Japanese Classification of Esophageal Cancer, 12th Edition: Part I.

This is the first half of English edition of Japanese Classification of Esophageal Cancer, 12th Edition that was published by the Japan Esophageal Society in 2022.

Japanese Classification of Esophageal Cancer, 12th Edition: Part II.

This is the second half of English edition of Japanese Classification of Esophageal Cancer, 12th Edition that was published by the Japan Esophageal Society in 2022.

Remarkable response as a new indicator for endoscopic evaluation of local efficacy of non-surgical treatments for esophageal cancer.

In Japan, standard of care of the patients with resectable esophageal cancer is neoadjuvant chemotherapy (NAC) followed by esophagectomy. Patients unfitted for surgery or with unresectable locally advanced esophageal cancer are generally indicated with definitive chemoradiotherapy (CRT). Local disease control is undoubtful important for the management of patients with esophageal cancer, therefore endoscopic evaluation of local efficacy after non-surgical treatments must be essential. The significant shrink of primary site after NAC has been reported as a good indicator of pathological good response as well as favorable survival outcome after esophagectomy. And patients who could achieve remarkable shrink to T1 level after CRT had favorable outcomes with salvage surgery and could be good candidates for salvage endoscopic treatments. Based on these data, "Japanese Classification of Esophageal Cancer, 12th edition" defined the new endoscopic criteria "remarkable response (RR)", that means significant volume reduction after treatment, with the subjective endoscopic evaluation are proposed. In addition, the finding of local recurrence (LR) at primary site after achieving a CR was also proposed in the latest edition of Japanese Classification of Esophageal Cancer. The findings of LR are also important for detecting candidates for salvage endoscopic treatments at an early timing during surveillance after CRT. The endoscopic evaluation would encourage us to make concrete decisions for further treatment indications, therefore physicians treating patients with esophageal cancer should be well-acquainted with each finding.

Potential for expanding indications and curability criteria of endoscopic resection for early gastric cancer in elderly patients: results from a Japanese multicenter prospective cohort study.

BACKGROUND AND AIMS: Evidence for endoscopic resection (ER) in elderly patients with early gastric cancer (EGC) is limited. We assessed its clinical outcomes, and explored new indications and curability criteria. METHODS: We analyzed data from a Japanese multicenter prospective cohort study. Patients aged ≥75 years with EGC treated with ER were included. We classified "eCuraC-2 (corresponding to noncurative ER, defined in the Japanese gastric cancer treatment guidelines)" into "elderly-high (EL-H)" (>10% estimated metastatic risk) and "elderly-low (EL-L)" (≤10%). RESULTS: In total, 3,371 patients with 3,821 EGCs were included; endoscopic submucosal dissection (ESD) was the prominent treatment choice. Among them, 3,586 lesions met the guidelines' ER indications and 235 did not. The proportions of en bloc and R0 resections and perforations were 98.9%, 94.4%, and 0.8%, respectively, in EGCs within the indications. In EGCs beyond the indications, they were 99.5%, 85.4%, and 5.9%, respectively, for lesions diagnosed as ≤3 cm, and 96.0%, 64.0%, and 18.0% for those >3 cm. Curative ER ("eCuraA/B") and EL-L were observed in 83.6% and 6.2% of lesions within the indications, respectively, and in 44.2% and 16.8% of lesions <3 cm beyond the indications, respectively. The 5-year cumulative gastric cancer death rates following eCuraA/B and EL-H were 0.3% (95% CI, 0.2-0.6) and 3.5% (2.0-5.7), respectively. Following EL-L, the rate was 0.9% (0.2-3.5) even without subsequent treatment. CONCLUSIONS: Usefulness of ESD for elderly EGC patients was confirmed by their clinical outcomes. Lesions ≤3 cm and EL-L emerged as new ER indication and curability criterion, respectively.

A simpler diagnostic algorithm of the Japan Esophageal Society classification for Barrett's esophagus-related superficial neoplasia.

BACKGROUND: We previously developed a Japan Esophageal Society Barrett's Esophagus (JES-BE) magnifying endoscopic classification for superficial BE-related neoplasms (BERN) and validated it in a nationwide multicenter study that followed a diagnostic flow chart based on mucosal and vascular patterns (MP, VP) with nine diagnostic criteria. Our present post hoc analysis aims to further simplify the diagnostic criteria for superficial BERN. METHODS: We used data from our previous study, including 10 reviewers' assessments for 156 images of high-magnifying narrow-band imaging (HM-NBI) (67 dysplastic and 89 non-dysplastic histology). We statistically analyzed the diagnostic performance of each diagnostic criterion of MP (form, size, arrangement, density, and white zone), VP (form, caliber change, location, and greenish thick vessels [GTV]), and all their combinations to achieve a simpler diagnostic algorithm to detect superficial BERN. RESULTS: Diagnostic accuracy values based on the MP of each single criterion or combined criteria showed a marked trend of being higher than those based on VP. In reviewers' assessments of visible MPs, the combination of irregularity for form, size, or white zone had the highest diagnostic performance, with a sensitivity of 87% and a specificity of 91% for dysplastic histology; in the assessments of invisible MPs, GTV had the highest diagnostic performance among the VP of each single criterion and all combinations of two or more criteria (sensitivity, 93%; specificity, 92%). CONCLUSION: The present post hoc analysis suggests the feasibility of further simplifying the diagnostic algorithm of the JES-BE classification. Further studies in a practical setting are required to validate these results.

Predictive Factors for the Outcome of Unsupervised Endoscopic Submucosal Dissection During the Initial Learning Curve with Prevalence-Based Indication.

BACKGROUND: For an adequate educational strategy of ESD in non-Asian settings with prevalence-based indication it is essential to define adequate lesions, suitable for the beginner without on-site expert-supervision. AIMS: We analyzed possible predictors for outcome parameters of effectiveness and safety during the initial learning curve. METHODS: The first 120 ESDs of four operators (n = 480), performed between 2007 and 2020 in four tertiary hospitals, were enrolled. Uni-/multivariable regression analysis was done with sex, age, pretreated lesion, lesion size, organ, and organ-based localization as possible independent predictors for en bloc resection (EBR), complication, and resection speed. RESULTS: Rates of EBR, complication, and resection speed were 84.5%, 14.2%, and 6.20 (± 4.45) cm2/h. Independent predictors for EBR were pretreated lesion (OR 0.27 [0.13-0.57], p < 0.001) and non-colonic ESD (OR 2.29 [1.26-4.17] (rectum)/5.72 [2.36-13.89] (stomach)/7.80 [2.60-23.42] (esophagus), p < 0.001), for complication pretreated lesion (OR 3.04 [1.46-6.34], p < 0.001) and lesion size (OR 1.02 [1.004-1.04], p = 0.012) and for resection speed pretreated lesion (RC - 3.10 [- 4.39 to - 1.81], p < 0.001), lesion size (RC 0.13 [0.11-0.16], p < 0.001) and male patient (RC - 1.11 [- 1.85 to - 0.37], p < 0.001). We found no significant difference in the incidence of technically unsuccessful resections in esophageal (1/84), gastric (3/113), rectal (7/181), and colonic (3/101) ESDs (p = 0.76). Technical failure was mainly caused by complication and fibrosis/pretreatment. CONCLUSION: During the initial learning curve of an unsupervised ESD program with prevalence-based indication, pretreated lesions and colonic ESDs should be avoided. In contrast, lesion size and organ-based localizations have less predictive value for the outcome.

Type B2 vessels and infiltrative growth patterns b and c are associated with lymphatic invasion in pT1a-lamina propria mucosa esophageal squamous cell carcinoma.

BACKGROUND: Tumor growth pattern correlates with outcomes in patients with esophageal squamous cell carcinoma (ESCC), however, the clinical significance of the tumor growth pattern in pT1a-lamina propria mucosa (LPM) type of ESCC was unclear. This study was conducted to clarify clinicopathological features of tumor growth patterns in pT1a-LPM type ESCC and the relationship between tumor growth patterns and magnifying endoscopic findings. METHODS: Eighty-seven lesions diagnosed as pT1a-LPM ESCC were included. Clinicopathological findings including tumor growth pattern and narrow band imaging with magnifying endoscopy (NBI-ME) in the LPM area were investigated. RESULTS: Eighty-seven lesions were classified as infiltrative growth pattern-a (INF-a): expansive growth (n = 81), INF-b: intermediate growth (n = 4) and INF-c: infiltrative growth pattern (n = 2). Lymphatic invasion was shown in one INF-b and one INF-c lesion. NBI-ME and histopathological images were matched for 30 lesions. The microvascular pattern was classified into types B1 (n = 23) and B2 (n = 7) using the JES classification. All 23 type B1 lesions were classified as INF-a without lymphatic invasion. Type B2 lesions were classified as INF-a (n = 2), INF-b (n = 4) and INF-c (n = 1), and lymphatic invasion was present in two lesions (INF-b and INF-c). The rate of lymphatic invasion was significantly higher in type B2 than type B1 (p = 0.048). CONCLUSIONS: The tumor growth pattern of pT1a-LPM ESCC was mostly INF-a in type B1 patterns. Type B2 patterns are rarely present in pT1a-LPM ESCC, however lymphatic invasion with INF-b or INF-c was frequently observed. Careful observation before endoscopic resection with NBI-ME is important to identify B2 patterns to predict histopathology.

Concurrent chemoradiotherapy using proton beams can reduce cardiopulmonary morbidity in esophageal cancer patients: a systematic review.

This systematic review was performed to investigate the superiority of proton beam therapy (PBT) to photon-based radiotherapy (RT) in treating esophageal cancer patients, especially those with poor cardiopulmonary function. The MEDLINE (PubMed) and ICHUSHI (Japana Centra Revuo Medicina) databases were searched from January 2000 to August 2020 for studies evaluating one end point at least as follows; overall survival, progression-free survival, grade ≥ 3 cardiopulmonary toxicities, dose-volume histograms, or lymphopenia or absolute lymphocyte counts (ALCs) in esophageal cancer patients treated with PBT or photon-based RT. Of 286 selected studies, 23 including 1 randomized control study, 2 propensity matched analyses, and 20 cohort studies were eligible for qualitative review. Overall survival and progression-free survival were better after PBT than after photon-based RT, but the difference was significant in only one of seven studies. The rate of grade 3 cardiopulmonary toxicities was lower after PBT (0-13%) than after photon-based RT (7.1-30.3%). Dose-volume histograms revealed better results for PBT than photon-based RT. Three of four reports evaluating the ALC demonstrated a significantly higher ALC after PBT than after photon-based RT. Our review found that PBT resulted in a favorable trend in the survival rate and had an excellent dose distribution, contributing to reduced cardiopulmonary toxicities and a maintained number of lymphocytes. These results warrant novel prospective trials to validate the clinical evidence.

Clinical course and management of adverse events after endoscopic resection of superficial duodenal epithelial tumors: Multicenter retrospective study.

OBJECTIVES: This study aimed to elucidate the clinical course and management of adverse events (AEs) after endoscopic resection (ER) for superficial duodenal epithelial tumors (SDETs). METHODS: Consecutive patients who underwent ER of SDETs between January 2008 and July 2018 at 18 Japanese institutions were retrospectively enrolled. The study outcomes included the clinical course, management, and risk of surgical conversion with perioperative AEs after ER for SDETs. RESULTS: Of the 226 patients with AEs, the surgical conversion rate was 8.0% (18/226), including 3.7% (4/108), 1.0% (1/99), and 50.0% (12/24) of patients with intraoperative perforation, delayed bleeding, or delayed perforation, respectively. In the multivariate logistic analysis, involvement of the major papilla (odds ratio [OR] 12.788; 95% confidence interval [CI] 2.098-77.961, P = 0.006) and delayed perforation (OR 37.054; 95% CI 10.219-134.366, P < 0.001) were significant risk factors for surgical conversion after AEs. Delayed bleeding occurred from postoperative days 1-14 or more, whereas delayed perforation occurred within 3 days in all cases. CONCLUSIONS: The surgical conversion rate was higher for delayed perforation than those for other AEs after ER of SDETs. Involvement of the major papilla and delayed perforation were significant risk factors for surgical conversion following AEs. In addition, reliable prevention of delayed perforation is required for 3 days after duodenal ER to prevent the need for surgical interventions.

Characteristics of synchronous and metachronous duodenal tumors and association with colorectal cancer: a supplementary analysis.

BACKGROUND: We previously reported outcomes of endoscopic resection for duodenal tumors in a large cohort. This study investigated the frequency and characteristics of synchronous and metachronous lesions, and their association with colorectal advanced adenoma (CAA) and colorectal cancer (CRC). METHODS: Patients underwent duodenal endoscopic resection during January 2008 to December 2018. Background and characteristics, incidence of synchronous and metachronous lesions, and incidence of CAA and CRC were investigated. Patients without synchronous lesions were classified as the single group, and those with synchronous lesions as the synchronous group. Patients were also classified as the metachronous and non-metachronous groups. The characteristics among the groups were compared. RESULTS: We included 2658 patients with 2881 duodenal tumors: 2472 (93.0%) patients had single, 186 (7.0%) had synchronous, and 54 (2.0%) had metachronous lesions. The 5-year cumulative incidence of metachronous lesions was 4.1%. In total, 208 (7.8%) had CAA and 127 (4.8%) patients had CRC, and colonoscopy was performed in 936 (35.2%) patients. The incidence of CAA in the synchronous groups tended to be higher compared with that in the single groups (11.8% vs 7.5%, adjusted risk ratio 1.56), and the incidence of CRC in the metachronous groups tended to be higher compared with that in the non-metachronous groups (13.0% vs 4.6%, adjusted risk ratio 2.75), but there was no difference after adjusting for colonoscopy. CONCLUSIONS: This study showed the incidence of synchronous and metachronous duodenal lesions. There was no significant difference in incidence of CAA and CRC among each group, but further studies are warranted.

Multi-institutional questionnaire on treatment strategies for superficial entire circumferential esophageal squamous cell carcinoma.

Objectives: Recent innovations in prophylactic treatment with steroids have overcome the issue of esophageal stricture after endoscopic submucosal dissection (ESD), except in entire circumferential esophageal squamous cell carcinoma (EC-ESCC). Current Japanese guidelines weakly recommend performing ESD for clinical epithelial/lamina propria EC-ESCC with a longitudinal extension <50 mm upon implementing prophylactic treatment against stricture. However, the accurate indications for ESD in EC-ESCC remain unknown, and strategies differ among institutions. The aim of this study was to understand the initial treatment strategy for EC-ESCC and prophylactic treatment after ESD against esophageal stricture. Methods: A questionnaire survey was conducted across 16 Japanese high-volume centers on the initial treatment for EC-ESCC according to the invasion depth and longitudinal extension, and prophylactic treatment against stricture. Results: ESD was performed as the initial treatment not only in clinical epithelial/lamina propria lesions <50 mm (88-94% of institutions), but also in clinical epithelial/lamina propria ≥50 mm (44-50% of institutions) and clinical muscularis mucosae/SM1 (submucosal invasion depth invasion within 200 µm) lesions <50 mm (56-75% of institutions). Regarding prophylactic treatment against esophageal stricture, although there was a common point of local steroid injection, the details and administration of other treatments varied among institutions. Conclusions: As ESD was performed with expanded indications for EC-ESCC than those recommended by the guidelines in more than half of the institutions, the validity of ESD for expanded EC-ESCC needs to be clarified. For that, it is necessary to prospectively collect short- and long-term outcomes after ESD and other treatments, including esophagectomy or chemoradiotherapy.

Curative Management After Endoscopic Resection for Esophageal Squamous Cell Carcinoma Invading Muscularis Mucosa or Shallow Submucosal Layer-Multicenter Real-World Survey in Japan.

INTRODUCTION: Curative management after endoscopic resection (ER) for esophageal squamous cell carcinoma (ESCC), which invades the muscularis mucosa (pMM-ESCC) or shallow submucosal layer (pSM1-ESCC), has been controversial. METHODS: We identified patients with pMM-ESCC and pSM1-ESCC treated by ER. Outcomes were the predictive factors for regional lymph node and distant recurrence, and survival data were based on the depth of invasion, lymphovascular invasion (LVI), and additional treatment immediately after ER. RESULTS: A total of 992 patients with pMM-ESCC (n = 749) and pSM1-ESCC (n = 243) were registered. According to the multivariate Cox proportional hazards analysis, pSM1-ESCC (hazard ratio = 1.88, 95% confidence interval 1.15-3.07, P = 0.012) and LVI (hazard ratio = 6.92, 95% confidence interval 4.09-11.7, P < 0.0001) were associated with a risk of regional lymph node and distant recurrence. In the median follow-up period of 58.6 months (range 1-233), among patients with risk factors (pMM-ESCC with LVI or pSM1-ESCC), the 5-year overall survival rates, relapse-free survival rates, and cause-specific survival rates of patients with additional treatment were significantly better than those of patients without additional treatment; 85.4% vs 61.5% ( P < 0.0001), 80.5% vs 53.3% ( P < 0.0001), and 98.5% vs 93.1% ( P = 0.004), respectively. There was no difference in survival rate between the chemoradiotherapy and surgery groups. DISCUSSION: pSM1 and LVI were risk factors for metastasis after ER for ESCC. To improve the survival, additional treatment immediately after ER, such as chemoradiotherapy or surgery, is effective in patients with these risk factors.

Clinical factors associated with noncurative endoscopic submucosal dissection for the expanded indication of intestinal-type early gastric cancer: Post hoc analysis of a multi-institutional, single-arm, confirmatory trial (JCOG0607).

OBJECTIVES: The multi-institutional, single-arm, confirmatory trial JCOG0607 showed excellent efficacy of endoscopic submucosal dissection (ESD) for the expanded indication of intramucosal intestinal-type early gastric cancer (EGC), which consists of two groups: lesions >2 cm if clinical finding of ulcer (cUL)-negative, or those ≤3 cm if cUL-positive because of the expected low risk of lymph node metastasis. However, the proportion of noncurative resections (NCR) requiring additional surgery was high (32.4%). This post hoc analysis aimed to explore the clinical factors associated with NCR. METHODS: As the expanded indication includes two different groups, we explored the clinical factors associated with NCR separately in cUL-negative (>2 cm) and cUL-positive (≤3 cm) groups using the log-linear model. RESULTS: Two hundred and sixty cUL-negative and 206 cUL-positive EGCs were analyzed. The proportions of NCR were 33.8% in the cUL-negative group and 29.6% in the cUL-positive group. A multivariable analysis demonstrated that moderately differentiated predominant histology diagnosed in pretreatment biopsy (risk ratio [RR] 1.93, 95% confidence interval [CI] 1.34-2.77, P < 0.001) and lesion in the upper stomach (RR 1.75, 95% CI 1.03-2.96, P = 0.038) in the cUL-negative EGCs, and tumor size >2 cm (RR 1.78, 95% CI 1.22-2.58, P = 0.003) and female sex (RR 1.62, 95% CI 1.07-2.44, P = 0.021) in the cUL-positive EGCs were independent factors associated with NCR. CONCLUSIONS: Clinical risk factors associated with NCR were different between cUL-negative and cUL-positive EGCs. To avoid NCR, we need to take these factors into account when deciding expanded indications for ESD.

Long-term Survival After Endoscopic Resection For Gastric Cancer: Real-world Evidence From a Multicenter Prospective Cohort.

BACKGROUND & AIMS: We aimed to clarify the long-term outcomes of endoscopic resection (ER) for early gastric cancers (EGCs) based on pathological curability in a multicenter prospective cohort study. METHODS: We analyzed the long-term outcomes of 9054 patients with 10,021 EGCs undergoing ER between July 2010 and June 2012. Primary endpoint was the 5-year overall survival (OS). The hazard ratio for all-cause mortality was calculated using the Cox proportional hazards model. We also compared the 5-year OS with the expected one calculated for the surgically resected patients with EGC. If the lower limit of the 95% confidence interval (CI) of the 5-year OS exceeded the expected 5-year OS minus a margin of 5% (threshold 5-year OS), ER was considered to be effective. Pathological curability was categorized into en bloc resection, negative margins, and negative lymphovascular invasion: differentiated-type, pT1a, ulcer negative, ≤2 cm (Category A1); differentiated-type, pT1a, ulcer negative, >2 cm or ulcer positive, ≤3 cm (Category A2); undifferentiated-type, pT1a, ulcer negative, ≤2 cm (Category A3); differentiated-type, pT1b (SM1), ≤3 cm (Category B); or noncurative resections (Category C). RESULTS: Overall, the 5-year OS was 89.0% (95% CI, 88.3%-89.6%). In a multivariate analysis, no significant differences were observed when the hazard ratio of Categories A2, A3, and B were compared with that of A1. In all the pathological curability categories, the lower limit of the 95% CI for the 5-year OS exceeded the threshold 5-year OS. CONCLUSION: ER can be recommended as a standard treatment for patients with EGCs fulfilling Category A2, A3, and B, as well as A1 (UMIN Clinical Trial Registry, UMIN000005871).

Comprehensive registry of esophageal cancer in Japan, 2015.

BACKGROUND: The registration committee for esophageal cancer in the Japan Esophageal Society (JES) has collected the patients' characteristics, treatment, and outcomes of patients who underwent any treatment during 2015 in Japan. METHODS: We analyzed patients' data who had visited the participating hospitals in 2015. We collected the data using the National Clinical Database with a web-based data collection system. We used the Japanese Classification of Esophageal Cancer 10th edition by JES and the TNM classification by the Union of International Cancer Control (UICC) for cancer staging. RESULTS: A total of 9368 cases were registered from 355 institutions in Japan. Squamous cell carcinoma and adenocarcinoma accounted for 86.7% and 7.4%, respectively. The 5-year survival rates of patients treated by endoscopic resection, concurrent chemoradiotherapy, radiotherapy alone, and esophagectomy were 87.2%, 33.5%, 24.2%, and 59.9%, respectively. Esophagectomy was performed in 5172 cases. Minimally invasive approaches were selected for 60.6%, and 54.4% underwent thoracoscopic esophagectomy. The operative mortality (within 30 days after surgery) was 0.79% and the hospital mortality was 2.3%. The survival curves showed an excellent discriminatory ability both in the clinical and pathologic stages by the JES system. The survival of pStage IV was better than IIIC in the UICC system because pStage IV included the patients with supraclavicular lymph node metastasis (M1 LYM). CONCLUSION: We hope this report improves all aspects of diagnosing and treating esophageal cancer in Japan.

Efficacy and Safety of a Novel Hemostatic Peptide Solution During Endoscopic Submucosal Dissection: A Multicenter Randomized Controlled Trial.

INTRODUCTION: To compare the effectiveness of the novel hemostatic peptide, TDM-621, with that of conventional hemostatic methods in treating intraoperative blood oozing during endoscopic submucosal dissection (ESD). METHODS: This multicenter, open-label, randomized controlled trial involved 227 patients with gastric and rectal epithelial tumors in whom ESD was indicated. Patients in whom the source of blood oozing was difficult to identify with waterjet washing during the procedure and required hemostasis with hemostatic forceps were randomly assigned to the TDM-621 and control groups. The TDM-621 group (in which hemostasis was achieved with TDM-621, followed by coagulation hemostasis with hemostatic forceps, as needed) was compared with the control group (in which hemostasis was achieved with hemostatic forceps). The primary end point was the mean number of coagulations with hemostatic forceps, determined by a blinded independent review committee. The secondary end points were the rate of achievement of hemostasis with only TDM-621, the dosage of TDM-621, and adverse events in the TDM-621 group. RESULTS: The mean number of coagulations with hemostatic forceps was significantly reduced in the TDM-621 group (1.0 ± 1.4) compared with that in the control group (4.9 ± 5.2) ( P < 0.001). The rate of hemostasis achievement with only TDM-621 was 62.2%; the mean dosage of TDM-621 was 1.75 ± 2.14 mL. The rates of grade ≥3 adverse events were 6.2% and 5.0% in the TDM-621 and control groups, respectively. DISCUSSION: TDM-621 is a useful, easily operable hemostatic peptide for treatment of blood oozing during gastric and rectal ESD, with no serious safety concerns.

Chronological Changes in Mucosal Deformity by Endoscopic Suturing after Gastric Endoscopic Submucosal Dissection: A Multicenter Retrospective Analysis.

INTRODUCTION: Endoscopic suturing of a mucosal defect is expected to prevent postoperative bleeding after endoscopic submucosal dissection (ESD). Endoscopic suturing causes mucosal deformity, which may interfere with endoscopic surveillance thereafter. We retrospectively investigated long-term chronological changes in mucosal suturing by endoscopic suturing. METHODS: Forty-three patients who underwent endoscopic hand suturing (EHS) after gastric ESD at three institutions were enrolled. First, our hypothesis that the suturing sites healed via inflammation, disappearance of mucosal inversion, and flattening was validated. Subsequently, the duration required to reach each healing step was evaluated. RESULTS: A total of 137 follow-up endoscopies were assessed, in which all cases showed the hypothesized chronological course on the suturing sites. The 95th percentiles of the duration when showing the disappearance of the inflammatory change and the inverted change were 63 days and 15.5 months after the procedure, respectively. DISCUSSION/CONCLUSION: The data show that the mucosal deformity induced by EHS disappeared within 16 months. Endoscopic suturing is thus considered to have a negligible effect on endoscopic surveillance following the procedure.