Colorectal tumours and pit pattern

Advanced colorectal polyp detection techniques

A long-term follow-up of the landmark National Polyp Study recently showed that colonoscopy was associated with critical clinical benefit, including reduced overall death rate, colorectal cancer (CRC) death rate, and CRC incidence Zauber et al. (N Engl J Med 366(8):687-96, 2012). This and other recent studies emphasize the need for high-quality colonoscopy to realize maximal benefit. Adenoma detection has emerged as an important predictor of quality colonoscopy. Studies from Europe have shown that individuals whose colonoscopy was performed by a physician with high adenoma detection have a much lower likelihood of interval CRC. Studies now suggest that it is possible to train endoscopists to improve their adenoma detection rate. The specific methods associated with higher quality colonoscopy include careful inspection behind folds, washing the colon surface, adequate insufflation, and recognition of subtle flat polyps. Use of high-definition white light colonoscopy, chromoendoscopy, and cap-fitted colonoscopy has also been studied as potential methods for increasing adenoma detection. We will review these methods and techniques in this article.

Endoscopic resection of large colon polyps

Endoscopic resection, including polypectomy, endoscopic mucosal resection, and endoscopic submucosal dissection, is the preferred treatment method of large colorectal polyps. Its safety and efficacy have been shown. Endoscopic removal techniques are important because they provide a resection specimen for precise histopathologic staging to further direct diagnosis, prognosis, and management decisions. Used according to its indications, it provides curative resection and obviates the higher morbidity, mortality, and cost associated with alternative surgical treatment.

Possibility of ex vivo animal training model for colorectal endoscopic submucosal dissection

PURPOSE

Colorectal endoscopic submucosal dissection (ESD) has not been standardized due to technical difficulties and requires extensive training for reliability. Ex vivo animal model is convenient, but has no blood flow. The objective of this study is to evaluate the characteristics of various ex vivo animal models including a blood flow model for colorectal ESD training and the usefulness of practicing endoscopic hemostasis and closure using an animal model.

METHODS

Harvested porcine cecum, rectum, and stomach and bovine cecum and rectum were analyzed regarding ease of mucosal injection, degree of submucosal elevation, and status of the proper muscle layer. Ex vivo animal model with blood flow was made using the bovine cecum. The vessel around the cecum was detached, and red ink was injected. Endoscopic hemostasis for perioperative hemorrhage and endoscopic closure for perforation were performed in this model.

RESULTS

Mucosal injection was easily performed in the bovine cecum and rectum. Submucosal elevation was low in the bovine cecum, while the proper muscle layer was not tight in the porcine rectum and bovine cecum. Endoscopic hemostasis were accomplished in six (60 %) out of ten procedures of the ex vivo blood flow model. In two non-experts, the completion rates of endoscopic closure were 40 and 60 % in the first five procedures. These rates became 100 % in the last five procedures.

CONCLUSIONS

We have evaluated the characteristics of various ex vivo animal models and shown the possibility of training for endoscopic hemostasis and endoscopic closure in the ex vivo animal model.

Validity of the usefulness of microvascular architecture and microsurface structure using magnifying endoscopy with narrow-band imaging in the colorectal neoplasm

BACKGROUND

Magnifying endoscopy (ME) with narrow-band imaging (NBI) has been described as useful in diagnosing colorectal neoplasms. However, there is no standardized simple classification system, and its usefulness in comparison with pit pattern diagnosis by magnifying chromoendoscopy (MC) is unclear. The aim of this study was to investigate the usefulness of evaluations of microvascular architecture (MV) and microsurface structure (MS) by ME with NBI in the diagnosis of colorectal neoplasms.

METHODS

A total of 360 colorectal neoplasms were analyzed by retrospective analysis of prospectively collected data. The vessel plus surface (VS) classification system was applied for ME with NBI diagnosis. The main outcome measurement was comparison of the diagnostic performance of ME with NBI and MC.

RESULTS

The sensitivity of ME with NBI and MC for the diagnosis of adenomas was 91.9% and 95.7%, respectively, and their specificity was 79.2% and 79.9%, respectively. The sensitivity of ME with NBI and MC for the diagnosis of cancer was 70.5% and 79.9%, respectively, and the specificity was 95.3% and 95.7%, respectively. The sensitivity of ME with NBI and MC for the diagnosis of cancer with deep submucosal invasion was 50.0% and 88.0%, respectively (P < 0.0001), and their specificity was 100% and 82.8%, respectively (P < 0.0001).

CONCLUSIONS

The specificity of evaluation of MV and MS by ME with NBI for the diagnosis of cancer with deep submucosal invasion was much higher than that of pit pattern analysis by MC.

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

INTRODUCTION

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

FINDINGS AND CONCLUSIONS

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

Image-enhanced endoscopy for diagnosis of colorectal tumors in view of endoscopic treatment

Recently, image-enhanced endoscopy (IEE) has been used to diagnose gastrointestinal tumors. This method is a change from conventional white-light (WL) endoscopy without dyeing solution, requiring only the push of a button. In IEE, there are many advantages in diagnosis of neoplastic tumors, evaluation of invasion depth for cancerous lesions, and detection of neoplastic lesions. In narrow band imaging (NBI) systems (Olympus Medical Co., Tokyo, Japan), optical filters that allow narrow-band light to pass at wavelengths of 415 and 540 nm are used. Mucosal surface blood vessels are seen most clearly at 415 nm, which is the wavelength that corresponds to the hemoglobin absorption band, while vessels in the deep layer of the mucosa can be detected at 540 nm. Thus, NBI also can detect pit-like structures named surface pattern. The flexible spectral imaging color enhancement (FICE) system (Fujifilm Medical Co., Tokyo, Japan) is also an IEE but different to NBI. FICE depends on the use of spectral-estimation technology to reconstruct images at different wavelengths based on WL images. FICE can enhance vascular and surface patterns. The autofluorescence imaging (AFI) video endoscope system (Olympus Medical Co., Tokyo, Japan) is a new illumination method that uses the difference in intensity of autofluorescence between the normal area and neoplastic lesions. AFI light comprises a blue light for emitting and a green light for hemoglobin absorption. The aim of this review is to highlight the efficacy of IEE for diagnosis of colorectal tumors for endoscopic treatment.

Endoscopy in screening for digestive cancer

The aim of this study is to describe the role of endoscopy in detection and treatment of neoplastic lesions of the digestive mucosa in asymptomatic persons. Esophageal squamous cell cancer occurs in relation to nutritional deficiency and alcohol or tobacco consumption. Esophageal adenocarcinoma develops in Barrett's esophagus, and stomach cancer in chronic gastric atrophy with Helicobacter pylori infection. Colorectal cancer is favoured by a high intake in calories, excess weight, low physical activity. In opportunistic or individual screening endoscopy is the primary detection procedure offered to an asymptomatic individual. In organized or mass screening proposed by National Health Authorities to a population, endoscopy is performed only in persons found positive to a filter selection test. The indications of primary upper gastrointestinal endoscopy and colonoscopy in opportunistic screening are increasingly developing over the world. Organized screening trials are proposed in some regions of China at high risk for esophageal cancer; the selection test is cytology of a balloon or sponge scrapping; they are proposed in Japan for stomach cancer with photofluorography as a selection test; and in Europe, America and Japan; for colorectal cancer with the fecal occult blood test as a selection test. Organized screening trials in a country require an evaluation: the benefit of the intervention assessed by its impact on incidence and on the 5 year survival for the concerned tumor site; in addition a number of bias interfering with the evaluation have to be controlled. Drawbacks of screening are in the morbidity of the diagnostic and treatment procedures and in overdetection of none clinically relevant lesions. The strategy of endoscopic screening applies to early cancer and to benign adenomatous precursors of adenocarcinoma. Diagnostic endoscopy is conducted in 2 steps: at first detection of an abnormal area through changes in relief, in color or in the course of superficial capillaries; then characterization of the morphology of the lesion according to the Paris classification and prediction of the risk of malignancy and depth of invasion, with the help of chromoscopy, magnification and image processing with neutrophil bactericidal index or FICE. Then treatment decision offers 3 options according to histologic prediction: abstention, endoscopic resection, surgery. The rigorous quality control of endoscopy will reduce the miss rate of lesions and the occurrence of interval cancer.

Digital chromoendoscopy for diagnosis of diminutive colorectal lesions

Introduction. To compare the accuracy of digital and real-time chromoendoscopy for the differential diagnosis of diminutive (<5 mm) neoplastic and nonneoplastic colorectal lesions. Materials and Methods. This is a prospective randomized study comparing the Fujinon intelligent color enhancement (FICE) system (65 patients/95 lesions) and indigo carmine (69 patients/120 lesions) in the analysis of capillary meshwork and pit pattern, respectively. All lesions were less than 5 mm in diameter, and magnification was used in both groups. Histopathology was the gold standard examination. Results. Of 215 colorectal lesions, 153 (71.2%) were adenomas, and 62 were hyperplastic polyps (28.8%). Morphological analysis revealed 132 (61.4%) superficial lesions, with 7 (3.3%) depressed lesions, and 83 (38.6%) protruding lesions. Vascular meshwork analysis using FICE and magnification resulted in 91.7% sensitivity, 95.7% specificity, and 92.6% accuracy in differentiating neoplastic from nonneoplastic lesions. Pit pattern analysis with indigo carmine and magnification showed 96.5% sensitivity, 88.2% specificity, and 94.2% accuracy for the same purpose. Conclusion. Both magnifying virtual chromoendoscopy and indigo carmine chromoendoscopy showed high accuracy in the histopathological diagnosis of colorectal lesions less than 5 mm in diameter.

Current clinical applications of magnifying endoscopy with narrow band imaging in the stomach

Narrow band imaging (NBI), in conjunction with magnifying endoscopy (ME), has arisen more and more attention in the area of advanced endoscopy. By enhancing the mucosal microvascular architecture and surface pattern, it is feasible to use ME-NBI to identify subtle changes associated with gastric inflammation, atrophy, intestinal metaplasia, and early gastric cancer. The new technique thus plays a valuable role in therapeutic decision-making, endoscopic treatment process, postoperative evaluation, and follow-up examination. To date, many criteria or evaluation method of ME-NBI has been proposed. This paper aims to summarize the various diagnosing classifications and the current clinical applications of ME-NBI in the stomach.

Computer-aided colorectal tumor classification in NBI endoscopy using local features

An early detection of colorectal cancer through colorectal endoscopy is important and widely used in hospitals as a standard medical procedure. During colonoscopy, the lesions of colorectal tumors on the colon surface are visually inspected by a Narrow Band Imaging (NBI) zoom-videoendoscope. By using the visual appearance of colorectal tumors in endoscopic images, histological diagnosis is presumed based on classification schemes for NBI magnification findings. In this paper, we report on the performance of a recognition system for classifying NBI images of colorectal tumors into three types (A, B, and C3) based on the NBI magnification findings. To deal with the problem of computer-aided classification of NBI images, we explore a local feature-based recognition method, bag-of-visual-words (BoW), and provide extensive experiments on a variety of technical aspects. The proposed prototype system, used in the experiments, consists of a bag-of-visual-words representation of local features followed by Support Vector Machine (SVM) classifiers. A number of local features are extracted by using sampling schemes such as Difference-of-Gaussians and grid sampling. In addition, in this paper we propose a new combination of local features and sampling schemes. Extensive experiments with varying the parameters for each component are carried out, for the performance of the system is usually affected by those parameters, e.g. the sampling strategy for the local features, the representation of the local feature histograms, the kernel types of the SVM classifiers, the number of classes to be considered, etc. The recognition results are compared in terms of recognition rates, precision/recall, and F-measure for different numbers of visual words. The proposed system achieves a recognition rate of 96% for 10-fold cross validation on a real dataset of 908 NBI images collected during actual colonoscopy, and 93% for a separate test dataset.

Differentiation between sessile serrated adenoma/polyp and non-sessile serrated adenoma/polyp in large hyper plastic polyp: A Japanese collaborative study

A hyperplastic polyp (HP) >10 mm is described as a large hyperplastic polyp (LHP). Previous studies have considered LHP and sessile serrated adenoma/polyp (SSA/P) as synonymous. Although HP and SSA/P have previously been morphologically distinguished, differences between LHP and SSA/P have not yet been reported. The present study aimed to define the differences between SSA/P and non-SSA/P in LHP using immunohistochemistry for Ki67. Colorectal serrated lesions (>10 mm) that were completely resected by endoscope and derived from 11 institutions in Japan [Dokkyo Medical University School of Medicine (Mibu), Takahiro Fujii Clinic (Tokyo), Sano Hospital (Kobe), Oda GI Clinic, Hattori GI Endoscopy and Oncology Clinic (Kumamoto), Ohta Clinic (Nagoya), Hiroshima University (Hiroshima), Iwate Medical University (Morioka), Juntendo and Kyorin Universities (Tokyo) as well as Toyama University (Toyama)] affiliated with the Japanese Society for Cancer of the Colon and Rectum (JSCCR) between January 2003 and December 2010 were selected. The histological criteria of the Japanese Society for Cancer of the Colon and Rectum (JSCCR, project meeting; editor-in chief, Takashi Yao) were used to distinguish SSA/P and non-SSA/P from LHP. Non-SSA/P comprises both incomplete SSA/P and HP. A total of 154 samples diagnosed as SSA/P or non-SSA/P from 148 patients were used. This study comprised 107 SSA/P and 47 non-SSA/P cases, whereby lesions were located on the right side of the colon (73.2 and 26.8%, respectively). Ki67-positivity in SSA/Ps was significantly higher compared to non-SSA/Ps. A greater number of SSA/Ps in LHP were located on the right side of the colon compared to the left side. SSA/Ps occurring on the right side of the colon may be precursor lesions of colorectal carcinoma in serrated neoplasia pathways. In conclusion, LHPs and SSA/Ps limited to the right side of the colon are suggested to be clinically treated as the same type of lesions.

Delaunay triangulation-based pit density estimation for the classification of polyps in high-magnification chromo-colonoscopy

In this work we propose a method to extract shape-based features from endoscopic images for an automated classification of colonic polyps. This method is based on the density of pits as used in the pit pattern classification scheme which is commonly used for the classification of colonic polyps. For the detection of pits we employ a noise-robust variant of the LBP operator. To be able to be robust against local texture variations we extend this operator by an adaptive thresholding. Based on the detected pit candidates we compute a Delaunay triangulation and use the edge lengths of the resulting triangles to construct histograms. These are then used in conjunction with the k-NN classifier to classify images. We show that, compared to a previously developed method, we are not only able to almost always get higher classification results in our application scenario, but that the proposed method is also able to significantly outperform the previously developed method in terms of the computational demand.

Wide field endoscopic resection for advanced colonic mucosal neoplasia: current status and future directions

Most colonic adenomas are ≤ 10 mm and are routinely treated by colonoscopic polypectomy with long-term health benefits. Nonpolypoid lesions ≥ 20 mm, whether sessile or flat and laterally spreading, are forms of advanced mucosal neoplasia that cannot be managed by conventional polypectomy and are often referred for surgery. However, the majority of these lesions when carefully assessed are found to be noninvasive and can be safely and effectively treated by advanced endoscopic techniques including endoscopic mucosal resection or endoscopic submucosal dissection with resultant cost, morbidity, and mortality benefits. Lesion assessment is a critical component. Enhanced imaging methods provide the opportunity for accurate pathological characterization, informing treatment decisions, without the need for previous histologic confirmation. Techniques of advanced endoscopic resection are still in evolution and further improvements, including hybrid techniques, bringing less technically challenging and shorter procedures with superior safety can be reasonably expected in the next decade. Safety is a fundamental consideration. Methods of early recognition of complications, risk stratification, and management pathways are being developed and refined. Standardization, validation, and adoption of these technological developments will improve endoscopic interpretation and therapy and in combination with an increased understanding of adenoma molecular biology, will result in a progressively more individualized lesion-specific endoscopic approach. The future of advanced endoscopic resection in the colon is promising, and the next few years should see the boundaries of endoscopic resection expand well beyond the limits of what we know today.

Colorectal surveillance interval assignment based on in vivo prediction of polyp histology: impact of endoscopic quality improvement program

BACKGROUND

Validated training methods are needed before in vivo optical diagnosis can be used to guide colorectal cancer surveillance interval assignments.

OBJECTIVES

To assess the impact of endoscopist training on accuracy of surveillance intervals based on in vivo optical diagnosis.

DESIGN

Prospective, randomized study.

SETTING

Tertiary referral center.

PATIENTS

A total of 1231 patients with colorectal polyps (before training, n = 577; after training, n = 654).

INTERVENTIONS

Endoscopists were randomized to either participate or not participate in two 1-hour training sessions. Endoscopists' in vivo pathology predictions were recorded for all resected polyps. The accuracy of in vivo prediction-guided surveillance intervals were compared with pathology-guided intervals as the criterion standard. Surveillance interval accuracy before and after training were analyzed.

MAIN OUTCOME MEASUREMENTS

Surveillance interval accuracy based on in vivo polyp predictions with pathology-guided intervals as criterion standard before and after a training intervention.

RESULTS

Optically predicted surveillance intervals for the trained group of endoscopists had an overall accuracy of 84% (242/287) before training and 82% (261/317) after training. There was little evidence to suggest that training had a meaningful impact on the accuracy of optically predicted surveillance intervals (odds ratio 1.20; 95% CI, 0.76-1.89, P = .44).

LIMITATIONS

Limitations include small sample size, lack of endoscopist prediction confidence levels, and optional use of narrow-band imaging.

CONCLUSIONS

Surveillance interval accuracy did not meet published thresholds (>90%) to use in vivo optical diagnosis without pathologic confirmation. Larger studies, focused specifically on the impact of training, are needed to validate methods to improve polyp diagnosis and surveillance predication accuracy.

Molecular alterations in colitis-associated colorectal neoplasia: study from a low prevalence area using magnifying chromo colonoscopy

BACKGROUND AND AIM

Longstanding ulcerative colitis (UC) predisposes to colorectal cancer (CRC). To understand the molecular pathogenesis of colitis-associated colorectal neoplasia (UC-CRN), we studied the frequency of microsatellite instability (MSI) and mutations in p53, BRAF and KRAS genes in the tissues of patients with long standing UC with or without neoplasia and compared them with colitis patients without risk of neoplasia, and those with sporadic colorectal neoplasia (S-CRN) in an area with lower prevalence for either disease.

METHODS

Biopsies were obtained during magnifying chromo colonoscopy or routine colonoscopy in consecutive UC patients with high risk (UC-HR) and low risk (UC-LR) of neoplasia, and those with S-CRN. MSI (NCI-Bethesda panel) and mutations in p53, KRAS and BRAF genes were analysed.

RESULTS

Twenty-eight patients with UC-HR, 30 with UC-LR and 30 with S-CRN were included. Six (21.4%) of UC-HR had neoplasia (Progressors). MSI was not detected in the UC-CRN group as compared to 5 (16.7%) in the S-CRN group. p53 mutations occurred in 1 (3.3%) of UC-LR, increasing to 6 (27.3%, P<0.05) and 3 (50%, P<0.05) in the UC-HR subgroups without and with neoplasia respectively, as against 10 (33.3%) in sporadic neoplasia group. KRAS mutations were found only in the presence of neoplasia. None showed the BRAF mutation.

CONCLUSIONS

In a population with a lower prevalence for UC and CRC, the molecular pathogenesis of colitis-associated colorectal neoplasia is comparable to that reported from areas with a higher prevalence of these diseases, MSI being an exception.

Endoscopic image analysis in semantic space

A novel approach to the design of a semantic, low-dimensional, encoding for endoscopic imagery is proposed. This encoding is based on recent advances in scene recognition, where semantic modeling of image content has gained considerable attention over the last decade. While the semantics of scenes are mainly comprised of environmental concepts such as vegetation, mountains or sky, the semantics of endoscopic imagery are medically relevant visual elements, such as polyps, special surface patterns, or vascular structures. The proposed semantic encoding differs from the representations commonly used in endoscopic image analysis (for medical decision support) in that it establishes a semantic space, where each coordinate axis has a clear human interpretation. It is also shown to establish a connection to Riemannian geometry, which enables principled solutions to a number of problems that arise in both physician training and clinical practice. This connection is exploited by leveraging results from information geometry to solve problems such as (1) recognition of important semantic concepts, (2) semantically-focused image browsing, and (3) estimation of the average-case semantic encoding for a collection of images that share a medically relevant visual detail. The approach can provide physicians with an easily interpretable, semantic encoding of visual content, upon which further decisions, or operations, can be naturally carried out. This is contrary to the prevalent practice in endoscopic image analysis for medical decision support, where image content is primarily captured by discriminative, high-dimensional, appearance features, which possess discriminative power but lack human interpretability.

Characterization of lymphoid follicles with red ring signs as first manifestation of early Crohn's disease by conventional histopathology and confocal laser endomicroscopy

BACKGROUND AND AIMS

Clinical observations suggest that the lymphoid follicles (LFs) may play a crucial role in the pathogenesis of inflammatory bowel disease (IBD), especially in Crohn's disease (CD) as the site of initial mucosal inflammation. The aim of this study was to compare the morphology of LFs in CD, ulcerative colitis (UC) and control patients using confocal laser endomicroscopy (CLE) in correlation to histological and immunohistochemical findings of biopsies.

METHODS

79 patients with IBD (46 with CD, 32 with UC and 1 patient with indeterminate colitis) and 67 controls patients were enrolled prospectively in this study. Median age was 32.5 years (range 19-65) and 37.4 years (range 20-65 years) respectively. To analyze the LFs, standardized images from the terminal ileum and the colon were taken using white-light video endoscopes. Additionally, CLE was performed to analyze subsurface structure of LFs. Targeted biopsies of LFs were analyzed using haematoxylin and eosin stain and immunohistochemistry.

RESULTS

LFs were seen in all parts of the lower GI tract, but mostly in the terminal ileum and cecum. Endoscopy in 15 out of 17 patients with the first manifestation of CD showed LFs surrounded by red ring (so-called red ring sign, RRS). Histologically, LFs with RRS showed hypervascularization at the base of the LFs associated with numerous CD15-positive granulocytes. Similar features were not seen in LFs without RRS and in the control group. In some LFs with RRS early aphthous ulcers were seen. Using CLE, RRS showed abolished normal crypt architecture, crypt distortion, increased cellular infiltrate within the lamina propria, and dilated vessels.

CONCLUSION

LFs with RRS probably represent an early sign of aphthous ulcers in early CD and, thus, may be considered as early markers of first manifestation and flares in CD.

The detection of surface patterns by flexible spectral imaging color enhancement without magnification for diagnosis of colorectal polyps

PURPOSE

Flexible spectral imaging color enhancement (FICE), or image-enhanced endoscopy, can enhance visualization of surface and vascular patterns of colorectal polyps. Resolution of FICE has recently been improved. We evaluated diagnostic accuracy for neoplastic and non-neoplastic colorectal polyp differentiation with detection of surface patterns by FICE without magnification.

METHODS

Retrospective analysis of 151 colorectal polyps evaluated by FICE without magnification was performed. Neoplastic surface patterns were defined as tubular and oval pit. We aimed to determine sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy in correlating diagnosis by FICE without magnification with histology. Moreover, findings were compared to those of white-light endoscopy (WL) and chromoendoscopy (CHR).

RESULTS

Of the 151 colorectal polyps, 95 were identified as neoplastic and 56 were identified as non-neoplastic. FICE without magnification had a sensitivity of 89.4%, specificity of 89.2%, PPV of 93.4%, NPV of 83.3%, and accuracy of 89.4%. The accuracy of FICE value was higher than that of WL (sensitivity of 74.7%, specificity of 73.2%, PPV of 82.5%, NPV of 63.0%, and accuracy of 74.1%) and was worse than that of CHR (sensitivity of 96.8%, specificity of 89.2%, PPV of 93.9%, NPV of 96.1%, and accuracy of 94.7%). Imaging evaluation was validated by inter-/intra-observer measurements, demonstrating consistent results.

CONCLUSIONS

The detection of surface patterns by FICE without magnification is useful for differential diagnosis of colorectal polyps. We believe that FICE without magnification is more convenient and easier method than CHR.

Importance of histological evaluation in endoscopic resection of early colorectal cancer

The diagnostic criteria for colonic intraepithelial tumors vary from country to country. While intramucosal adenocarcinoma is recognized in Japan, in Western countries adenocarcinoma is diagnosed only if the tumor invades to the submucosa and accesses the muscularis mucosae. However, endoscopic therapy, including endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), is used worldwide to treat adenoma and early colorectal cancer. Precise histopathological evaluation is important for the curativeness of these therapies as inappropriate endoscopic therapy causes local recurrence of the tumor that may develop into fatal metastasis. Therefore, colorectal ESD and EMR are not indicated for cancers with massive submucosal invasion. However, diagnosis of cancer with massive submucosal invasion by endoscopy is limited, even when magnifying endoscopy for pit pattern and narrow band imaging and flexible spectral imaging color of enhancement are performed. Therefore, occasional cancers with massive submucosal invasion will be treated by ESD and EMR. Precise histopathological evaluation of these lesions should be performed in order to determine the necessity of additional therapy, including surgical resection.

Computer-generated surface and tone enhancements to distinguish neoplastic from non-neoplastic colon polyps less than 1 cm in diameter

BACKGROUND AND STUDY AIMS

Computer-generated enhancements, which can highlight the surface and color of a colonic lesion, may be helpful to predict the histology; however, it remains unclear whether this technology can distinguish neoplastic from non-neoplastic colon polyps when the polyps are <1 cm without magnification.

PATIENTS AND METHODS

Images of colorectal polyps less than 1 cm in diameter were obtained from 54 patients who underwent non-magnified colonoscopy with surface enhancement (SE) and tone enhancement (TE). We calculated the sensitivity, specificity, and accuracy in the prediction of histology. Inter- and intra-observer consistency was evaluated by inviting four endoscopists to rate 45 static images.

RESULTS

Overall sensitivity, specificity, and accuracy following the sequence of SE, TE colon, and TE pit pattern modes were 87.7% (95% confidence interval 81.3-94.1%), 84.1% (76.9-91.3%), and 86.1% (79.4-92.8%), respectively. For each modality, the results were 75.0% (68.7-81.3%), 82.7% (77.2-88.2%), and 77.2% (71.1-83.3%) for SE; 71.1% (64.5-77.7%), 78.8 (72.8-84.8), and 73.3% (66.8-79.8%) for TE colon mode; and 75.0% (68.7-81.3%), 80.8% (75.0-86.8%), and 76.7% (70.5-82.9%) for TE pit pattern mode. Their inter- and intra-observer agreements were all fair (κ range 0.522-0.568) and good (0.605-0.694), respectively. When the same rater evaluated the same lesion under different modalities, eight of 45 (18%) polyps yielded discordant interpretations, and the possibility of incorrect diagnoses was the highest with the TE colon mode.

CONCLUSION

Computer-generated enhancements are satisfactory in predicting the histology of small colon polyps without the need for magnification. This advantage is mostly related to the pit pattern enhancement.

Autofluorescence imaging and the quantitative intensity of fluorescence for evaluating the dysplastic grade of colonic neoplasms

BACKGROUND AND AIMS

Autofluorescence imaging (AFI) is a novel technology which can capture fluorescence emitted from intestinal tissues. While AFI is useful for detecting colorectal neoplasms, it is unclear whether AFI can facilitate the diagnosis by differentiating the extent of dysplasia of colorectal neoplasms. This study investigated the efficacy of AFI in discriminating high-grade from low-grade adenoma.

MATERIALS AND METHODS

Sixty-seven patients who underwent colonoscopy with AFI were enrolled in this study. The AFI images obtained from 158 lesions in these patients were visually classified into four categories, namely, green (G), green with magenta spots (GM), magenta with green spots (MG), and magenta (M), according to their color intensities, immediately after the examination. The AFI images of the lesions were quantified using an image-analytical software program (F index). Either the F index or the visual assessment was prospectively compared with the dysplastic grade.

RESULTS

The F index of the high-grade adenomas was significantly lower than that of the low-grade adenomas, hyperplasia, and normal mucosa (p < 0.05). The incidence of the lesions classified into the M classification for high-grade adenomas (55.6%) was significantly higher than that of either low-grade adenomas (20.8%) or hyperplasia (0%). No correlation was observed between the F index or the visual classification and the tumor shape. The F index was not influenced by the size of the lesion, while the size was significantly associated with the visual classification of AFI.

CONCLUSIONS

AFI, particularly the F index, is considered to be a useful procedure for estimating the dysplastic grade of colonic adenomas.

Narrow-band imaging of meshed capillary vessels for differential diagnosis of colorectal lesions

AIM: To evaluate the value of narrow-band imaging (NBI) in tissue characterization and differential diagnosis.

METHODS: A series of 75 patients with 116 colorectal lesions were studied. According to Yoshiki Wada's typing method, the vascular patterns of colorectal lesions were divided into six species: honey-comb, faint, network, dense, irregular, and sparse. During NBI, the microvascular architecture on the surface of the detected lesions was observed. Results of NBI were compared with histological results.

RESULTS: Most hyperplastic polyps showed a faint pattern. The vascular patterns of adenomas were mainly the network or dense pattern. The major vascular patterns of cancers were the irregular and sparse patterns. When we assumed that the faint pattern was diagnostic for hyperplastic polyps, we could differentiate between neoplastic and non-neoplastic lesions with a sensitivity of 94.6% and a specificity of 78.6%. The accuracy, positive predictive value and negative predictive value of capillary patterns (CP) under NBI were 88.8%, 88.6% and 89.2%, respectively (P < 0.01). Likewise, irregular and sparse patterns were assumed to be indices of cancer, and the sensitivity. specificity and accuracy were 100.0%, 87.5% and 91.4%, respectively (P < 0.01). When lesions < 10 mm were classified into 2 groups: polyps with invisible or faintly visible meshed capillary (MC) vessels as nonneoplastic and those with clearly visible MC vessels as neoplastic, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 89.7%, 80.5%, 81.4%, 89.2% and 85.0%, respectively (P < 0.01).

CONCLUSION: NBI is valuable for distinguishing between neoplastic and non-neoplastic lesions, as well as between cancers and adenomas, and for differential diagnosis of lesions < 10 mm.

Association between plasma 25-hydroxyvitamin D and colorectal adenoma according to dietary calcium intake and vitamin D receptor polymorphism

The anticarcinogenic potential of vitamin D might be mediated by not only calcium metabolism but also other mechanisms initiated by vitamin D receptor (VDR). The authors measured plasma 25-hydroxyvitamin D in healthy volunteer examinees who underwent total colonoscopy in Tokyo, Japan, 2004-2005, and evaluated its influence on colorectal adenoma, both alone and in interaction with VDR polymorphisms, which correspond to the FokI and TaqI restriction sites. The main analysis of plasma 25-hydroxyvitamin D included 737 cases and 703 controls. Compared with the lowest quintile of plasma 25-hydroxyvitamin D, only the highest was related to a significantly decreased odds ratio of colorectal adenoma (odds ratio = 0.64, 95% confidence interval: 0.45, 0.92). In contrast, all but the lowest quintile of dietary calcium intake presented similarly reduced odds ratios (odds ratio for the highest = 0.67, 95% confidence interval: 0.47, 0.95). Of note, the association between plasma 25-hydroxyvitamin D levels and colorectal adenoma was modified by the TaqI polymorphism of the VDR gene (P(interaction) = 0.03) but not by dietary calcium intake (P(interaction) = 0.93). These observations highlight the importance of vitamin D in colorectal tumorigenesis. Vitamin D might protect against colorectal neoplasia, mainly through mechanisms other than the indirect mechanism via calcium metabolism.

Diagnostic performance of chromoendoscopy and narrow band imaging for colonic neoplasms: a meta-analysis

AIM

We conducted a meta-analysis to compare the diagnostic test performance of chromoendoscopy and narrow band imaging (NBI) for colonic neoplasms.

METHOD

MEDLINE, EMBASE and the Cochrane Library were searched (1966 to March 2009). Articles were included if: (i) chromoendoscopy or NBI was used, (ii) sensitivity and specificity were reported; (iii) absolute numbers of true-positive, false-positive, true-negative and false-negative results were provided or could be calculated; and (iv) pathology was used as the reference standard. Sensitivity and specificity were pooled using random effects model. Secondary analyses were conducted by limiting the studies in which magnifying endoscopy was used alone as a diagnostic modality, and polyp size and macroscopic appearance of lesions were not considered.

RESULTS

Of 1342 screened articles, 27 met the inclusion criteria. Pooled sensitivity for chromoendoscopy and NBI was 0.94 (95% CI, 0.92-0.95) and 0.94 (0.91-0.97), and specificity was 0.82 (0.77-0.88) and 0.86 (0.83-0.89), respectively. There were no differences in sensitivity (P = 0.99) or specificity (P = 0.54) between the two methods. In the secondary analysis, pooled sensitivity for choromoendoscopy and NBI was 0.93 (95% CI, 0.90-0.97) and 0.96 (0.93-0.99) and specificity was 0.80 (0.73-0.87) and 0.85 (0.78-0.92). respectively. Overall, the pooled false-negative rate was 0.057 (95% CI, 0.040-0.73) for chromoendoscopy and 0.057 (95% CI, 0.028-0.085) for NBI.

CONCLUSION

Chromoendoscopy and NBI had similar diagnostic test characteristics in the assessment of colonic neoplasms; however, the false-negative rate for both methods of 5.7% is an unacceptably high rate and currently therefore, neither method is ready for general use.

Colonoscopy: new approaches to better outcomes

PURPOSE OF REVIEW

Prevention of colorectal cancer relies on the detection and removal of colorectal neoplasia. Recent advances in mucosal imaging and inspection techniques have increased the detection of small and diminutive colorectal polyps with unknown clinical impact. The ability to accurately predict whether a polyp is neoplastic may allow for an optical triage approach to polyp management, improving efficiency while reducing the cost and risk of polypectomy.

RECENT FINDINGS

High-definition white light colonoscopy, cap-fitted colonoscopy, and dye-based pan-chromoendoscopy have each shown to increase polyp detection. Virtual chromoendoscopy, although not beneficial for polyp detection, allows for accurate in-vivo prediction of polyp pathology. Endoscopists' behaviors, independent of patient factors, strongly influence adenoma detection. Training methods focused on the techniques of high adenoma detectors also increase adenoma and polyp detection.

SUMMARY

Advances in mucosal imaging and improvements in inspection technique have allowed us to detect more polyps and to predict their pathology with greater accuracy. An optical triage approach to either 'diagnose and discard' or 'diagnose and leave behind' has the potential to reduce the risk and cost of polypectomy.

Clinical usefulness of pit patterns for detecting colonic lesions requiring surgical treatment

BACKGROUND

The number of patients suffering from colorectal cancer is increasing. According to Japanese guidelines, lesions with a submucosal invasive depth >1,000 μm should be treated with radical proctocolectomy. We propose and evaluate a new clinical classification for pit patterns that uses endoscopy to assess lesion depth for determination of the appropriate therapeutic approach for early colorectal cancers and adenomas.

METHODS

Endoscopic images of colorectal adenomas and early cancer cases with type V(I) pit pattern, resected surgically or endoscopically from April 2002 to April 2007 at Showa University Yokohama Northern Hospital, were utilized for analysis. Each image was retrospectively analyzed for (A) pit narrowness, (B) irregular pit margins, and (C) indistinct stromal staining. Sensitivity, specificity, and predictive value were evaluated as major outcomes, using pathological results as the standard.

RESULT

In total, 186 cases were assessed. With all features considered (A, B, and C), the sensitivity, specificity, and positive and negative predictive values were 47.8%, 86.3%, 66.0%, and 74.2%, respectively. When limited to two features (A and B), these values were 75.3%, 81.2%, 70.2%, and 84.8%, respectively.

CONCLUSION

Our results suggest that the established criteria can, to a certain degree, distinguish between high and low irregularity in colorectal lesions with V(I) pit pattern indicating submucosal cancer infiltration of more or less than 1,000 μm with the clinical consequence of surgery versus endoscopic mucosal resection/endoscopic mucosal dissection.

Quantitative analysis of colorectal lesions observed on magnified endoscopy images

BACKGROUND

Various surface mucosal pit patterns, as recognized by endoscopists, correlate with the histologic features of colorectal cancers. We investigated whether magnified endoscopy images of these pit patterns could be analyzed quantitatively and thus facilitate computer-aided diagnosis of colorectal lesions.

METHODS

We applied both texture analysis and scale-invariant feature transform (SIFT) descriptors and discriminant analysis to magnified endoscopy images of 165 neoplastic colorectal lesions (pit patterns: type III(L)/IV, n = 44; type V(I)-mildly irregular, n = 36; type V(I)-severely irregular, n = 45; type V(N), n = 40) [histologic findings: tubular adenoma (TA), n = 56; carcinoma with intramucosal or even scant submucosal invasion (M/SM-s), n = 52, carcinoma with massive submucosal invasion (SM-m), n = 57]. We analyzed differences in pit pattern values and corresponding histologic values to determine whether the values were diagnostically meaningful.

RESULTS

Gray-level difference matrix (GLDM) inverse difference moment and spatial gray-level dependence matrix (SGLDM) local homogeneity values differed significantly between type III(L)/IV and type V(N) pit patterns. Values differed significantly for each analyzed feature between type III(L)/IV and type V(I)-severely irregular patterns and were high but descending for type III(L)/IV, type V(I)-mildly irregular, and type V(I)-severely irregular pit patterns (in that order). Similarly, texture analysis yielded high but descending values for TA, M/SM-s, and SM-m (in that order). Furthermore, SIFT descriptors and discriminant analysis yielded differences that were superior to those obtained by texture analyses.

CONCLUSIONS

Computer analysis of magnified endoscopy images for the diagnosis of colorectal lesions appears feasible. We anticipate further developments in the computer-aided diagnosis of pit patterns on magnified endoscopy images.

Endoscopic mucosal resection in colorectal lesion: a safe and effective procedure even in lesions larger than 2 cm and in carcinomas

CONTEXT: Endoscopic mucosal resection is a minimally invasive technique used in the treatment of colorectal neoplasms, including early carcinomas of different size and morphology. OBJECTIVES: To evaluate procedure safety, efficacy, outcomes, and recurrence rate in endoscopic mucosal resection of colorectal lesions. METHODS: A total of 172 lesions in 156 patients were analyzed between May 2003 and May 2009. All lesions showed pit pattern suggestive of neoplasia (Kudo types III-V) at high-magnification chromocolonoscopy with indigo carmine. The lesions were evaluated for macroscopic classification, size, location, and histopathology. Lesions 20 mm or smaller were resected en bloc and lesions larger than 20 mm were removed using the piecemeal technique. Complications and recurrence were analyzed. Patients were followed up for 18 months. RESULTS: There were 83 (48.2%) superficial lesions, 57 (33.1%) depressed lesions, 44 (25.6%) laterally spreading tumors, and 45 (26.2%) protruding lesions. Mean lesion size was 11.5 mm ± 9.6 mm (2 mm-60 mm). Patients' mean age was 61.6 ± 12.5 years (34-93 years). Regarding lesion site, 24 (14.0%) lesions were located in the rectum, 68 (39.5%) in the left colon, and 80 (46.5%) in the right colon (transverse, ascending, and cecum). There were 167 (97.1%) neoplasms: 142 (82.5%) adenomatous lesions, 24 (14.0%) intramucosal carcinomas, and 1 (0.6%) invasive carcinoma. En bloc resection was performed in 158 (91.9%) cases and piecemeal resection in 14 (8.1%). Bleeding occurred in 5 (2.9%) cases. Recurrence was observed in 4.1% (5/122) of cases and was associated with lesions larger than 20 mm (P<0.01), piecemeal resection (P<0.01), advanced neoplasm (P = 0.01), and carcinoma compared to adenoma (P = 0.04). CONCLUSIONS: Endoscopic mucosal resection of colorectal lesions is a safe and effective procedure, with low complication and local recurrence rates. Recurrence is associated with lesions larger than 20 mm and carcinomas.

Correlation of narrow band imaging with magnifying colonoscopy and histology in colorectal tumors

BACKGROUND/AIMS

Narrow band imaging (NBI) is a new technique that uses optical filters for imaging of mucosal morphology. The aim of this study was to correlate findings of NBI with magnifying colonoscopy and histology for prediction of neoplastic colorectal lesion.

METHODS

Between September 2005 and December 2007, 107 colon polyps from 68 patients were detected by conventional colonoscopy and subsequently evaluated by NBI with magnifying colonoscopy and analyzed for a pit pattern and a capillary pattern. More analysis was done regarding thickness and irregularity of capillary features.

RESULTS

Pit pattern with NBI magnification to discriminate between neoplastic and non-neoplastic lesions had a sensitivity of 88.9% and a specificity of 87.5%; capillary pattern yielded test performance characteristics of 91.9% and 87.5%. In respect of capillary thickness, invisible capillaries were found significantly more often in hyperplastic lesions. All thick capillaries were found in neoplastic polyps, and found significantly more often in carcinomas with submucosal massive invasion (sm-m) (p<0.01). In respect of capillary irregularity, invisible capillaries were found significantly more often in hyperplasic lesions, and severely irregular capillaries were found significantly more often in sm-m lesions (p<0.01).

CONCLUSIONS

Observation of capillary thickness and irregularity by NBI magnification is useful for correlating histological grade with carcinoma, especially with depth of submucosal invasion.

Correlation of narrow band imaging with magnifying colonoscopy and histology in colorectal tumors

Background/Aims

Narrow band imaging (NBI) is a new technique that uses optical filters for imaging of mucosal morphology. The aim of this study was to correlate findings of NBI with magnifying colonoscopy and histology for prediction of neoplastic colorectal lesion.

Methods

Between September 2005 and December 2007, 107 colon polyps from 68 patients were detected by conventional colonoscopy and subsequently evaluated by NBI with magnifying colonoscopy and analyzed for a pit pattern and a capillary pattern. More analysis was done regarding thickness and irregularity of capillary features.

Results

Pit pattern with NBI magnification to discriminate between neoplastic and non-neoplastic lesions had a sensitivity of 88.9% and a specificity of 87.5%; capillary pattern yielded test performance characteristics of 91.9% and 87.5%. In respect of capillary thickness, invisible capillaries were found significantly more often in hyperplastic lesions. All thick capillaries were found in neoplastic polyps, and found significantly more often in carcinomas with submucosal massive invasion (sm-m) (p<0.01). In respect of capillary irregularity, invisible capillaries were found significantly more often in hyperplasic lesions, and severely irregular capillaries were found significantly more often in sm-m lesions (p<0.01).

Conclusions

Observation of capillary thickness and irregularity by NBI magnification is useful for correlating histological grade with carcinoma, especially with depth of submucosal invasion.

Differentiating small polyp histologies using real-time screening colonoscopy with Fuji Intelligent Color Enhancement

BACKGROUND & AIMS

There are limited data describing the performance of Fuji Intelligent Color Enhancement (FICE, EC 590 ZW; Fujinon Inc, Saitama, Japan) for differentiating polyp histologies during screening colonoscopy. We evaluated the ability of an endoscopist to diagnose small polyp histology during a screening colonoscopy using FICE.

METHODS

A prospective study was performed on 763 consecutive, asymptomatic subjects who were undergoing screening colonoscopy. Pit patterns and vascular patterns were used to predict the histology of 525 polyps (mean size, 4.5 ± 2.2 mm, 315 adenomas) of less than 10 mm using FICE with high magnification and without. The performances of the FICE analyses were calculated and compared with the results from the histopathology.

RESULTS

The overall accuracy achieved by FICE with high magnification in the diagnosis of adenomas of less than 10 mm (87.0%) was significantly greater than that achieved without high magnification (80.4%; P < .05). Moreover, the improvement of accuracy attained when using high-magnification FICE was most pronounced and significant compared without using high-magnification FICE in the diagnosis for diminutive polyps (≤5 mm; 85.4% vs 79.1%; P < .05). Among all types of adenomas, the sensitivity of FICE was lowest for sessile serrated adenomas (38.5% vs 89.4%; P < .01), even when FICE was used with high magnification.

CONCLUSIONS

FICE with high magnification is better for differentiating the histology of small polyps during screening colonoscopy than FICE without high magnification, especially for diminutive polyps. Large-scale studies are needed to improve the identification of serrated adenomas and small diminutive polyps using FICE.

Mucin phenotype and narrow-band imaging with magnifying endoscopy for differentiated-type mucosal gastric cancer

BACKGROUND

Several studies have described the surface glandular structure in differentiated early gastric cancer observed by narrow-band imaging with magnifying endoscopy (NBI-ME) in two main patterns, i.e., a papillary or granular structure in an intralobular loop pattern (ILL) and a pit structure in a fine network pattern (FNP). However, it is uncertain why the NBI-ME findings of differentiated-type carcinomas are divided into two main patterns. We investigated the significance of the mucin phenotype in the morphogenetic difference between ILL and FNP.

METHODS

We evaluated 120 intramucosal, well- or predominantly well-differentiated tubular adenocarcinomas. In each lesion, one area that showed the predominant pattern of microsurface structures and microvessels was selected and marked by electrocoagulation for a strict comparative study by NBI-ME and pathological investigation. NBI-ME findings were classified into three patterns: ILL, FNP, and intermediate. Mucin phenotypes were judged as gastric, intestinal, or gastrointestinal type by immunohistochemistry.

RESULTS

The mucin phenotype was gastric or gastrointestinal type in 24 (92.3%) of 26 ILL lesions. Intestinal phenotype was observed in 22 (84.6%) of 26 FNP lesions. The gastrointestinal phenotype was observed in 50 (73.5%) of 68 intermediate pattern lesions. The mucin phenotype and NBI-ME results were significantly correlated (P < 0.001).

CONCLUSIONS

The mucin phenotype of differentiated early gastric cancer might be involved in morphogenetic differences between the papillary and pit structures visualized by NBI-ME.

Colorectal cancer screening in patients with ulcerative and Crohn's colitis with use of colonoscopy, chromoendoscopy and confocal endomicroscopy

BACKGROUND

Patients with ulcerative colitis and Crohn's colitis have increased risk of colorectal cancer. Current screening endoscopy protocols based on white light endoscopy (WLE) and random biopsies are laborious and of uncertain sensitivity. Novel endoscopic techniques include chromoendoscopy (CE) and confocal laser endomicroscopy (CLE).

AIM

The aim was to compare WLE and CE for the detection of intraepithelial neoplasia (IEN). Furthermore, we analysed the sensitivity and specificity of CE and CLE for the diagnosis of IEN.

METHODS

The cohort consisted of 30 patients examined by WLE, CE with 0.4% indigocarmine, and by a CLE system Pentax EC-3870CIFK during one examination. Additional 15 patients were examined by conventional protocol only. Random biopsies and biopsies from all suspicious lesions were taken. We compared the number of IENs detected by WLE and CE and analysed the predictive values of CE and CLE for the histology diagnosis.

RESULTS

There were 1584 random biopsies (35.2 per patient) taken. There were 78 targeted biopsies (1.7 per patient) taken in 24 of 45 patients examined by WLE and an additional 36 biopsies in 16 of 30 patients examined by CE (1.17 additional per patient). There were no IENs found on random biopsies versus six low-grade or high-grade IENs in four patients (two detected by WLE, four additional by CE) from targeted biopsies, P=0.02. A total of 100 suspicious lesions were detected and analysed by CE and histology. CLE could not examine 32 of 100 lesions (two of 30 flat vs. 30 of 70 pedunculated lesions, P=0.0002, odds ratio 10.5). The sensitivity of CE/CLE for low-grade or high-grade IEN was 100/100%, the specificity 96.8/98.4%, positive predictive value was 62.5/66.7% and negative predictive value was 100/100%.

CONCLUSION

Targeted biopsies are superior to random biopsies in the screening of IEN in patients with inflammatory bowel disease. CE increases the diagnostic yield of WLE. In our study CLE did not provide additional clinical benefits.

Cancer surveillance strategies in ulcerative colitis: the need for modernization

The risk of colorectal cancer is increased in patients with long-standing ulcerative colitis. Traditional surveillance has centered around regular standard white-light colonoscopy, with multiple biopsies aimed at detecting dysplasia or the identification of early cancer. This has resulted in only a modest reduction in cancer incidence and mortality. A better understanding of disease risk factors may allow endoscopic resources to be more focused on patients at higher risk. In addition, advanced endoscopic techniques have the potential to improve dysplasia detection, minimize the need for routine biopsies, and allow for the removal of dysplastic lesions, avoiding the need for surgery. Techniques such as magnification colonoscopy, chromoendoscopy, narrow band imaging, autofluorescence, and confocal endomicroscopy may all have a role to play in improving the benefits of endoscopic surveillance. Revised endoscopic surveillance strategies are proposed, incorporating aspects of risk stratification, a well-established practice in noncolitis-related colorectal cancer screening, and some of these new technologies.

Expression of IGF-1R in Colorectal Polyps and its Role in Colorectal Carcinogenesis

Insulin-like Growth Factor Receptor 1 (IGF-1R) may play a role in the neoplastic progression of colorectal cancer because it is related to both cellular proliferation and differentiation. The aim of this study was to further elucidate the role of IGF-1R in colorectal carcinogenesis by evaluating IGF-1R expression in different types of precancerous colorectal polyps and comparing its expression to normal mucosa and colorectal carcinoma. A total of 47 colorectal polyps and their respective adjacent normal mucosa were collected from 32 patients. In addition, 20 colorectal adenocarcinoma tissues were obtained from patients undergoing colorectal resection, and 12 normal non-malignant colorectal mucosal tissues collected from outpatients served as the control group. The pit patterns of polyps were classified by the Kudo classification scheme through magnifying chromoendoscopy. Immunohistochemistry and quantitative real-time RT-PCR were utilized for expression analysis of IGF-1R in colorectal mucosa, polyps, and adenocarcinoma tissue. The results of immunohistochemistry showed no significant differences in IGF-1R expression in inflammatory polyps compared with their surrounding normal mucosa by the Mann-Whitney U test (p = 0.251); however, tubular adenoma and villous adenoma tissues exhibited significantly higher levels of IGF-1R expression (p = 0.000). The results of real-time RT-PCR showed that IGF-1R was transcribed at a high level in colorectal adenomatous polyps and adenocarcinoma compared with their respective paired normal mucosa. Spearman's rank correlation two-variable analysis was used to demonstrate a significant correlation between the expression of IGF-1R and neoplastic progression from normal mucosa to adenomatous polyps and finally to colorectal cancer (r = 0.574, p = 0.000). This study suggests that the expression of IGF-1R correlates with the degree of carcinogenesis. In addition, these results demonstrated that there is a significant correlation between the level of IGF-1R expression and pit patterns of polyps (r = 0.432, p = 0.002). Thus, IGF-1R might be a factor in the morphological change of colorectal mucosal crypts, and it may play an important role in the growth and malignant transformation of precancerous polyps. These results suggest that IGF-1R can be considered a biomarker for the stage and risk of carcinogenesis during neoplastic initiation and progression along the colorectal normal mucosa-polyp-cancer sequence. Inhibitors of IGF-1R are not only a promising targeted anticancer strategy, but also a possible option for the chemoprevention of colorectal cancer.

Endoscopic diagnosis and treatment of ulcerative colitis

Ulcerative colitis (UC), one of non-specific chronic inflammatory conditions of the gastrointestinal tract with unknown complex etiology, is a chronic inflammatory bowel disorder characterized by diffuse mucosal inflammation of the colorectum with exacerbations and remissions. Nowadays, the diagnosis of UC is based mainly on symptoms, endoscopic findings, and histopathologic grading of biopsy specimens. However, there is a lack of a gold standard for the diagnosis of UC. Endoscopy is the cornerstone for diagnosis and evaluation of UC and plays a significant role in diagnosis, evaluating disease activity, malignancy surveillance and treatment. Over recent decades, the emergence of new imaging techniques, including endoscopic ultraonography, chromoendoscopy, magnification endoscopy, narrow-band endoscopic imaging, and laser scanning confocal microendoscopy, has provided a great boost to endoscopic diagnosis and treatment of UC. In this article, we will review the recent advances in endoscopic diagnosis and treatment of UC.

Endoscopic discrimination of sessile serrated adenomas from other serrated lesions

Sessile serrated adenoma (SSA) is a proposed precursor of colorectal carcinogenesis. This study aimed to analyze the potential of endoscopy to discriminate SSA from other serrated lesions, specifically traditional serrated adenoma (TSA) and hyperplastic polyp (HP). Of 145 serrated lesions, 111 sessile serrated lesions including 32 TSAs, 25 SSAs and 54 HPs were analyzed for size, color, location and morphologic features using conventional endoscopy and magnifying chromoendoscopy. SSA was preferentially located in the right colon, whereas TSA and HP were located in the left colon. The sizes of SSA and TSA were larger than those of HP. The lesion color was indistinguishable among TSA, SSA and HP. Macroscopically, a pinecone-like or two-tier raised appearance were found more frequently in TSA than in SAA and HP. Under magnified chromoendoscopic observation, the stellar III(L) pit pattern and fern-like appearance were observed more frequently in TSA than in SAA and HP. In conclusion, endoscopic discrimination between SSA and other sessile serrated lesions based on morphological features was difficult. However, size and location of the lesions facilitated diagnosis.

Gender difference in the association of insulin and the insulin-like growth factor axis with colorectal neoplasia

OBJECTIVE

Accumulating evidence has implicated insulin and the insulin-like growth factor (IGF) axis in colorectal carcinogenesis. Of interest, adiposity is likely to impose a greater risk on men than on women, which indicates that the association of insulin and the IGF axis with colorectal neoplasia may differ by gender. However, epidemiological evidence for this possible gender difference is limited to date.

METHODS

We measured plasma concentrations of C-peptide, IGF-I and IGF-binding proteins (IGFBPs) 1 and 3 in 1520 healthy volunteer examinees who underwent total colonoscopy between February 2004 and February 2005, and cross-sectionally investigated the association of these biomarkers with colorectal adenoma by gender. An unconditional logistic regression model was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) for colorectal adenoma after adjustment for potential confounders.

RESULTS

We observed a positive association of C-peptide and IGF-I (P (trend)<0.001 and 0.02, respectively) and an inverse association of IGFBP-1 (P (trend)=0.002) with colorectal adenoma in men. Adjusted ORs of colorectal adenoma for the highest compared with the lowest quartile were also statistically significant for C-peptide (OR: 2.62, 95% CI: 1.71-4.01), IGF-I (OR: 1.63, 95% CI: 1.08-2.46) and IGFBP-1 (OR: 0.49, 95% CI: 0.32-0.75). In contrast, no measurable association was seen in women. Corresponding ORs for C-peptide, IGF-I and IGFBP-1 were 0.98 (95% CI: 0.56-1.71), 0.79 (95% CI: 0.44-1.43) and 1.05 (95% CI: 0.60-1.86), respectively. The gender difference was statistically significant for C-peptide (P (interaction)=0.03) and marginally significant for IGF-I and IGFBP-1 (P (interaction)=0.14 and 0.12, respectively).

CONCLUSION

Our observations suggest that insulin and the IGF axis act differently by gender in colorectal carcinogenesis, at least in its early stage. The findings of this study further our understanding of the complexities of the gender difference in the association between adiposity and colorectal neoplasia.

Schwann cell hamartoma: case report

Background

Colorectal polyps of mesenchymal origin represent a small percentage of gastrointestinal (GI) lesions. Nevertheless, they are encountered with increasing frequency since the widespread adoption of colonoscopy screening.

Case presentation

We report a case of a small colonic polyp that presented as intramucosal diffuse spindle cell proliferation with a benign cytological appearance, strong and diffuse immunoreactivity for S-100 protein, and pure Schwann cell phenotype. Careful morphological, immunohistochemical and clinical evaluation emphasize the differences from other stromal colonic lesions and distinguish it from schwannoma, a circumscribed benign nerve sheath tumor that rarely arises in the GI tract.

Conclusion

As recently proposed, this lesion was finally described as mucosal Schwann cell hamartoma.

Endoscopic mucosal resection outcomes and prediction of submucosal cancer from advanced colonic mucosal neoplasia

BACKGROUND & AIMS

Large sessile colonic polyps usually are managed surgically, with significant morbidity and potential mortality. There have been few prospective, intention-to-treat, multicenter studies of endoscopic mucosal resection (EMR). We investigated whether endoscopic criteria can predict invasive disease and direct the optimal treatment strategy.

METHODS

The Australian Colonic Endoscopic (ACE) resection study group conducted a prospective, multicenter, observational study of all patients referred for EMR of sessile colorectal polyps that were 20 mm or greater in size (n=479, mean age, 68.5 y; mean lesion size, 35.6 mm). We analyzed data on lesion characteristics and procedural, clinical, and histologic outcomes. Multiple logistic regression analysis identified independent predictors of EMR efficacy and recurrence of adenoma, based on findings from follow-up colonoscopy examinations.

RESULTS

Risk factors for submucosal invasion were as follows: Paris classification 0-IIa+c morphology, nongranular surface, and Kudo pit pattern type V. The most commonly observed lesion (0-IIa granular) had a low rate of submucosal invasion (1.4%). EMR was effective at completely removing the polyp in a single session in 89.2% of patients; risk factors for lack of efficacy included a prior attempt at EMR (odds ratio [OR], 3.8; 95% confidence interval, 1.77-7.94; P=.001) and ileocecal valve involvement (OR, 3.4; 95% confidence interval, 1.20-9.52; P=.021). Independent predictors of recurrence after effective EMR were lesion size greater than 40 mm (OR, 4.37; 95% confidence interval, 2.43-7.88; P<.001) and use of argon plasma coagulation (OR, 3.51; 95% confidence interval, 1.69-7.27; P=.0017). There were no deaths from EMR; 83.7% of patients avoided surgery.

CONCLUSIONS

Large sessile colonic polyps can be managed safely and effectively by endoscopy. Endoscopic assessment identifies lesions at increased risk of containing submucosal cancer. The first EMR is an important determinant of patient outcome-a previous attempt is a significant risk factor for lack of efficacy.

Color treatment in endoscopic image classification using multi-scale local color vector patterns

In this work we propose a novel method to describe local texture properties within color images with the aim of automated classification of endoscopic images. In contrast to comparable Local Binary Patterns operator approaches, where the respective texture operator is almost always applied to each color channel separately, we construct a color vector field from an image. Based on this field the proposed operator computes the similarity between neighboring pixels. The resulting image descriptor is a compact 1D-histogram which we use for a classification using the k-nearest neighbors classifier.

To show the usability of this operator we use it to classify magnification-endoscopic images according to the pit pattern classification scheme. Apart from that, we also show that compared to previously proposed operators we are not only able to get competitive classification results in our application scenario, but that the proposed operator is also able to outperform the other methods either in terms of speed, feature compactness, or both.

Comparative evaluation of endoscopic factors from conventional colonoscopy and narrow-band imaging of colorectal lesions

BACKGROUND

Narrow-band imaging (NBI) diagnosis of colorectal lesions requires further consideration and standardized classification for attaining consensus among endoscopists.

OBJECTIVE

Compare vascular findings and diagnosis of colorectal lesions using various endoscopic images to assess effectiveness of NBI with magnification.

METHOD

Three endoscopic factors (vascular findings; diagnosis from NBI with magnification images; and total diagnosis from all available colonoscopic images including white light endoscopy, chromoendoscopy, NBI with magnification and magnifying chromoendoscopy) for 15 colorectal lesions were evaluated by 12 expert colonoscopists (Group A), 36 endoscopists not expert in colonoscopy (Group B) and 55 individuals not medical doctors, but familiar with gastrointestinal endoscopy or other medical products (Group C). We calculated accuracy percentages for all three endoscopic factors based on responses from each group. Highest percentage for vascular finding, NBI with magnification diagnosis and total diagnosis for each lesion assumed to be opinion of each group. We compared incidence of agreement among three groups and calculated invasion depth diagnostic accuracy rate for each group.

RESULTS

For vascular findings from NBI with magnification images, incidence of complete agreement among three groups was 46.7%, incidence of disagreement among three groups was 46.7% and incidence of complete disagreement among three groups was 6.7%. For diagnosis from NBI with magnification images and total diagnosis from all available endoscopic images, incidence of complete agreement, disagreement and complete disagreement were 40.0%, 60.0% and 0.0%, respectively, and 60.0%, 40.0% and 0.0%, respectively. Invasion depth diagnostic accuracy from NBI with magnification images and all available endoscopic images were 60.0% and 73.3%, respectively, in Group A; 46.7% and 66.7%, respectively, in Group B; and 46.6% and 60.0%, respectively, in Group C.

CONCLUSION

Results suggest some level of educational training is required for effective application of NBI with magnification for precise diagnosis of colorectal lesions.

The benefit of using narrow-band imaging systems for observation of capillary networks before determining of treatments for early colon cancer

INTRODUCTION

This study examined whether magnifying endoscopy with narrow-band Imaging observation could be useful selecting the appropriate treatment for early colon cancer.

PATIENTS AND METHODS

We analyzed 551 cases of colon tumors excised endoscopically or surgically, comprising 68 with large hyperplastic polyps, 25 traditional serrated adenomas, 141 tubular adenomas, 177 intramucosal cancers and 140 submucosal invasive (SM) cancers. We classified capillary network pattern into four types according to the degree of dilatation, irregularity and distribution of microcapillary features. These results were then compared with the histological findings.

RESULTS

The comparison of capillary pattern and histological features showed microcapillary networks by magnifying endoscopy with narrow-band imaging observation in intramucosal lesion or SM cancer with remnant neoplastic glands at the superficial layer.

CONCLUSIONS

The remaining microcapillary network was designed to maintain the architecture of neoplastic glands, even in the presence of subumucosal invasion. Consequently, loss of this network could correlate with depth of tumor invasion and histological reaction. Therefore, even if the tumor, remained of network was diagnosed to invade into SM layer, it should be checked up further examination by using magnifying endoscopy with crystal violet staining.

Clinical usefulness of narrow band imaging magnifying classification for colorectal tumors based on both surface pattern and microvessel features

We use the narrow band imaging (NBI) magnifying classification (Hiroshima Classification) on the basis of both their surface pattern and microvascular architecture to characterize colorectal tumors. Herein, we describe the Hiroshima Classification in detail and provide statistical data supporting its usefulness in diagnosing histologic type, whether a hyperplastic lesion, tubular adenoma, carcinoma with intramucosal to submucosal scanty invasion or carcinoma with submucosal massive invasion, and thus in selecting the appropriate treatment strategy. We also discuss the circumstances in which the Hiroshima Classification must be augmented by conventional pit pattern diagnosis. NBI magnification is easily carried out. We strongly recommend application of NBI magnification to the differential diagnosis of colorectal lesions as well as treatment decision making.

Vascular pattern classification of colorectal lesions with narrow band imaging magnifying endoscopy

Magnifying narrow band imaging (NBI) has enabled to observe the vascular pattern of colorectal lesions. Their broad findings have been divided into six groups according to endoscopical vascular features: normal, faint, network, dense, irregular and sparse. Most hyperplastic polyps show a faint pattern. The vascular patterns of adenomas are mainly network or dense ones. The predominant vascular patterns of cancer were irregular and sparse. Indeed, irregular pattern has found to be characteristic for protruded or flat-elevated cancer, whereas sparse pattern unique for depressed cancer. Through NBI, neoplastic lesions could be differentiated from those non-neoplastic with sensitivity of 83.5%, specificity of 98.7% and accuracy of 98.2%. It was able to distinguish between massively submucosal invasive cancers and slightly submucosal invasive cancers by using the vascular pattern with 91.0% sensitivity and 79.4% specificity. The overall accuracy was 88.3%. NBI system has showed to be a valuable technique for distinguishing neoplastic from non-neoplastic lesions, as well as massively from slightly submucosal invasive cancer. Therefore, vascular pattern analysis might be a promising tool for determining treatment selection, whether endoscopical or surgically.