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Background: The goal of surveillance after the endoscopic resection of colorectal tumors is to reduce colorectal cancer (CRC) incidence and mortality. Considering the effective use of the limited endoscopic capacity and the cost of surveillance, it is desirable to develop a surveillance program that is as minimal as possible. In Europe (European Society of Gastrointestinal Endoscopy [ESGE]) and the USA (Multi-Society Task Force [MSTF]), after the results of the National Polyp Study (NPS) were established, guidelines were developed that stratified risk based on initial endoscopy, and surveillance programs for each risk group were proposed. More than 10 years later, the “colonoscopy screening and surveillance guidelines” were developed with the basic principle of “aiming for zero CRC deaths during surveillance, bowel preservation, and emphasis on patient quality of life” as the guideline principles in Japan. Summary: Randomized controlled trials to evaluate the appropriate surveillance intervals after endoscopic resection of colorectal tumors, the NPS, the Nottingham Study, and the Japan Polyp Study (JPS), are summarized. The ESGE, USMSTF, and Japanese guidelines compared low-risk adenoma, high-risk adenoma, advanced neoplasia, piecemeal resection, and serrated lesions by category. Key Messages: Surveillance guidelines based on risk stratification were developed in Japan. Guidelines are meaningful only when they are effectively utilized in clinical practice. They must also be revised based on new evidence. It is hoped that new knowledge will be accumulated, especially in Japan, on topics that are currently lacking.

Background: Peutz-Jeghers syndrome (PJS) is a rare disease characterized by the presence of hamartomatous polyposis throughout the gastrointestinal tract, except for the esophagus, along with characteristic mucocutaneous pigmentation. It is caused by germline pathogenic variants of the STK11 gene, which exhibit an autosomal dominant mode of inheritance. Some patients with PJS develop gastrointestinal lesions in childhood and require continuous medical care until adulthood and sometimes have serious complications that significantly reduce their quality of life. Hamartomatous polyps in the small bowel may cause bleeding, intestinal obstruction, and intussusception. Novel diagnostic and therapeutic endoscopic procedures such as small-bowel capsule endoscopy and balloon-assisted enteroscopy have been developed in recent years. Summary: Under these circumstances, there is growing concern about the management of PJS in Japan, and there are no practice guidelines available. To address this situation, the guideline committee was organized by the Research Group on Rare and Intractable Diseases granted by the Ministry of Health, Labour and Welfare with specialists from multiple academic societies. The present clinical guidelines explain the principles in the diagnosis and management of PJS together with four clinical questions and corresponding recommendations based on a careful review of the evidence and involved incorporating the concept of the Grading of Recommendations Assessment, Development and Evaluation system. Key Messages: Herein, we present the English version of the clinical practice guidelines of PJS to promote seamless implementation of accurate diagnosis and appropriate management of pediatric, adolescent, and adult patients with PJS.

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. 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. 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. 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.

BackgroundEndoscopic submucosal dissection (ESD) for remnant gastric cancer (RGC) after distal gastrectomy (DG) is considered technically challenging due to the narrow working space, and severe fibrosis and staples from the previous surgery. Technical difficulties of ESD for RGC after DG have not been thoroughly investigated. This study aimed to develop and validate a risk-scoring system for assessing the technical difficulty of ESD for RGC after DG in a large multicenter cohort.MethodsWe investigated patients who underwent ESD for RGC after DG in 10 institutions between April 2008 and March 2018. A difficult case was defined as ESD lasting ≥ 120 min, involving piecemeal resection, or the occurrence of perforation during the procedure. A risk-scoring system for the technical difficulty of the procedure was developed based on multiple logistic regression analyses, and its performance was internally validated using bootstrapping.ResultsA total of 197 consecutive patients with 201 lesions were analyzed. There were 90 and 111 difficult and non-difficult cases, respectively. The scoring model consisted of four independent risk factors and points of risk scores were assigned for each as follows: tumor size > 20 mm: 2 points; anastomosis site: 2 points; suture line: 1 point; and non-expert endoscopist: 2 points. The C-statistics of the scoring system for technical difficulty was 0.72.ConclusionsWe developed a validated risk-scoring model for predicting the technical difficulty of ESD for RGC after DG that can contribute to its safer and more reliable performance.

Background Previous studies have yielded conflicting results on the adenoma detection rate with narrow band imaging (NBI) compared with white light imaging (WLI). To overcome the confounding factors of these studies, we aimed to evaluate the colonic adenoma detection rate with primary NBI versus that with primary WLI by using consistent NBI system, endoscope, and imaging settings, and experienced colonoscopists. Methods In this multicenter prospective trial, 813 patients were randomized to undergo high-definition, tandem colonoscopy in the right colon with either NBI followed by WLI (NBI–WLI group) or WLI followed by NBI (WLI–NBI group). The NBI settings were fixed at surface structure enhancement level A-5 and adaptive index of hemoglobin color enhancement level 3. All detected polyps were resected or biopsied for histopathological analysis. The primary and secondary outcome measures were the adenoma detection rates and miss rates, respectively, with primary imaging. Results The NBI–WLI and WLI–NBI groups comprised 389 and 393 patients, respectively, who met the inclusion criteria. The groups did not differ significantly in age, gender, institution, indication for colonoscopy, bowel preparation, or observation time. The adenoma detection rates of primary NBI and WLI were 42.3 and 42.5 %, respectively [difference not significant (NS)]. The adenoma miss rate was significantly less with primary NBI than with primary WLI (21.3 vs. 27.8 %; p  = 0.03). Conclusions NBI does not improve the adenoma detection rate during primary colonoscopy; however, it has a lower miss rate for adenoma lesions in the proximal colon than WLI.

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor. Some papers have reported that colonoscopy could be used to treat PEComa with a predominantly pedunculated polyp, whereas surgical intervention is often required for cases with submucosal‐type tumors. These findings suggest that the morphology of PEComa changes dramatically with disease progression. Because of the rapid progression of PEComa, endoscopic treatment remains challenging, and early‐stage PEComa morphology is not well understood. A 64‐year‐old man presented to our hospital for a follow‐up colonoscopy after undergoing multiple polypectomies. He had a medical history of colorectal adenoma and prostate cancer. A 4‐mm pale blue elevated but not pedunculated lesion was observed in the transverse colon, an area where he had not had polyps previously. Since no epithelial change was observed, the presence of a submucosal tumor, such as a gastrointestinal stromal tumor, was suspected. Cold snare polypectomy was performed, and the lesion was completely resected. Histological evaluation using hematoxylin and eosin staining identified that the submucosal tumor included thickened vascular walls and adipose tissue. Although fragmented due to significant degeneration, spindle‐shaped cells staining positive for smooth muscle actin were observed within and surrounding the unstructured hyalinized tissue with calcifications. Based on these findings, the lesion was diagnosed as angiomyolipoma, a subtype of PEComa. Complete resection was confirmed by histopathology. To our knowledge, this PEComa is the smallest of any PEComa reported in the literature. Our finding provides valuable insights into the very early stage of colorectal PEComas.

Background Capillary patterns (CP) observed by magnifying Narrow Band Imaging (NBI) are useful for differentiating non-adenomatous from adenomatous colorectal polyps. However, there are few studies concerning the effectiveness of magnifying NBI for determining the depth of invasion in early colorectal neoplasms. We aimed to determine whether CP type IIIA/IIIB identified by magnifying NBI is effective for estimating the depth of invasion in early colorectal neoplasms. Methods A series of 127 consecutive patients with 130 colorectal lesions were evaluated from October 2005 to October 2007 at the National Cancer Center Hospital East, Chiba, Japan. Lesions were classified as CP type IIIA or type IIIB according to the NBI CP classification. Lesions were histopathologically evaluated. Inter and intraobserver variabilities were assessed by three colonoscopists experienced in NBI. Results There were 15 adenomas, 66 intramucosal cancers (pM) and 49 submucosal cancers (pSM): 16 pSM superficial (pSM1) and 33 pSM deep cancers (pSM2-3). Among lesions diagnosed as CP IIIA 86 out of 91 (94.5%) were adenomas, pM-ca, or pSM1; among lesions diagnosed as CP IIIB 28 out of 39 (72%) were pSM2-3. Sensitivity, specificity and diagnostic accuracy of the CP type III for differentiating pM-ca or pSM1 (<1000 μm) from pSM2-3 (≥1000 μm) were 84.8%, 88.7 % and 87.7%, respectively. Interobserver variability: κ = 0.68, 0.67, 0.72. Intraobserver agreement: κ = 0.79, 0.76, 0.75 Conclusion Identification of CP type IIIA/IIIB by magnifying NBI is useful for estimating the depth of invasion of early colorectal neoplasms.

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. 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. 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. 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.

Background Complete endoscopic resection of superficial non-ampullary duodenal epithelial tumors (SNADETs) is technically difficult, especially with an extremely high risk of adverse event (AE), although various endoscopic resection methods including endoscopic mucosal resection (EMR), underwater EMR (UEMR), and endoscopic submucosal dissection (ESD) have been tried for SNADETs. Accordingly, a novel simple resection method that can completely resect tumors with a low risk of AEs should be developed. Aims A resection method of Noninjecting Resection using Bipolar Soft coagulation mode (NIRBS) which has been reported to be effective and safe for colorectal lesions is adapted for SNADETs. In this study we evaluated its effectiveness, safety, and simplicity for SNADETs measuring ≤ 20 mm. Results This study included 13 patients with resected lesions with a mean size of 7.8 (range: 3–15) mm. The pathological distributions of the lesions were as follows: adenomas, 77% ( n  = 10) and benign and non-adenomatous lesions, 23% ( n  = 3). The en bloc and R0 resection rate was 100% ( n  = 13). The median procedure duration was 68 s (32–105). None of the patients presented with major AEs including bleeding and perforation. Conclusions Large studies such as prospective, randomized, and controlled trials should be conducted for the purpose of validating effectiveness, safety, and simplicity of the NIRBS for SNADETs measuring ≤ 20 mm suggested in this study.

Objectives Although accurate assessment of polyp morphology helps endoscopists select the appropriate management for colorectal polyps, some studies have reported unsatisfactory accuracy in such assessment. This study aimed to clarify the usefulness of a short educational video available on the Internet for accurate polyp morphology assessment. Methods This was a multicenter randomized controlled trial. Participants were randomly assigned to the pre‐ or post‐education groups after a pre‐test comprising images of 42 polyps, including 12 laterally spreading tumors. Participants who scored ≥ 80% on the pre‐test were excluded. Only the post‐education group completed the diagnostic test after watching an online educational video. The primary outcome was the difference in diagnostic accuracy between the pre‐test and diagnostic tests for each group. Results Of the 296 endoscopists enrolled from 48 institutions, 34 missed the test deadline, and 29 who scored ≥ 80% in the pre‐test were excluded. The primary outcome analysis sets were 117 and 116 in the pre‐ and post‐education groups, respectively. The mean pre‐test accuracies in the pre‐education and post‐education groups were 60.6% and 60.7%, respectively. The difference in diagnostic accuracy between the pre‐test and diagnostic test was significantly higher in the post‐education than the pre‐education group (12.0 points, 95% confidence interval [CI] 9.9–14.1 and 2.3 points, 95% CI 0.9–3.6; p < 0.001). Conclusion This multicenter randomized controlled trial demonstrated the usefulness of a short educational video for accurate polyp morphology assessment.