High-magnification colonoscopy (with videos)

Detection of nonpolypoid colorectal neoplasia using magnifying endoscopy in colonic inflammatory bowel disease

Patients with inflammatory bowel diseases (IBD) have a high risk of colitis-associated dysplasia and cancer. It is important that careful surveillance with colonoscopy is performed for all patients with IBD and, more frequently, for those considered to be at high risk. Traditionally, flat dysplasia in ulcerative colitis has been considered to be detectable only by using random biopsy specimens of mucosa that appeared unremarkable during endoscopy. However, recent studies have shown that most of them are visible; thus, their detection as nonpolypoid colorectal neoplasms is an integral component in the prevention of colitic cancer.

Brief education on microvasculature and pit pattern for trainees significantly improves estimation of the invasion depth of colorectal tumors

Objectives. This study was performed to evaluate the effectiveness of education for trainees on the gross findings identified by conventional white-light endoscopy (CWE), the microvascular patterns identified by magnifying narrow-band imaging endoscopy (MNE), and the pit patterns identified by magnifying chromoendoscopy (MCE) in estimation of the invasion depth of colorectal tumors. Methods. A total of 420 endoscopic images of 35 colorectal tumors were used. Five trainees estimated the invasion depth of the tumors by reviewing the CWE images before education. Afterwards, the trainees estimated the invasion depth of the same tumors after brief education on CWE, MNE and MCE images, respectively. Results. The initial diagnostic accuracy for deep submucosal invasion before education and after education on CWE, MNE, and MCE findings was 54.3%, 55.4%, 67.4%, and 76.6%, respectively. The diagnostic accuracy increased significantly after MNE education (P = 0.028). The specificity for deep submucosal invasion before education and after education on CWE, MNE, and MCE findings was 47.9%, 45.7%, 65.0%, and 80.7%, respectively. The specificity increased significantly after MNE (P = 0.002) and MCE (P = 0.005) education. Conclusion. Brief education on microvascular pattern identification by MNE and pit pattern identification by MCE significantly improves trainees' estimations of the invasion depth of colorectal tumors.

Endoscopic features and management of diminutive colorectal submucosal invasive carcinoma

BACKGROUND AND AIM

The vast majority of diminutive (∼5 mm) colorectal tumors consist of a very low prevalence of advanced neoplasia, and a predict-resect-and-discard policy has been proposed recently in Western countries. The histology of some diminutive colorectal tumors reveals carcinoma, not adenoma, although the frequency is relatively low. Clarifying the endoscopic features of diminutive submucosal invasive colorectal carcinoma (CRC) during colonoscopy is important for managing diminutive lesions.

METHODS

A total of 111 cases of submucosal invasive CRC ≤ 10 mm were analyzed. The incidence of submucosal invasion in early CRC per gross type, size, location, pit pattern diagnosis, and rate of lymph node (LN) metastasis was evaluated.

RESULTS

In diminutive tumors, the overall submucosal invasion rate in early CRC was 9.6%; however, depressed tumors had a significantly higher frequency of submucosal invasion than protruded or flat elevated tumors. There were no significant differences in the distribution of submucosal invasive CRC between the diminutive tumors and those that were 6-10 mm. The pit pattern diagnosis of diminutive submucosal invasive CRC was type VI pit pattern in all cases. Each case of submucosal invasive CRC was completely resected by en bloc endoscopic resection, and there were no cases of LN metastasis.

CONCLUSION

Diminutive tumors with depression have a high frequency of submucosal invasive CRC and an initial indication for endoscopic resection.

Expanding indications for ESD: mucosal disease (upper and lower gastrointestinal tract)

Endoscopic resection is now considered a curative procedure for early gastric cancer. In Japan, it has increasingly replaced surgical resection for this indication, although in the West it has not been universally accepted as a first-line treatment. Recently, endoscopic submucosal dissection has been increasingly applied to colorectal disease, although it has not become a standard therapeutic procedure for early colorectal carcinoma because of its technical difficulty, the relatively long procedure time required, and the risk of complications, such as perforation and bleeding.

Is it possible to discriminate between neoplastic and nonneoplastic lesions in ulcerative colitis by magnifying colonoscopy?

BACKGROUND

Colitis-associated cancer/dysplasia is an intestinal tract condition that can affect the life expectancy of patients with ulcerative colitis. It is often difficult to detect neoplastic lesions. This study evaluated whether any endoscopic features are effective for distinguishing colitis-associated cancer/dysplasia from nonneoplastic lesions in patients with ulcerative colitis.

METHODS

The study involved 52 patients with 61 lesions treated at Hiroshima University Hospital between September 1999 and May 2012: 10 patients with 11 dysplastic lesions, 5 patients with 5 intramucosal carcinomas, 3 patients with 3 submucosal carcinomas, and 34 patients with 42 nonneoplastic lesions. All patients had undergone targeted biopsy. Endoscopic findings were compared between patients with biopsy-determined neoplasia and those with biopsy-determined nonneoplasia. Multivariate regression analysis was performed to identify magnifying chromocolonoscopy features predictive of neoplasia.

RESULTS

No significant difference was found in conventional endoscopy features between the neoplastic and nonneoplastic lesions. Under magnifying chromocolonoscopy, the pit density of the neoplastic lesions was found to be significantly greater than that of the nonneoplastic lesions (89% [17/19] versus 60% [25/42], respectively). Pit margins were more frequently irregular in the neoplastic lesions than in the nonneoplastic lesions (63% [12/19] versus 33% [14/42], respectively).

CONCLUSIONS

In differentiating between colitis-associated neoplastic and nonneoplastic lesions, focus should be on the high residual density of pits and irregular pit margins observed under magnifying chromocolonoscopy.

Advanced endoscopic imaging: a review of commercially available technologies

The rapid strides made in innovative endoscopic technology to improve mucosal visualization have revolutionized endoscopy. Improved lesion detection has allowed the modern endoscopist to provide real-time optical diagnosis. Improvements in image resolution, software processing, and optical filter technology have resulted in the commercial availability of high-definition endoscopy as well as optical contrast techniques such as narrow-band imaging, flexible spectral imaging color enhancement, and i-scan. Along with autofluorescence imaging and confocal laser endomicroscopy, these techniques have complemented and enhanced traditional white light endoscopy. They have the potential to serve as red-flag techniques to improve detection of mucosal abnormalities as well as allow optical diagnosis and virtual histology of detected lesions. This review will focus on these emerging commercially available technologies and aims to provide an overview of the technologies, their clinical applicability, and current status.

When is local excision appropriate for "early" rectal cancer?

Local excision is increasingly performed for “early stage” rectal cancer in the US; however, local recurrence after local excision has become a controversial issue in Western countries. Local recurrence is considered to originate based on the type of tumor and procedure performed, and in surgical margin-positive cases. This review focuses on the inclusion criteria of “early” rectal cancers for local excision from the Western and Japanese points of view. “Early” rectal cancer is defined as T1 cancer in the rectum. Only the tumor grade and depth of invasion are the “high risk” factors which can be evaluated before treatment. T1 cancers with sm1 or submucosal invasion <1,000 μm are considered to be “low risk” tumors with less than 3.2 % nodal involvement, and are considered to be candidates for local excision as the sole curative surgery. Tumors with a poor tumor grade should be excluded from local excision. Digital examination, endoscopy or proctoscopy with biopsy, a barium enema study and endorectal ultrasonography are useful for identifying “low risk” or excluding “high risk” factors preoperatively for a comprehensive diagnosis. The selection of an initial local treatment modality is also considered to be important according to the analysis of the nodal involvement rate after initial local treatment and after radical surgery.

Risk factors for vertical incomplete resection in endoscopic submucosal dissection as total excisional biopsy for submucosal invasive colorectal carcinoma

PURPOSE

Endoscopic submucosal dissection (ESD) for colorectal tumor is a minimally invasive treatment. Histologic information obtained from the entire ESD specimen is important for therapy selection in submucosal invasive colorectal carcinoma (SMca). This study aimed to identify risk factors for vertical incomplete resection (vertical margin-positive [VM+]) when ESD was performed as total excisional biopsy for SMca.

METHODS

From June 2003 through December 2011, 78 SMca cases were resected by ESD at Hiroshima University Hospital. Patient and tumor characteristics, intraoperative variables, and histopathology were compared between the VM+ group and the vertical complete resection (vertical margin-negative) group. The ability of magnifying endoscopy (ME) and endoscopic ultrasonography (EUS) to predict VM+ was assessed.

RESULTS

ESD resulted in VM+ in eight cases (10.3 %), with a greater percentage invading to a depth of ≥2,000 vs. <2,000 μm (P = 0.047). Severe submucosal fibrosis was found in five of the eight cases (62.5 %, P = 0.017). Poor differentiation was seen at the deepest invasive portion in six cases (75.0 %), and two of six cases had an invasion depth <2,000 μm. Of 39 EUS cases, 36 not showing deep invasion close to the muscularis propria were completely resected by ESD.

CONCLUSIONS

Submucosal fibrosis and poor differentiation at the deepest invasive portion may be risk factors for VM+ in colorectal ESD for tumors with submucosal deep invasion. ME plus EUS is more likely to help determine whether ESD is indicated as complete total excisional biopsy for SMca.

Characteristic magnifying narrow-band imaging features of colorectal tumors in each growth type

PURPOSE

We investigated the surface characteristics and vascular patterns of colorectal tumors according to growth type by means of magnifying narrow-band imaging (NBI).

METHODS

Four hundred ninety-seven colorectal tumors larger than 10 mm (204 tubular adenomas [TAs], 199 frankly invasive intramucosal carcinomas to shallow invasive submucosal [M/SM-s] carcinomas, and 94 deeply invasive submucosal [SM-d] carcinomas) were analyzed. These colorectal tumors were classified according to growth type as follows: polypoid type, n = 224; laterally spreading tumor-granular (LST-G) type, n = 133; and LST-non-granular (LST-NG) type, n = 140. Surface and vascular patterns were evaluated in relation to histology and growth type.

RESULTS

The absent and irregular surface patterns were observed in approximately 40 % of the SM-d carcinomas of the polypoid and LST-G type. The unclear surface pattern was more frequent in tumors of the LST-NG type than in those of other growth types, regardless of histology. Among TAs and M/SM-s carcinomas, the dense vascular pattern was most frequent in polypoid type, the dense and corkscrew vascular patterns were most frequent in the LST-G type, and the honeycomb and avascular and/or fragmentary patterns were most frequent in the LST-NG type. The avascular and/or fragmentary vessel pattern was more frequent in SM-d carcinomas than in TA and M/SM-s carcinomas, regardless of growth type.

CONCLUSIONS

A part of LST-NG was difficult to identify the NBI magnifying surface pattern. Although NBI magnifying findings were almost same in each type lesion in SM-d lesion, those of LST-NG were different from those of LST-G and polypoid type in M/SM-s lesion.

Endoscopic assessment of colorectal cancer with superficial or deep submucosal invasion using magnifying colonoscopy

Among early colorectal carcinoma, endoscopic treatment is generally indicative for cases with intramucosal to submucosal (SM) superficial invasion, because cases with SM deep invasion should be treated surgically due to the risk of lymph node metastasis. It is important, therefore, to distinguish between superficial and deep SM invasion in early colorectal carcinoma prior to treatment. In this review we assessed the clinical usefulness and knack of pit pattern and narrow band imaging (NBI) diagnosis using magnifying observation. VN type pit pattern, type C3 in NBI Hiroshima classification and NBI type 3 in NBI international colorectal endoscopic (NICE) classification are useful predictors of SM deep invasion. In NBI magnifying observation evaluation of both the vascular pattern and surface pattern are important. We have to use pit pattern diagnosis and NBI magnifying diagnosis as the situation demands with the knowledge of both advantage and disadvantage in each diagnostic method.

Warning for unprincipled colorectal endoscopic submucosal dissection: accurate diagnosis and reasonable treatment strategy

Piecemeal endoscopic mucosal resection (EMR) is generally indicated for laterally spreading tumors (LST) >2 cm in diameter. However, the segmentation of adenomatous parts does not affect the histopathological diagnosis and completeness of cure. Thus, possible indications for piecemeal EMR are both adenomatous homogenous-type granular-type LST (LST-G) and LST-G as carcinoma in adenoma without segmentalizing the carcinomatous part. Diagnosis of the pit pattern using magnifying endoscopy is essential for determining the correct treatment and setting segmentation borders. In contrast, endoscopic submucosal dissection (ESD) is indicated for lesions requiring endoscopic en bloc excision, as it is difficult to use the snare technique for en bloc excisions such as in non-granular-type LST (LST-NG), especially for the pseudodepressed type, tumors with a type VI pit pattern, shallow invasive submucosal carcinoma, largedepressed tumors and large elevated lesions, which are often malignant (e.g. nodular mixed-type LST-G). Other lesions, such as intramucosal tumor accompanied by submucosal fibrosis, induced by biopsy or peristalsis of the lesion; sporadic localized tumors that occur due to chronic inflammation, including ulcerative colitis; and local residual early carcinoma after endoscopic treatment, are also indications for ESD. In clinical practice, an efficient endoscopic treatment with segregation of ESD from piecemeal EMR should be carried out after a comprehensive evaluation of the completeness of cure, safety, clinical simplicity, and cost-benefit, based on an accurate preoperative diagnosis.

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.

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.

Current status and future perspectives of endoscopic submucosal dissection for colorectal tumors

Endoscopic submucosal dissection (ESD) allows for en bloc tumor resection irrespective of the size of the lesion. In Japan, ESD has been established as a standard method for endoscopic ablation of malignant tumors in the upper gastrointestinal tract. Although the use of colorectal ESD has been gradually spreading with the development of numerous devices, ESD has not yet been fully established as a standard therapeutic method for colorectal lesions. Currently, colorectal ESD is performed as an 'advanced medical treatment' without national health insurance coverage. With the recent accumulation of numerous cases, the safety and simplicity of colorectal ESD have improved remarkably. Currently in Japan, a prospective multicenter cohort study organized by the Japan Gastroenterological Endoscopy Society is ongoing to clarify the safety and efficacy of colorectal ESD to obtain remuneration from national health insurance. In this report, we showed the outcome regarding safety and efficacy of colorectal ESD through a review of the published work. Of 2719 cases with colorectal ESD at 13 institutions, the complete en bloc resection and perforation rates were 82.8% (61-98.2%, 2082/2516) and 4.7% (1.4-8.2%, 127/2719), respectively. Additional surgery for perforation was very rare because perforations were tiny enough to be closed endoscopically by clips in most of the cases and treated conservatively. In the near future, colorectal ESD will be a common therapeutic method for early colorectal carcinoma.

Proficiency in the diagnosis of nonpolypoid colorectal neoplasm yields high adenoma detection rates

BACKGROUND AND AIMS

Current efforts to prevent colorectal cancer focus on the detection and removal of neoplasms. Nonpolypoid colorectal neoplasms (NP-CRN) have a subtle appearance that can be difficult to recognize during colonoscopy. Endoscopists must first be familiar with the patterns of NP-CRN in order to detect and diagnose them. We studied the adenoma detection rates of endoscopists who had trained to detect NP-CRN, versus endoscopists who had not.

DESIGN

Retrospective Nested Case Control Study.

SETTING

Outpatient Screening Colonoscopy.

PARTICIPANTS

Adult Veterans.

INTERVENTION

Proficiency in the features and diagnosis of NP-CRN.

MAIN OUTCOMES MEASUREMENTS

Adenoma detection.

RESULTS

In total, 462 patients had screening colonoscopies-267 by colonoscopists who had trained in the features and diagnosis of NP-CRN. Patient characteristics were similar between groups-the majority were men with a mean age of 62 ± 6 years. Neoplasia was more prevalent (45.7 vs. 34.9%; p = 0.02) in patients evaluated by the trained compared to the conventionally trained group. Trained colonoscopists had a higher adenoma detection rate (0.76 vs. 0.54 adenomas per patient, p < 0.001); removed a higher proportion of neoplasia (77 vs. 35%, p < 0.001); and more frequently diagnosed NP-CRN lesions (OR 2.98, 95% CI: 1.46-6.08) compared to colonoscopists without supplemental training.

CONCLUSIONS

Endoscopists who are proficient in the detection of NP-CRN had significantly higher adenoma detection rates-of both polypoid and flat adenomas-compared to endoscopists without training, and were more specific in resection of adenomatous over hyperplastic lesions.

High technology imaging in digestive endoscopy

A thorough endoscopic visualization of the digestive mucosa is essential for reaching an accurate diagnosis and to treat the different lesions. Standard white light endoscopes permit a good mucosa examination but, nowadays, the introduction of powerful endoscopic instrumentations increased ability to analyze the finest details. By applying dyes and zoom-magnification endoscopy further architectural detail of the mucosa can be elucidated. New computed virtual chromoendoscopy have further enhanced optical capabilities for the evaluation of submucosal vascolar pattern. Recently, confocal endomicroscopy and endocytoscopy were proposed for the study of ultrastructural mucosa details. Because of the technological contents of powerful instrumentation, a good knowledge of implemented technologies is mandatory for the endoscopist, nowadays. Nevertheless, there is a big confusion about this topic. We will try to explain these technologies and to clarify this terminology.

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.

Epigenetic alteration of DNA in mucosal wash fluid predicts invasiveness of colorectal tumors

Although conventional colonoscopy is considered the gold standard for detecting colorectal tumors, accurate staging is often difficult because advanced histology may be present in small colorectal lesions. We collected DNA present in mucosal wash fluid from patients undergoing colonoscopy and then assessed the methylation levels of four genes frequently methylated in colorectal cancers to detect invasive tumors. We found that methylation levels in wash fluid were significantly higher in patients with invasive than those with noninvasive tumors. Cytologic and K-ras mutation analyses suggested that mucosal wash fluid from invasive tumors contained greater numbers of tumor cells than wash fluid from noninvasive tumors. Among the four genes, levels of mir-34b/c methylation had the greatest correlation with the invasion and showed the largest area under the receiver operating characteristic curve (AUC = 0.796). Using cutoff points of mir-34b/c methylation determined by efficiency considerations, the sensitivity/specificity were 0.861/0.657 for the 13.0% (high sensitivity) and 0.765/0.833 for the 17.8% (well-balanced) cutoffs. In the validation test set, the AUC was also very high (0.915), the sensitivity/specificity were 0.870/0.875 for 13.0% and 0.565/0.958 for 17.8%. Using the diagnostic tree constructed by an objective algorithm, the diagnostic accuracy of the invasiveness of colorectal cancer was 91.3% for the training set and 85.1% for the test set. Our results suggest that analysis of the methylation of DNA in mucosal wash fluid may be a good molecular marker for predicting the invasiveness of colorectal tumors.

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.

Imaging by Magnifying Endoscopy with NBI Implicates the Remnant Capillary Network As an Indication for Endoscopic Resection in Early Colon Cancer

Introduction. This study examined whether magnifying endoscopy with NBI observation (ME-NBI) could be useful selecting the appropriate treatment for submucosal invasive cancer (SM cancer). Patients and Methods. We analyzed 515 cases of colon tumors excised endoscopically or surgically. We classified capillary network pattern into four types according to the degree of dilatation, irregularity, and distribution of microcapillary features. Results. The comparison of capillary pattern and histological features revealed microcapillary networks by using confocal laser-scanning microscopy and ME-NBI in intramucosal lesion or SM cancer with remnant neoplastic glands at the superficial layer. In contrast, the network was absent in SM cancer with desmoplastic reactions, which invaded deeper into the submucosal layer. Conclusions. The remaining microcapillary network is designed to maintain the architecture of neoplastic glands. Consequently, loss of this network could correlate with depth of tumor invasion and desmoplastic reaction. Therefore, we can decide the appropriate treatment by using ME-NBI method.

Evaluation of new subclassification of type V(I) pit pattern for determining the depth and type of invasion of colorectal neoplasm

BACKGROUND

Colorectal neoplasms with a type V(I) pit pattern include various lesions, such as adenomas, intramucosal cancers, and submucosal carcinomas.

METHODS

We analyzed 96 colorectal neoplasms with a type V(I) pit pattern and identified six different variants: (1) unclear outline of the pit; (2) irregular margins of the pit; (3) narrowing of the pit; (4) ragged array of the pit; (5) high residual density of the pit; (6) abnormal branching of the pit. We examined the relationship between the appearance of each V(I) pit pattern and histology, including the depth of invasion.

RESULTS

In univariate logistic regression analysis the unclear outline, irregular margins, and narrowing of the pit were significantly associated with a submucosal (SM) invasion ≥1000 μm (P < 0.01). In multivariate logistic regression analysis, unclear outline of the pit was shown to be the only significant predictor of highly invasive submucosal cancer (odds ratio = 24.20, P < 0.0001). Regarding tumor morphology, the following were significantly associated with an SM invasion ≥1000 μm: in protruded type, ragged array (P = 0.022), irregular margins of the pit (P = 0.011), and unclear outline of the pit (P < 0.01); in flat type, irregular margins of the pit (P < 0.01) and unclear outline of the pit (P < 0.01); and in the depressed type, narrowing of the pit (P = 0.015) and unclear outline of the pit (P < 0.01).

CONCLUSIONS

Subclassification of the type V(I) pit pattern is useful for determining the depth of invasion of colorectal neoplasms.

Quantitative analysis and development of a computer-aided system for identification of regular pit patterns of colorectal lesions

BACKGROUND

Because pit pattern classification of colorectal lesions is clinically useful in determining treatment options for colorectal tumors but requires extensive training, we developed a computerized system to automatically quantify and thus classify pit patterns depicted on magnifying endoscopy images.

OBJECTIVE

To evaluate the utility and limitations of our automated pit pattern classification system.

DESIGN

Retrospective study.

SETTING

Department of endoscopy at a university hospital.

MAIN OUTCOME MEASUREMENTS

Performance of our automated computer-based system for classification of pit patterns on magnifying endoscopic images in comparison to classification by diagnosis of the 134 regular pit pattern images by an endoscopist.

RESULTS

For type I and II pit patterns, the results of discriminant analysis were in complete agreement with the endoscopic diagnoses. Type IIIl was diagnosed in 29 of 30 cases (96.7%) and type IV was diagnosed in 1 case. Twenty-nine of 30 cases (96.7%) were diagnosed as type IV pit pattern. The overall accuracy of our computerized recognition system was 132 of 134 (98.5%).

CONCLUSIONS

Our system is best characterized as semiautomated but is a step toward the development of a fully automated system to assist in the diagnosis of colorectal lesions based on classification of pit patterns.

Computerized virtual chromoendoscopy versus indigo carmine chromoendoscopy combined with magnification for diagnosis of small colorectal lesions: a randomized and prospective study

BACKGROUND AND STUDY AIMS

Magnifying colonoscopy with indigo carmine dye and the analysis of the capillary and the pit patterns by computed virtual chromoendoscopy (Fujinon Intelligent Color Enhancement, FICE) with magnification are effective for the differential diagnosis of neoplastic and non-neoplastic lesions. This study aimed to compare the accuracy of virtual and real chromoendoscopy in differentiating neoplastic and non-neoplastic colorectal lesions.

PATIENTS AND METHODS

A prospective randomized trial of magnification colonoscopy with targeted FICE (Group I - 72 patients/111 lesions) versus magnification colonoscopy with targeted indigo carmine dye (Group II - 72 patients/137 lesions) was performed in consecutive patients with lesions 1 cm or less. Histopathology of the specimens was regarded as the gold standard.

RESULTS

In group I, 86 (77.5%) lesions showed an intense vascular pattern (positive capillary meshwork), of which 80 (93%) were histologically confirmed as adenomas. From 25 lesions with negative capillary meshwork, 23 (92%) were non-neoplastic. Sensitivity, specificity, accuracy, positive and negative predictive values of the capillary meshwork for the differential diagnosis of these lesions was 97.8, 79.3, 92.8, 93 and 92%, respectively. The same parameters for pit pattern analysis by FICE were 92.7, 82.3, 90.1, 93.8 and 80%, respectively. Indigo carmine magnified chromoscopy showed sensitivity, specificity, accuracy, positive and negative predictive values of 97, 88.9, 94.9, 96.1 and 91.4%, respectively in the discrimination between neoplastic and non-neoplastic lesions.

CONCLUSION

Magnified virtual chromoendoscopy is as accurate as indigo carmine magnified chromoendoscopy in distinguishing between neoplastic from non-neoplastic small colorectal lesions.

Characterization of colorectal tumors using narrow-band imaging magnification: combined diagnosis with both pit pattern and microvessel features

OBJECTIVE

We aimed to clarify the clinical usefulness of narrow-band imaging (NBI) magnification for evaluating both pit appearances and microvessel architecture in comparison with evaluation of microvessel architecture alone in invasion depth of colorectal tumors.

MATERIAL AND METHODS

A total of 189 colorectal lesions [37 adenomas, 73 intramucosal to scanty submucosal invasive carcinomas and 79 massive submucosal invasive (SM-m) carcinomas] were analyzed. All lesions showing irregular pit structure were observed by NBI magnifying endoscopy. Based on both pit appearance and microvessel features, lesions were classified into three grades (C1, C2, C3), as described previously. Also, lesions were classified as high or low by microvessel irregularity. Furthermore, the histopathological background and the inter- and intraobserver variability of C subtype were assessed.

RESULTS

The SM-m rate of C1, C2 and C3 was 5.2, 60.5 and 92.7%, respectively. On the other hand, SM-m rate of lesion with mildly and highly irregular vessels was 13.3 and 55.0%, respectively. For the histopathological background, a high percentage of destruction of the glandular orifice, disappearance of the lamina muscularis mucosae and superficial exposure of desmoplastic reaction (DR) were observed in type C3. For C subtype classification of NBI magnification findings, the kappa value for interobserver variability was 0.749, and the kappa value for intraobserver variability was 0.745.

CONCLUSIONS

NBI magnification findings evaluated by both pit appearances and microvessel features (C subtype) showing a good kappa value in variability are more useful in invasion depth diagnosis of colorectal tumor than those evaluated by microvessel features alone.

Non-polypoid colorectal neoplasms in ulcerative colitis

The incidence of colorectal cancer associated with ulcerative colitis (UC) increases with time. It is imperative to identify dysplasia-associated lesions or masses (DALM) and non-polypoid colorectal neoplasms (NP-CRN) to reduce the morbidity and mortality from colorectal cancer associated with UC. Recent findings suggest most dysplastic lesions in UC can be considered as visible under careful endoscopic observation. To find NP-CRN in UC, the careful examination of well-prepared mucosa and noting subtle differences is necessary. Magnifying chromoendoscopy, therefore, can be useful to endoscopically diagnose these subtle findings. The authors believe that targeted biopsies during chromoendoscopy will increasingly be used and replace random biopsies in the future.

Advances in endoscopic imaging of colorectal neoplasia

Colon cancer screening is arguably the most important activity performed by gastroenterologists. Recent decreases in rates of death from colorectal cancer indicate that screening methods such as colonoscopy have a positive impact. There is still room for improvement, however, particularly in prevention of right-sided colon cancer. Practice issues, such as making colonoscopy more comfortable, safer, and less costly, are keys to continued success in cancer prevention. Colonoscopy techniques, technologies, and quality control measures have advanced to improve detection, classification, and removal of early neoplasias. In particular, slow, careful inspection of the colon by gastroenterologists who have been trained in lesion recognition has improved rates of detection of polypoid and flat neoplasias. Image enhancement methods such as chromoendoscopy have greatly improved neoplasia detection in patients with chronic colitis, but are not widely used because they are perceived as inconvenient. More convenient methods, such as "digital" chromoendoscopy, show promise but have had mixed results. Ultra-high magnification systems, including optical magnification and confocal endomicroscopy, can be used during the colonoscopy examination to evaluate small polyps, allowing physicians to make immediate diagnoses and decisions about whether to remove polyps. In patients with inflammatory bowel disease, improved imaging techniques could eliminate the needs for analysis of randomly selected biopsy samples and resection of all (neoplastic and non-neoplastic) polyps. It is important to maintain high standards of quality for colonoscopy examination, detection, and removal of high-risk lesions, as well as to make colon cancer screening more widely accepted and affordable for the entire at-risk population.

Large endoscopic mucosal resection for colorectal tumors exceeding 4 cm

AIM: To evaluate the feasibility and the outcome of endoscopic mucosal resection (EMR) for large colorectal tumors exceeding 4 cm (LCRT) undergoing piecemeal resection.

METHODS: From January 2005 to April 2008, 146 digestive tumors larger than 2 cm were removed with the EMR technique in our department. Of these, 34 tumors were larger than 4 cm and piecemeal resection was carried out on 26 colorectal tumors. The mean age of the patients was 71 years. The mean follow-up duration was 12 mo.

RESULTS: LCRTs were located in the rectum, left colon, transverse colon and right colon in 58%, 15%, 4% and 23% of cases, respectively. All were sessile tumors larger than 4 cm with a mean size of 4.9 cm (4-10 cm). According to the Paris classification, 34% of the tumors were type Is, 58% type IIa, 4% type IIb and 4% type IIc. Pathological examination showed tubulous adenoma in 31%, tubulo-villous adenoma in 27%, villous adenoma in 42%, high-grade dysplasia in 38%, in situ carcinoma in 19% of the cases and mucosal carcinoma (m2) in 8% of the cases. The two cases (7.7%) of procedural bleeding that occurred were managed endoscopically and one small perforation was treated with clips. During follow-up, recurrence of the tumor occurred in three patients (12%), three of whom received endoscopic treatment.

CONCLUSION: EMR for tumors larger than 4 cm is a safe and effective procedure that could compete with endoscopic submucosal dissection, despite providing incomplete histological assessment.

Prediction of histology and invasive depth of colorectal neoplasia based on morphology of surface depression using magnifying chromocolonoscopy

BACKGROUND AND STUDY AIMS

Estimation of histology and depth of invasion in early colorectal neoplasia is essential for patient treatment. We therefore conducted a prospective study to examine whether the morphology of depression area contained at the surface of colorectal neoplasia can be used for predicting the histology and invasive depth.

METHODS

A series of 228 consecutive patients with 296 colorectal lesions were studied. All lesions were evaluated by magnifying chromocolonoscopy. Surface depression contained in the lesions was noted and the depressive morphology was further divided into two subgroups of type I and type II. All of the lesions were resected endoscopically or surgically and examined histologically for comparison.

RESULTS

A total of 296 lesions were evaluated, of which 66 (22.3%) contained an area of central depression, including 43 in nonpolypoid (flat and depressed) lesions (66%) and 23 in polypoid (10%). The overall accuracy of depressive morphology for distinction between low-grade dysplasia and high-grade dysplasia/invasive cancer, and between m-sm1 and sm2-sm3 was 86.4% and 84.8%, respectively.

CONCLUSIONS

Depression was predominantly contained in nonpolypoid colorectal neoplasia. Morphology of depression observed by magnifying chromocolonoscopy could be used as a complementary method to assess the degree of atypia and invasive depth in colorectal neoplasia.

Clinicopathologic features and endoscopic mucosal resection of laterally spreading tumors: experience from China

BACKGROUND

Laterally spreading tumors (LSTs) are being increasingly reported nowadays in Japan and the western countries with the application of magnification chromoendoscopy. The aim of this study was to analyze the clinicopathologic features of LSTs and to assess the outcome and safety of endoscopic mucosal resection (EMR) in China.

PATIENTS AND METHODS

One hundred nine patients with LSTs who underwent magnification chromoendoscopy were studied retrospectively. Clinicopathological features of 111 LSTs were analyzed. The efficacy and safety of EMR was assessed in 79 LSTs based on the outcome of follow-up colonoscopy and resection-related complications.

RESULTS

A total of 111 LSTs were diagnosed in 109 patients, including 89 (80%) laterally spreading tumor-granular (LST-G) type and 22 (20%) laterally spreading tumor-non-granular (LST-NG) type. There was significant difference in the dominant pit pattern between LST-G type and LST-NG type (p < 0.001). Type IV pit pattern (62%) was the main crypt pattern in LST-G type; whereas, type IIIL (50%) and type V pit pattern (36%) were predominant crypt patterns in LST-NG type. EMR was performed for 103 lesions. Six of the nine lesions with type V(I) pit pattern were completely resected by EMR. Eleven (14%) local recurrent lesions were detected in 79 follow-up lesions and were treated successfully during the follow-up.

CONCLUSIONS

The type of dominant pit pattern was different between LST-G type and LST-NG type. Many LSTs with a type V(I) pit pattern can be completely resected by EMR. EMR technique is a safe and efficacious treatment method for LST.

Knack and practical technique of colonoscopic treatment focused on endoscopic mucosal resection using snare

Endoscopic mucosal resection (EMR) is one of the main treatment modalities for broad-based protruded-type or flat-type lesions of colorectal tumors. In this report, the procedures and skills required for EMR, which forms the basis of colonoscopic treatment, are described based on the current situation. The knack of EMR is to understand the characteristics and selection of an adequate snare in each situation, selection of adequate local injection drug, to learn techniques of local injection, to master skilful snaring techniques, to estimate the degree of radial cure of locally resected regions using magnifying observation and the practice of additional trimming. As a result of the practice and learning of these points, EMR, including piecemeal resection, can be enough for curative treatment of colorectal tumor. We can and should differentiate EMR from endoscopic submucosal dissection (ESD) for various types of colorectal tumor according to detailed endoscopic diagnosis using magnification prior to treatment.

Evaluation of the clinical outcomes associated with EXERA II and LUCERA endoscopes

AIM

Regarding the assessment of colonic lesions, important differences between Japan and the Western world have emerged during the last decade. The aim of this study was to compare the clinical outcomes of the same equipment when used in Japan or in France.

METHOD

Chromoscopy has not been extensively accepted in the West, in contrast to the wide acceptance in Japan which is probably due to the national screening programme for early gastric cancer. With the development of narrow-band imaging (NBI) we might expect a more generalized approach to the clinical use of various classifications. Narrow band imaging might be an important step towards virtual chromoscopy. A total of 48 patients were examined with back-to-back colonoscopy, using a non-sequential (EXERA II, Olympus Medical Systems Corp., Tokyo, Japan) endoscope, and a sequential endoscope (LUCERA, Olympus Medical Systems Corp.).

RESULTS

Education differences also play a role in the evaluation of the clinical outcome of the endoscopy. In Japan, detailed classification of the morphology of the detected lesion is done as a preliminary characterization step before the treatment decision. In the West a treatment decision immediately leads to the therapeutic outcome (non-neoplastic or neoplastic; removed or not). This study showed clearly that, with the same equipment, we obtained identical results for image quality of image in Japan and France. Non-Japanese endoscopists could achieve the same results as Japanese colleagues if knowledge of the minute classification is more widely accepted.

CONCLUSION

While the differences in the evaluation of the clinical outcome are mostly cultural, the analysis of endoscopic imaging indicates that the LUCERA and EXERA series provide the same clinical benefit.

Therapeutic strategy for colorectal laterally spreading tumor

Most colorectal tumors larger than 20 mm in diameter are called laterally spreading tumors (LST), most of which are adenomatous lesions. Laterally spreading tumors are classified into two types according to their morphology, granular type (LST-G) and non-granular type (LST-NG). Each type has two subtypes. The former consists of a 'homogenous type' and a 'nodular mixed type', while the latter consists of a 'flat elevated (FE) type' and a 'psedodepressed (PD) type'. In LST-G and LST-NG FE types, type V pit pattern with magnification enables the recognition of the carcinomatous or submucosal invasive area. Most of these adenomatous large lesions can be cured by scheduled endoscopic piecemeal mucosal resection (EPMR). However, LST-G with large whole nodular type or type V pit pattern, which cannot be resected en bloc with a snare, is an indication for endoscopic submucosal dissection (ESD). The LST-NG PD has a high frequency of submucosal invasion and the submucosal invasive area cannot be recognized correctly in the pseudodepression with magnification prior to endoscopic treatment. Therefore, en bloc resection with ESD should be applied to LST-NG PD. The therapeutic strategy for choosing between EPMR and ESD for large LST lesions should therefore be determined based on the macroscopic findings of their subtype and pit pattern findings.

Estudo comparativo entre MBI (FICE®) e a magnificação com índigo-carmin no diagnóstico diferencial de lesões neoplásicas e não-neoplásicas de cólon e reto

CONTEXTO: O uso da cromoscopia virtual com sistema de imagem multibanda poderia auxiliar no diagnóstico in vivo de neoplasias colônicas. Objetivo - Avaliar a exatidão da magnificação associada à cromoendoscopia eletrônica ou com índigo-carmin na distinção entre lesões neoplásicas e não-neoplásicas do cólon e reto. MÉTODOS: Foram avaliadas prospectivamente 157 lesões colorretais em 75 pacientes. Empregou-se o sistema FICE® para a análise dos padrões de capilares, com a malha capilar negativa sendo considerada padrão de lesões não-neoplásicas, e a malha capilar positiva, o padrão das neoplasias. Após esta avaliação, ainda usando o sistema FICE®, o padrão de criptas foi definido conforme a classificação de Kudo. Por fim, instilou-se índigo-carmin à 0,8% e outro estudo das criptas foi realizado. RESULTADOS: Entre as 157 lesões colorretais, classificou-se 116 como malha capilar positiva, sendo 115 confirmadas histologicamente como neoplasias. Já entre as 41 lesões com malha capilar negativa, 32 eram não-neoplásicas. A sensibilidade foi de 92,7%, a especificidade de 97% e a precisão de 93,6%. Os padrões de criptas tipo I e II representaram as lesões não-neoplásicas e os tipos III-V, as neoplásicas. Com a utilização da cromoscopia eletrônica, observou-se sensibilidade de 94,4%, especificidade de 97% e precisão de 94,9%. Já com o uso da magnificação associada ao índigo-carmin, a sensibilidade foi de 97,6%, a especificidade de 93,9% e a precisão de 96,8%. CONCLUSÕES: Tanto a cromoendoscopia eletrônica, quanto o uso do índigo-carmin, associados à magnificação de imagens, apresentaram precisão elevada quanto ao diagnóstico histopatológico e não houve diferença estatística entre ambos os métodos.

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.

Colorectal endoscopic submucosal dissection: present status and future perspective, including its differentiation from endoscopic mucosal resection

Endoscopic submucosal dissection (ESD) allows en bloc resection of a lesion, irrespective of the size of the lesion. ESD has been established as a standard method for the endoscopic ablation of malignant tumors in the upper gastrointestinal (GI) tract in Japan. Although the use of ESD for colorectal lesions has been studied via clinical research, ESD is not yet established as a standard therapeutic method for colorectal lesions because colorectal carcinoma has unique pathological, organ specific characteristics that differ radically from those of the esophagus and stomach, and scope handling and control is more difficult in the colorectum than in the upper GI tract. Depending on the efficacy of endoscopic mucosal resection (EMR) and the clinicopathological characteristics of the colorectal tumor, the proposed indications for colorectal ESD are as follows: (1) lesions difficult to remove en bloc with a snare EMR, such as nongranular laterally spreading tumors (particularly the pseudo depressed type), lesions showing a type VI: pit pattern, and large lesions of the protruded type suspected to be carcinoma; (2) lesions with fibrosis due to biopsy or peristasis; (3) sporadic localized lesions in chronic inflammation such as ulcerative colitis; and (4) local residual carcinoma after EMR. Colorectal ESD is currently in the development stage, and a standard protocol will be available in the near future. We hope that colorectal tumors will be efficiently treated by a treatment method appropriately selected from among EMR, ESD, and surgical resection after precise preoperative diagnosis based on techniques such as magnifying colonoscopy.

Efficacy of the invasive/non-invasive pattern by magnifying chromoendoscopy to estimate the depth of invasion of early colorectal neoplasms

OBJECTIVE

During colonoscopy, estimation of the depth of invasion in early colorectal lesions is crucial for an adequate therapeutic management and for such task, magnifying chromoendoscopy (MCE) has been proposed as the best in vivo method. However, validation in large-scale studies is lacking. The aim of this prospective study was to clarify the effectiveness of MCE in the diagnosis of the depth of invasion of early colorectal neoplasms in a large series.

METHODS

A total of 4,215 neoplastic lesions were evaluated using MCE from October 1998 to September 2005 at the National Cancer Center Hospital, Tokyo, Japan. Lesions were prospectively classified according to the clinical classification of the pit pattern: invasive pattern or non-invasive pattern. All lesions were histopathologically evaluated.

RESULTS

There were 3,371 adenomas, 612 intramucosal cancers (m-ca), 232 submucosal cancers (sm-ca): 52 sm superficial (sm1) and 180 sm deep cancers (sm 2-3). Among lesions diagnosed as invasive pattern, 154 out of 178 (86.5%) were sm2-3, while among lesions diagnosed as non-invasive pattern, 4,011 out of 4,037 (99.4%) were adenomas, m-ca, or sm1. Sensitivity, specificity and diagnostic accuracy of the invasive pattern to differentiate m-ca or sm1 (< 1000 microm) from sm2-3 (> or = 1000 microm) were 85.6%, 99.4%, and 98.8%, respectively.

CONCLUSION

The determination of invasive or non-invasive pattern by MCE is a highly effective in vivo method to predict the depth of invasion of colorectal neoplasms.

Indications and techniques for lower intestinal endoscopy

The search for inflammatory and neoplastic lesions are the main indications for colonoscopy. A high rate of detection of polyps has become a quality criterion that depends on skilled handling of the colonoscope, on expertise and concentration during the examination, on excellent bowel preparation, and on a high standard of technical equipment. The diagnostic benefits outweigh the risk of bleeding, perforation and infection in almost all situations. Contraindications are signs of perforated intestine or imminent perforation due to deep ulcerations, necroses, or fulminant colitis. The patient's comorbidity must be considered to assess the physical stress of bowel preparation, colonoscopy and sedation. Informed consent is necessary and must be documented in all cases. It is advisable to explain planned therapeutic manoeuvres before the examination, since all non-invasive polyps must be removed completely. Total colonoscopy is possible in 95-99% of cases, but technical efforts are under way to solve the problem of looping and fixed colon angulations. Optimising optical imaging is another main focus of industrial development. The combination of narrow-band imaging, zoom magnification, and high-definition processor technology is currently the most promising tool for identifying small and flat lesions in the colon.

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.

Endoscopic submucosal dissection for colorectal neoplasia: possibility of standardization

BACKGROUND

Endoscopic submucosal dissection (ESD) has been positively applied to and gradually standardized for early stomach cancer, particularly in Japan. However, because it is technically difficult to perform ESD of the colon, ESD is not a commonly used technique.

OBJECTIVE

The aim of this study was to evaluate the possibility of standardizing colorectal ESD.

SETTING

ESD was performed at the Department of Endoscopy, Hiroshima University Hospital.

DESIGN

Time required for ESD, rate of complete en bloc resection, complication, and postoperative local persistence and recurrence were investigated retrospectively in 70 cases of colorectal neoplasia, wherein the lesion was more than 20 mm in diameter.

INTERVENTIONS

All lesions were resected by ESD.

RESULTS

The average (+/-SD) time required for ESD was 70.5+/-45.9 minutes (range, 15-180 minutes), and the histologic rate of complete en bloc resection was 80.0% (56/70). With regard to complication, 1.4% of cases of postoperative hemorrhage (1/70) and 10.0% of cases of perforation (7/70) were observed in total. The rate of perforation was investigated with respect to the type of knife used for ESD and the period after the induction of ESD. The rate of perforation markedly decreased with the practice of the technique. Moreover, the rate of perforation was high when an insulated-tip diathermic knife was used; practicing this technique was insufficient to reduce the rate of perforation. The average duration of follow-up was 614+/-289.5 days, and no case of local persistence and recurrence or metastasis was observed.

LIMITATIONS

The ESD technique depends on the level of each skill of each colonoscopist.

CONCLUSIONS

With regard to ESD of the colon, complication, eg, perforation, could be decreased by sufficient practice and selection of an appropriate knife. It is suggested that, in the near future, ESD will be standardized for the colon.