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Objectives: This study investigated the incidence of lymph node metastasis and long-term outcomes in patients with T1 colorectal cancer where endoscopic submucosal dissection (ESD) resulted in noncurative treatment. It is focused on those with deep submucosal invasion, a factor considered a weak predictor of lymph node metastasis in the absence of other risk factors., Methods: This nationwide, multicenter, prospective study conducted a post-hoc analysis of 141 patients with T1 colorectal cancer ≥20 mm where ESD of the lesion resulted in noncurative outcomes, characterized by poor differentiation, deep submucosal invasion (≥1000 μm), lymphovascular invasion, high-grade tumor budding, or positive vertical margins. Clinicopathologic features and patient prognoses focusing on lesion sites and additional surgery requirements were evaluated. Lymph node metastasis incidence in the low-risk T1 group, identified by deep submucosal invasion as the sole high-risk histological feature, was assessed., Results: Lymph node metastasis occurred in 14% of patients undergoing additional surgery post-noncurative endoscopic submucosal dissection for T1 colorectal cancer. In the low-risk T1 group, in the absence of other risk factors, the frequency was 9.7%. The lymph node metastasis rates in patients with T1 colon and rectal cancers did not differ significantly (14% vs. 16%). Distant recurrence was observed in one patient (2.3%) in the ESD only group and in one (1.0%) in the additional surgery group, both of whom had had rectal cancer removed., Conclusion: The risk of lymph node metastasis or distant occurrence was not negligible, even in the low-risk T1 group. The findings suggest the need for considering additional surgery, particularly for rectal lesions (Clinical Trial Registration: UMIN000010136)., (© 2024 Japan Gastroenterological Endoscopy Society.)

Objectives: Endoscopic hand suturing (EHS) is a novel technique for closing a mucosal defect after endoscopic submucosal dissection (ESD). We investigated the technical feasibility of colorectal EHS using a modified flexible through-the-scope needle holder., Methods: This was a prospective multicenter study conducted at two referral centers between June 2022 and April 2023. This study included colorectal neoplasms 20-50 mm in size located in the sigmoid colon or rectum. A modified flexible through-the-scope needle holder, with an increased jaw width to facilitate needle grasping, was used for colorectal EHS. The primary end-points were sustained closure rate on second-look endoscopy (SLE) performed on postoperative days 3-4 and suturing time for colorectal EHS. Secondary end-points included complete closure rate and delayed adverse events., Results: We enrolled 20 colorectal neoplasms in 20 patients, including four patients receiving antithrombotic agents. The tumor location was as follows: lower rectum (n = 8), upper rectum (n = 2), rectosigmoid colon (n = 4), and sigmoid colon (n = 6), and the median mucosal defect size was 37 mm (range, 21-65 mm). The complete closure rate was 90% (18/20 [95% confidence interval (CI) 68.3-98.8%]), and the median suturing time was 49 min (range, 23-92 min [95% CI 35-68 min]). Sustained closure rate on SLE was 85% (17/20 [95% CI 62.1-96.8%]). No delayed adverse events were observed., Conclusion: EHS demonstrated a high sustained closure rate. Given the long suturing time and technical difficulty, EHS should be reserved for cases with a high risk of delayed adverse events., (© 2024 Japan Gastroenterological Endoscopy Society.)

Objectives: There are several types of colorectal cancer (CRC) according to the detection methods and intervals, including interval CRC (iCRC) and postcolonoscopy CRC (PCCRC). We aimed to examine their proportions and characteristics., Methods: We conducted a multicenter prospective study using questionnaires in Japan ("C-DETECT study"), in which differences in CRC characteristics according to detection methods and intervals were examined from consecutive adult patients. Because the annual fecal immunochemical test (FIT) was used in population-based screening, the annual FIT-iCRC was assessed., Results: In total, 1241 CRC patients (1064 with invasive CRC) were included. Annual FIT-iCRC (a), 3-year PCCRC (b), and CRC detected within 1 year after a positive FIT with noncompliance to colonoscopy (c) accounted for 4.5%, 7.0%, and 3.9% of all CRCs, respectively, and for 3.9%, 5.4%, and 4.3% of invasive CRCs, respectively. The comparison among these (a, b, c) and other CRCs (d) demonstrated differences in the proportions of ≥T2 invasion ([a] 58.9%, [b] 44.8%, [c] 87.5%, [d] 73.0%), metastasis ([a] 33.9%, [b] 21.8%, [c] 54.2%, [d] 43.9%), right-sided CRC ([a] 42.9%, [b] 40.2%, [c] 18.8%, [d] 28.6%), and female sex ([a] 53.6%, [b] 49.4%, [c] 27.1%, [d] 41.6%). In metastatic CRC, (a) and (b) showed a higher proportions of BRAF mutations ([a] [b] 12.0%, [c] [d] 3.1%)., Conclusions: Annual FIT-iCRC and 3-year PCCRC existed in nonnegligible proportions. They were characterized by higher proportions of right-sided tumors, female sex, and BRAF mutations. These findings suggest that annual FIT-iCRC and 3-year PCCRC may have biological features different from those of other CRCs., (© 2024 Japan Gastroenterological Endoscopy Society.)

Objectives: We previously demonstrated that a favorable long-term prognosis indicated that endoscopic submucosal dissection (ESD) could be the standard treatment for large colorectal epithelial neoplasms, but the usefulness of ESD for local residual or recurrent tumors with submucosal fibrosis has not been fully demonstrated. The aim of the present study was to assess the usefulness of ESD for local residual or recurrent colorectal tumors., Methods: We conducted a nationwide multicenter prospective study to evaluate the outcomes of ESD for colorectal tumors. In this post hoc analysis, a total of 54 local residual or recurrent colorectal tumors in 54 patients were included, and we analyzed the short-term and long-term outcomes of ESD for these lesions., Results: The median size of the lesions was 16.0 (interquartile range [IQR] 11-25) mm. ESD was completed in 53 cases (98.1%) with a median procedure time of 65.0 min, but it was discontinued in one case because of submucosal cancer invasion. En bloc resection was achieved in 52 cases (96.3%), whereas R0 resection was achieved in 45 cases (83.3%). Intraoperative perforation was observed in four cases (7.4%) and delayed perforation in one (1.9%), but all cases could be managed conservatively. Delayed bleeding was not observed. There were no significant differences in short-term outcomes between the rectal and colonic lesions. There was no recurrence of the tumor during the median follow-up period of 60 (IQR 50-64) months., Conclusion: An analysis of our multicenter prospective study suggests that ESD is an effective salvage management for local residual or recurrent colorectal lesions., (© 2024 Japan Gastroenterological Endoscopy Society.)

Objectives: The incidence of colorectal neuroendocrine tumors (NETs) has increased with colorectal cancer screening programs and increased colonoscopies. The management of colorectal NETs has recently shifted from radical surgery to endoscopic resection. We aimed to evaluate the short-term outcomes of various methods of endoscopic resection for colorectal NETs., Methods: Among those registered in the C-NET STUDY, patients with colorectal NETs who underwent endoscopic treatment as the initial therapy were included. Short-term outcomes, such as the en bloc resection rate and R0 resection (en bloc resection with tumor-free margin) rate, were analyzed based on treatment modalities., Results: A total of 472 patients with 477 colorectal NETs received endoscopic treatment. Of these, 418 patients with 421 lesions who met the eligibility criteria were included in the analysis. The median age of the patients was 55 years, and 56.9% of them were men. The lower rectum was the most commonly affected site (88.6%), and lesions <10 mm accounted for 87% of the cases. Endoscopic submucosal resection with a ligation device (ESMR-L, 56.5%) was the most common method, followed by endoscopic submucosal dissection (ESD, 31.4%) and endoscopic mucosal resection using a cap (EMR-C, 8.5%). R0 resection rates <10 mm were 95.5%, 94.8%, and 94.3% for ESMR-L, ESD, and EMR-C, respectively. All 16 (3.8%) patients who developed treatment-related complications could be treated conservatively. Overall, 23 (5.5%) patients had incomplete resection without independent clinicopathological risk factors., Conclusion: ESMR-L, ESD, and EMR-C were equally effective and safe for colorectal NETs with a diameter <10 mm., (© 2023 Japan Gastroenterological Endoscopy Society.)

Objectives: Magnifying endoscopy with narrow-band imaging (M-NBI) is useful for the optical diagnosis of gastrointestinal neoplasms. However, the utility of M-NBI in screening esophagogastroduodenoscopy (EGD) is unclear. We aimed to evaluate the diagnostic ability of the magnification endoscope (ME) in screening EGD for a population with a low prevalence of upper gastrointestinal cancers., Methods: Overall, 4887 asymptomatic examinees without a history of laryngopharyngeal and/or upper gastrointestinal neoplasms who underwent opportunistic screening EGD between April 2011 and December 2017 were enrolled in this retrospective study. The examinees were categorized into two groups depending on whether screening EGD was performed using ME (ME group) or not (non-ME group). Using a propensity score-matched analysis, the diagnostic ability of EGD was compared between the two groups., Results: In total, 1482 examinees (30%) were allocated to the ME group and 3405 (70%) to the non-ME group. Thirty-five epithelial neoplasms were detected in 30 examinees (0.6%). The groups were matched for baseline characteristics (1481 pairs). Both groups showed no significant difference in the epithelial neoplasm detection rate (0.8% vs. 0.3%; P = 0.14). The biopsy rate was significantly lower in the ME group than in the non-ME group (12% vs. 15%; P = 0.003). The positive predictive value (PPV) for biopsy was significantly higher in the ME group than in the non-ME group (6.6% vs. 2.8%; P = 0.048)., Conclusions: Using an ME for screening EGD in an apparently healthy, asymptomatic population could reduce unnecessary biopsies by improving PPV for biopsy without decreasing the epithelial neoplasm detection rate., (© 2021 Japan Gastroenterological Endoscopy Society.)

Objectives: Endoscopic mucosal resection (EMR) is the gold standard for the treatment of noninvasive large colorectal lesions, despite challenges associated with nonlifting lesions and a high rate of local recurrence. Endoscopic submucosal dissection (ESD) offers the possibility of overcoming these EMR limitations. However, a higher risk of complications and longer procedure time prevented its dissemination. As ESD now provides more stable results because of standardized techniques compared with those used earlier, this study aimed to quantify the rates of en bloc and curative resections, as well as ESD complications, in the present situation., Methods: A multicenter, large-scale, prospective cohort trial of ESD was conducted at 20 institutions in Japan. Consecutive patients scheduled for ESD were enrolled from February 2013 to January 2015., Results: ESD was performed for 1883 patients (1965 lesions). The mean procedure time was 80.6 min; en bloc and curative resections were achieved in 1759 (97.0%) and 1640 (90.4%) lesions, respectively, in epithelial lesions ≥20 mm. Intra- and postprocedural perforations occurred in 51 (2.6%) and 12 (0.6%) lesions, respectively, and emergency surgery for adverse events was performed in nine patients (0.5%)., Conclusions: This trial conducted after the standardization of the ESD technique throughout Japan revealed a higher curability, shorter procedure time, and lower risk of complications than those reported previously. Considering that the target lesions of ESD are more advanced than those of EMR, ESD can be a first-line treatment for large colorectal lesions with acceptable risk and procedure time. (Clinical Trial Registration: UMIN000010136)., (© 2021 Japan Gastroenterological Endoscopy Society.)

Objectives: Surgery is recommended for early gastric cancer (EGC) beyond the endoscopic resection (ER)-indication for the risk of lymph node metastasis; however, ER may be chosen as a "relative ER-indication" considering age and comorbidities. This study aimed to compare outcomes of endoscopic submucosal dissection (ESD) only and surgery (primary surgery and additional surgery after non-curative ESD) among elderly patients with relative ER-indication EGC and to further assess prognostic factors., Methods: Outcomes of ESD and surgery (417 cases; 114 ESD, 303 surgery) in elderly patients (≥75 years) with relative ER-indication EGC were retrospectively analyzed. Prognostic factors were also examined., Results: During the observation period (median; ESD, 34 months; surgery, 61 months), 29% of ESD and 35% of surgery patients died, including 4% and 5% from gastric cancer (GC), respectively. ESD showed lower overall survival (OS) than surgery (P = 0.027) but comparable disease-free survival (P = 0.916). OS-associated factors were age and prognostic nutritional index (PNI) in males (age ≥79, hazard ratio [HR] 2.21, P = 0.001; PNI <45, HR 2.06, P = 0.031) and age in females (age ≥82, HR 4.06, P = 0.004). Treatment was not a prognostic factor in either subgroup. Pathological category ≥pT1b2 (submucosal invasion ≥500 µm) and lymphovascular invasion (LVI) were significantly associated with GC death (mortality: ≥pT1b2, 7.7%, P = 0.002; LVI, 10.1%, P < 0.001)., Conclusions: In elderly patients with relative ER-indication EGC, ESD may have comparable long-term efficacy to surgery, and treatment selection had a minor contribution to OS. For patients with poor preoperative prognostic factors, diagnostic ESD may be performed first, followed by additional surgery based on pathological results., (© 2021 Japan Gastroenterological Endoscopy Society.)

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles., (© 2021 Japan Gastroenterological Endoscopy Society.)

Objectives: Preoperative colonoscopy is often incomplete for stenotic colorectal cancers (CRC). This prospective observational study aimed to evaluate the ability of an ultrathin colonoscope (UTC) to inspect the whole colon by passing through the stenotic CRC., Methods: All patients who underwent preoperative colonoscopy for stenotic CRCs at Shizuoka Cancer Center were examined for eligibility. If a standard colonoscope (PCF-H290ZI) could not pass because of a stenosis, the patients were recruited. All of the eligible patients were prospectively enrolled when informed consent could be obtained, and complete colonoscopy was attempted again using an UTC (PCF-PQ260L). Patients with stent placement and those requiring right hemicolectomy were not recruited. Primary endpoints were pass-through and cecal intubation rates. The detected synchronous neoplasias (adenomas and cancers) and their pathological findings after resection were evaluated., Results: A total of 100 patients were enrolled between September 2017 and February 2019. The mean age was 65.6 ± 10.8 years, and 59% were male. The pass-through and cecal intubation rates were 67% (67/100) and 58% (58/100), respectively. Synchronous lesions located proximal to the stenoses were detected in 65.5% (38/58) of the complete colonoscopies, with a total of 86 lesions, including 18 advanced neoplasias with three invasive cancers., Conclusion: When standard colonoscopy cannot pass through stenotic CRC, ultrathin colonoscopy can be considered as an option to inspect the whole colon proximal to the stenosis because treatment strategy can potentially be changed by detecting synchronous neoplasias proximal to the stenosis before surgery. (UMIN000028505)., (© 2020 Japan Gastroenterological Endoscopy Society.)

Background and Aim: Fragmentation of endoscopically resected colorectal polyps during retrieval is one of the limitations for appropriate pathological diagnosis; however, little is known about steps to reduce it. We aimed to evaluate the effect of removing the suction valve button, which is one of the intricate parts of the endoscope, during polyp suction retrieval for fragmentation and pathological diagnosis., Methods: We retrospectively reviewed the polyps retrieved by suctioning. We used the propensity score matching method to adjust for difference between the button-attached and button-removed groups. Outcomes of fragmentation, pathological diagnosis of non-neoplastic polypectomy (NNP), and pathological cut-end among neoplastic lesions were evaluated., Results: On the basis of propensity score matching, 322 pairs of cases were selected for analysis. After matching, the difference in the variables between the two groups was closely balanced. The fragmentation rate was significantly different between the groups (button-attached 36.6% vs. button-removed 22.4%, P < 0.001). No significant difference in the NNP rate was observed between the two groups (button-attached 8.4% vs. button-removed 9.9%). The rate of unclear cut-end was lower in the button-removed group than in the button-attached group (16.2% vs. 9.1%, P = 0.010). In the multivariate analysis, button removal was independently associated with reductions of fragmentation (odds ratio [OR] 0.508, P < 0.001) and unclear cut-end (OR 0.503, P = 0.009). Also, NNP was associated with smaller lesion size (OR 0.364, P < 0.001), but not with button removal., Conclusions: Suction valve button removal during polyp suction retrieval was an effective method to decrease the rates of fragmentation and histological unclear margins., (© 2020 Japan Gastroenterological Endoscopy Society.)

Background: Magnifying narrow-band imaging (M-NBI) and magnifying chromoendoscopy (M-CE) enable accurate diagnosis of T1 colorectal cancer, but the diagnostic yields from combined M-NBI and CE have not been fully analyzed. We aimed to evaluate the diagnostic yield of combining Japan NBI Expert Team (JNET) classification using M-NBI and M-CE., Methods: Superficial colorectal lesions ≥10 mm removed at a Japanese tertiary cancer center between February 2016 and December 2018 were included. We analyzed the relationship between JNET classification, M-CE findings, and histological results based on prospectively collected endoscopic and pathologic data., Results: A total of 1573 lesions, including 56 superficial submucosal invasive cancers, 160 deep submucosal invasive cancers, and 81 advanced cancers (≥T2) were analyzed. The probability of deeply invasive cancer (95% confidence interval) was 1.8% (1.1-2.8), 30.1% (25.4-35.1), and 96.6% (91.5-99.1) in JNET Types 2A, 2B, and 3, respectively. The probability of deeply invasive cancer in JNET Type 2B lesions with non-V, VL, and VH pit pattern was 4.3%, 16.6%, 76.0%, respectively (P < 0.001)., Conclusions: Our study showed the stratification by M-NBI using JNET classification and the effect of additional M-CE for JNET Type 2B lesions., (© 2020 Japan Gastroenterological Endoscopy Society.)

Objectives: Technical difficulties in colorectal endoscopic submucosal dissections (ESD) result in en bloc resection failure or perforation. This study aimed to develop and validate a risk score for predicting en bloc resection failure or perforation in ESD of colorectal neoplasms., Methods: This single-center observational study included 1133 colorectal neoplasms treated with ESD in a Japanese tertiary cancer center. With a derivation set (n = 716), we performed multiple logistic regression to identify significant risk factors for en bloc resection failure or perforation. Based on odds ratios, we developed a risk score, ranging from 0 to 10: 0-1 'low risk' (LR); 2-4 'moderate risk' (MR); and 5-10 'high risk' (HR). An independent validation set comprised prospectively enrolled subjects (n = 417) that underwent ESDs from January 2014 to August 2016. The performance of the risk score for predicting en bloc resection failure or perforation for each risk tier was evaluated., Results: The baseline incidences of en bloc resection failure or perforation were 14.5% and 5.5% in the derivation and validation sets, respectively. We identified the following significant risk factors: endoscopist experience, tumor location, morphology, scope operability, underlying fold, and fold convergence. In the validation set, the incidences of en bloc resection failure or perforation were 0% in the LR tier (n = 62; 14.8%), 2.3% in the MR tier (n = 293; 70.4%), and 25.8% in the HR tier (n = 62; 14.8%) (P < 0.001, Cochran-Armitage trend test)., Conclusions: A risk scoring system, which was developed and prospectively validated, can successfully estimate the incidence of en bloc resection failure or perforation., (© 2019 Japan Gastroenterological Endoscopy Society.)

Objectives: The Japan Esophageal Society classification has been widely applied for predicting the invasion depth of superficial esophageal squamous cell carcinomas (SESCCs). Although Type B2 of the classification clinically corresponds to SESCCs with muscularis mucosa or slight submucosal invasion (MM/SM1), diagnostic yield based on Type B2 is insufficient. This study aimed to investigate risk factors for misdiagnosis in preoperative invasion depth staging., Methods: We included a total of 104 SESCCs in which Type B2 was observed by magnifying endoscopy. SESCCs were classified as either correct diagnosis (pMM/SM1, 39 lesions), overdiagnosis (epithelium or the lamina propria [pEP/LPM], 34 lesions), or underdiagnosis (deep invasion into the submucosa [pSM2-3], 31 lesions) based on pathological depth of invasion. The association between misdiagnosis and endoscopic features, including distinct features, was evaluated using logistic regression analysis. Distinct features were defined as nodular protrusion, thickness, and/or clearly depressed area. The diameter of type B2 area was endoscopically measured, and the cut-off value was determined using a receiver operating characteristic curve., Results: Type B2 area <6 mm (area under the curve, 0.776) and Type B2 vessels around erosion were significantly associated with overdiagnosis (odds ratio, 16.6 and 11.0, respectively), while distinct features were significantly associated with underdiagnosis (odds ratio, 8.7). Adjusted by these misdiagnosis factors, positive predictive value of Type B2 significantly improved from 38% to 65% (P < 0.01)., Conclusions: Lesions with a small Type B2 area (<6 mm) and/or Type B2 vessels around erosion should be diagnosed as EP/LPM and lesions with distinct features as SM2-3., (© 2019 Japan Gastroenterological Endoscopy Society.)

Background and Aim: The Japan narrow-band imaging (NBI) Expert Team (JNET) was organized to unify four previous magnifying NBI classifications (the Sano, Hiroshima, Showa, and Jikei classifications). The JNET working group created criteria (referred to as the NBI scale) for evaluation of vessel pattern (VP) and surface pattern (SP). We conducted a multicenter validation study of the NBI scale to develop the JNET classification of colorectal lesions., Methods: Twenty-five expert JNET colonoscopists read 100 still NBI images with and without magnification on the web to evaluate the NBI findings and necessity of the each criterion for the final diagnosis., Results: Surface pattern in magnifying NBI images was necessary for diagnosis of polyps in more than 60% of cases, whereas VP was required in around 90%. Univariate/multivariate analysis of candidate findings in the NBI scale identified three for type 2B (variable caliber of vessels, irregular distribution of vessels, and irregular or obscure surface pattern), and three for type 3 (loose vessel area, interruption of thick vessel, and amorphous areas of surface pattern). Evaluation of the diagnostic performance for these three findings in combination showed that the sensitivity for types 2B and 3 was highest (44.9% and 54.7%, respectively), and that the specificity for type 3 was acceptable (97.4%) when any one of the three findings was evident. We found that the macroscopic type (polypoid or non-polypoid) had a minor influence on the key diagnostic performance for types 2B and 3., Conclusion: Based on the present data, we reached a consensus for developing the JNET classification., (© 2018 Japan Gastroenterological Endoscopy Society.)

Background and Aim: Endoscopic submucosal dissection (ESD) for colorectal neoplasms (CRN) of >50 mm is considered technically difficult. The ITknife nano™ was developed specifically for ESD of CRN and esophageal superficial neoplasms; however, only limited data are available regarding its use in this procedure. Here we assessed the safety and efficacy of ESD using the ITknife nano™ for large CRN (>50 mm)., Methods: We carried out a retrospective study, including consecutive patients with CRN larger than 50 mm that were treated by ESD between September 2002 and August 2016 at our institution. To clarify features of the ITknife nano™ and to assess its safety and efficacy, we compared en bloc/curative resection rates, complications, and resection speed between ESD done using the Dual knife™ with and without the ITknife nano™., Results: We analyzed a total of 177 ESD-treated large CRN (median tumor size, 61 mm). Among the 133 CRN treated by ESD using the ITknife nano™, en bloc and curative resection rates were 96.2% and 80.5%, respectively. Perforation occurred in eight cases (6.0%) and delayed bleeding in four cases (3.0%). All complications were endoscopically managed. Resection speed was significantly faster for ESD using the ITknife nano™ (25.3 mm 2 /min) compared to using the Dual knife™ only (19.9 mm 2 /min; P = 0.02)., Conclusions: Use of the ITknife nano™ for ESD treatment of large CRN (>50 mm) is feasible and may contribute to reduced procedure times. Further controlled studies are needed to confirm these findings., (© 2017 The Authors. Digestive Endoscopy © 2017 Japan Gastroenterological Endoscopy Society.)

Many clinical studies on narrow-band imaging (NBI) magnifying endoscopy classifications advocated so far in Japan (Sano, Hiroshima, Showa, and Jikei classifications) have reported the usefulness of NBI magnifying endoscopy for qualitative and quantitative diagnosis of colorectal lesions. However, discussions at professional meetings have raised issues such as: (i) the presence of multiple terms for the same or similar findings; (ii) the necessity of including surface patterns in magnifying endoscopic classifications; and (iii) differences in the NBI findings in elevated and superficial lesions. To resolve these problems, the Japan NBI Expert Team (JNET) was constituted with the aim of establishing a universal NBI magnifying endoscopic classification for colorectal tumors (JNET classification) in 2011. Consensus was reached on this classification using the modified Delphi method, and this classification was proposed in June 2014. The JNET classification consists of four categories of vessel and surface pattern (i.e. Types 1, 2A, 2B, and 3). Types 1, 2A, 2B, and 3 are correlated with the histopathological findings of hyperplastic polyp/sessile serrated polyp (SSP), low-grade intramucosal neoplasia, high-grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively., (© 2016 Japan Gastroenterological Endoscopy Society.)

Background and Aim: We have previously reported excellent cecal intubation rates using a short double-balloon endoscope in patients with a history of incomplete colonoscopy. However, data on the endoscopic treatment of colorectal tumors using a double-balloon endoscope are limited. The aim of the present study was to evaluate the efficacy and safety of endoscopic intervention of colorectal tumors using a short double-balloon endoscope., Methods: We analyzed data from a multicenter, prospective study on 110 patients (62 men, median age 66.5 years) who underwent total colonoscopy after incomplete colonoscopy to assess the characteristics of colorectal tumors, endoscopic interventions, and complications., Results: In all, 113 colorectal tumors were detected in 55 patients; 109 of the tumors were adenomas (24 advanced adenomas) and two each were intramucosal and advanced cancers. Locations of the lesions were eight in the cecum, 30 in the ascending colon, 18 in the transverse colon, 12 in the descending colon, 34 in the sigmoid colon, five in the rectosigmoid and six in the rectum. Average tumor diameter was 6.8 ± 6.3 mm. Fifty-nine polypectomies, 22 endoscopic mucosal resections, four hot biopsies, and six cold biopsies were done. All endoscopic interventions were successfully completed and no complications were noted. Two advanced cancers were located in the ascending colon and only a double-balloon endoscope could reach them to take a biopsy sample., Conclusion: Double-balloon endoscopy is effective and safe for endoscopic intervention of colorectal tumors, irrespective of the location, in patients after incomplete colonoscopy., (© 2014 The Authors. Digestive Endoscopy © 2014 Japan Gastroenterological Endoscopy Society.)

Background: Previous reports on percutaneous endoscopic gastrostomy (PEG) for bowel decompression have included a relatively small number of patients and the details of post-procedural outcomes and complications are lacking. The aim of the present study was to evaluate the outcomes and safety of PEG for bowel decompression in a relatively large number of patients with malignant bowel obstruction., Patients and Methods: Over a 10-year period, 76 patients with malignant bowel obstruction were referred to the main referral cancer center in Shizuoka prefecture for PEG to obtain decompression. The method for gastrostomy was carried out by the pull-method, the modified introducer method and the percutaneous endoscopic gastrojejunostomy method. Patient demographics, procedural success, complications, elimination of nasal intubation, and survival were reviewed., Results: Successful placement was achieved in 93% of patients (71/76). Procedure-related complications occurred in 21% ofpatients (15/71), of which the majority involved stomal leakage (eight patients), and wound infection (six patients). There were no procedure-related deaths. Among the 55 patients who required nasal intubation before PEG, a trans-gastrostomy intestinal tube was inserted in 16 patients. The need for further nasal intubation was eliminated in 96% of the patients (53/55). The median survival time was 63 days (range, 8-444 days) after PEG placement., Conclusions: PEG for bowel decompression in patients with malignant obstruction can be carried out with an acceptable risk of minor complications. In combination with a trans-gastrostomy intestinal tube insertion, the elimination of nasal intubation can be achieved in most patients., (© 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.)

Recent advances in endoscopic diagnosis and treatment techniques have led to a marked increase in the detection and endoscopic treatment of early colorectal cancers (CRC). According to the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines, T1-CRC with a negative vertical margin, well- or moderately differentiated adenocarcinoma, no evidence of vascular or lymphatic invasion, and depth of invasion <1000 μm are considered to have a low risk of lymph node metastasis. However, T1-CRC with any of these risk factors are considered to have a high risk of lymph node metastasis. T1-CRC is considered to have a good prognosis if additional surgery is carried out. We experienced two cases of recurrence despite curative surgical resection of T1 rectal cancer., (© 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.)

Endoscopic submucosal dissection (ESD) was first applied in the resection of large colorectal tumors 10 years ago. Frequent complications and technical difficulties were serious problems at first, but were gradually improved with experience. Here, we describe the indications, technical aspects and management of complications of ESD for colorectal tumors. In 2009, we introduce the use of small tip insulation-tipped diathermic (IT) knife. Features separating it from the IT knife and IT Knife2 are a smaller ceramic tip and small round disk at the root of the tip. During submucosal dissection, the small tip IT knife could dissect large pieces of tissue intact. This allows us to shorten the procedure time, particularly the submucosal dissection component. A total of 146 ESD for 140 patients were performed between January 2009 and July 2011. En bloc, and en bloc and R0 resection rates were 92.5% and 83.6%, respectively. Median procedural time was 48.5 min for 40.5 mm specimens. Perforation and delayed bleeding occurred in 2.1% and 1.4%, respectively. We successfully performed ESD for colorectal tumors with a shortened procedure time while preserving quality and safety., (© 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.)

Aim: The primary purpose of this questionnaire survey study was to determine the current status of colorectal endoscopic submucosal dissection (ESD) in specialized Japanese referral centers before and after introduction of a government-approved advanced medical treatment system; and, secondly, to determine the current status of colorectal ESD in other Asian specialized referral centers., Methods: A total of 1321 colorectal ESDs were performed in 11 institutions including two Asian centers outside Japan., Results: Overall en-bloc resection, curative resection, R0 resection, perforation, delayed bleeding and emergency surgery rates were 95.4%, 89.1%, 87.2%, 2.9%, 2.5% and 0.2%, respectively. Similar clinical results were reported in the two Asian centers., Conclusion: There were no significant differences with regards to clinical results between the two periods although the perforation rate decreased from 3.3% to 2.4%. In addition, colorectal ESD has become increasingly standardized technically at specialized referral centers not only in Japan, but several other Asian referral institutions as well., (© 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.)

Background and Aim: No studies have previously described the learning curve for colonic endoscopic submucosal dissection (ESD). The aim of the present study was to describe the learning curve for ESD of large colorectal tumors based on a single colonoscopist's experience., Methods: ESD was carried out for 120 colorectal tumors in 115 patients (68 males, median age 70 years). All procedures were carried out by a single experienced colonoscopist. The cases were grouped chronologically into three periods: (1st): cases 1-40; (2nd): cases 41-80; and (3rd): cases 81-120., Results: The learning curve was the changes in proficiency over time. Proficiency was expressed as procedure time per unit area of specimen. In the 1st, 2nd and 3rd periods, the proficiencies were 18.9, 12.6 and 12.9 (min/cm(2) ), respectively. The proficiencies in the 2nd and 3rd periods were significantly shorter than in the 1st period (t-test, P < 0.05). The en-bloc resection rates of the 1st, 2nd and 3rd periods were 92.5% (37/40), 90% (36/40) and 97.5% (39/40), respectively. The en-bloc and R0 resection rates of the 1st, 2nd and 3rd periods were 85% (34/40), 77.5% (31/40) and 92.5% (37/40), respectively. The perforation rates of the 1st, 2nd and 3rd periods were 12.5% (5/40), 5% (2/40) and 5% (2/40), respectively., Conclusion: Based on our analysis of the learning curve, approximately 80 procedures must be carried out to acquire skill with ESD for large colorectal tumors. However, approximately 40 procedures were sufficient to acquire skill in avoiding perforations during the ESD procedure., (© 2010 The Authors. Digestive Endoscopy © 2010 Japan Gastroenterological Endoscopy Society.)

Local recurrence rates after endoscopic piecemeal mucosal resection (EPMR) typically range from 10 to 23%. In our previous study, the local recurrence rate after a piecemeal resection was significantly higher than that after an en bloc resection, irrespective of tumor size or macroscopic features. To reduce local recurrence after an EPMR, it is important to carefully note the circumferences of the edge and base of the ulcer. Recently, endoscopic submucosal dissection (ESD) was developed and recognized for its effectiveness in large, complete, en bloc resections and precise pathological assessments. ESD also showed lower local recurrence rates, ranging from 0 to 3% in previous, retrospective studies. However, ESD showed a higher perforation rate and longer procedure times; thus, it is necessary to improve ESD. An appropriate surveillance interval after EPMR was still controversial, and recommendations of some guidelines ranged from 2 to 9 months. In order to determine the appropriate interval, a randomized controlled study is necessary.

Flat and depressed (nonpolypoid) colorectal lesions have been described for over two decades by Japanese investigators. These neoplastic lesions are typically smaller than polypoid ones and can be more difficult to identify during screening colonoscopy. In particular, depressed type colorectal lesions are usually small in size, with a number of studies showing them to be at greater risk for developing high-grade dysplasia or submucosal invasive cancer. It has also been suggested that they may follow a different carcinogenic pathway to flat elevated or protruding adenomas. This paper summarizes recent data of nonpolypoid colorectal neoplasms from Western and Asian countries.