Efficacy and safety of same-day preparation with sodium picosulfate plus magnesium citrate on the day of colonoscopy for bowel preparation: Multicenter, single-arm, open-label study.

BACKGROUND AND AIM: Sodium picosulfate plus magnesium citrate (SP + MC) is a well-tolerated bowel preparation agent. However, Japan currently approves only two methods of taking SP + MC: the day-before and split-dose preparation, without approval of same-day preparations. This study aimed to evaluate the efficacy and safety of same-day SP + MC preparations. METHODS: This was a multicenter, single-arm, nonrandomized, open-label study. We enrolled 145 Japanese patients between June and December 2023. The patients received two sachets of SP + MC dissolved in 300 ml of water and 1200 mL or more of clear liquid on the day of colonoscopy. Bowel cleansing efficacy, adverse events (AEs), and patient satisfaction were evaluated. RESULTS: Of the enrolled patients, 137 underwent colonoscopy according to our protocol. Bowel preparation was adequate in 133 patients (97.1%). The mean total Boston Bowel Preparation Score was 8.3 ± 1.2. Five patients experienced AEs (3.6%): two (1.5%), abdominal pain; one (0.73%), ischemic enteritis; one (0.73%), vomiting or nausea; and one (0.73%), headache. All AEs were treated conservatively. None of the patients exhibited abnormal blood test results or clinical symptoms after receiving SP + MC. Regarding patient satisfaction, all patients were able to take SP + MC as directed; 136 (99.2%) expressed a preference for this bowel preparation for future colonoscopies. CONCLUSION: The same-day SP + MC preparation showed high bowel-cleansing efficacy and satisfaction in Japanese patients without serious AEs.

Novel scale for evaluating the therapeutic efficacy of per-oral endoscopic myotomy in achalasia.

BACKGROUND: Symptom scales for achalasia after per-oral endoscopic myotomy (POEM) are lacking. This study aimed to propose a new scale based on the conventional Eckardt score (c-ES) and evaluate persistent symptoms that impair patients' quality of life (QOL) post-POEM. METHODS: Dysphagia, regurgitation, and chest pain frequencies were assessed using a 6-point scale modified-ES (m-ES) after POEM, with "occasional" symptoms on the c-ES further subdivided into three-period categories on m-ES. Symptom severity was further evaluated using a 5-point scale ranging from 1 to 5 points, with a score ≥ 3 points defined as persistent symptoms impairing QOL. We analyzed the correlation between the m-ES and severity score, diagnostic performance of the m-ES for persistent symptoms, and overlaps between each residual symptom. RESULTS: Overall, 536 patients (median follow-up period, 2.9 years) post-POEM were included in this multicenter study. Significant correlations were observed between the m-ES and severity scores for dysphagia (r = 0.67, p < 0.01), regurgitation (r = 0.73, p < 0.01), and chest pain (r = 0.85, p < 0.01). Twenty-six patients (4.9%) had persistent symptoms post-POEM, and 23 of them had m-ES-specific symptom frequency ≥ once a month, which was determined as the optimal frequency threshold for screening persistent symptoms. The total m-ES predicted persistent symptoms more accurately than the total c-ES (area under the curve: 0.95 vs. 0.79, p < 0.01). Furthermore, dysphagia and chest pain were the major residual symptoms post-POEM covering 91.4% of regurgitation. CONCLUSIONS: The new post-POEM scale successfully evaluated the QOL-based patient symptom severities. Our study implied the possibility of a simpler scale using residual dysphagia and chest pain.

Randomised controlled, patient-blinded, multicentre, superiority trial to evaluate the efficacy of the line-attached sheath-type traction device for endoscopic submucosal dissection in patients with superficial gastric neoplasms.

INTRODUCTION: EndoTrac is a line-attached sheath-type traction device that enables us to control the direction and the force of traction during endoscopic submucosal dissection (ESD). The efficacy of EndoTrac for gastric ESD has not been fully verified. METHODS AND ANALYSIS: The G-Trac study is a multicentre (nine general hospitals and two university hospitals in Japan) collaborative trial assessing the efficacy of EndoTrac for gastric ESDs. Patients with superficial gastric neoplasms will be enrolled and randomly assigned to undergo either conventional ESD or EndoTrac ESD. Allocation will be stratified according to tumour location, operator experience and tumour diameter at an allocation rate of 1:1. The type of endoknife used will be confirmed before randomisation. The primary outcome, procedure time, will be compared between the groups in both intention-to-treat and per-protocol analyses using the Wilcoxon rank sum test. The efficacy-related, safety-related and device-related outcomes will be assessed in the secondary analysis. The planned sample size of the 142 patients in the two groups will enable us to detect a difference with a power of 80% by using the Wilcoxon rank sum test, assuming an effect size of 0.54, asymptotic relative efficiency of 0.864 and a two-sided type 1 error rate of 5%. ETHICS AND DISSEMINATION: This trial was approved by the certified review board of Kobe University (22 December 2022). The results from this trial will be disseminated through peer-review journals, presentations at national and international conferences, and data sharing with other researchers. TRIAL REGISTRATION NUMBER: jRCT1052220166.

Peroral Endoscopic Myotomy in Pediatric Patients with Achalasia up to 12 Years of Age: A Pilot Study in a Single-Center Experience in Japan.

INTRODUCTION: Peroral endoscopic myotomy (POEM) is a minimally invasive endoscopic procedure for achalasia; its indication has expanded from adults to children. We aimed to evaluate the postoperative efficacy and antireflex status of POEM in young children with achalasia aged 12 years or younger. PATIENTS: AND METHODS: Pediatric patients with achalasia aged 18 years or younger who underwent POEM in our hospital between 2016 and 2021 were included and divided into two age groups: group A (≤ 12 years) and group B (13-18 years). The success rate (Eckardt score ≤ 3), endoscopic reflux findings, and antiacid use at 1 year postoperatively were compared between the groups. RESULTS: Ten patients (four boys and six girls; Chicago classification type I: five, type II: four, and unclassified: one) were included. Mean age and preoperative Eckardt scores in groups A (n = 4) and B (n = 6) were 9.2 ± 3.0 versus 15.6 ± 0.6 years (p = 0.001) and 5.5 ± 3.9 versus 7.2 ± 3.7 (p = 0.509), respectively, and mean operative time and myotomy length were 51.3 ± 16.6 versus 52.5 ± 13.2 minutes (p = 0.898) and 10.8 ± 4.6 versus 9.8 ± 3.2 cm (p = 0.720), respectively. The 1-year success rate was 100% in both groups. Mild esophagitis (Los Angeles classification B) was endoscopically found in one patient in each group (16.7 vs. 25.0%, p = 0.714), and antiacid use was required in three patients (group A, two; group B, one; 50.0 vs. 16.7%, p = 0.500). CONCLUSION: The success rate of POEM within 1 year in young children with achalasia aged 12 years or younger was equal to that in adolescent patients. However, young children tended to require antiacids 1 year postoperatively; therefore, long-term follow-up is necessary.

Peroral endoscopic myotomy for a pediatric case of suspected congenital esophageal stenosis.

Video 1Peroral endoscopic myotomy for a pediatric case of suspected congenital esophageal stenosis.

Achalasia phenotypes and prediction of peroral endoscopic myotomy outcomes using machine learning.

OBJECTIVES: High-resolution manometry (HRM) and esophagography are used for achalasia diagnosis; however, achalasia phenotypes combining esophageal motility and morphology are unknown. Moreover, predicting treatment outcomes of peroral endoscopic myotomy (POEM) in treatment-naïve patients remains an unmet need. METHODS: In this multicenter cohort study, we included 1824 treatment-naïve patients diagnosed with achalasia. In total, 1778 patients underwent POEM. Clustering by machine learning was conducted to identify achalasia phenotypes using patients' demographic data, including age, sex, disease duration, body mass index, and HRM/esophagography findings. Machine learning models were developed to predict persistent symptoms (Eckardt score ≥3) and reflux esophagitis (RE) (Los Angeles grades A-D) after POEM. RESULTS: Machine learning identified three achalasia phenotypes: phenotype 1, type I achalasia with a dilated esophagus (n = 676; 37.0%); phenotype 2, type II achalasia with a dilated esophagus (n = 203; 11.1%); and phenotype 3, late-onset type I-III achalasia with a nondilated esophagus (n = 619, 33.9%). Types I and II achalasia in phenotypes 1 and 2 exhibited different clinical characteristics from those in phenotype 3, implying different pathophysiologies within the same HRM diagnosis. A predictive model for persistent symptoms exhibited an area under the curve of 0.70. Pre-POEM Eckardt score ≥6 was the greatest contributing factor for persistent symptoms. The area under the curve for post-POEM RE was 0.61. CONCLUSION: Achalasia phenotypes combining esophageal motility and morphology indicated multiple disease pathophysiologies. Machine learning helped develop an optimal risk stratification model for persistent symptoms with novel insights into treatment resistance factors.

Assessment of predictive factors associated with the technical difficulty of endoscopic submucosal dissection for superficial esophageal squamous cell carcinoma: Japanese multicenter retrospective study.

OBJECTIVES: Endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma (ESCC) is performed for the treatment of lesions with varied backgrounds and factors. However, the predictive factors associated with the technical difficulty of ESD remain unknown in patients with varied lesions. Therefore, this study aimed to identify the predictive factors associated with the technical difficulty of ESD for ESCC using a retrospective cohort. METHODS: This multicenter, retrospective study was conducted in 10 hospitals in Japan. Consecutive patients who underwent esophageal ESD between January 2013 and December 2019 were enrolled. Lesions of subepithelial tumors, adenocarcinoma, and adenoma were excluded. Difficult lesions were defined as ESD requiring a long procedure time (≥120 min), perforation development, piecemeal resection, or discontinued ESD. In the present study, the clinical factors were assessed to identify the technical difficulty of ESD using univariate and multivariate analyses. RESULTS: Among 1708 lesions treated with esophageal ESD, eight subepithelial tumors, 44 adenocarcinomas, and two adenomas were excluded. Finally, 1505 patients with 1654 lesions were analyzed, and 217 patients with 217 lesions (13.1%) were classified as patients with difficult lesions. In multivariate analysis, the predictive factors associated with the technical difficulty of ESD were as follows: tumors with varices, tumors with diverticulum, antiplatelet use (discontinued), circumference of tumor (≥1/2), preoperative tumor size ≥30 mm, trainee, and nonhigh-volume center. CONCLUSION: This multicenter retrospective study identified the predictive factors associated with the technical difficulty of ESD for ESCC with varied backgrounds and factors.

Biological and clinical significance of the YKL-40/osteopontin-integrin ß4-p70S6K axis induced by macrophages in early oesophageal squamous cell carcinoma.

M2 macrophages contribute to the progression of oesophageal squamous cell carcinoma (ESCC); however, the roles of M2 macrophages in early ESCC remain unclear. To clarify the biological mechanisms underlying the interaction between M2 macrophages and oesophageal epithelial cells in early-stage ESCC, in vitro co-culture assays between the immortalised oesophageal epithelial cell line Het-1A and cytokine-defined M2 macrophages were established. Co-culture with M2 macrophages promoted the proliferation and migration of Het-1A cells via the mTOR-p70S6K signalling pathway activated by YKL-40, also known as chitinase 3-like 1, and osteopontin (OPN) that were hypersecreted in the co-culture supernatants. YKL-40 and OPN promoted the above phenotypes of Het-1A by making a complex with integrin ß4 (ß4). Furthermore, YKL-40 and OPN promoted M2 polarisation, proliferation, and migration of macrophages. To validate the pathological and clinical significances of in vitro experimental results, immunohistochemistry of human early ESCC tissues obtained by endoscopic submucosal dissection (ESD) was performed, confirming the activation of the YKL-40/OPN-ß4-p70S6K axis in the tumour area. Moreover, epithelial expression of ß4 and the number of epithelial and stromal infiltrating YKL-40- and OPN-positive cells correlated with the Lugol-voiding lesions (LVLs), a well-known predictor of the incidence of metachronous ESCC. Furthermore, the combination of high expression of ß4 and LVLs or high numbers of epithelial and stromal infiltrating YKL-40- and OPN-positive immune cells could more clearly detect the incidence of metachronous ESCC than each of the parameters alone. Our results demonstrated that the YKL-40/OPN-ß4-p70S6K axis played important roles in early-stage ESCC, and the high expression levels of ß4 and high numbers of infiltrating YKL-40- and OPN-positive immune cells could be useful predictive parameters for the incidence of metachronous ESCC after ESD. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Clinical characteristics of absent contractility and ineffective esophageal motility: a multicenter study in Japan.

BACKGROUND AND AIM: Absent contractility (AC) and ineffective esophageal motility (IEM) are esophageal hypomotility disorders diagnosed using high-resolution manometry (HRM). Patient characteristics and disease course of these conditions and differential diagnosis between AC and achalasia are yet to be elucidated. METHODS: A multicenter study involving 10 high-volume hospitals was conducted. Starlet HRM findings were compared between AC and achalasia. Patient characteristics including underlying disorders and disease courses were analyzed in AC and IEM. RESULTS: Fifty-three patients with AC and 92 with IEM were diagnosed, while achalasia was diagnosed in 1784 patients using the Chicago classification v3.0 (CCv3.0). The cut-off integrated relaxation pressure (IRP) value at 15.7 mmHg showed maximum sensitivity (0.80) and specificity (0.87) for differential diagnosis of AC from type I achalasia. While most ACs were based on systemic disorders such as scleroderma (34%) and neuromuscular diseases (8%), 23% were sporadic cases. The symptom severity of AC was not higher than that of IEM. Regarding the diagnosis of IEM, the more stringent CCv4.0 excluded 14.1% of IEM patients than the CCv3.0, although patient characteristics did not change. In patients with the hypomotile esophagus, concomitance of reflux esophagitis was associated with low distal contractile integral and IRP values. AC and IEM transferred between each other, paralleling with the underlying disease course, although no transition to achalasia was observed. CONCLUSION: A successful determination of the optimal cut-off IRP value was achieved using the starlet HRM system to differentiate AC and achalasia. Follow-up HRM is also useful for differentiating AC from achalasia. Symptom severity may depend on underlying diseases instead of hypomotility severity.

Long-Term Outcomes of Endoscopic Submucosal Dissection for Early Remnant Gastric Cancer: A Retrospective Multicenter Study.

INTRODUCTION: Favorable long-term outcomes of endoscopic submucosal dissection (ESD) for early remnant gastric cancer (ERGC) have been reported in single-center studies from advanced institutions. However, no studies have examined the long-term outcomes using a multicenter database. This study aimed to investigate the long-term outcomes of the aforementioned approach using a large multicenter database. METHODS: This retrospective multicenter cohort study included 242 cases with 256 lesions that underwent ESD for ERGC between April 2009 and March 2019 across 12 centers. We investigated the long-term outcomes of these patients with the Kaplan-Meier method, and the relationship between curability, additional treatment, or hospital category, and the survival time was evaluated using the log-rank test. RESULTS: During the median follow-up period of 48.4 months, the 5-year overall survival rate was 81.3%, and the 5-year gastric cancer-specific survival rate was 98.1%. The survival time of patients of endoscopic curability (eCura) C-2 without additional surgery was significantly shorter than the corresponding of patients of eCura A/B/C-1 and eCura C-2 with additional surgery. There was no significant difference in either overall survival or gastric cancer-specific survival rate between the high-volume and non-high-volume hospitals. CONCLUSION: The gastric cancer-specific survival of ESD for ERGC using a multicenter database was favorable. ESD for ERGC is widely applicable regardless of the hospital case volume. Management in accordance with the latest guidelines will lead to long-term survival.

Characteristics of Gastric Stasis due to Deformation after Endoscopic Submucosal Dissection in the Lower Part of the Stomach.

INTRODUCTION: Gastric stasis due to deformation occurs after endoscopic submucosal dissection in the lower part of the stomach. Endoscopic balloon dilation can improve gastric stasis due to stenosis; however, endoscopic balloon dilation cannot improve gastric stasis due to deformation. Furthermore, the characteristics of gastric stasis due to deformation are unknown. This study aimed to evaluate the characteristics of gastric stasis due to deformation after endoscopic submucosal dissection in the lower part of the stomach, focusing on the differences between stenosis and deformation. METHODS: We retrospectively reviewed 41 patients with gastric stasis after endoscopic submucosal dissection in the lower part of the stomach. We evaluated the characteristics of cases with gastric stasis due to deformation, such as the risk factors of deformation and the rate of deformation in each group with risk factors. RESULTS: Deformation was observed in 12% (5/41) of the patients with gastric stasis. All cases of deformation had a circumferential extent of the mucosal defect greater than 3/4. The number of cases with pyloric dissection was significantly lower in the deformation group than in the non-deformation group (0% vs. 72%; p = 0.004). The deformation group also had a significantly higher number of cases with angular dissection than the non-deformation group (100% vs. 17%; p < 0.001). Moreover, the deformation cases had a significantly larger specimen diameter (p < 0.001). Deformation was observed only in cases with angular and non-pyloric dissections. Deformation was not observed in cases with angular and pyloric dissections. CONCLUSIONS: All cases of gastric stasis due to deformation had a circumferential extent of the mucosal defect greater than 3/4. Deformation was also likely to occur in cases with a larger dissection that exceeded the angular region without pyloric dissection.

Risk scoring system for the preprocedural prediction of the clinical failure of peroral endoscopic myotomy: a multicenter case-control study.

BACKGROUND: Peroral endoscopic myotomy (POEM) is effective for the management of achalasia and its variants; however, it can be ineffective in some patients. We aimed to develop and validate a risk scoring system to predict the clinical failure of POEM preoperatively. METHODS: Consecutive patients who underwent POEM in 14 high volume centers between 2010 and 2020 were enrolled in this study. Clinical failure was defined as an Eckardt score of ≥ 4 or retreatment. A risk scoring system to predict the short-term clinical failure of POEM was developed using multivariable logistic regression and internally validated using bootstrapping and decision curve analysis. RESULTS: Of the 2740 study patients, 112 (4.1 %) experienced clinical failure 6 months after POEM. Risk scores were assigned for three preoperative factors as follows: preoperative Eckardt score (1 point), manometric diagnosis (-4 points for type II achalasia), and a history of prior treatments (1 point for pneumatic dilation or 12 points for surgical/endoscopic myotomy). The discriminative capacity (concordance statistics 0.68, 95 %CI 0.62-0.72) and calibration (slope 1.15, 95 %CI 0.87-1.40) were shown. Decision curve analysis demonstrated its clinical usefulness. Patients were categorized into low (0-8 points; estimated risk of clinical failure < 5 %) and high risk (9-22 points; ≥ 5 %) groups. The proportions of clinical failure for the categories were stratified according to the mid-term outcomes (log-rank test, P < 0.001). CONCLUSIONS: This risk scoring system can predict the clinical failure of POEM preoperatively and provide useful information when making treatment decisions.

Risk-scoring system for predicting challenging cases of peroral endoscopic myotomy.

OBJECTIVES: Peroral endoscopic myotomy (POEM) is an effective treatment for esophageal motility disorders including achalasia and its variants. However, some surgeons have encountered challenging cases. This study aimed to develop a risk-scoring system to predict challenging cases of POEM. METHODS: Consecutive patients who underwent POEM between April 2015 and March 2020 at our hospital were included in this single-center retrospective study. Challenging cases of POEM were defined as patients with any of the following: (i) procedure time ≥90 min; (ii) mucosal perforation; (iii) pneumothorax; and (iv) major bleeding. A risk-scoring system for predicting challenging cases was developed based on multivariate logistic regression and internal validation was performed using the bootstrap method. Clinical usefulness was evaluated using a decision curve analysis. RESULTS: Of the 467 patients, 59 (12.6%) had challenging POEM. A risk-scoring system consisted of four variables: duration of symptoms ≥5 years (assigned score, 1 point), antithrombotics use (1 point), manometric diagnosis of achalasia variants (2 points), and dilation grade 3 (2 points). Our scoring system showed satisfactory discrimination (area under the receiver operating characteristic curve, 0.69; 95% confidence interval [CI] 0.61-0.77) and calibration (slope, 0.99; 95% CI 0.65-1.35). The decision curve analysis demonstrated its clinical usefulness. CONCLUSIONS: We established a risk-scoring system to predict challenging cases of POEM. This scoring system may aid the selection of patients who require treatment from experienced surgeons.

Impact of peroral endoscopic myotomy on high-resolution manometry findings and their association with the procedure's outcomes.

BACKGROUND AND AIMS: Peroral endoscopic myotomy (POEM) is conducted for patients with esophageal motility disorders based on high-resolution manometry (HRM) findings. However, the impact of POEM on HRM findings and the associations between post-POEM HRM and outcomes have not been clarified. METHODS: In a multicenter, observational, cohort study, patients with achalasia treated by POEM received follow-up HRM. Associations between patient characteristics, POEM procedures, and post-POEM HRM findings, including integrated relaxation pressure (IRP) and distal contractile integral (DCI), were investigated. Furthermore, POEM procedure outcomes were compared with post-POEM HRM findings. RESULTS: Of 2171 patients, 151 (7.0%) showed residual high post-POEM IRP (≥26 mm Hg; Starlet [Starmedical Ltd, Tokyo, Japan]). In a multivariate analysis, high pre-POEM IRPs (odds ratio [OR], 24.3) and gastric myotomy >2 cm (OR, .22) were found to be positive and negative predictive factors of high post-POEM IRPs, respectively. Peristalsis recovery (DCI ≥500 mm Hg/cm/s, at least 1 swallow; Starlet) was visible in 121 of 618 patients (19.6%) who had type II to III achalasia. High pre-POEM IRP (OR, 2.65) and DCI ≥500 (OR, 2.98) predicted peristalsis recovery, whereas esophageal dilation (OR, .42) predicted a risk of no recovery. Extended myotomy did not reveal a significant impact on peristalsis recovery. High or low post-POEM IRP and DCI did not increase the incidence of clinical failure, reflux esophagitis, or symptomatic GERD. CONCLUSIONS: Extended gastric myotomy decreased IRP values, whereas peristalsis recovery depended on the characteristics of achalasia. A residual high post-POEM IRP does not necessarily mean clinical failure. Routine HRM follow-up is not recommended after POEM.

Subtype of Achalasia and Integrated Relaxation Pressure Measured Using the Starlet High-resolution Manometry System: A Multicenter Study in Japan.

Background/Aims: ManoScan and Sandhill high-resolution manometry (HRM) systems are used worldwide; however, the diagnosis of achalasia on the Starlet HRM system is not fully characterized. Furthermore, the impact of calcium channel blockers and nitrites in treating achalasia has not been investigated using HRM. Management of recurrent cases is a priority issue, although few studies have examined patient characteristics. Methods: We conducted a multicenter, large-scale database analysis. First, the diagnosis of treatment-naive achalasia in each HRM system was investigated. Next, patient characteristics were compared between type I-III achalasia, and the impact of patient characteristics, including calcium channel blocker and nitrite use for integrated relaxation pressure (IRP) values, were analyzed. Finally, patient characteristics with recurrent achalasia were elucidated. Results: The frequency of type I achalasia with Starlet was significantly higher than that with ManoScan and Sandhill HRM systems. In achalasia, multivariate analysis identified male sex, advanced age, long disease duration, obesity, type I achalasia, and sigmoid type as risk factors related to normal IRP values (< 26 mmHg). Calcium channel blockers and nitrites use had no significant impact on the IRP values, although achalasia symptoms were indicated to be alleviated. In recurrent cases, the IRP value was significantly lower, and advanced age, long disease duration, and sigmoid type were more common than in treatment-naive patients. Conclusions: We should cautiously interpret the type of achalasia and IRP values in the Starlet HRM system. Symptoms of recurrent cases are related to disease progression rather than IRP values, which should be considered in decision making.

Efficacy of peroral endoscopic myotomy for esophageal motility disorders after gastric surgery: Japan Achalasia Multicenter Study.

OBJECTIVES: Patients with esophageal motility disorders (EMDs) including achalasia after gastric surgery have not been thoroughly characterized. Furthermore, the efficacy of peroral endoscopic myotomy (POEM) in this population should be clarified. METHODS: In this retrospective multicenter study of 3707 patients with EMDs, 31 patients (0.8%) had a history of gastric surgery. Patient characteristics and POEM efficacy were compared between patients with and without previous gastric surgery. RESULTS: In patients with EMD after gastric surgery, age at EMD diagnosis was higher (72.0 years), male sex was predominant (90.3%), and the American Society of Anesthesiologists physical status score was higher (≥II, 48.4%). High-resolution manometry (HRM) findings did not reveal significant differences. In patients who underwent gastric surgery, atrophic gastritis was common (80.6%), and gastric cancer was the primary surgical indication (32.3%). Distal gastrectomy was performed in 28 patients (90.3%). POEM was effective (3.3% adverse events; 100% treatment success). The incidence rates of reflux esophagitis (RE) and symptomatic gastroesophageal reflux disease (GERD) were 60.0% and 16.7%, respectively, without significant intergroup differences, and severe RE was not observed in the long-term follow-up. Extended gastric myotomy was a risk factor for RE. CONCLUSION: Patients with gastric surgery often present severe disease manifestations; the surgical indication is mainly gastric cancer. HRM findings can be similarly used for diagnosis in patients with and without gastric surgery. POEM maintains safety and efficacy with acceptable RE and symptomatic GERD rates. To prevent RE, extended myotomy should be avoided.