE

To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy.

DESIGN

An open prospective study.

SETTING

Jichi Medical University, Japan.

PATIENTS

A total of 133 colonoscopy cases.

MAIN OUTCOME MEASUREMENT

A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps < or =5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification.

RESULTS

A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy.

CONCLUSIONS

Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.

Detectability of colorectal neoplastic lesions using a narrow-band imaging system: a pilot study

BACKGROUND AND AIM

Flat and depressed colorectal neoplastic lesions can be difficult to identify using conventional colonoscopy techniques. Narrow-band imaging (NBI) provides unique views especially of mucosal vascular network and helps in visualization of neoplasia by improving contrast. The aim of this study was to assess the feasibility of using NBI for colorectal neoplasia screening.

METHODS

Forty-seven consecutive patients, who underwent high definition colonoscopy (HDC) screening examinations revealing neoplastic lesions, were enrolled in our prospective study. No biopsies or resections were performed during the initial HDC, but patients in whom lesions were detected underwent further colonoscopies using NBI, with the results of the first examination blinded from the colonoscopist. They then received appropriate treatment. We compared diagnostic detection rates of neoplastic lesions for HDC and NBI procedures using total number of all identified neoplastic lesions as reference standard.

RESULTS

Altogether, 153 lesions were detected and analyzed in 43 patients. Mean diagnostic extubation times were not significantly different (P = 0.18), but the total number of lesions detected by NBI was higher (134 vs 116; P = 0.02). Based on macroscopic type, flat lesions were identified more often by NBI (P = 0.04). As for lesion size, only flat lesions < 5 mm were detected more frequently (P = 0.046). Lesions in the right colon were identified more often by NBI (P = 0.02), but NBI missed two flat lesions >or= 10 mm located there.

CONCLUSIONS

Narrow band imaging colonoscopy may represent a significant improvement in the detection of flat and diminutive lesions, but a future multi-center controlled trial should be conducted to fully evaluate efficacy for screening colonoscopies.

Is diagnostic and therapeutic endoscopy currently appropriate?: suggestions for improvement

Endoscopy is the driving force in gastroenterology today, and recent exciting advances in technology have extended its frontiers at an unprecedented rate. We have a wider range of diagnostic and therapeutic possibilities at our disposal with more detailed methods available to analyse what we see on our video screens. We can access the small bowel lumen with consistency and intra-abdominal operations have been performed through the mouth and anus so where are the current limitations of the procedure? In spite of these remarkable advances many challenges remain for both the endoscopist and for industry, they are mainly ones associated with human weakness. Endoscopy is an art, performed by individuals who require training and continued education and it is done to patients who are vulnerable, afraid and often seriously unwell. It is human aspects of endoscopy that require improvement. This chapter addresses the areas where endoscopy is falling short and suggests what can be done to improve practice. Changes are needed in management, information technology, education, team working, quality, patient comfort and safety. There also remain a number of areas where improved technology may be able to reduce human error.

Impact of wide-angle, high-definition endoscopy in the diagnosis of colorectal neoplasia: a randomized controlled trial

BACKGROUND & AIMS

It is essential to optimize standard colonoscopy technique to be able to increase polyp detection. We sought to compare the performance of colonoscopy using a high-definition, wide-angle endoscope (HDE) versus a standard colonoscope (SC) for the detection of colorectal neoplasia.

PATIENTS AND METHODS

All consecutive consenting adult patients referred from primary care centers were included and randomly assigned at a 1:1 ratio to undergo HDE or SC. Times to reach and withdraw from the cecum were measured. Morphology, size, location, and pathologic diagnosis of each polyp were recorded. Sample size calculation resulted in a total of 682 patients needed.

RESULTS

A total of 693 consecutive patients fulfilled all inclusion criteria (73 excluded owing to insufficient bowel preparation). Each arm included 310 patients with no baseline characteristic differences. Time to reach the cecum was slightly superior for SC (8.9 +/- 4.8 minutes vs 8.2 +/- 4.5 minutes; P = .055). Pathology examination was feasible in 418 lesions (272 adenomas, 109 hyperplastic polyps, and 37 inflammatory lesions). Both techniques detected a similar number and type of lesions, and there were no differences in the distribution along the colon, in the degree of dysplasia, or morphology of adenomas. The per-patient basis analyses demonstrated that there were no differences between the 2 arms of the study in the detection rates of polyps (SC, 0.84 +/- 1.59; HDE, 0.83 +/- 1.30), adenomas (0.45 +/- 1.07 vs 0.43 +/- 0.87), small adenomas (0.22 +/- 0.71 vs 0.28 +/- 0.78), flat adenomas (0.30 +/- 0.91 vs 0.21 +/- 0.63), or hyperplastic polyps (0.16 +/- 0.50 vs 0.18 +/- 0.54).

CONCLUSION

HDE did not detect significantly more colorectal neoplasia than SC.

A comparative study of standard vs. high definition colonoscopy for adenoma and hyperplastic polyp detection with optimized withdrawal technique

BACKGROUND

Colonoscopy has a known miss rate for polyps and adenomas. High definition (HD) colonoscopes may allow detection of subtle mucosal change, potentially aiding detection of adenomas and hyperplastic polyps.

AIM

To compare detection rates between HD and standard definition (SD) colonoscopy.

METHODS

Prospective, cohort study with optimized withdrawal technique (withdrawal time >6 min, antispasmodic, position changes, re-examining flexures and folds). One hundred and thirty patients attending for routine colonoscopy were examined with either SD (n = 72) or HD (n = 58) colonoscopes.

RESULTS

Groups were well matched. Sixty per cent of patients had at least one adenoma detected with SD vs. 71% with HD, P = 0.20, relative risk (benefit) 1.32 (95% CI 0.85-2.04). Eighty-eight adenomas (mean +/- standard deviation 1.2 +/- 1.4) were detected using SD vs. 93 (1.6 +/- 1.5) with HD, P = 0.12; however more nonflat, diminutive (<6 mm) adenomas were detected with HD, P = 0.03. Twenty-three proximal hyperplastic polyps (0.32 +/- 0.58) were detected with SD vs. 31 (0.53 +/- 0.86) with HD, P = 0.35. Overall prevalence of proximal large (>9 mm) hyperplastic polyps was 7% (0.09 +/- 0.36).

CONCLUSIONS

High definition did not lead to a significant increase in adenoma or hyperplastic polyp detection, but may help where comprehensive lesion detection is paramount. High detection rates appear possible with either SD or HD, when using an optimized withdrawal technique.

Automated quantification of colonic crypt morphology using integrated microscopy and optical coherence tomography

Colonic crypt morphological patterns have shown a close correlation with histopathological diagnosis. Imaging technologies such as high-magnification chromoendoscopy and endoscopic optical coherence tomography (OCT) are capable of visualizing crypt morphology in vivo. We have imaged colonic tissue in vitro to simulate high-magnification chromoendoscopy and endoscopic OCT and demonstrate quantification of morphological features of colonic crypts using automated image analysis. 2-D microscopic images with methylene blue staining and correlated 3-D OCT volumes were segmented using marker-based watershed segmentation. 2-D and 3-D crypt morphological features were quantified. The accuracy of segmentation was validated, and measured features are in agreement with known crypt morphology. This work can enable studies to determine the clinical utility of high-magnification chromoendoscopy and endoscopic OCT, as well as studies to evaluate crypt morphology as a biomarker for colonic disease progression.

Efficacy of chromoendoscopy with indigocarmine for the detection of ascending colon and cecum lesions

OBJECTIVE

Previous data suggest that routine chromoendoscopy may increase detection rates of diminutive or flat lesions. The aim of this study was to evaluate the usefulness of chromoendoscopy in the ascending colon and cecum, where the incidence of diminutive or flat lesions is high.

MATERIAL AND METHODS

Between June 2006 and September 2006, a total of 316 consecutive patients were prospectively enrolled in this study. The patients were randomly divided into two groups (control group: 158 patients, chromoendoscopy group: 158 patients). If the quality of bowel preparation was poor or cecal intubation was not achieved, the patient was excluded from the study. In the control group, the ascending colon and cecum were observed twice without chromoendoscopy. In the chromoendoscopy group, the cecum and ascending colon were reinspected following staining with indigocarmine solution after conventional examination of the cecum and ascending colon. Finally, a total of 151 and 149 patients were enrolled in the control and chromoendoscopy groups, respectively.

RESULTS

The chromoendoscopy group differed significantly from the control group in the number of additionally detected polyps (control: 14 versus chromoendoscopy: 62, p<0.001) and in the number of patients with additionally detected polyps (control: 12 versus chromoendoscopy: 50, p<0.001). Multivariate analysis revealed that detection of polyps after indigocarmine spraying was independently associated with a high body mass index and older age (p = 0.045 and p = 0.006, respectively).

CONCLUSIONS

With chromoendoscopy using indigocarmine, more polyps can be detected in the ascending colon and cecum as compared with using conventional colonoscopy.

Does autofluorescence imaging videoendoscopy system improve the colonoscopic polyp detection rate?--a pilot study

OBJECTIVES

Colonoscopy is considered the gold standard for the detection of colorectal polyps; however, polyps can be missed with conventional white light (WL) colonoscopy. The aim of this pilot study was to evaluate whether a newly developed autofluorescence imaging (AFI) system can detect more colorectal polyps than WL.

METHODS

A modified back-to-back colonoscopy using AFI and WL was conducted for 167 patients in the right-sided colon including cecum, ascending and transverse colon by a single experienced colonoscopist. The patient was randomized to undergo the first colonoscopy with either AFI or WL (group A: AFI-WL, group B: WL-AFI). The time needed for both insertion and examination for withdrawal and all lesions detected in the right-sided colon were recorded.

RESULTS

Eighty-three patients were randomized to group A and 84 to group B. The total number of polyps detected by AFI and WL colonoscopy was 100 and 73, respectively. The miss rate for all polyps with AFI (30%) was significantly less than that with WL (49%) (P= 0.01).

CONCLUSIONS

AFI detects more polyps in the right-sided colon compared to WL colonoscopy.

Chromoscopic endomicroscopy: in vivo cellular resolution imaging of the colorectum

Advances in imaging technology and engineering have now permitted functional integration of a confocal endomicroscope into the distal tip of a conventional video colonoscope enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. For the first time, the endoscopist is now able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time. A new era in endoscopic imaging has therefore begun - histoendoscopy. In addition to providing a high-accuracy in vivo optical biopsy tool for the differentiation between benign hyperplasia, intra-epithelial neoplasia and carcinoma in sporadic cohorts, endomicroscopy with targeted biopsies has now been shown to increase the yield of intra-epithelial neoplasia complicating ulcerative colitis. Furthermore, recent data examining endomicroscopic molecular ex vivo imaging using anti-CD44v6 antibody has identified aberrant crypt foci based on their surface molecular expression. Receptor overexpression in vivo in humans may, in the near future, be exploited for the diagnosis of inflammation, neoplasia and in predicting targeted molecular therapy. Endomicroscopy will be key to this immuno-imaging interface. Within the present review, we discuss the current clinical evidence in support of confocal endomicroscopy and explore the new diagnostic possibilities for this technology.

Comparative study of conventional colonoscopy and pan-colonic narrow-band imaging system in the detection of neoplastic colonic polyps: a randomized, controlled trial

BACKGROUND

Detection and removal of adenomas by colonoscopy is an important means for preventing cancer; however, small adenomas may be missed during colonoscopy. The narrow-band imaging (NBI) system clearly enhances the microvasculature in neoplastic lesions, making it appear as a dark complex. Therefore, the NBI system may improve the detection of colonic neoplasias. However, no randomized, controlled trials have evaluated the efficacy of a pan-colonic NBI system in adenoma detection. We conducted a randomized, controlled trial to determine the efficacy of the pancolonic NBI system in adenoma detection.

METHODS

Two hundred forty-three patients were randomized, 121 to conventional colonoscopy and 122 to pan-colonic NBI system. Demographics, indication for colonoscopy, and quality of preparation were similar between groups.

RESULTS

Extubation time was not significantly different between the conventional colonoscopy and pan-colonic NBI system. The proportions of patients with at least one adenoma and those with multiple adenomas were not significantly different between groups. However, the pan-colonic NBI system significantly increased the total number of adenomas detected (P < 0.05) and the number of diminutive (<5 mm) adenomas detected (P < 0.05). The pan-colonic NBI system allowed detection of more diminutive adenomas in the distal colon than did conventional colonoscopy (P < 0.01), and more patients in the NBI group had at least one diminutive adenoma than in the control group (P < 0.05).

CONCLUSIONS

The pan-colonic NBI system improves the total number of adenomas detected, including significantly more diminutive adenomas, without prolongation of extubation time. These results indicate that routine use of the NBI system for surveillance of diminutive adenomas may be recommended.

Adenoma detection rate and the quality of colonoscopy: the sword has two edges

With the increasing demand for colonoscopy for colorectal cancer screening and surveillance of colorectal adenomas and carcinomas, there has been an increasing emphasis on the quality of colonoscopy. Few publications have considered the full implications of pushing the adenoma detection rate as a prime quality indicator. In this article, some of the potential problems with this course are discussed and an alternative approach is suggested. Although defining and measuring quality in colonoscopy is important, further work needs to be done to arrive at a practical, clinically meaningful way of quality assessment.

Diagnostic targeting of colon cancer using a novel fluorescent somatostatin conjugate in a mouse xenograft model

Colorectal carcinoma is one of the more prevalent, highly malignant human tumors, occurring in about 7% of the population. However, if diagnosed and treated in its early stages, colon cancer is curable. In our study, we used a mouse xenograft model to investigate the capability of a fluorescent conjugate of a novel synthetic somatostatin (SST) analog to improve detection of human colorectal tumors that are characterized by over-expressed SST receptors. Human HT-29 colon carcinomas were induced in nude mice. After administration of the fluorescent SST conjugate, in vivo low- and high-magnification fluorescence microscopy, as well as high-resolution spectrally resolved imaging were performed, and the time-dependent biodistribution was determined quantitatively (using fiber-optic spectroscopy). Administration of the conjugate (at concentrations of 6 mg/kg body weight) enabled targeting small (1-5 mm diameter) tumors with high sensitivity and selectivity. Toxicity studies at dosages up to 1,000 mg/kg body weight did not reveal any drug related abnormalities. In conclusion, the SST conjugate significantly enhanced the detection of HT-29 colon tumors by fluorescence imaging because of a 5- to 8-fold increase in the contrast between malignant and normal tissues.

Sporadic and syndromic hyperplastic polyps and serrated adenomas of the colon: classification, molecular genetics, natural history, and clinical management

There is now strong evidence for an alternative pathway of colorectal carcinogenesis implicating hyperplastic polyps and serrated adenomas. This article briefly reviews the evidence for this serrated pathway, provides diagnostic criteria for clinically significant hyperplastic polyps and allied serrated polyps, and suggests how this information may be translated into safe, effective guidelines for colonoscopy-based colon cancer prevention. Consideration also is given to the definition and management of hyperplastic polyposis syndrome. The currently proposed management plan for serrated polyps is tentative because of incomplete knowledge of the nature and behavior of these polyps. This article highlights key areas warranting further research.

In vivo confocal laser scanning chromo-endomicroscopy of colorectal neoplasia: changing the technological paradigm

Recently, miniaturization of a novel confocal laser endomicroscope (Optiscan Pty, Notting Hill, Victoria, Australia) has permitted functional integration into the distal tip of a conventional video colonoscope (Pentax EC3870K; Pentax, Tokyo, Japan) enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. Using endomicroscopy and intravenous sodium fluorescein as a contrast agent, 'virtual histology' can be created, which allows visualization of both the surface epithelium, and some of the lamina propria (down to a quarter of a millimetre), including the microvasculature. Confocal endomicroscopy may have major implications in the future of colonoscopy as uniquely it allows in vivo diagnosis of colonic intraepithelial neoplasia and carcinoma enabling 'smart' biopsy targeting and hence potentially influencing 'on table' management decisions. Initial pilot data have now shown that confocal imaging in vivo using the newly developed EC3870K has high overall accuracy for the immediate diagnosis of intraepithelial neoplasia and carcinoma in sporadic screened cohorts, but also has a role in the detection of intraepithelial neoplasia detection in chronic ulcerative colitis cancer screening when used in conjunction with methylene blue chromoscopy. We discuss the current evidence in support of confocal endomicroscopy in the colorectum and explore the new diagnostic possibilities for this technology.

Reducing the incidence and mortality of colon cancer: mass screening and colonoscopic polypectomy

Most colon cancers arise from conventional adenomatous polyps (conventional adenoma-to-carcinoma sequence), while some colon cancers appear to arise from the recently recognized serrated adenomatous polyp (serrated adenoma-to-carcinoma theory). Because conventional adenomas and serrated adenomas are usually asymptomatic, mass screening of asymptomatic patients has become the cornerstone for detecting and eliminating these precursor lesions to reduce the risk of colon cancer. Colonoscopy has become the primary screening test because of its high sensitivity and specificity, and the ability to perform polypectomy. Other screening tests include guaiac tests or fecal immunochemical tests (FIT) for fecal occult blood, and flexible sigmoidoscopy. A minimal colonoscopic withdrawal time of 6 minutes is important to maximize polyp detection at colonoscopy. Chromoendoscopy is an experimental technique used to highlight abnormal colonic areas to identify neoplastic tissue and to potentially determine the histology of colonic polyps at colonoscopy based on superficial pit anatomy.

Narrow-band imaging colonoscopy--a pilot feasibility study for the detection of polyps and correlation of surface patterns with polyp histologic diagnosis

BACKGROUND

Colonoscopy is the preferred screening method for colorectal cancer. However, it has a substantial miss rate for colon polyps, and several techniques have been attempted to improve this limitation. Narrow-band imaging (NBI) is a novel technology that enhances the visualization of surface mucosal and vascular patterns.

OBJECTIVE

The aim of this study was to determine the detection rate of additional polyps by NBI after removal of polyps visualized by standard white light colonoscopy (WLC) and to correlate the surface mucosal and vascular patterns with polyp histologic diagnosis.

DESIGN

This was a prospective pilot feasibility study.

SETTING

Kansas City Veterans Affairs Medical Center.

PATIENTS

Subjects referred for screening colonoscopy were prospectively enrolled.

METHODS

Subjects underwent colonoscopy after enrollment. After intubation of the cecum, colonic segments were sequentially examined, initially with WLC with removal of polyps followed by re-examination of the same segment with NBI. Additional polyps seen with NBI were photographed for their surface patterns and then removed. The total number of polyps visualized by WLC and NBI was calculated and the surface patterns were then correlated with polyp histologic features.

RESULTS

Forty patients were enrolled in the study, all men, 32 white. The mean age was 62 years. A total of 72 polyps were detected by WLC (43 tubular adenoma, 28 hyperplastic polyps), whereas NBI detected an additional 51 polyps, of which 29 were tubular adenomas and 22 were hyperplastic. Five different surface/vascular patterns were observed: fine capillary network with absent mucosal pattern, circular pattern with dots, round/oval pattern, tubular pattern, and gyrus pattern. The sensitivity, specificity, and overall accuracy of the first two patterns for hyperplastic polyps were 86%, 96%, and 92%, respectively, and of the latter three patterns for tubular adenomas were 96%, 86%, and 92%, respectively.

CONCLUSIONS

This pilot study demonstrates the feasibility of polyp detection and histologic correlation with NBI. These findings need to be confirmed in future randomized controlled trials.

Clinical significance of type VI pit pattern subclassification in determining the depth of invasion of colorectal neoplasms

AIM: To clarify whether subclassification of the type V_I pit pattern on the basis of magnifying colonoscopy findings is useful in determining the type and depth of invasion of colorectal neoplasms.

METHODS: We retrospectively analyzed 272 colorectal neoplasms (117 dysplasias and 155 submucosal invasive carcinomas; 228 patients) with a type V pit pattern [type V_I, n = 202; type V_N, n = 70 (Kudo and Tsuruta classification system)]. We divided lesions with a type V_I pit pattern into two subclasses, mildly irregular lesions and severely irregular lesions, according to the prominent and detailed magnifying colonoscopy findings. We examined the relation between these two subclasses and histology/invasion depth.

RESULTS: One hundred and four lesions (51.5%) were judged to be mildly irregular, and 98 lesions (48.5%) were judged to be severely irregular. Ninety-seven (93.3%) mildly irregular lesions showed dysplasias or submucosal invasion of less than 1000 &mgr;m (SM < 1000 &mgr;m). Fifty-five (56.1%) severely irregular lesions showed submucosal invasion equal to or deeper than 1000 &mgr;m (SM ≥ 1000 &mgr;m). Mild irregularity was found significantly more often in dysplasias or lesions with SM < 1000 &mgr;m than in lesions with SM ≥ 1000 &mgr;m (P < 0.01).

CONCLUSION: Subclassification of the type V_I pit pattern is useful for identifying dysplasias or lesions with SM < 1000 &mgr;m.

Review article: New developments in colonic imaging

BACKGROUND

Colonoscopic detection and removal of neoplasia from the colorectum prevent the development of colorectal cancer. Sporadic adenomas and neoplasia associated with ulcerative colitis are frequently missed during colonoscopy, as a result of which, interval cancers might develop.

AIM

To review new developments in colonoscopic imaging concerning the detection of neoplasia.

METHODS

Medical databases were searched for relevant publications, dealing with advanced endoscopic imaging techniques during colonoscopy.

RESULTS

Pancolonic chromoendoscopy has shown to increase the detection of sporadic adenomas and ulcerative colitis associated neoplasia, at the expense of longer examination times. As chromoendoscopy is labour intensive and time-consuming, its widespread use has been hampered. Narrow band imaging is a novel endoscopic imaging technique, which enhances mucosal and vascular details. Recent studies indicate that narrow band imaging has a high yield for neoplasia; however, no improvement compared to standard colonoscopy has been demonstrated. Autofluorescence imaging is another new technique for which blue endoscopic light is used to induce mucosal autofluorescence. So far, preliminary results have shown promising results of autofluorescence imaging for neoplasia detection.

CONCLUSION

Whether chromoendoscopy or novel advanced imaging techniques will change current colonoscopic practice depends on results of future studies comparing these different colonoscopic techniques.

Techniques for targeting screening in ulcerative colitis

Patients with longstanding chronic ulcerative colitis are "at risk" of developing colorectal cancer. Approximately 1 in 6 patients will die as a result of colorectal malignancy, which can often be difficult to detect using conventional "white light" colonoscopy. New endoscopic techniques and technologies including the use of dye sprays, "chromoendoscopy", high magnification chromoscopic colonoscopy and recently chromoscopic assisted confocal laser scanning in vivo endomicroscopy have now been introduced to improve the diagnostic yield of intraepithelial neoplasia at screening colonoscopy. This review details the true "risk" of colorectal cancer complicating ulcerative colitis, discusses the objective evidence to support current endoscopic screening guidelines, and describes the imminent technological paradigm shift about to occur in the endoscopic management and detection of intraepithelial neoplasia.

Diagnostics of inflammatory bowel disease

The diagnosis of inflammatory bowel disease (IBD) with its 2 main subforms, Crohn's disease and ulcerative colitis, is based on clinical, endoscopic, radiologic, and histologic criteria. This paradigm remains unchanged despite the advent of new molecular technologies for the examination of serum proteins and genetic sequences, respectively. The main innovations in diagnostic technologies include the development of more sophisticated endoscopic and noninvasive imaging techniques with the aim of improving the identification of complications, in particular malignant diseases associated with IBD. The future will see further progress in the identification of genetic susceptibility factors and of protein biomarkers and their use to describe the molecular epidemiology of IBD. It can be expected that future diagnostic algorithms will include molecular parameters to detect early disease or guide therapies by predicting the individual course of disease.

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

BACKGROUND

Although conventional colonoscopy is the most sensitive test available for the investigation of the colorectum for polyps, there are data that raise concerns about its sensitivity. Chromoscopy may be one way of enhancing the ability for colonoscopy to detect polyps particularly diminutive flat lesions that may be otherwise difficult to detect.

OBJECTIVES

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

SEARCH STRATEGY

MEDLINE, EMBASE and the Cochrane Library databases were searched along with a hand search of abstracts from relevant meetings. Search terms included randomised trials containing combinations of the following: 'chromoscopy' 'colonoscopy' 'dye-spray' 'chromo-endoscopy' 'indigo-carmine' 'magnifying endoscopy'.

SELECTION CRITERIA

All prospective randomised trials comparing chromoscopic with conventional endoscopic examination of the lower gastrointestinal tract were included. Patients with inflammatory bowel disease or polyposis syndromes were excluded.

DATA COLLECTION AND ANALYSIS

Three reviewers assessed the methodological quality of potentially eligible trials and 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 patients with multiple neoplastic lesions and the extubation time.

MAIN RESULTS

Four trials were include that met the inclusion criteria and although there were some methodological drawbacks and differences in study design, combining the results showed a significant difference in favour of chromoscopy for all detection outcomes. In particular, chromoscopy is likely to yield significantly more patients with at least one neoplastic lesion (OR 1.61 (CI 1.24-2.09)) and significantly more patients with three or more neoplastic lesions (OR 2.55 (CI 1.49-4.36)). Not surprisingly the withdrawal times were significantly slower for the chromoscopy group.

AUTHORS' CONCLUSIONS

There appears to be strong evidence that chromoscopy enhances the detection of neoplasia in the colon and rectum. Patients 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.

Novel clinical in vivo roles for indigo carmine: high-magnification chromoscopic colonoscopy

Since the adenoma-carcinoma sequence was first proposed by Morson in the 1970s, it has become widely accepted that detection and subsequent removal of polypoid adenomas from the colon reduces the incidence of colorectal cancer. These adenomas are relatively easy to detect by conventional colonoscopy; however, large population studies have shown that despite resection of polypoid adenomas, interval colorectal cancers still occurred. Recent advances in technology have given today's endoscopists access to high-resolution and high-magnification scopes, which has facilitated detection of flat and depressed colorectal lesions. Current data suggest that such morphologically distinct lesions may account for up to 30% of all colorectal adenomas. Furthermore, flat and depressed lesions of the large bowel may confer greater malignant potential compared to polypoid adenomas. The majority of flat lesions show only subtle changes by conventional colonoscopy, but the use of stains, such as indigocarmine, in addition to magnification colonoscopy can enhance their detection significantly. In this paper, we discuss the rationale for detecting flat colorectal lesions. We explore the use of high-magnification colonoscopy and chromoendoscopy, with particular reference to the application of indigocarmine, in this patient group. We also discuss the novel therapeutic techniques now available for these lesions.

High yields of small and flat adenomas with high-definition colonoscopes using either white light or narrow band imaging

BACKGROUND & AIMS

Detection of adenomas is an important goal of colonoscopy. Narrow band imaging (NBI) might highlight adenomas and lead to higher rates of adenoma detection.

METHODS

This was a randomized controlled trial of colonoscopy withdrawal in white light versus NBI in 434 patients aged 50 years or older with intact colons. All examinations were performed by a single experienced endoscopist with a known high detection rate of adenomas using high-definition, wide-angle (170 degrees field of view) colonoscopes.

RESULTS

There was no difference in the percent of patients with >or=1 adenoma for the entire cohort in white light (67%) versus NBI (65%) (P = .61) or in the subset of 257 patients with indication screening (58% vs 57%; P = .91). Both the prevalences of adenomas and the numbers of adenomas per colonoscopy are the highest ever reported in colonoscopy studies. The high prevalence rates of adenomas were accounted for by detection of large numbers of adenomas, including flat adenomas, which were <or=5 mm.

CONCLUSIONS

NBI did not result in better detection of adenomas by an endoscopist with a known high detection rate using white light. This result does not exclude a possible benefit of NBI in reducing variation between endoscopists in detection of adenomas. The very high adenoma detection rate in this study suggests that high definition should be directly tested for its effect on detection of adenomas.

Risk for high-grade dysplasia or invasive carcinoma in colorectal flat adenomas in a Spanish population

AIM

to determine the frequency and malignancy risk of colonic flat adenomas among patients with colorectal polyps in a Spanish population.

METHODS

1300 consecutive colonoscopic examinations were reviewed; 640 polyps were detected and removed endoscopically in 298 patients. Chromoendoscopy with 0.2% indigo carmine was applied to clarify the macroscopical appearance of flat lesions. The following data was collected for flat and protruding polyps: size, location (proximal or distal to splenic flexure), histology (neoplastic or non neoplastic), high grade dysplasia (HGD) and submucosal invasive carcinoma (SIC) or beyond.

RESULTS

490 polyps (76.6%) were adenomas and 150 (23.4%) hyperplastic; 114 (23.3%) adenomas were flat (3 flat-depressed) whereas 376 (76.7%) were protruding. The diameter of flat and protruding adenomas was 9.2 +/- 7.9. mm and 7.0 +/- 5.9 mm, respectively (p < 0.001). A proximal location was more frequent for flat (63.1%) than for protruding adenomas (48.7%) (p = 0.003). The rate of HGD or SIC was significantly higher in flat than in protruding adenomas (7.0 vs 2.6%; p < 0.04). Two of the 3 flat-depressed lesions (both <or= 10 mm in diameter) were carcinomas (T1 and T2, respectively). Flat adenomas had an increased risk for HGD or SIC (OR = 2,7; CI, 1,04-7,04; p < 0.05).

CONCLUSIONS

In a Spanish population, flat adenomas represent nearly one quarter of all colorectal neoplastic polyps, their most frequent location being the right colon and they bear a higher risk of malignancy than protruding adenomas, especially for the flat depressed type.

Detection and treatment of early flat and depressed colorectal cancer using high-magnification chromoscopic colonoscopy: a change in paradigm for Western endoscopists?

Japanese researchers reported flat and depressed colorectal lesions in the 1980s. Such lesions were thought irrelevant to Western populations and described as "Phantom" or "Akitas" carcinoma. Many depressed neoplasms arise through the de novo pathogenic sequence and demonstrate early invasive characteristics. All investigators report difficulties in identifying flat and depressed lesions using conventional colonoscopy. Failure to detect and treat such lesions may be responsible for the current shortfalls in secondary colorectal cancer prevention. Given the introduction of colorectal cancer screening programs in the United Kingdom, Europe, and the United States, it is essential to re-evaluate the significance of flat lesions as applicable to Western cohorts and explore the safety and efficacy of new endoscopic technology and interventional therapeutics.

Endoscopic mucosal resection for flat neoplasia in chronic ulcerative colitis: can we change the endoscopic management paradigm?

BACKGROUND

The potential of endoscopic mucosal resection (EMR) for treating flat dysplastic lesions in chronic ulcerative colitis (CUC) has not been addressed so far. Historically, such lesions were referred for colectomy. Furthermore, there are only limited data to support endoscopic resection of exophytic adenoma-like mass (ALM) lesions in colitis.

AIMS

To evaluate the safety and clinical outcomes of patients with colitis undergoing EMR for Paris class 0-II and class I ALM compared with sporadic controls. Secondary aims were to re-evaluate the prevalence, anatomical "mapping" and histopathological characteristics of both Paris class 0-II and class I lesions in the context of CUC.

METHODS

Prospective clinical, pathological and outcome data of patients with colitis-associated Paris class 0-II and Paris class I ALM treated with EMR (primary end points being colorectal cancer development, resection efficacy, metachronous lesion rates and post-resection recurrence rates) were compared with those of sporadic controls.

RESULTS

204 lesions were diagnosed in 169 patients during the study period: 167 (82%) diagnosed at "entry" colonoscopy, and 36 (18%) diagnosed at follow-up. 170 ALMs, 18 dysplasia-associated lesion masses (DALMs) and 16 cancers were diagnosed. A total of 4316 colonoscopies were performed throughout the study period (median per patient: 6; range: 1-8). The median follow-up period for the complete cohort was 4.1 years (range: 3.6-5.21). 1675 controls were included from our prospective database of patients without CUC who had undergone EMR for sporadic Paris class 0-II and snare polypectomy of Paris type I lesions from 1998 onwards, and were considered to be at moderate to high lifetime risk of colorectal cancer. 3792 colonoscopies were performed throughout the study period in this group (median per patient: 4; range: 1-7). The median follow-up period was 4.8 years (range: 2.9-5.2). No statistically significant differences were observed between the CUC study group and controls with respect to age, sex, median number of colonoscopies per patient, median follow-up duration, post-resection complications, median lesional diameter or interval cancer rates. However, there was a significant between-group difference regarding the prevalence of Paris class 0-II lesions in the CUC group (82/155 (61%)) compared with controls (285/801 (35%); chi(2) = 31.13; p<0.001). Furthermore, recurrence rates of lateral spreading tumours were higher in the colitis cohort (1/7 (14%)) than among controls (0/10 (0%); p = 0.048 (95% CI 11.64% to 40.21%)).

CONCLUSIONS

Flat DALM, similarly to Paris class I ALM, can be managed safely by EMR in CUC. A change in management paradigm to include EMR for the resection of flat dysplastic lesions in selected cases is proposed.

Magnifying endoscopy with narrow band imaging for diagnosis of colorectal tumors

BACKGROUND

Narrow band imaging (NBI) uses optical filters for red-green-blue sequential illumination and narrows the bandwidth of spectral transmittance.

OBJECTIVE

This study aimed to clarify the clinical usefulness of NBI magnification in assessment of pit patterns for diagnosis of colorectal tumors.

DESIGN

This was a retrospective study.

SETTING

Department of Endoscopy, Hiroshima University Hospital.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 148 colorectal lesions, 16 hyperplasias, 84 tubular adenomas, and 48 early carcinomas were examined and diagnosed histologically. Mean size of lesions was 15.6+/-7.28 mm. Lesions were observed first under NBI magnification without chromoendoscopy and then under standard magnification with chromoendoscopy, and pit patterns were recorded. Results of NBI magnification were compared with those of standard magnification with chromoendoscopy to assess the clinical usefulness of NBI magnification for diagnosing colorectal neoplasia.

RESULTS

Correspondence between the two diagnostic methods was 88% (14/16) for type II, 100% (2/2) for type IIIs, 98% (73/75) for type IIIl, 88% (7/8) for type IV, 78% (25/32) for type Vi, and 100% (3/3) for type Vn pit patterns. NBI depicted brownish change on the basis of surface capillaries in 6% (1/16) of hyperplasia and 99% (83/84) of tubular adenomas. This difference in color depiction was significant.

LIMITATIONS

This study was performed in single center.

CONCLUSIONS

Determination of pit patterns of colorectal neoplasias by NBI magnification was nearly the same as that by standard magnification with chromoendoscopy. Furthermore, NBI can distinguish neoplastic and nonneoplastic lesions without chromoendoscopy.

[Emerging concepts in colorectal serrated polyps]

Colorectal serrated polyps are heterogeneous epithelial lesions characterized by a serrated architecture. They include the classical hyperplastic polyps and the much rarer serrated adenomas and mixed polyps. Whereas serrated adenomas are composed of an unequivocal adenomatous epithelium with architectural serrated, mixed polyps include two separate hyperplastic and adenomatous components. During the past few years, another type of serrated polyp with only very subtle proliferation abnormalities has been described. These atypical serrated polyps may occur either sporadically or in the context of colorectal polyposis. Despite their close resemblance to traditional hyperplastic polyps, some authors argued that they should be regarded as authentically neoplastic lesions and have proposed to call them "sessile serrated adenomas". Their malignant potential requires their removal when discovered during colonoscopy. This article reviews the histological features, the endoscopic appearance, the natural history and the molecular phenotype of the different categories of serrated polyps and introduces the concept of "serrated neoplastic pathway" in the development of colorectal cancer.

Endoscopist can be more powerful than age and male gender in predicting adenoma detection at colonoscopy

BACKGROUND AND AIMS

Both advancing age and male gender are known predictors of adenomas and large adenomas at colonoscopy. However, the importance of endoscopist compared with both age and gender as predictors of adenomas is not known. In this study, we assessed the adenoma detection rates of nine endoscopists performing colonoscopy and the effects of endoscopist on adenoma detection compared with the established predictors of advancing age and male gender.

METHODS

Consecutive colonoscopy reports by nine attending gastroenterologists at Indiana University Hospital between January 1999 and January 2004 were obtained. Patients with indications for inflammatory bowel disease (IBD), inherited colon cancer syndromes, or who were referred for polypectomy were excluded.

RESULTS

There were 10,034 included colonoscopies. The overall mean age (yr) +/- SD for the entire cohort was 56.0 +/- 13.5, range 14-93 yr. Multivariate analysis indicated that both advancing age and male gender were powerful predictors of adenomas, both for the overall cohort and in those >or=50 of age (P<or= 0.0001). The prevalence of adenomas increased from 14.6% at age 30 to 35.2% at age 70. Men had more adenomas than women (24.4%vs 16.6%, P<or= 0.0001). Among patients >or=50 yr of age, the range of detection of at least one adenoma per colonoscopy by nine colonoscopists was 15.5-41.1%, at least two adenomas was 4.9-20.0%, at least three adenomas was 0.8-10.8%, and at least one adenoma >or=1.0 cm was 1.7-6.2%, and the range of adenomas detected per colonoscopy was 0.21-0.86. Differences between endoscopists were significant (P < 0.001).

CONCLUSION

Who performs the procedure can be more important than age and gender in predicting adenomas at colonoscopy. Our results underscore the need to measure adenoma detection rates in the continuous quality improvement process and to report them to endoscopists. Additional data are needed to determine whether corrective measures can reduce variation in adenoma detection rates.

Novel colorectal endoscopic in vivo imaging and resection practice: a short practice guide for interventional endoscopists

Colorectal cancer remains a leading cause of cancer death in the UK. With the advent of screening programmes and developing techniques designed to treat and stage colorectal neoplasia, there is increasing pressure on the colonoscopist to keep up to date with the latest practices in this area. This review looks at the basic principles behind endoscopic mucosal resection and forward to the potential endoscopic tools, including high-magnification chromoscopic colonoscopy, high-frequency miniprobe ultrasound and confocal laser scanning endomicroscopic colonoscopy, that may soon become part of routine colorectal cancer management.

Olympus Lucera high-resolution vascular ectasia mapping in combination with the type V crypt pattern for the invasive depth estimation and nodal disease estimation in Paris type II colorectal cancers: a comparative prospective analysis to 20 MHz ultrasound

INTRODUCTION

Flat and depressed neoplastic lesions of the colorectum [Paris type (PT) 0-II] localized to the superficial submucosal (sm) layer can be managed using endoscopic mucosal resection. Successful endoluminal management can be enhanced using endoscopic or ultrasound tools that help predict the degree of sm invasion. Previous studies addressing invasive depth estimation using high-magnification chromoscopic colonoscopy showed a low specificity for deep sm layer 3 invasion with miniprobe ultrasound demonstrating better nodal and T stage in vivo prediction. High-resolution vascular mapping of lesions can show microvascular superficial changes that may predict sm invasive disease.

AIMS

Vascular mapping in combination with high-magnification chromoscopic colonoscopy (HMCC) may provide an accurate tool for the invasive depth estimation of PT type II neoplastic lesions as compared with high frequency 20/12.5 MHz miniprobe ultrasound.

METHODS

Sixty-eight patients with a known diagnosis of PT II neoplasia were imaged using 3 "back to back" imaging modalities. Phase 1-vascular ectasia mapping; phase 2-HMCC with crypt analysis according to Nagata criteria; phase 3-12.5/20 MHz miniprobe ultrasound. Lesions predicted as T0/1/N0 were resected using endoscopic mucosal resection with the remaining referred for surgery. Each imaging modality was then compared with the resected histopathologic specimen used as the "gold standard."

RESULTS

N=68 lesions (19 sm1/13 sm2/36 sm3). Overall accuracy of Nagata criteria, Nagata criteria combined with vascular mapping, and ultrasound staging was 65%, 78%, and 94%, respectively (P<0.001) when observing the between phase differences. Fifty-two lesions were resected surgically. The prevalence of node positive disease was 16% (8/52) with the remaining 44/52 (84%) being confirmed pN0 at histopathology. The kappa coefficient of agreement between invasive depth estimation (using histopathology as the gold standard), Nagata stage, Nagata stage plus vascular ectasia mapping and ultrasound stage was 0.47, 0.65, and 0.9, respectively. A significant improvement in between phase differences was observed (P=0.001).

CONCLUSIONS

This is the first study to address the in vivo clinical utility of vascular mapping in combination with HMCC for the T and N staging of PT II neoplasia. Combination imaging may provide an adequate clinical tool for both T and N stage assessment in vivo and help stratify those patients at high risk for T2/N1 disease that may benefit from further high-frequency miniprobe ultrasound (HFUS) assessment and possible primary surgical excision. This is important in the clinical context, given the high overall costs of a second HFUS examination, limitation of HFUS resources, and safe selection of patients undergoing primary endoscopic resection versus surgical resection.

Optical adjuncts for enhanced colonoscopic diagnosis

Background

Optical techniques using previously unexploited properties of light interaction with tissue may be valuable in the detection, diagnosis and staging of colorectal neoplasia.

Methods

A Medline search (1990 to present) was conducted on optical diagnostics in the detection of colorectal neoplasia. The reference list of each identified article was reviewed for further relevant papers.

Results and conclusion

Chromoendoscopy is the only optical adjunct to colonoscopy that has been tested in large randomized clinical trials. It improves the detection of small and flat colorectal adenomas, and of neoplasia in chronic ulcerative colitis and hereditary non-polyposis colorectal cancer. All other techniques are the subject of ongoing research and the practicality of population screening with any of the methods has yet to be established. Optical techniques may, however, permit immediate clinical diagnosis, removing the need for histological analysis. They may also improve the diagnosis of early colonic neoplasia.

Maximizing detection of adenomas and cancers during colonoscopy

Some patients who undergo colonoscopy that appeared to have cleared the colorectum of neoplasia return within a short interval (1-3 yr) with colorectal cancer. Although several a priori mechanisms could account for this occurrence, wide variation in detection rates of adenomas and cancer at colonoscopy suggests that suboptimal colonoscopic technique is a significant contributor. Optimal technique with white-light colonoscopy involves taking adequate time for inspection during withdrawal (an average of at least 6 min in normal colons), interrogating the proximal sides of folds, flexures, and valves, clearing fluid and debris, and distending adequately. Some adjunctive techniques are directed toward exposing more colonic mucosa during colonoscopy. Wide-angle colonoscopy appears to improve efficiency but does not eliminate miss rates. Colonoscopy in retroflexion was unsuccessful in reducing miss rates in one study, whereas cap-fitted colonoscopy was successful in reducing miss rates in one small study. Techniques to improve detection of flat lesions include pancolonic chromoendoscopy (CE). In two randomized controlled trials, CE improved adenoma detection, but CE does not appear to provide substantially greater yields than those obtained by the more sensitive white-light colonoscopists. Narrow band imaging and autofluorescence are being assessed for improved detection of flat lesions. Adenoma detection rates are an important measure of the quality of colonoscopy and should be reported to endoscopists in quality improvement programs in colonoscopy.

The impact of colon preparation timing on colonoscopic detection of colorectal neoplasms--a prospective endoscopist-blinded randomized trial

OBJECTIVES

Timing of colon preparation might influence the cleansing condition of the colon and therefore affect the quality and diagnostic yield of colonoscopy. This study compared two different timings of colon preparation to assess the efficacy of colon cleansing and diagnostic yield of colorectal neoplasms during colonoscopy.

METHODS

One hundred twenty-one eligible subjects who had colorectal neoplasms detected at a screening colonoscopy were randomly assigned to receive colon preparation with polyethylene glycol electrolyte lavage solution (PEG-ELS) either on the day of (on the day group) or the night before (previous night group) a second colonoscopy. The condition of colon preparation and the diagnostic yield of colorectal neoplasms were recorded and compared between the two groups for the initial and second colonoscopies.

RESULTS

Fifty-nine subjects received colon preparation on the night before and 60 subjects received colon preparation the day of a second colonoscopy. Colon preparation for the second colonoscopy was better in the on-the-day group than in the previous night group (P= 0.003). Colon preparation for the second colonoscopy was better for each group in comparison with the initial colonoscopy (P < 0.0001). An interobserver variability analysis using 20 randomly selected colonoscopies from the two groups revealed good correlation among four colonoscopists. More lesions were detected in group A during the second colonoscopy (P= 0.028).

CONCLUSION

Colon preparation on the day of colonoscopy has a better cleansing quality and higher diagnostic yield. Subjects who had lesions detected during the initial screening colonoscopy had better colon cleansing for the second colonoscopy regardless of the timing of preparation.

High prevalence of sessile serrated adenomas with BRAF mutations: a prospective study of patients undergoing colonoscopy

BACKGROUND & AIMS

Sporadic colorectal cancers with a high degree of microsatellite instability are a clinically distinct subgroup with a high incidence of BRAF mutation and are widely considered to develop from serrated polyps. Previous studies of serrated polyps have been highly selected and largely retrospective. This prospective study examined the prevalence of sessile serrated adenomas and determined the incidence of BRAF and K-ras mutations in different types of polyps.

METHODS

An unselected consecutive series of 190 patients underwent magnifying chromoendoscopy. Polyp location, size, and histologic classification were recorded. All polyps were screened for BRAF V600E and K-ras codon 12 and 13 mutations.

RESULTS

Polyps were detected in 72% of patients. Most (60%) were adenomas (tubular adenomas, tubulovillous adenomas), followed by hyperplastic polyps (29%), sessile serrated adenomas (SSAs; 9%), traditional serrated adenomas (0.7%), and mixed polyps (1.7%). Adenomas were more prevalent in the proximal colon (73%), as were SSAs (75%), which tended to be large (64% >5 mm). The presence of at least one SSA was associated with increased polyp burden (5.0 vs 2.5; P < .0001) and female sex (P < .05). BRAF mutation was rare in adenomas (1/248 [0.4%]) but common in SSAs (78%), traditional serrated adenomas (66%), mixed polyps (57%), and microvesicular hyperplastic polyps (70%). K-ras mutations were significantly associated with goblet cell hyperplastic polyps and tubulovillous adenomas (P < .001).

CONCLUSIONS

The prevalence of SSAs is approximately 9% in patients undergoing colonoscopy. They are associated with BRAF mutation, proximal location, female sex, and presence of multiple polyps. These findings emphasize the importance of identifying and removing these lesions for endoscopic prevention of colorectal cancer.

The timing of bowel preparation before colonoscopy determines the quality of cleansing, and is a significant factor contributing to the detection of flat lesions: A randomized study

AIM: To compare the cleansing quality of polyethylene glycol electrolyte solution and sodium phosphate with different schedules of administration, and to evaluate whether the timing of the administration of bowel preparation affects the detection of polyps.

METHODS: One hundred and seventy-seven consecutive outpatients scheduled for colonoscopy were randomized in one of four groups to receive polyethylene glycol electrolyte solution or oral sodium phosphate with two different timing schedules. Quality of cleansing, polyp detection, and tolerance were evaluated.

RESULTS: Patients receiving polyethylene glycol or sodium phosphate on the same day as the colonoscopy, obtained good to excellent global cleansing scores more frequently than patients who received polyethylene glycol or sodium phosphate on the day prior to the procedure (P < 0.001). Flat lesions, but not flat adenomas, were more frequent in patients prepared on the same day (P = 0.02).

CONCLUSION: The quality of colonic cleansing and the detection of flat lesions are significantly improved when the preparation is taken on the day of the colonoscopy.