High-magnification colonoscopy (with videos)

Approaches and considerations in the endoscopic treatment of T1 colorectal cancer

The detection of early colorectal cancer (CRC) is increasing through the implementation of screening programs. This increased detection enhances the likelihood of minimally invasive surgery and significantly lowers the risk of recurrence, thereby improving patient survival and reducing mortality rates. T1 CRC, the earliest stage, is treated endoscopically in cases with a low risk of lymph node metastasis (LNM). The advantages of endoscopic treatment compared with surgery include minimal invasiveness and limited tissue disruption, which reduce morbidity and mortality, preserve bowel function to avoid colectomy, accelerate recovery, and improve cost-effectiveness. However, T1 CRC has a risk of LNM. Thus, selection of the appropriate treatment between endoscopic treatment and surgery, while avoiding overtreatment, is challenging considering the potential for complete resection, LNM, and recurrence risk.

Comparative Cost Analysis Between Endoscopic Resection and Surgery for Submucosal Colorectal Cancer

BACKGROUND

There are few studies analyzing the cost of endoscopic resection and surgical resection in the treatment of submucosal colorectal cancer.

OBJECTIVE

The objective was to perform a detailed cost analysis of endoscopic resection and surgical resection for submucosal colorectal cancer.

DESIGN

This was a retrospective observational study.

SETTING

This study was conducted at a tertiary academic center.

PATIENTS

Medical records of 484 patients with submucosal colorectal cancer who underwent endoscopic resection or surgical resection between July 2003 and July 2015 were reviewed.

MAIN OUTCOME MEASUREMENTS

The total costs during index admission and follow-up as well as clinical outcomes between the 2 groups were compared in the whole cohort and propensity score-matched cohort.

RESULTS

In the propensity score-matched analysis ( n = 155 in each group), the endoscopic resection and surgical resection groups did not show significant differences in the rates of procedure-related adverse events (6.5% vs 3.9%; p = 0.304) and recurrence (0.6% vs 1.3%; p > 0.99). Readmission was more common in the endoscopic resection group (40.6% vs 11.0%; p < 0.001) because 64 (41.3%) patients underwent additional surgery for endoscopic noncurative resection. The endoscopic resection group had a lower cost during the index admission (1335.6 vs 6698.4 USD; p < 0.001), whereas the surgical resection group had a lower cost during follow-up (2488.7 vs 5035.7 USD; p < 0.001). The total cumulative cost was lower in the endoscopic resection group (6371.3 vs 9187.1 USD; p < 0.001). The same trend was observed in the whole cohort without propensity score matching.

LIMITATIONS

A limitation of this study was the retrospective nature of analysis.

CONCLUSIONS

The total cumulative cost for treatment and follow-up for submucosal colorectal cancer was lower in the endoscopic resection group, which had comparable oncologic outcomes as the surgical resection group. Endoscopic resection can be considered a cost-effective option for initial treatment for submucosal colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B881 .

ANLISIS COMPARATIVO DE COSTOS ENTRE LA RESECCIN ENDOSCPICA Y LA CIRUGA PARA EL CNCER COLORRECTAL SUBMUCOSO

ANTECEDENTES: Existen pocos estudios que analizan el costo de la resección endoscópica y la resección quirúrgica en el tratamiento del cáncer colorrectal submucoso.OBJETIVO: El objetivo fue realizar un análisis detallado de costos tanto de la resección endoscópica y la resección quirúrgica para el cáncer colorrectal submucoso.DISEÑO: Este fue un estudio observacional retrospectivo.AJUSTE: Este estudio se realizó en un centro académico terciario.PACIENTES: Se revisaron las historias clínicas de 484 pacientes con cáncer colorrectal submucoso que fueron sometidos a resección endoscópica o resección quirúrgica entre julio de 2003 y julio de 2015.PRINCIPALES MEDICIONES DE RESULTADOS: Los costos totales durante la admisión índice y el seguimiento, así como los resultados clínicos entre los dos grupos, fueron comparados en toda la cohorte y la cohorte emparejada por puntuación de propensión.RESULTADOS: En el análisis emparejado por puntuación de propensión ( n = 155 en cada grupo), los grupos de resección endoscópica y resección quirúrgica no mostraron diferencias significativas en las tasas de eventos adversos relacionados con el procedimiento (6,5% vs 3,9%, p = 0,304) y recurrencia (0,6% vs 1,3%, p > 0,99). La readmisión fue más común en el grupo de resección endoscópica (40,6% vs 11,0%, p < 0,001) porque 64 (41,3%) pacientes fueron sometidos a una cirugía adicional para lograr la resección en aquellos casos en que la resección endoscópica no fue curativa. El grupo de resección endoscópica tuvo un costo menor durante el ingreso índice (1335.6 vs 6698.4 USD, p < 0.001), mientras que el grupo de resección quirúrgica tuvo un costo menor durante el seguimiento (2488.7 vs 5035.7 USD, p < 0.001). El costo total acumulado fue menor en el grupo de resección endoscópica (6371,3 vs 9187,1 USD, p < 0,001). La misma tendencia se observó en toda la cohorte sin emparejamiento por puntuación de propensión.LIMITACIONES: La naturaleza retrospectiva del análisis.CONCLUSIONES: El costo total acumulado para el tratamiento y seguimiento del cáncer colorrectal submucoso fue menor en el grupo de resección endoscópica, que tuvo resultados oncológicos comparables a los del grupo de resección quirúrgica. La resección endoscópica puede considerarse una opción rentable para el tratamiento inicial del cáncer colorrectal submucoso. Consulte Video Resumen en http://links.lww.com/DCR/B881 . (Traducción-Dr Osvaldo Gauto ).

Resection depth and layer of underwater versus conventional endoscopic mucosal resection of intermediate-sized colorectal polyps: A pilot study

Background and study aims  Curability of colorectal tumors is associated with resection depth and layer in endoscopic resection. Underwater endoscopic mucosal resection (UEMR) has not undergone sufficient histopathological evaluation. We conducted a pilot study to compare the effectiveness, including resection depth and layer, of UEMR and conventional endoscopic mucosal resection (CEMR). Patients and methods  This study was a single-center, retrospective study. Patients with colorectal lesions were treated by UEMR or CEMR between January 2018 and March 2020. Eligible patients were selected from included patients in a 1:1 ratio using propensity score matching. We compared the resection depth and layer and treatment results between the UEMR and CEMR groups. Results  We evaluated 55 patients undergoing UEMR and 291 patients undergoing CEMR. Using propensity score matching, we analyzed 54 lesions in each group. The proportion of specimens containing submucosal tissue was 100 % in both groups. The median thickness of the submucosal tissue was significantly greater in the CEMR group than in the UEMR group [1235 µm (95 % confidence interval [CI], 1020-1530 µm) vs. 950 µm (95 % CI, 830-1090 µm), respectively]. However, vertical margins were negative in all lesions in both groups. Conclusions  Our findings suggest that the median thickness of submucosal tissue in the UEMR group was about 1,000 μm. Even though the resection depth achieved with UEMR was more superficial than that achieved with CEMR, UEMR may be a treatment option, especially for colorectal lesions ≤ 20 mm in diameter without suspicious findings of submucosal deeply invasive cancer.

Endoscopic diagnosis and treatment of early colorectal cancer

Early colorectal cancer refers to cancer in the colorectum that is confined to the mucosa or submucosa and does not invade the muscularis propria, irrespective of lymph node or distant metastasis. As the number of persons undergoing screening colonoscopy increases, the proportion of patients diagnosed with precancerous colorectal lesions and early colorectal cancer also increases. In the last decade, innovative optical technologies for endoscopic diagnosis have been introduced and endoscopic treatment techniques such as endoscopic submucosal dissection have provided major breakthroughs in the management of early colorectal cancer. With these remarkable developments, endoscopic treatment has established itself as an alternative to surgical resection in the treatment of early colorectal cancer. This review will discuss the endoscopic diagnosis and treatment of early colorectal cancer. Furthermore, the unmet needs in this field and the latest research addressing those issues will be summarized.

Endoscopic Recognition and Classification of Colorectal Polyps

Colonoscopy allows the performing endoscopist to thoroughly evaluate superficial colon lesions based on morphologic features such as size, location, shape, and surface pattern and also perform endoscopic resection where appropriate. Different elements of polyp characterization have been incorporated into systems that standardize this evaluation process and elucidate the likelihood of submucosal invasion or malignancy. Lesions which have invaded the submucosa are more likely to metastasize and are often not appropriate for endoscopic resection. It is, therefore, essential for the proceduralist to understand the multiple elements of lesion characterization and how they fit into the existing classification schemes.

Depth diagnosis of early colorectal cancer: Magnifying chromoendoscopy or image enhanced endoscopy with magnification?

Depth diagnosis is extremely crucial in making a treatment choice between endoscopic resection and surgery in the early stages of cancers. Among several imaging modalities, we use magnifying endoscopy to diagnose lesions by close observation of the findings at mucosal surface layer. In combination with topical staining, magnifying endoscopy enables us to assess the definite pit structure, which referred to as magnifying chromoendoscopy (MCE). The pit pattern classification by MCE was proposed and is now widely accepted as the standard diagnostic criteria for colorectal lesions. Meanwhile, image enhanced endoscopy (IEE) represented by narrow-band imaging was developed to improve the visibility of surface and vascular findings without dyeing. Recent collaborative work performed by endoscopic experts in Japan yielded the unified diagnostic criteria, the Japan NBI Expert Team (JNET) classification, based on the findings of IEE with magnification. In this review, focusing on MCE and IEE with magnification, we aimed to give an outline of the pit pattern classification and the JNET classification, and further discuss their accuracy rate of depth diagnosis of early colorectal lesions by performing a review of the related literature. Both modalities have a high accuracy rate of nearly 90% for depth diagnosis. IEE with magnification is an ideal modality because it helps observe lesions without dye spraying; however, lesions with JNET type 2B have an inadequate diagnostic ability, which should be complemented by MCE. We conclude that accurate diagnosis is possible by examining lesions using both modalities properly to overcome the limitations of each modality.

Artificial Intelligence-Based Colorectal Polyp Histology Prediction by Using Narrow-Band Image-Magnifying Colonoscopy

Background/Aims

We have been developing artificial intelligence based polyp histology prediction (AIPHP) method to classify Narrow Band Imaging (NBI) magnifying colonoscopy images to predict the hyperplastic or neoplastic histology of polyps. Our aim was to analyze the accuracy of AIPHP and narrow-band imaging international colorectal endoscopic (NICE) classification based histology predictions and also to compare the results of the two methods.

Methods

We studied 373 colorectal polyp samples taken by polypectomy from 279 patients. The documented NBI still images were analyzed by the AIPHP method and by the NICE classification parallel. The AIPHP software was created by machine learning method. The software measures five geometrical and color features on the endoscopic image.

Results

The accuracy of AIPHP was 86.6% (323/373) in total of polyps. We compared the AIPHP accuracy results for diminutive and non-diminutive polyps (82.1% vs. 92.2%; p=0.0032). The accuracy of the hyperplastic histology prediction was significantly better by NICE compared to AIPHP method both in the diminutive polyps (n=207) (95.2% vs. 82.1%) (p<0.001) and also in all evaluated polyps (n=373) (97.1% vs. 86.6%) (p<0.001)

Conclusions

Our artificial intelligence based polyp histology prediction software could predict histology with high accuracy only in the large size polyp subgroup.

Underwater endoscopic mucosal resection versus endoscopic submucosal dissection for 20-30 mm colorectal polyps

BACKGROUND AND AIM

Endoscopic submucosal dissection (ESD) for large polyps provides a high en bloc resection rate, accurate pathological diagnosis, and low recurrence rate. However, ESD requires advanced techniques, and underwater endoscopic mucosal resection (UEMR) is an alternative. We investigated the efficacy and safety of UEMR for 20-30 mm colorectal lesions compared with ESD.

METHODS

We retrospectively evaluated systematically collected data of patients who underwent UEMR or ESD for 20-30 mm sessile colorectal lesions. Outcome measures were the incidence of local recurrence, procedure time, en bloc resection rate, and incidence of adverse events. We performed propensity score matching and inverse probability weighting adjustment to control for possible confounders.

RESULTS

We evaluated 125 patients undergoing UEMR and 306 patients undergoing ESD. Using propensity score matching, we analyzed 74 lesions in each group. UEMR had a shorter procedure time than ESD [6.7 min (95% confidence interval (CI), 5.3-8.1 min) vs 64.8 min (95% CI, 57.4-72.2 min), respectively]. Although the en bloc resection rate with UEMR was inferior to ESD [61% (95% CI, 49-72%) vs 99% (95% CI, 93-100%), respectively], there was no significant difference in the local recurrence rate between the procedures [0% (95% CI, 0-4.0%) in each group]. Inverse probability weighting adjustment revealed that neither ESD nor UEMR had a significant association with local recurrence.

CONCLUSIONS

Underwater endoscopic mucosal resection for 20-30  mm colorectal lesions was comparable with ESD regarding long-term outcomes, with a shorter procedure time, despite the lower en bloc resection rate.

Clinically Available Optical Imaging Technologies in Endoscopic Lesion Detection: Current Status and Future Perspective

Endoscopic optical imaging technologies for the detection and evaluation of dysplasia and early cancer have made great strides in recent decades. With the capacity of in vivo early detection of subtle lesions, they allow modern endoscopists to provide accurate and effective optical diagnosis in real time. This review mainly analyzes the current status of clinically available endoscopic optical imaging techniques, with emphasis on the latest updates of existing techniques. We summarize current coverage of these technologies in major hospital departments such as gastroenterology, urology, gynecology, otolaryngology, pneumology, and laparoscopic surgery. In order to promote a broader understanding, we further cover the underlying principles of these technologies and analyze their performance. Moreover, we provide a brief overview of future perspectives in related technologies, such as computer-assisted diagnosis (CAD) algorithms dealing with exploring endoscopic video data. We believe all these efforts will benefit the healthcare of the community, help endoscopists improve the accuracy of diagnosis, and relieve patients' suffering.

Impact of submucosal saline solution injection for cold snare polypectomy of small colorectal polyps: a randomized controlled study

BACKGROUND AND AIMS

Cold snare polypectomy (CSP) of small colorectal polyps is widely used. However, the technique is still troubled by insufficient resection depth, which may prevent precise pathologic evaluation. In this study, we investigated whether submucosal injection of saline solution helps to achieve deeper resection in CSP.

METHODS

The study was a single-center, prospective, randomized trial. Patients with small (3- to 10-mm diameter) nonpedunculated adenomatous or sessile serrated colorectal polyps were randomly allocated to either conventional CSP (C-CSP) or CSP with submucosal injection (CSP-SI). Primary outcome was the rate of complete muscularis mucosae (MM) resection, defined by the proportion of MM under the tumor more than 80% of the tumor's horizontal dimension. Secondary outcomes were the rates of negative lateral and vertical margins, fragmentation of resected specimens, conversion to hot snare mucosal resection, intraprocedural bleeding, delayed bleeding, and perforation.

RESULTS

Two hundred fourteen patients were randomly assigned to the CSP-SI (n = 107) or C-CSP (n = 107) group. The rate of complete MM resection was 43.9% in the CSP-SI group and 53.3% in the C-CSP group, a statistically insignificant difference. The rates of negative lateral margin and vertical margin (42.3% and 56.7%, respectively) in the CSP-SI group were significantly lower than those (58% and 76%) in the C-CSP group (P = .03 and P = .006, respectively). There was no polypectomy-related major bleeding or perforation.

CONCLUSIONS

Saline solution injection into the submucosa did not improve the resection depth of CSP of small colorectal polyps, and the method resulted in lower rates of negative lateral and vertical margins of resected lesions. (Clinical trial registration number: UMIN000037980.).

Magnification endoscopy in combination with acetic acid enhancement and narrow-band imaging for the accurate diagnosis of colonic neoplasms

Background and study aims  Magnification endoscopy with narrow-band imaging (NBIME) and NBIME with acetic acid enhancement (A-NBIME) enable visualization of the vascular and microstructural patterns of colorectal polyp. We compared the diagnostic accuracy and reproducibility of white light endoscopy (WLE), NBIME, and A-NBIME for predictive histologic diagnosis. Patients and methods  Consecutive colorectal polyps (N = 628; 38 hyperplasias, 488 adenomas, 72 M-SM1 cancers, and 30 SM2 cancers) were photographed with WLE, NBIME, and A-NBIME. Endoscopic images were independently reviewed by three experts, according to the traditional criteria for WLE, the Japan NBI Expert Team classification for NBIME, and pit pattern classification for A-NBIME to compare diagnostic accuracy and interobserver diagnostic agreement among modalities. Results  The specificity (95 % confidence interval) of hyperplasia and SM2 cancer with WLE were 98.2 % (96.8 %-99.1%) and 99.4 % (98.5 %-99.9 %), respectively, showing high accuracy for endoscopic resection without magnifying observation. Diagnostic accuracy of WLE, NBIME, and A-NBIME was 80.8 % (77.4 %-83.8 %), 79.3 % (75.9 %-82.4 %), and 86.1 % (83.2 %-88.7 %), respectively, showing the highest accuracy for A-NBIME among modalities ( P  < .05). NBIME showed a lower PPV for M-SM1 cancer ( P  < .05), as with WLE ( P  = .08) compared to A-NBIME. Fleiss's kappa values for WLE, NBIME, and A-NBIME diagnosis were 0.43 (0.39 - 0.46), 0.52 (0.49 - 0.56) and 0.65 (0.62 - 0.69), respectively, showing insufficient reproducibility of WLE and superiority of A-NBIME among modalities. Conclusion  WLE showed high accuracy for endoscopic resection of colorectal polyps in expert diagnosis. NBIME demonstrated a higher diagnostic reproducibility than WLE. A-NBIME showed possible superiority among modalities in both diagnostic accuracy and reproducibility.

Kudo’s Classification for Colon Polyps Assessment Using a Deep Learning Approach

Colorectal cancer (CRC) is the second leading cause of cancer death in the world. This disease could begin as a non-cancerous polyp in the colon, when not treated in a timely manner, these polyps could induce cancer, and in turn, death. We propose a deep learning model for classifying colon polyps based on the Kudo’s classification schema, using basic colonoscopy equipment. We train a deep convolutional model with a private dataset from the University of Deusto with and without using a VGG model as a feature extractor, and compared the results. We obtained 83% of accuracy and 83% of F1-score after fine tuning our model with the VGG filter. These results show that deep learning algorithms are useful to develop computer-aided tools for early CRC detection, and suggest combining it with a polyp segmentation model for its use by specialists.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer

The number of deaths from colorectal cancer in Japan continues to increase. Colorectal cancer deaths exceeded 50,000 in 2016. In the 2019 edition, revision of all aspects of treatments was performed, with corrections and additions made based on knowledge acquired since the 2016 version (drug therapy) and the 2014 version (other treatments). The Japanese Society for Cancer of the Colon and Rectum guidelines 2019 for the treatment of colorectal cancer (JSCCR guidelines 2019) have been prepared to show standard treatment strategies for colorectal cancer, to eliminate disparities among institutions in terms of treatment, to eliminate unnecessary treatment and insufficient treatment and to deepen mutual understanding between healthcare professionals and patients by making these guidelines available to the general public. These guidelines have been prepared by consensuses reached by the JSCCR Guideline Committee, based on a careful review of the evidence retrieved by literature searches and in view of the medical health insurance system and actual clinical practice settings in Japan. Therefore, these guidelines can be used as a tool for treating colorectal cancer in actual clinical practice settings. More specifically, they can be used as a guide to obtaining informed consent from patients and choosing the method of treatment for each patient. Controversial issues were selected as clinical questions, and recommendations were made. Each recommendation is accompanied by a classification of the evidence and a classification of recommendation categories based on the consensus reached by the Guideline Committee members. Here, we present the English version of the JSCCR guidelines 2019.

Japan Gastroenterological Endoscopy Society guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection

Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also several types of precarcinomatous adenomas. It is important to establish practical guidelines wherein preoperative diagnosis of colorectal neoplasia and selection of endoscopic treatment procedures are appropriately outlined and to ensure that actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society compiled colorectal endoscopic submucosal dissection/endoscopic mucosal resection guidelines by using evidence-based methods in 2014. The first edition of these guidelines was published 5 years ago. Accordingly, we have published the second edition of these guidelines based on recent new knowledge and evidence.

Role of magnetic resonance imaging in organ-preserving strategies for the management of patients with rectal cancer

Total mesorectal excision has been the most effective treatment strategy adopted to reduce local recurrence rates among patients with rectal cancer. The morbidity associated with this radical surgical procedure led surgeons to challenge the standard therapy particularly when dealing with superficial lesions or good responders after neoadjuvant radiotherapy, to which radical surgery may be considered overtreatment. In this subset of patients, less invasive procedures in an organ-preserving strategy may result in good oncological and functional outcomes. In order to tailor the most appropriate treatment option, accurate baseline staging and reassessment of tumor response are relevant. MRI is the most robust tool for the precise selection of patients that are candidates for organ preservation; therefore, radiologists must be familiar with the criteria used to guide the management of these patients. The purpose of this article is to review the relevant features that radiologists should know in order to provide valuable information during the multidisciplinary discussion and ultimate management decision.

Role of Magnification Chromoendoscopy in the Management of Colorectal Neoplastic Lesions Suspicious for Submucosal Invasion

BACKGROUND

Correctly predicting the depth of tumor invasion in the colorectal wall is crucial for successful endoscopic resection of superficial colorectal neoplasms.

OBJECTIVE

The aim of this study was to assess the accuracy of magnifying chromoendoscopy in a Western medical center to predict the depth of invasion by the pit pattern classification in patients with colorectal neoplasms with a high risk of submucosal invasion.

DESIGN

This single-center retrospective study, from a prospectively collected database, was conducted between April 2009 and June 2015.

SETTINGS

The study was conducted at a single academic center.

PATIENTS

Consecutive patients with colorectal neoplasms with high risk of submucosal invasion were included. These tumors were defined by large (≥20 mm) sessile polyps (nonpedunculated), laterally spreading tumors, or depressed lesions of any size.

INTERVENTIONS

Patients underwent magnifying chromoendoscopy and were classified according to the Kudo pit pattern. The therapeutic decision, endoscopic or surgery, was defined by the magnification assessment.

MAIN OUTCOME MEASURES

Sensitivity, specificity, and positive and negative predictive values of magnifying chromoendoscopy for assessment of these lesions were determined.

RESULTS

A total of 123 lesions were included, with a mean size of 54.0 ± 37.1 mm. Preoperative magnifying chromoendoscopy with pit pattern classification had 73.3% sensitivity, 100% specificity, 100% positive predictive value, 96.4% negative predictive value, and 96.7% accuracy to predict depth of invasion and consequently to guide the appropriate treatment. Thirty-three rectal lesions were also examined by MRI, and 31 were diagnosed as T2 lesions. Twenty two (70.1%) of these lesions were diagnosed as noninvasive by magnifying colonoscopy, were treated by endoscopic resection, and met the curative criteria.

LIMITATIONS

This was a single-center retrospective study with a single expert endoscopist experience.

CONCLUSIONS

Magnifying chromoendoscopy is highly accurate for assessing colorectal neoplasms suspicious for submucosal invasion and can help to select the most appropriate treatment. See Video Abstract at http://links.lww.com/DCR/A920.

Pine-cone and villi patterns are endoscopic signs suggestive of ulcerative colitis-associated colorectal cancer and dysplasia

BACKGROUND AND AIMS

The appropriate site for targeted biopsy during surveillance colonoscopy for ulcerative colitis (UC) is still unclear. We aimed to clarify key endoscopic findings suggestive of neoplastic lesions for targeted biopsy in UC.

METHODS

First, we created 769 stereomicroscopic pictures (509 neoplastic, 260 non-neoplastic) mimicking magnifying colonoscopic images from surgically resected specimens, including areas surrounding 25 neoplastic lesions in 15 patients with colitis-associated cancer at a single referral center. Second, we validated the results by using 113 magnifying endoscopic images (64 neoplastic, 49 non-neoplastic) from 39 lesions in 26 patients. Two evaluators, blinded to the pathologic diagnosis, independently classified them according to Kudo's pit pattern and surface morphology, such as pine-cone/villi patterns. The correlation between stereomicroscopic and pathologic findings (neoplastic vs non-neoplastic) for each image was investigated. The interobserver agreement was assessed using kappa statistics.

RESULTS

In the stereomicroscopic analysis, neoplastic pit patterns (types III-V) were significantly correlated with the presence of neoplasia (sensitivity 77.4%, specificity 89.5%, kappa value 0.677). Pine-cone/villi patterns also showed high specificity (96.8%) but low sensitivity (21.4%, kappa value 0.625) for neoplasia. Endoscopic validation showed similar trends. A revision of the endoscopic findings of flat dysplasia with non-neoplastic pit patterns revealed that a reddish area may facilitate the identification of such lesions.

CONCLUSIONS

Targeted biopsies are recommended, especially for lesions showing pine-cone/villi patterns in addition to neoplastic pit patterns. For flat "non-neoplastic pit patterns," a reddish area may be an indication for a biopsy.

Chromoendoscopy for Dysplasia Surveillance in Inflammatory Bowel Disease

Long-standing ulcerative colitis (UC) and extensive Crohn's colitis confer increased risk for development of colorectal cancer. Screening and surveillance colonoscopy programs aim to identify, resect, or detect dysplasia or colorectal cancer. Dysplastic lesions can be removed by endoscopic resection and patients with unresectable lesions can be referred for colectomy at an earlier stage, with the goal of reducing overall morbidity and mortality from colorectal cancer. Surveillance colonoscopy for patients with inflammatory bowel disease (IBD) is endorsed by multiple specialty societies. High-definition endoscopy systems provide improved image resolution, and application of dilute indigo carmine or methylene blue for chromoendoscopy can provide increased contrast. International specialty society guidelines differ in their recommendations regarding use of chromoendoscopy for dysplasia surveillance, with some guidelines advocating a risk-stratified surveillance strategy. In this review, we discuss chromoendoscopy technique, training, implementation, yield as compared with standard-definition and high-definition white light colonoscopy, and positioning of this technique in clinical practice.

Transfer learning for Bag-of-Visual words approach to NBI endoscopic image classification

We address a problem of endoscopic image classification taken by different (e.g., old and new) endoscopies. Our proposed method formulates the problem as a constraint optimization that estimates a linear transformation between feature vectors (or Bag-of-Visual words histograms) in a framework of transfer learning. Experimental results show that the proposed method works much better than the case without feature transformation.

Management of complex polyps of the colon and rectum

PUPRPOSE

Benign polyps that are technically challenging and unsafe to remove via polypectomy are known as complex polyps. Concerns regarding safety and completeness of resection dictate they undergo advanced endoscopic techniques, such as endoscopic mucosal resection or surgery. We provide a comprehensive overview of complex polyps and current treatment options.

METHODS

A review of the English literature was conducted to identifyarticles describing the management of complex polyps of the colon and rectum.

RESULTS

Endoscopic mucosal resection is the standard of care for the majority of complex polyps. Only polyps that fail endoscopic mucosal resection or are highly suspicious of invasive cancer but which cannot be removed endoscopically warrant surgery.

CONCLUSION

Several factors influence the treatment of a complex polyp; therefore, there cannot be a "one-size-fitsall" approach. Treatment should be tailored to the lesion's characteristics, the risk of adverse events, and the resources available to the treating physician.

Validity of conventional endoscopy using "non-extension sign" for optical diagnosis of colorectal deep submucosal invasive cancer

BACKGROUND AND STUDY AIMS

 The non-extension sign relates to a localized increase in thickness and rigidity due to deep submucosal invasive (SM-d: depth of 1000 μm or more) cancer. The present study aimed to evaluate the efficacy of the non-extension sign in assessing the optical diagnosis of colorectal SM-d cancer.

PATIENTS AND METHODS

 We retrospectively analyzed 309 patients with 315 early colorectal cancers that had been endoscopically or surgically resected. The non-extension sign was judged from chromoendoscopy (CE) using conventional white-light imaging with indigo carmine, and is taken to be positive when any one of the findings of rigidity of a circular arc, trapezoid elevation, or converging mucosal folds are seen. We assessed comparing the accuracy of CE, magnifying chromoendoscopy (M-CE), and magnifying narrow-band imaging (M-NBI) for the optical diagnosis of colorectal SM-d cancer.

RESULTS

Sensitivity, specificity, and accuracy for the diagnosis of SM-d cancer were 66.0 %, 95.8 %, and 86.3 % for CE; 80 %, 90.7 %, and 87.3 % for M-CE; and 65.0 %, 94.4 %, and 85.1 % for M-NBI, respectively. The specificity of CE was significantly higher than that of M-CE ( P  = 0.034). The sensitivity of M-CE was significantly higher than that of CE ( P  = 0.026). In a comparison of positive and negative groups for the non-extension sign in SM-d cancer, SM invasion was significantly deeper in the positive group than in the negative group (3012.5 μm vs 2002.4 μm, respectively; P  < 0.0001) and the rate of lymphovascular invasion was significantly higher in the positive group than in the negative group (63.6 % vs 41.2 %, respectively; P  = 0.032).

CONCLUSIONS

 The non-extension sign offers high diagnostic specificity for SM-d cancer, and surgery should be considered in patients with a positive non-extension sign.

Application of image-enhanced endoscopy in diagnosis of colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies, and in China the incidence and mortality of CRC are among the top in the world. Early diagnosis of CRC can improve the prognosis significantly. Image enhancement techniques have already been applied to endoscopy, including narrow band imaging, flexible spectral imaging, i-Scan, and blue laser imaging endoscopy system. These techniques, combined with image pre-processing or post-processing method, might improve the detection of lesions by enhancing the color contrast between lesions and their surrounding mucosa. Nowadays, several classification systems for colorectal tumors have been established based on the surface pattern and microvascular morphology of lesions. Image enhancement technology might display the microvascular structures more clearly and determine the malignancy and infiltrating depth of lesions more accurately.

Clinicopathologic and endoscopic features of early-stage colorectal serrated adenocarcinoma

Background

Serrated adenocarcinoma (SAC) is a distinct colorectal carcinoma variant that accounts for approximately 7.5% of all advanced colorectal carcinomas. While its prognosis is worse than conventional carcinoma, its early-stage clinicopathologic features are unclear. We therefore aimed to clarify the clinicopathologic and endoscopic characteristics of early-stage SACs.

Methods

Forty consecutive early-stage SAC patients at Hiroshima University Hospital were enrolled; SACs were classified into epithelial serration (Group A, n = 17) and non-epithelial serration (Group B, n = 23) groups. Additionally, we classified serrated adenoma into 4 types: sessile serrated adenoma (SSA), traditional serrated adenoma (TSA), unclassified, and non-serrated adenoma type.

Results

There were significant differences between Groups A and B in terms of tumor size (27.6 vs. 43.1 mm), incidences of T1 carcinoma (71% vs. 13%), and having the same color as normal mucosa (47% vs. 17%), respectively (p <0.01). In SACs >20 mm, the incidence of T1 carcinoma in Group A (70%) was significantly greater than that in Group B (13%) (p <0.05). There were significant differences in ‘Japan NBI Expert Team’ type 3 and type V pit pattern classifications between the 2 groups. The average TSA-type tumor size (42.6 mm) was significantly larger than that of the SSA (17.2 mm) and non-serrated component types (18.3 mm). The incidences of submucosal invasion in SSA- (80%), unclassified- (100%), and non-serrated-type (100%) tumors were significantly higher than that in the TSA type (11%).

Conclusions

Epithelial serration in the cancerous area and a non-TSA background indicated aggressive behavior in early-stage SACs.

Computer-Aided Diagnosis in Colorectal Cancer: Current Concepts and Future Prospects

Colorectal cancer is an important health issue, both in terms of the number of people affected and the associated costs. Colonoscopy is an important screening method that has a positive impact on the survival of patients with colorectal cancer. The association of colonoscopy with computer-aided diagnostic tools is currently under researchers’ focus, as various methods have already been proposed and show great potential for a better management of this disease. We performed a review of the literature and present a series of aspects, such as the basics of machine learning algorithms, different computational models as well as their benchmarks expressed through measurements such as positive prediction value and accuracy of detection, and the classification of colorectal polyps. Introducing computer-aided diagnostic tools can help clinicians obtain results with a high degree of confidence when performing colonoscopies. The growing field of machine learning in medicine will have a big impact on patient management in the future.

Clinical impact of surveillance colonoscopy using magnification without diminutive polyp removal

BACKGROUND AND AIM

In Western countries, endoscopic removal of all adenomas during colonoscopy is recommended. The present study evaluates the usefulness of magnifying colonoscopy without removal of diminutive (≤5 mm) colorectal polyps.

METHODS

Patients with diminutive polyps who were observed for over 5 years using magnification at Hiroshima University Hospital were selected retrospectively. Lesions ≥6 mm in size, depressed lesions, and lesions with type V pit pattern were indications for endoscopic resection. We investigated the characteristics of lesions indicated for endoscopic resection detected on surveillance colonoscopy and the risk factors for the incidence of lesions indicated for endoscopic resection.

RESULTS

A total of 706 consecutive patients were enrolled. Sixty-eight lesions indicated for endoscopic resection were detected, averaging 9.0 ± 4.8 mm, and 33 (49%) lesions were located in the right colon. Pathological diagnoses were adenoma, Tis carcinoma, and T1 carcinoma in 58 (85%), eight (12%), and two (3%) lesions, respectively. Five lesions were considered to grow from previously detected diminutive polyps. Relative risks for the incidence of a lesion indicated for endoscopic resection were 1.76 (95% confidence interval [CI], 1.004-3.23) for males compared with females, 3.76 (95% CI, 2.03-7.50) for more than three polyps at initial colonoscopy compared with one polyp, and 2.84 (95% CI, 1.43-5.24) for patients with carcinoma at initial colonoscopy compared with patients with no lesion indicated for endoscopic resection. Nine carcinomas were resected endoscopically.

CONCLUSION

Diminutive low-grade adenomas detected by using magnifying colonoscopy may not necessarily require removal.

A guide to multimodal endoscopy imaging for gastrointestinal malignancy - an early indicator

Multimodality imaging is an essential aspect of endoscopic surveillance for the detection of neoplastic lesions, such as dysplasia or intramucosal cancer, because it improves the efficacy of endoscopic surveillance and therapeutic procedures in the gastrointestinal tract. This approach reveals mucosal abnormalities that cannot be detected by standard endoscopy. Currently, these imaging techniques are divided into those for primary detection and those for targeted imaging and characterization, the latter being used to visualize areas of interest in detail and permit histological evaluation. This Review outlines the use of virtual chromoendoscopy, narrow-band imaging, autofluorescence imaging, optical coherence tomography, confocal endomicroscopy and volumetric laser endomicroscopy as new imaging techniques for diagnostic investigation of the gastrointestinal tract. Insights into use of multimodal endoscopic imaging for early disease detection, in particular for pre-malignant lesions, in the oesophagus, stomach and colon are described.

Successful Resection of a Large Rectal Adenoma Using the Transsacral Approach

The transsacral approach is not routinely used for treating rectal tumors. We report the case of a 65-year-old man with a large adenoma at the posterior wall of the mid-rectum who was treated via the transsacral approach. The same lesion had been treated using transsacral endoscopic microsurgery 8 years previously. Moreover, 11 years previously he had undergone a laparotomy for bladder cancer, and an Indiana pouch had been constructed. Abdominal computed tomography showed that the pouch was adjacent to the rectum. Therefore, the less-invasive transsacral approach, rather than the transabdominal approach, was chosen for treatment. The lesion was successfully resected, without disturbing the pouch. Histological analysis indicated tubular adenoma, with a small focus of intramucosal adenocarcinoma, and negative margins. Thus, we achieved successful resection of mid-rectal lesions via the transsacral approach, without the morbidity associated with major laparotomy. We suggest that this procedure should be a part of a surgeon's armamentarium.

Current practices in endoscopic submucosal dissection for colorectal neoplasms: a survey of indications among Korean endoscopists

Background/Aims

The indications for colorectal endoscopic submucosal dissection (ESD) vary in clinical practice. To establish colorectal ESD as a standard treatment, standard indications are essential. For establishing standard indications for colorectal ESD, we surveyed the preferences and criteria of endoscopists for colorectal ESD in their practices.

Methods

A multiple-choice questionnaire was sent to 27 members of the Korean Society of Gastrointestinal Endoscopy/ESD group. The indications of endoscopists for selecting ESD as a treatment for colorectal tumors ≥2 cm in diameter were surveyed.

Results

On the basis of the preprocedural assessment of histology, adenoma with high-grade dysplasia, mucosal cancer, and shallow submucosa invasive cancer were included in the indication for ESD. Based on gross morphology, laterally spreading tumor (LST) granular nodular mixed type, LST-nongranular (LST-NG) flat elevated type, and LST-NG pseudodepressed type were included. On the basis of the pit pattern by Kudo classification, types III, IV, and V-I were included. Based on the narrow band imaging pattern by Sano classification, types II and III-a were included. Other lesions, such as sporadic localized tumors in chronic inflammation and local residual early carcinoma after endoscopic resection, were also included in the indication for ESD.

Conclusions

The indications of Korean endoscopists for colorectal ESD are broader than those in recent guidelines, and tend to include more benign-looking tumors. To find the appropriate indications for colorectal ESD, systematic data collection and analysis are required to reach a consensus in a timely manner.

Clinical impact and characteristics of the narrow-band imaging magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team

BACKGROUND AND AIMS

The Japan NBI Expert Team (JNET) was established in 2011 and has proposed a universal narrow-band imaging (NBI) magnifying endoscopic classification of colorectal tumors. The aim of this study was to evaluate the clinical usefulness of the JNET classification for colorectal lesions.

METHODS

We analyzed 2933 colorectal lesions, which were diagnosed by NBI magnifying observation before endoscopic treatment or surgery. The colorectal lesions consisted of 136 hyperplastic polyps/sessile serrated polyps (HPs/SSPs), 1926 low-grade dysplasia (LGD), 571 high-grade dysplasia (HGD), 87 superficial submucosal invasive (SM-s) carcinomas, and 213 deep submucosal invasive (SM-d) carcinomas. We evaluated the relationship between the JNET classification and the histologic findings of these lesions.

RESULTS

The sensitivity, specificity, positive and negative predictive values, and accuracy of Type 1 lesions for the diagnosis of HP/SSP were, respectively, 87.5%, 99.9%, 97.5%, 99.4%, and 99.3%; of Type 2A lesions for the diagnosis of LGD were 74.3%, 92.7%, 98.3%, 38.7%, and 77.1%; of Type 2B lesions for the diagnosis of HGD/SM-s carcinoma were 61.9%, 82.8%, 50.9%, 88.2%, and 78.1%; for Type 3 lesions for the diagnosis of SM-d carcinoma were 55.4%, 99.8%, 95.2%, 96.6%, and 96.6%, respectively.

CONCLUSIONS

Types 1, 2A, and 3 of the JNET classification were very reliable indicators for HP/SSP, LGD, and SM-d carcinoma, respectively. However, the specificity and positive predictive value of Type 2B were relatively lower than those of others. Therefore, an additional examination such as pit pattern diagnosis using chromoagents is necessary for accurate diagnosis of Type 2B lesions.

Clinical usefulness of magnifying endoscopy for non-ampullary duodenal tumors

Study aims This study aimed to investigate the clinical usefulness of magnifying endoscopy (ME) for non-ampullary duodenal tumors. Patients and methods We enrolled 103 consecutive patients with non-ampullary duodenal tumors that were observed by ME with narrow-band imaging (ME-NBI) and had pit pattern analysis before endoscopic resection at Hiroshima University Hospital before December 2014. ME-NBI images were classified as Type B or Type C according to the Hiroshima classification, and pit patterns were classified as regular or irregular. We studied the clinicopathological features and diagnoses with ME-NBI and pit pattern analyses according to the Vienna classification (category 3: 73 patients; category 4: 30 patients). Results Category 4 lesions were significantly larger than category 3 lesions. According to ME-NBI images, category 4 Type C lesions (83 %) were significantly more common than category 4 Type B lesions (17 %). According to pit pattern analyses, category 4 irregular lesions 4 (77 %) were significantly more common than category 4 regular lesions (23 %). The accuracies of using Type C ME-NBI images and irregular pit patterns to diagnose category 4 lesions were 87 % and 84 %, the sensitivities were 83 % and 77 %, and the specificities were 89 % and 88 %, respectively. There was no significant difference between ME-NBI and pit pattern analyses for diagnosing the histologic grade of non-ampullary duodenal tumors. Conclusion Our study showed that ME-NBI and pit pattern analysis had equivalent abilities to determine the histologic grade of non-ampullary duodenal tumors. ME-NBI may be more useful because it is a simple, less time-consuming procedure.

Colonic Polyps: Diagnosis and Surveillance

Colorectal cancer begins as a polyp that is a benign growth on the mucosal surface of the colon or rectum. Over a period of 5 to 15 years, polyps can degenerate into a cancer, thus invading the colonic wall. Colorectal screening methods are designed to diagnose and remove polyps before they acquire invasive potential and develop into cancer. Screening for colorectal cancer can prevent and reduce mortality. Given the benefits and effectiveness of screening, guidelines exist from multiple organizations. These guidelines risk-stratify patients to determine the age of screening initiation and the interval for repeat screening. Categories of colorectal cancer risk include average risk, increased risk, and high risk based on individual and family medical history. Screening methods vary widely in the ability to diagnose and treat polyps and in the degree of invasiveness or risk of complication to the patient. Colonoscopy is held as the "gold standard" by which all other methods are compared; however, less-invasive modalities including computed tomographic colonography are increasing in popularity.

Defocus-aware Dirichlet particle filter for stable endoscopic video frame recognition

BACKGROUND AND OBJECTIVE

A computer-aided system for colorectal endoscopy could provide endoscopists with important helpful diagnostic support during examinations. A straightforward means of providing an objective diagnosis in real time might be for using classifiers to identify individual parts of every endoscopic video frame, but the results could be highly unstable due to out-of-focus frames. To address this problem, we propose a defocus-aware Dirichlet particle filter (D-DPF) that combines a particle filter with a Dirichlet distribution and defocus information.

METHODS

We develop a particle filter with a Dirichlet distribution that represents the state transition and likelihood of each video frame. We also incorporate additional defocus information by using isolated pixel ratios to sample from a Rayleigh distribution.

RESULTS

We tested the performance of the proposed method using synthetic and real endoscopic videos with a frame-wise classifier trained on 1671 images of colorectal endoscopy. Two synthetic videos comprising 600 frames were used for comparisons with a Kalman filter and D-DPF without defocus information, and D-DPF was shown to be more robust against the instability of frame-wise classification results. Computation time was approximately 88ms/frame, which is sufficient for real-time applications. We applied our method to 33 endoscopic videos and showed that the proposed method can effectively smoothen highly unstable probability curves under actual defocus of the endoscopic videos.

CONCLUSION

The proposed D-DPF is a useful tool for smoothing unstable results of frame-wise classification of endoscopic videos to support real-time diagnosis during endoscopic examinations.

[Analysis of reasons of "incomplete" colonoscopy]

The objective of this study was to determine the reasons for incomplete colonoscopy, as well as evaluation of results preparation of patients for colonoscopy in a variety of ways, informative colonoscopy depending on the quality of preparation of the colon for examination.

MATERIAL AND METHODS

The material of this study was the results 104 of colonoscopies drawn from daily clinical practice. To prepare the colon for the study used the most available ways: 1) lavage solutions, 2) castor oil, 2 enemas in the morning and 2 in the evening, 3) enema, which the patients were chosen after consulting a doctor. To assess the preparedness of the colon to the study used a Boston-scale of assessment of quality of preparation of the colon for a colonoscopy". Preparation of the colon was improved by using a water jet pump of the company "Olympus" AFU100. Statistical analysis was performed using IBM SPSS Statistics 19.0.

RESULTS

Analysis of clinical specimens showed that in 13 (12.5%) of the observations to intubate the colon was not possible. The main reason is the poor preparation of the colon to the study, which failed to improve even with the aid of a water jet pump.

Computer-aided diagnosis of colorectal polyp histology by using a real-time image recognition system and narrow-band imaging magnifying colonoscopy

BACKGROUND AND AIMS

It is necessary to establish cost-effective examinations and treatments for diminutive colorectal tumors that consider the treatment risk and surveillance interval after treatment. The Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) committee of the American Society for Gastrointestinal Endoscopy published a statement recommending the establishment of endoscopic techniques that practice the resect and discard strategy. The aims of this study were to evaluate whether our newly developed real-time image recognition system can predict histologic diagnoses of colorectal lesions depicted on narrow-band imaging and to satisfy some problems with the PIVI recommendations.

METHODS

We enrolled 41 patients who had undergone endoscopic resection of 118 colorectal lesions (45 nonneoplastic lesions and 73 neoplastic lesions). We compared the results of real-time image recognition system analysis with that of narrow-band imaging diagnosis and evaluated the correlation between image analysis and the pathological results.

RESULTS

Concordance between the endoscopic diagnosis and diagnosis by a real-time image recognition system with a support vector machine output value was 97.5% (115/118). Accuracy between the histologic findings of diminutive colorectal lesions (polyps) and diagnosis by a real-time image recognition system with a support vector machine output value was 93.2% (sensitivity, 93.0%; specificity, 93.3%; positive predictive value (PPV), 93.0%; and negative predictive value, 93.3%).

CONCLUSIONS

Although further investigation is necessary to establish our computer-aided diagnosis system, this real-time image recognition system may satisfy the PIVI recommendations and be useful for predicting the histology of colorectal tumors.

Long-term outcomes after treatment for T1 colorectal carcinoma

PURPOSE

Long-term outcomes of patients with T1 colorectal carcinoma (CRC) treated by endoscopic resection (ER) or surgical resection are unclear in relation to the curative criteria in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines. The aim of this study was to retrospectively compare the long-term outcomes among patients with T1 CRC in relation to the treatment methods.

METHODS

We examined 322 T1 CRC cases treated between January 1992 and August 2008 at Hiroshima University Hospital. Patients who did not meet the curative criteria in the JSCCR guidelines were defined as "non-endoscopically curable" and classified into three groups: underwent ER alone (group A: 45 patients), underwent additional surgery after ER (group B: 106 patients), and underwent surgical resection alone (group C: 92 patients).

RESULTS

Of the 322 T1 CRC patients, 79 were categorized as endoscopically curable and 243 as non-endoscopically curable. Among the endoscopically curable T1 CRC patients, recurrence and 5-year OS rates were 0 and 94.2%, respectively. In groups A, B, and C, recurrence rates were 4.4, 6.6, and 4.3%, and OS rates were 85.6, 95.1, and 96.3%, respectively (p < 0.05). Local recurrence or distant/lymph node metastasis was observed in 13 patients (group A: 2; group B: 7; group C: 4). Death due to primary CRC occurred in six patients (group B: 4; group C: 2).

CONCLUSION

Long-term outcomes support the curative criteria according to the JSCCR guidelines. ER for T1 CRC did not worsen clinical outcomes in cases that required additional surgical resection.

Advanced gastrointestinal endoscopic imaging for inflammatory bowel diseases

Gastrointestinal luminal endoscopy is of paramount importance for diagnosis, monitoring and dysplasia surveillance in patients with both, Crohn’s disease and ulcerative colitis. Moreover, with the recent recognition that mucosal healing is directly linked to the clinical outcome of patients with inflammatory bowel disorders, a growing demand exists for the precise, timely and detailed endoscopic assessment of superficial mucosal layer. Further, the novel field of molecular imaging has tremendously expanded the clinical utility and applications of modern endoscopy, now encompassing not only diagnosis, surveillance, and treatment but also the prediction of individual therapeutic responses. Within this review, we describe how novel endoscopic approaches and advanced endoscopic imaging methods such as high definition and high magnification endoscopy, dye-based and dye-less chromoendoscopy, confocal laser endomicroscopy, endocytoscopy and molecular imaging now allow for the precise and ultrastructural assessment of mucosal inflammation and describe the potential of these techniques for dysplasia detection.

Image-enhanced endoscopy technology in the gastrointestinal tract: what is available?

Gastrointestinal malignancy accounts for approximately a fifth of all cancer deaths in the United Kingdom. By the time patients are symptomatic, lesions are often advanced, with limited treatment options available. The development of effective endoscopic therapies means that neoplastic lesions can now be treated with improved patient outcomes. This has led to a paradigm shift, whereby the aim of digestive endoscopy is to identify premalignant conditions or early neoplastic change, in order to make an impact on their natural history. This has necessitated an improvement in imaging techniques in order to identify subtle mucosal changes that may harbour precancerous cells. At present there is an array of available imaging modalities, each with implications on cost, training and lesion detection. Here we describe the scientific rationale behind the major commercially available techniques as well as offering a glimpse at possible future directions.

Colon adenocarcinoma with dome-like phenotype: characteristic endoscopic ultrasonography (EUS) findings

An 80-year-old man underwent colonoscopy for proctorrhagia. Conventional white-light imaging showed a superficially flat and elevated lesion that appeared to be a submucosal tumor of the sigmoid colon. Chromoendoscopy with Indigo Carmine showed that the margin of the tumor was covered with normal epithelium but that there was a slight depression on its surface. Magnification endoscopy with Crystal Violet staining revealed the amorphous surface structure of the depressed lesion, but the surrounding mucosa showed a normal pit pattern. Endoscopic ultrasonography demonstrated that a hypoechoic mass was located in the submucosal layer, and a biopsy specimen obtained from the surface of the lesion showed evidence of adenocarcinoma. We then performed sigmoidectomy on the patient. Immunohistochemically, the tumor cells were positive for two mismatch repair proteins (MLH1 and MSH2), but in situ hybridization revealed that the specimen was negative for the Epstein - Barr virus. We finally diagnosed the lesion as adenocarcinoma with a dome-like phenotype of the sigmoid colon.

JGES guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection

Colorectal endoscopic submucosal dissection (ESD) has become common in recent years. Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also many types of precarcinomatous adenomas. It is important to establish practical guidelines in which the preoperative diagnosis of colorectal neoplasia and the selection of endoscopic treatment procedures are properly outlined, and to ensure that the actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with the guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society has recently compiled a set of colorectal ESD/endoscopic mucosal resection (EMR) guidelines using evidence-based methods. The guidelines focus on the diagnostic and therapeutic strategies and caveat before, during, and after ESD/EMR and, in this regard, exclude the specific procedures, types and proper use of instruments, devices, and drugs. Although eight areas, ranging from indication to pathology, were originally planned for inclusion in these guidelines, evidence was scarce in each area. Therefore, grades of recommendation were determined largely through expert consensus in these areas.

Local recurrence after endoscopic resection for large colorectal neoplasia: a multicenter prospective study in Japan

OBJECTIVES

Conventional endoscopic resection (CER) is a widely accepted treatment for early colorectal neoplasia; however, large colorectal neoplasias remain problematic, as they necessitate piecemeal resection, increasing the risk of local recurrence. Endoscopic submucosal dissection (ESD) can improve the en bloc resection rate. This study aimed to evaluate local recurrence and its associated risk factors after endoscopic resection (ER) for colorectal neoplasias ≥20 mm.

METHODS

A multicenter prospective study at 18 medium- and high-volume specialized institutions was conducted in Japan. Follow-up colonoscopy was performed after 12 months in cases of complete resection and after 3-6 months in cases of incomplete resection. Local recurrence was confirmed by endoscopic findings and/or pathological analysis.

RESULTS

Follow-up colonoscopy was performed in 1,524 of 1,845 enrolled colorectal neoplasias (mean age, 65 years; 885 men; median tumor size, 32.8 mm). The local recurrence rates were 4.3% (65/1,524), 6.8% (55/808), and 1.4% (10/716) for the entire cohort, for CER, and for ESD, respectively. The relative risks of local recurrence were 0.21 (95% confidence interval, 0.11-0.39) with ESD compared with CER, 0.32 (95% confidence interval, 0.11-0.92) with en bloc ESD compared with en bloc CER, and 0.90 (95% confidence interval, 0.39-2.12) with piecemeal ESD compared with piecemeal CER. Significant factors associated with local recurrence were piecemeal resection, laterally spreading tumors of granular type, tumor size ≥40 mm, no pre-treatment magnification, and ≤10 years of experience in CER, and piecemeal resection only in ESD.

CONCLUSIONS

En bloc ESD reduces the local recurrence rate for large colorectal neoplasias. Piecemeal resection is the most important risk factor for local recurrence regardless of the ER method used.

Two-stage optical system for colorectal polyp assessments

BACKGROUND AND AIMS

Macroscopic real-time evaluations of the histopathology and degree of invasion of colorectal polyps help to select the most suitable endoscopic treatment method. Dual-focus (DF) narrow-band imaging (NBI) is a new imaging enhancement system that uses digital and optical methods to enhance the view of blood vessels on mucosal surfaces. However, the superiority of this technique over standard imaging techniques has not been previously reported. The aim of this study was to determine whether the two-stage optical systems in a new generation of endoscopes will increase the diagnostic accuracy of colorectal polyp recognition.

METHODS

The study included 270 patients, and 386 colorectal polyps were diagnosed and removed. The polyps were assessed with white light and NBI using one- and two-stage optical systems, respectively. After being classified according to the Kudo pit pattern schemes, the polyps were removed and histopathologically verified.

RESULTS

Regarding non-neoplastic lesions (Kudo I and II), no difference was observed in the recognition of polyps when using the NBI-DF function. We observed improved accuracy in the preliminary diagnoses of Kudo IIIL lesions (from 87.16 to 90.09%, p < 0.05) and Kudo IIIS lesions (from 87.29 to 92.79%, p < 0.01). NBI-DF also increased the accuracy of preliminary diagnoses of Kudo IV lesions (from 88.24 to 94.12%, p < 0.01). The Kudo V pit patterns were also more distinct with NBI-DF imaging, increasing the diagnostic accuracy from 91.67 to 100%.

CONCLUSIONS

Using a two-stage optical system with electronic colorization of the mucosa increased diagnostic accuracy for differentiating colorectal polyps with neoplastic potential.

Assessment and management of the malignant colorectal polyp

Colorectal cancer is the second most common cancer affecting men and women in England. The introduction of National Bowel Cancer Screening in 2006 has led to a rise in the proportion of colorectal cancers detected at an early stage. Many screen-detected cancers are malignant colorectal polyps and may potentially be cured with endoscopic resection, without recourse to the risk of major surgery or prolonged adjuvant therapies. Endoscopic decision making is crucial to select those early lesions that may be suitable for local endoscopic excision as well as identifying lesions for surgical resection, thus avoiding unnecessary surgical intervention in some and ensuring potentially curative surgery in others. This paper uses the current evidence base to provide a structured approach to the assessment of potentially malignant polyps and their management. http://group.bmj.com/products/journals/instructions-for-authors/licence-forms.

Magnification endoscopy with acetic acid enhancement and a narrow-band imaging system for pit pattern diagnosis of colorectal neoplasms

BACKGROUND AND GOALS

Pit pattern (PP) analysis of colorectal neoplasms using magnification chromoendoscopy with crystal violet (CV-MCE) is useful for predicting histologic features, but it is time consuming. Capillary pattern analysis by magnification endoscopy with narrow-band imaging (NBIME) is a useful and simpler procedure, but its diagnostic accuracy may be inferior to CV-MCE. NBIME with acetic acid enhancement (A-NBIME) is effective for rapid visualization of gastric mucosal microstructures. We performed a prospective study to compare the diagnostic reliability and feasibility of A-NBIME and CV-MCE in PP diagnosis of colorectal neoplasms.

STUDY

The present study consisted of 3 protocols: Study-1 assessed 56 colorectal lesions photographed with A-NBIME and CV-MCE, and the endoscopic images were reviewed by 3 experts to compare the diagnostic concordance; study-2 assessed 202 colorectal lesions photographed with A-NBIME in 116 consecutive patients and the correlation between PP and histologic findings; study-3 randomly allocated 100 patients with colorectal lesions equally to A-NBIME and CV-MCE, and compared the procedure time and visible ratio of PP.

RESULTS

The κ value for interobserver agreement for A-NBIME and CV-MCE was 0.71 (0.66 to 0.75) and 0.80 (0.75 to 0.85), respectively. Intraobserver agreement between modalities for each reviewer was 0.79 (0.70 to 0.88), 0.80 (0.71 to 0.90), and 0.74 (0.67 to 0.82). Non-neoplastic polyps and massively invasive submucosal adenocarcinomas were statistically related to type II and type VI-H/VN. The procedure time was statistically shorter with A-NBIME than with CV-MCE (31 vs. 81 s), and the visible ratio of PP was equivalent (98.9% vs. 98.3%).

CONCLUSIONS

A-NBIME is comparable with CV-MCE in PP diagnosis of colorectal neoplasms and is a simpler technique.

Evidence-based clinical practice guidelines for management of colorectal polyps

BACKGROUND

Recently in Japan, the morbidity of colorectal polyp has been increasing. As a result, a large number of cases of colorectal polyps that are diagnosed and treated using colonoscopy has now increased, and clinical guidelines are needed for endoscopic management and surveillance after treatment.

METHODS

Three committees [the professional committee for making clinical questions (CQs) and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee by moderators] were organized. Ten specialists for colorectal polyp management extracted the specific clinical statements from articles published between 1983 and September 2011 obtained from PubMed and a secondary database, and developed the CQs and statements. Basically, statements were made according to the GRADE system. The expert panel individually rated the clinical statements using a modified Delphi approach, in which a clinical statement receiving a median score greater than seven on a nine-point scale from the panel was regarded as valid.

RESULTS

The professional committee created 91CQs and statements for the current concept and diagnosis/treatment of various colorectal polyps including epidemiology, screening, pathophysiology, definition and classification, diagnosis, treatment/management, practical treatment, complications and surveillance after treatment, and other colorectal lesions (submucosal tumors, nonneoplastic polyps, polyposis, hereditary tumors, ulcerative colitis-associated tumor/carcinoma).

CONCLUSIONS

After evaluation by the moderators, evidence-based clinical guidelines for management of colorectal polyps have been proposed for 2014.

Endoscopic diagnosis of invasion depth for early colorectal carcinomas: a prospective comparative study of narrow-band imaging, acetic acid, and crystal violet

Several studies have validated the effectiveness of narrow-band imaging (NBI) in estimating invasion depth of early colorectal cancers. However, comparative diagnostic accuracy between NBI and chromoendoscopy remains unclear. Other than crystal violet, use of acetic acid as a new staining method to diagnose deep submucosal invasive (SM-d) carcinomas has not been extensively evaluated. We aimed to assess the diagnostic accuracy and interobserver agreement of NBI, acetic acid enhancement, and crystal violet staining in predicting invasion depth of early colorectal cancers. A total of 112 early colorectal cancers were prospectively observed by NBI, acetic acid, and crystal violet staining in sequence by 1 expert colonoscopist. All endoscopic images of each technique were stored and reassessed. Finally, 294 images of 98 lesions were selected for evaluation by 3 less experienced endoscopists. The accuracy of NBI, acetic acid, and crystal violet for real-time diagnosis was 85.7%, 86.6%, and 92.9%, respectively. For image evaluation by novices, NBI achieved the highest accuracy of 80.6%, compared with that of 72.4% by acetic acid, and 75.8% by crystal violet. The kappa values of NBI, acetic acid, and crystal violet among the 3 trainees were 0.74 (95% CI 0.65-0.83), 0.68 (95% CI 0.59-0.77), and 0.70 (95% CI 0.61-0.79), respectively. For diagnosis of SM-d carcinoma, NBI was slightly inferior to crystal violet staining, when performed by the expert endoscopist. However, NBI yielded higher accuracy than crystal violet staining, in terms of less experienced endoscopists. Acetic acid enhancement with pit pattern analysis was capable of predicting SM-d carcinoma, comparable to the traditional crystal violet staining.

Towards safer and appropriate application of endoscopic submucosal dissection for T1 colorectal carcinoma as total excisional biopsy: future perspectives

According to the Japanese Society for Cancer of the Colon and Rectum Guidelines 2014 for the Treatment of Colorectal Cancer, cases with T1 colorectal carcinoma should be considered for additional colectomy with lymph node dissection when histologically complete en bloc resection is endoscopically carried out and when one of the four risk factors listed below is present. These four risk factors are: (i) submucosal (SM) invasion depth ≥1000 μm; (ii) positive vascular invasion; (iii) poorly differentiated adenocarcinoma, signet ring cell carcinoma, or mucinous carcinoma; and (iv) grade 2/3 budding at the deepest part of SM invasion. However, the probability of lymph node metastasis is extremely low if none of these risk factors are present, with the exception of SM invasion depth ≥1000 μm. Consequently, it is assumed that there will be an increasing number of cases where no additional surgery is done, or cases of moderate invasive carcinoma in which endoscopic treatment is carried out to achieve an excisional biopsy, for which complete resection is applicable. In these cases, the preoperative diagnosis, resection techniques such as endoscopic submucosal dissection, features of resected specimens, and the accuracy of pathological diagnosis are all extremely important.