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

Multidisciplinary Treatment Strategy for Early Colon Cancer: A Review-An English Version

Treatment for early colon cancer has progressed rapidly, with endoscopic resection and minimally invasive surgery. It is important to select patients without risk of lymph node metastasis before deciding on endoscopic resection for early colon cancer treatment. Pathological risk factors include histologic grade of cancer cell differentiation, lymphovascular invasion, perineural invasion, tumor budding, and deep submucosal invasion. These risk factors for predicting lymph node metastasis are crucial for determining the treatment strategy of endoscopic excision and radical resection for early colon cancer. A multidisciplinary approach is emphasized to establish a treatment strategy for early colon cancer to minimize the risk of complications and obtain excellent oncologic outcomes by selecting an appropriate treatment optimized for the patient's stage and condition. Therefore, we aimed to review the optimal multidisciplinary treatment strategies, including endoscopy and surgery, for early colon cancer.

[Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer]

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Clinical practice guideline for endoscopic resection of early gastrointestinal cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by <i>en bloc</i> fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Optical Technologies for Endoscopic Real-Time Histologic Assessment of Colorectal Polyps: A Meta-Analysis

OBJECTIVES

Accurate, real-time, endoscopic risk stratification of colorectal polyps would improve decision-making and optimize clinical efficiency. Technologies to manipulate endoscopic optical outputs can be used to predict polyp histology in vivo; however, it remains unclear how accuracy has progressed and whether it is sufficient for routine clinical implementation.

METHODS

A meta-analysis was conducted by searching MEDLINE, Embase, and the Cochrane Library. Studies were included if they prospectively deployed an endoscopic optical technology for real-time in vivo prediction of adenomatous colorectal polyps. Polyposis and inflammatory bowel diseases were excluded. Bayesian bivariate meta-analysis was performed, presenting 95% confidence intervals (CI).

RESULTS

One hundred two studies using optical technologies on 33,123 colorectal polyps were included. Digital chromoendoscopy differentiated neoplasia (adenoma and adenocarcinoma) from benign polyps with sensitivity of 92.2% (90.6%-93.9% CI) and specificity of 84.0% (81.5%-86.3% CI), with no difference between constituent technologies (narrow-band imaging, Fuji intelligent Chromo Endoscopy, iSCAN) or with only diminutive polyps. Dye chromoendoscopy had sensitivity of 92.7% (90.1%-94.9% CI) and specificity of 86.6% (82.9%-89.9% CI), similarly unchanged for diminutive polyps. Spectral analysis of autofluorescence had sensitivity of 94.4% (84.0%-99.1% CI) and specificity of 50.9% (13.2%-88.8% CI). Endomicroscopy had sensitivity of 93.6% (85.3%-98.3% CI) and specificity of 92.5% (81.8%-98.1% CI). Computer-aided diagnosis had sensitivity of 88.9% (74.2%-96.7% CI) and specificity of 80.4% (52.6%-95.7% CI). Prediction confidence and endoscopist experience alone did not significantly improve any technology. The only subgroup to demonstrate a negative predictive value for adenoma above 90% was digital chromoendoscopy, making high confidence predictions of diminutive recto-sigmoid polyps. Chronologic meta-analyses show a falling negative predictive value over time. A significant publication bias exists.

DISCUSSION

This novel approach to meta-analysis demonstrates that existing optical technologies are increasingly unlikely to allow safe "resect and discard" strategies and that step-change innovation may be required. A "diagnose and leave" strategy may be supported for diminutive recto-sigmoid polyps diagnosed with high confidence; however, limitations exist in the evidence base for this cohort.

Effectiveness of systematic training in the application of narrow-band imaging international colorectal endoscopic (NICE) classification for optical diagnosis of colorectal polyps: Experience from a single center in China

BACKGROUND AND AIM

To evaluate the effectiveness of systematic training in the application of narrow-band imaging (NBI) International Colorectal Endoscopic (NICE) classification for the prediction of the histology of colorectal polyps.

METHODS

This is a single-center study. In total, 260 still images of colorectal polyps from 225 patients were included. Two series of 130 images obtained using NBI and white light without magnification were distributed to 10 endoscopists-five highly experienced endoscopists (HEE group) and five less experienced endoscopists (LEE group)-for assessment using the NICE classification, before and after systematic training.

RESULTS

Before systematic training, accuracy in both groups was 79.54% and specificity was relatively poor (HEE: 62.46%, LEE: 69.23%, P = 0.297). After systematic training, specificity significantly improved (HEE: 96.61%, LEE: 97.54%, P = 0.000 and P = 0.013, respectively). Accuracy also significantly increased to 94.93% and 96.46% in the HEE and LEE groups, respectively. Sensitivity and negative predictive value did not significantly improve in the post-test; however, both were high in both the pre- and post-test. The κ-values in both groups were excellent (HEE: 0.93, LEE: 0.91). Among the components of the NICE classification, surface pattern yielded the highest performance, whereas color yielded the lowest.

CONCLUSION

Systematic, feedback-based, training programs can help achieve high accuracy and good interobserver agreement in the application of the NICE classification for the prediction of the histology of colorectal polyps by endoscopists with different levels of experience.

Observation of microvessels and invasion in early colorectal neoplasms on narrow band imaging: combination with CD34 and matrix metalloproteinase-7 expression

OBJECTIVE

The study aims to clarify the role of narrow band imaging (NBI) in the prediction of invasion depth and the formation of lesion appearance under NBI with immunohistochemical analysis.

MATERIALS AND METHODS

As a prospective single-center study, Sano's classification of capillary pattern (CP) was applied to differentiate early colorectal neoplasms under NBI observation. Only lesions with CP type III were analyzed, compared with final histologic findings, and further immunohistochemical analysis with CD34 and matrix metalloproteinase-7 (MMP-7) was performed.

RESULTS

As for the 203 cases of CP type III lesions, the sensitivity, specificity, and accuracy for CP type IIIA/IIIB were, respectively, 88.4, 93.6, and 92.5% to differentiate high-grade neoplasia or slight submucosal invasive carcinoma from deep submucosal invasive carcinoma. NBI prediction for invasion depth corresponded to immunohistochemical outcomes of CD34 and MMP-7, which might explain the reason why CP type IIIB displays nearly avascular or loose microvascular areas on the lesion surface.

CONCLUSION

NBI is of excellent use in predicting invasion depth for early colorectal neoplasms, and positive expression of MMP-7 is associated with the appearance of CP type IIIB.

Diagnostic performance of narrowed spectrum endoscopy, autofluorescence imaging, and confocal laser endomicroscopy for optical diagnosis of colonic polyps: a meta-analysis

BACKGROUND

Novel endoscopic technologies could allow optical diagnosis and resection of colonic polyps without histopathological testing. Our aim was to establish the sensitivity, specificity, and real-time negative predictive value of three types of narrowed spectrum endoscopy (narrow-band imaging [NBI], image-enhanced endoscopy [i-scan], and Fujinon intelligent chromoendoscopy [FICE]), confocal laser endomicroscopy (CLE), and autofluorescence imaging for differentiation between neoplastic and non-neoplastic colonic lesions.

METHODS

We identified relevant studies through a search of Medline, Embase, PubMed, and the Cochrane Library. Clinical trials and observational studies were eligible for inclusion when the diagnostic performance of NBI, i-scan, FICE, autofluorescence imaging, or CLE had been assessed for differentiation, with histopathology as the reference standard, and for which a 2 × 2 contingency table of lesion diagnosis could be constructed. We did a random-effects bivariate meta-analysis using a non-linear mixed model approach to calculate summary estimates of sensitivity and specificity, and plotted estimates in a summary receiver-operating characteristic curve.

FINDINGS

We included 91 studies in our analysis: 56 were of NBI, ten of i-scan, 14 of FICE, 11 of CLE, and 11 of autofluorescence imaging (more than one of the investigated modalities assessed in eight studies). For NBI, overall sensitivity was 91·0% (95% CI 88·6-93·0), specificity 85·6% (81·3-89·0), and real-time negative predictive value 82·5% (75·4-87·9). For i-scan, overall sensitivity was 89·3% (83·3-93·3), specificity 88·2% (80·3-93·2), and real-time negative predictive value 86·5% (78·0-92·1). For FICE, overall sensitivity was 91·8% (87·1-94·9), specificity 83·5% (77·2-88·3), and real-time negative predictive value 83·7% (77·5-88·4). For autofluorescence imaging, overall sensitivity was 86·7% (79·5-91·6), specificity 65·9% (50·9-78·2), and real-time negative predictive value 81·5% (54·0-94·3). For CLE, overall sensitivity was 93·3% (88·4-96·2), specificity 89·9% (81·8-94·6), and real-time negative predictive value 94·8% (86·6-98·1).

INTERPRETATION

All endoscopic imaging techniques other than autofluorescence imaging could be used by appropriately trained endoscopists to make a reliable optical diagnosis for colonic lesions in daily practice. Further research should be focused on whether training could help to improve negative predictive values.

FUNDING

None.

Colonic polyps: are we ready to resect and discard?

Colorectal cancer represents a major cause of mortality in Western countries, and population-based colonoscopy screening is supported by official guidelines. A significant determinant of the cost of colonoscopy screening/surveillance is driven by polypectomy of diminutive (≤5 mm) lesions. When considering the low prevalence of advanced neoplasia within diminutive polyps, the additional cost of pathologic examination is mainly justified by the need to differentiate between precancerous adenomatous versus hyperplastic polyps. The aim of this review is to summarize the data supporting the clinical application of a resect and discard strategy, also addressing the potential pitfalls associated with this approach.

New paradigms for colonoscopic management of diminutive colorectal polyps: predict, resect, and discard or do not resect?

The possibility to predict in vivo the histology of colorectal polyps by advanced endoscopic imaging has resulted in the implementation of a more conservative management for diminutive lesions detected at colonoscopy. In detail, a predict-and-do-not-resect strategy has been proposed for diminutive lesions located in the rectosigmoid tract, whilst a predict-resect-and-discard policy has been advocated for nonrectosigmoid diminutive polyps. Recently, the American Society for Gastrointestinal Endoscopy set required thresholds to be met, before allowing the adoption of these policies in the clinical field. The ability of current endoscopic imaging in reaching these thresholds would depend on a complex interaction among the accuracy of advanced endoscopic imaging in differentiating between adenomatous and hyperplastic lesions, the prevalence of (advanced) neoplasia within diminutive lesions, and the type of surveillance intervals recommended. Aim of this review is to summarize the data supporting the application of both a predict-and-do-not-resect and a predict-resect-and-discard policies, also addressing the potential pitfalls associated with these strategies.

Introduction: what are new roles of current colonoscopy?

The recent advances in endoscopic imaging technologies make great changes in the management of colorectal polyps. These changes include optical histologic diagnosis with high definition colonscopy, new management strategies such as resect and discard or do not resect, and differentiation of depth of submucosal invasion. In this focused review series, these new paradigms in management of colorectal polyps are discussed by three, world famous authors. First, Amit Rastogi explained optical diagnosis of small colorectal polyp with high definition colonoscopy using narrow band imaging. Second, Cesare Hassan explained new paradigms for colonoscopic management of diminutive colorectal polyps: resect and discard or do not resect. In the last, Shinji Tanaka described, in detail, endoscopic assessment of invasive colorectal cancer: slight vs. deep submucosal invasion. These focused review series introduce the new roles of current colonoscopy to readers and will help the readers to know how to use the new imaging technologies and paradigms in clinical practices.