The Role of an Undifferentiated Component in Submucosal Invasion and Submucosal Invasion Depth After Endoscopic Submucosal Dissection for Early Gastric Cancer

Comprehensive analysis of risk factors associated with submucosal invasion in patients with early-stage gastric cancer

BACKGROUND

Submucosal invasion in early-stage gastric cancer (GC) is a critical determinant of prognosis and treatment strategy, significantly influencing the risk of lymph node metastasis and recurrence. Identifying risk factors associated with submucosal invasion is essential for optimizing patient management and improving outcomes.

AIM

To comprehensively analyze clinical, imaging, and endoscopic characteristics to identify predictors of submucosal invasion in patients with early-stage differentiated GC.

METHODS

A retrospective study was conducted at our institution from January 2019 to January 2023, including 268 patients diagnosed with early-stage differentiated GC who underwent surgical resection or endoscopic submucosal dissection. Data were collected on demographic, clinical, imaging, and endoscopic characteristics, with endoscopic images reviewed independently by two gastroenterologists. Statistical analysis included univariate and multivariate logistic regression to identify significant predictors of submucosal invasion, and receiver operating characteristic (ROC) curve analysis to evaluate the predictive value of continuous variables.

RESULTS

A total of 268 patients were included, with 178 males and 90 females, and a mean age of 61.5 ± 9.8 years. Univariate analysis showed that male gender, history of alcohol consumption, smoking, and computed tomography-detected gastric wall thickening were more prevalent in patients with submucosal invasion. Significant endoscopic predictors included tumor location in the upper two-thirds of the stomach, depressed morphology, marginal elevation, and high color differences on white-light endoscopy (WLE) and linked color imaging (LCI). Multivariate analysis identified upper stomach location [odds ratio (OR): 5.268], depressed type (OR: 5.841), marginal elevation (OR: 4.132), and LCI color difference ≥ 18.1 (OR: 4.479) as significant predictors. ROC analysis showed moderate predictive value for lesion diameter, WLE, and LCI color differences (area under the curve: 0.630, 0.799, and 0.760, respectively).

CONCLUSION

Depressed-type lesions, marginal elevation, location in the upper two-thirds of the stomach, and significant color differences on LCI are high-risk indicators for submucosal invasion. These findings suggest that such lesions warrant more aggressive intervention to prevent disease progression and improve patient outcomes.

Interpretable deep learning model to predict lymph node metastasis in early gastric cancer using whole slide images

In early gastric cancer (EGC), the presence of lymph node metastasis (LNM) is a crucial factor for determining the treatment options. Endoscopic resection is used for treatment of EGC with minimal risk of LNM. However, owing to the lack of definitive criteria for identifying patients who require additional surgery, some patients undergo unnecessary additional surgery. Considering that histopathologic patterns are significant factor for predicting lymph node metastasis in gastric cancer, we aimed to develop a machine learning algorithm which can predict LNM status using hematoxylin and eosin (H&E)-stained images. The images were obtained from several institutions. Our pipeline comprised two sequential approaches including a feature extractor and a risk classifier. For the feature extractor, a segmentation network (DeepLabV3+) was trained on 243 WSIs across three datasets to differentiate each histological subtype. The risk classifier was trained with XGBoost using 70 morphological features inferred from the trained feature extractor. The trained segmentation network, the feature extractor, achieved high performance, with pixel accuracies of 0.9348 and 0.8939 for the internal and external datasets in patch level, respectively. The risk classifier achieved an overall AUC of 0.75 in predicting LNM status. Remarkably, one of the datasets also showed a promising result with an AUC of 0.92. This is the first multi-institution study to develop machine learning algorithm for predicting LNM status in patients with EGC using H&E-stained histopathology images. Our findings have the potential to improve the selection of patients who require surgery among those with EGC showing high-risk histological features.

Computed Tomography-Based Predictive Model for the Probability of Lymph Node Metastasis in Gastric Cancer: A Meta-analysis

OBJECTIVES

Whether or not a gastric cancer (GC) patient exhibits lymph node metastasis (LNM) is critical to accurately guiding their treatment and prognostic evaluation, necessitating the ability to reliably predict preoperative LNM status. The present meta-analysis sought to examine the diagnostic value of computed tomography (CT)-based predictive models as a tool to gauge the preoperative LNM status of patients with GC.

METHODS

Relevant articles were identified in the PubMed, Web of Science, and Wanfang databases. These studies were used to conduct pooled analyses examining sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) values, and area under the curve values were computed for summary receiver operating characteristic curves.

RESULTS

The final meta-analysis incorporated data from 15 studies, all of which were conducted in China, enrolling 3,817 patients with GC (LNM+: 1790; LNM-: 2027). The developed CT-based predictive model exhibited respective pooled sensitivity, specificity, PLR, and NLR values of 84% (95% confidence interval [CI], 0.79-0.87), 81% (95% CI, 0.76-0.85), 4.39 (95% CI, 3.40-5.67), and 0.20 (95% CI, 0.16-0.26). The identified results were not associated with significant potential for publication bias ( P = 0.071). Similarly, CT-based analyses of LN status exhibited respective pooled sensitivity, specificity, PLR, and NLR values of 62% (95% CI, 0.53-0.70), 77% (95% CI, 0.72-0.81), 2.71 (95% CI, 2.20-3.33), and 0.49 (95% CI, 0.40-0.61), with no significant risk of publication bias ( P = 0.984).

CONCLUSIONS

Overall, the present meta-analysis revealed that a CT-based predictive model may outperform CT-based analyses alone when assessing the preoperative LNM status of patients with GC, offering superior diagnostic utility.

Endoscopic Resection of Undifferentiated Early Gastric Cancer

Endoscopic resection (ER) is widely performed for early gastric cancer (EGC) with a negligible risk of lymph node metastasis (LNM) in Eastern Asian countries. In particular, endoscopic submucosal dissection (ESD) leads to a high en bloc resection rate, enabling accurate pathological evaluation. As undifferentiated EGC (UD-EGC) is known to result in a higher incidence of LNM and infiltrative growth than differentiated EGC (D-EGC), the indications for ER are limited compared with those for D-EGC. Previously, clinical staging as intramucosal UD-EGC ≤2 cm, without ulceration, was presented as 'weakly recommended' or 'expanded indications' for ER in the guidelines of the United States, Europe, Korea, and Japan. Based on promising long-term outcomes from a prospective multicenter study by the Japan Clinical Oncology Group (JCOG) 1009/1010, the status of this indication has expanded and is now considered 'absolute indications' in the latest Japanese guidelines published in 2021. In this study, which comprised 275 patients with UD-EGC (cT1a, ≤2 cm, without ulceration) treated with ESD, the 5-year overall survival (OS) was 99.3% (95% confidence interval, 97.1%-99.8%), which was higher than the threshold 5-year OS (89.9%). Currently, the levels of evidence grades and recommendations for ER of UD-EGC differ among Japan, Korea, and Western countries. Therefore, a further discussion is warranted to generalize the indications for ER of UD-EGC in countries besides Japan.

Management of Superficial Esophageal Squamous Cell Carcinoma and Early Gastric Cancer following Non-Curative Endoscopic Resection

According to the European and Japanese guidelines, additional treatment is recommended for cases of superficial esophageal squamous cell carcinoma (ESCC) and early gastric cancer (EGC) that do not meet the curability criteria for endoscopic resection (ER), i.e., non-curative ER, owing to the risk of lymph node metastasis (LNM). However, the rates of LNM in such cases were relatively low (e.g., 8% for EGC). Several recent advances have been made in this field. First, pathological risk stratification for metastatic recurrence following non-curative ER without additional treatment was developed for both superficial ESCC and EGC. Second, the pattern of metastatic recurrence and prognosis after recurrence following non-curative ER without additional treatment was found to be considerably different between superficial ESCC and EGC. Third, a combination of ER and selective chemoradiotherapy was developed as a minimally invasive treatment method for clinical T1b-SM ESCC. These findings may help clinicians decide the treatment strategy for patients following non-curative ER; however, for optimal therapeutic decision-making in such patients, it is also important to predict the prognosis other than SESCC or EGC and impaired quality of life. Thus, a novel algorithm that considers these factors, as well as metastatic recurrence, should be developed.

Is Additional Gastrectomy Required for Elderly Patients after Endoscopic Submucosal Dissection with Endoscopic Curability C-2 for Early Gastric Cancer?

BACKGROUND

With the ongoing growth of the aged population, the number of elderly patients suffering from gastric cancer has increased in Japan. Since the frequency of lymph node metastasis (LNM) in patients after endoscopic submucosal dissection (ESD) with endoscopic curability (eCura) C-2 for early gastric cancer (EGC) is relative low, the following question can be raised: "Is additional gastrectomy required for elderly patients with such criteria for ESD?"

SUMMARY

For therapeutic decision-making after ESD with eCura C-2, the risk of all-cause mortality and impaired quality of life (QoL) should thus be evaluated. Risk stratification of LNM and gastric cancer-specific mortality was established by the eCura system; however, it remains unclear how much these categories and treatment selection affect all-cause mortality. The contribution of prognostic tools for predicting all-cause mortality was noted to vary across the studies of patients with EGC; thus, further studies that investigate comprehensive geriatric assessment (CGA) may be required. Regarding the QoL, studies on elderly patients remain to be lacking. Furthermore, one of the issues with CGA and QoL tools is that they are time consuming. Key Messages: Combined evaluation of risk stratification of gastric cancer-specific mortality by the eCura system and risk of nongastric cancer-related mortality and impaired QoL may be the current optimal method to decide treatment strategy after ESD with eCura C-2 for EGC among elderly patients. A large-scale prospective study that investigates CGA domains is required to identify predictors of all-cause mortality and impaired QoL, and a more easily usable tool should be developed.

Enlarged folds on endoscopic gastritis as a predictor for submucosal invasion of gastric cancers

BACKGROUND

Accurate diagnosis of the depth of gastric cancer invasion is crucial in clinical practice. The diagnosis of gastric cancer depth is often made using endoscopic characteristics of the tumor and its margins; however, evaluating invasion depth based on endoscopic background gastritis remains unclear.

AIM

To investigate predicting submucosal invasion using the endoscopy-based Kyoto classification of gastritis.

METHODS

Patients with gastric cancer detected on esophagogastroduodenoscopy at Toyoshima Endoscopy Clinic were enrolled. We analyzed the effects of patient and tumor characteristics, including age, sex, body mass index, surveillance endoscopy within 2 years, current Helicobacter pylori infection, the Kyoto classification, and Lauren’s tumor type, on submucosal tumor invasion and curative endoscopic resection. The Kyoto classification included atrophy, intestinal metaplasia, enlarged folds, nodularity, and diffuse redness. Atrophy was characterized by non-reddish and low mucosa. Intestinal metaplasia was detected as patchy whitish or grayish-white flat elevations, forming an irregular uneven surface. An enlarged fold referred to a fold width ≥ 5 mm in the greater curvature of the corpus. Nodularity was characterized by goosebump-like multiple nodules in the antrum. Diffuse redness was characterized by uniform reddish non-atrophic mucosa in the greater curvature of the corpus.

RESULTS

A total of 266 gastric cancer patients (mean age, 66.7 years; male sex, 58.6%; mean body mass index, 22.8 kg/m²) were enrolled. Ninety-three patients underwent esophagogastroduodenoscopy for surveillance within 2 years, and 140 had current Helicobacter pylori infection. The mean Kyoto score was 4.54. Fifty-eight cancers were diffuse-type, and 87 cancers had invaded the submucosa. Multivariate analysis revealed that low body mass index (odds ratio 0.88, P = 0.02), no surveillance esophagogastroduodenoscopy within 2 years (odds ratio 0.15, P < 0.001), endoscopic enlarged folds of gastritis (odds ratio 3.39, P = 0.001), and Lauren’s diffuse-type (odds ratio 5.09, P < 0.001) were independently associated with submucosal invasion. Similar results were obtained with curative endoscopic resection. Among cancer patients with enlarged folds, severely enlarged folds (width ≥ 10 mm) were more related to submucosal invasion than mildly enlarged folds (width 5-9 mm, P < 0.001).

CONCLUSION

Enlarged folds of gastritis were associated with submucosal invasion. Endoscopic observation of background gastritis as well as the lesion itself may help diagnose the depth of cancer invasion.

Can we predict mediastinal lymph nodes metastasis in esophagogastric junction cancer? Results of a systematic review and meta-analysis

PURPOSE

The aim of this systematic review and meta-analysis was to define clinical indicator that predicts mediastinal lymph nodes metastasis (MLNM) in patients with Esophagogastric junction cancer (EGJC) to select patient population requiring esophagectomy.

METHODS

A systematic and electronic search of several electronic databases was performed up to August 2020. Studies containing information on risk factors for MLNM in patients diagnosed with EJGC and who underwent curative surgery were included.

RESULTS

Two predictors, including undifferentiated type (OR = 1.82, 95% CI = 1.07-3.10, p = 0.03) and esophageal invasion length (EIL) (OR = 10.95, 95% CI = 6.37-18.82, p < 0.00001) were identified as significant predictors for the risk of MLNM.

CONCLUSION

Knowledge of the associations of these clinicopathological features with MLNM can be useful in determining operative strategy for EGJC.

Factors associated with overall survival in early gastric cancer patients who underwent additional surgery after endoscopic submucosal dissection

BACKGROUND

Controversy exists about the benefit of additional surgery after endoscopic submucosal dissection (ESD) for early gastric cancer (EGC).

AIM

To examine risk factors for overall survival (OS) after additional surgery in patients with EGC who initially underwent ESD.

METHODS

This was a retrospective analysis of patients with EGC who underwent additional surgery after ESD at the Beijing Friendship Hospital affiliated to Capital Medical University between August 2012 and August 2019. OS was the primary outcome. Lymph node metastasis and residual tumor were secondary outcomes. Logistic regression models and Kaplan-Meier curves were used for further analysis.

RESULTS

Forty-two patients were evaluated, including 35 (83.3%) males and 7(16.7%) females. The mean age was 62 (range, 32-82) years. Male sex [hazard ratio (HR) = 21.906, 95% confidence interval (CI): 3.762-229.250; P = 0.039), T1b invasion (HR = 3.965, 95%CI: 1.109-17.432; P = 0.047), undifferentiated tumor (HR = 9.455, 95%CI: 0.946-29.482; P = 0.049), lymph node metastasis (HR = 2.126, 95%CI: 0.002-13.266; P = 0.031), and residual tumor (HR = 4.275, 95%CI: 1.049-27.420; P = 0.043) were independently associated with OS. The follow-up duration was 4-81 mo (median: 50.7 mo). OS was 77.0 ± 12.1 mo (95%CI: 53.3-100.7 mo). The 3-year and 5-year OS rates were 94.1% and 85%, respectively.

CONCLUSION

Male sex, T1b invasion, undifferentiated tumor, lymph node metastasis, and residual tumor are independently associated with OS in patients with EGC who underwent additional surgery after ESD.

Management following endoscopic resection in elderly patients with early-stage upper gastrointestinal neoplasia

With the ongoing increase in the aging population in Japan, the number of elderly patients among the total population with upper gastrointestinal (GI) neoplasia has also been increasing. As elderly patients present unique age-related variations in their physical condition, the therapeutic approach for upper GI neoplasia should be differentiated between elderly and nonelderly patients. According to the existing guidelines, additional treatment is the standard therapy in patients who undergo endoscopic resection (ER) with a possible risk of lymph node metastasis (LNM) for upper GI neoplasia. However, due to the relatively low rate of LNM, applying additional treatment in all elderly patients may be excessive. Although additional treatment has the advantage of reducing cancer-specific mortality, its disadvantages include deteriorated quality of life, complications, and mortality in surgery. In patients with early gastric cancer, we propose treatment decisions be made using a risk-scoring system for LNM and upon considering the physical condition of the patient after ER with curability C-2. In those with superficial esophageal squamous cell carcinoma with a possible risk of LNM after ER, selective chemoradiotherapy may be a less-invasive treatment option, although the present standard treatment is esophagectomy. When considering the treatment decision, achieving a "cure" of the tumor has been regarded as critical. However, as the main cause of mortality in elderly patients with ER for upper GI neoplasia is noncancer-related death, both achieving a "cure" and also a good level of "care" is important in the management of elderly patients.

A Recent Argument for the Use of Endoscopic Submucosal Dissection for Early Gastric Cancers

Endoscopic submucosal dissection (ESD) has become the standard treatment method for early gastric cancers (EGCs) due to the negligible risk for lymph node metastasis (LNM) in Eastern Asian countries. According to the guidelines, the curability of EGC after endoscopic resection was classified into three groups: curative resection, expanded curative resection, and noncurative resection. In Eastern Asian countries, a structured follow-up schedule is needed for patients undergoing curative resection and expanded curative resection. Conversely, in Western countries, additional surgery may be recommended for some patients undergoing expanded curative resection (ulcerated, undifferentiated, or slight submucosal invasion) due to the potential risk for LNM, even though specimens of ESD and surgery may not be handled with the same methodology as that used in Japan, which may lead to this slightly higher risk. In noncurative resection, additional surgery is the standard method after ESD because of the risk for LNM. However, in elderly patients and/or those with severe underlying diseases, the advantages and disadvantages of additional surgery should be considered when selecting a post-ESD treatment strategy for patients undergoing noncurative resection. Risk-scoring systems for LNM may facilitate clinical decisions for these patients. However, it should be noted that when recurrence was detected in patients who were followed up with no additional treatment after ESD with noncurative resection, most of them had a poor prognosis. To select an appropriate treatment method, especially in elderly patients undergoing ESD with noncurative resection, a new tool for evaluating the condition of patients should be established.

Predictors of lymph node metastasis and residual tumor in early gastric cancer patients after noncurative endoscopic resection: a systematic review and meta-analysis

BACKGROUND

It is challenging to identify the prevalence of lymph node metastasis (LNM) and residual tumor in patients with early gastric cancer (EGC) who underwent noncurative endoscopic resection (ER). This present meta-analysis was aimed to establish imperative potential predictive factors in order to select the optimal treatment method.

METHODS

A systematic literature search of PubMed, Embase, and Cochrane Library databases was performed through 1 February 2019 to identify relevant studies, which investigated risk factors for LNM and residual tumor in patients with EGC who underwent noncurative ER. Eligible data were systematically reviewed through a meta-analysis.

RESULTS

Overall, 12 studies investigating the risk factor of LNM were included, totaling 3015 patients, 7 of which also involved cancer residues. After the present meta-analysis, six predictors, including tumor size >30 mm, tumor invasion depth (⩾500 μm from the muscularis mucosae), macroscopic appearance, undifferentiated histopathological type, positive vertical margin, and presence of lymphovascular invasion (including lymphatic invasion and vascular invasion) were significantly associated with LNM, whereas tumor size >30 mm, positive horizontal margin, and positive vertical margin were identified as significant predictors for the risk of residual tumor. No evidence of publication bias was observed.

CONCLUSIONS

Six and three variables were established as significant risk factors for LNM and residual tumor in patients with EGC who underwent noncurative ER, respectively. Patients with EGC who present these risk factors after noncurative ER are strongly suggested to receive additional surgery, while others might be suitable for strict follow-up. This might shed some new light on the selection of follow-up treatment for noncurative ER.

Favorable Long-Term Outcomes of Endoscopic Submucosal Dissection for Differentiated-Type-Predominant Early Gastric Cancer with Histological Heterogeneity

It remains unclear whether endoscopic submucosal dissection (ESD) can be indicated for differentiated-type-predominant early gastric cancer mixed with a minor undifferentiated component (EGC with histological heterogeneity (HH)). Here, we reviewed and compared clinicopathologic characteristics and long-term outcomes of ESD of 257 patients with EGC-HH and those of 2386 patients with pure differentiated-type EGC (PuD-EGC). After ESD, EGC-HH was managed in the same way as PuD-EGC. EGC-HHs were significantly associated with larger tumor size, more frequent submucosal invasion, and lymphovascular invasion compared to PuD-EGCs. Despite these aggressive features of EGC-HH, no local recurrence or gastric cancer-related death occurred during a median of 58 months of follow up after ESD for EGC-HH, if curative resection was achieved. After curative ESD for EGC-HH, six patients had metachronous recurrence (5.0%) and one patient underwent extragastric recurrence in a regional lymph node (0.8%). All these recurrence cases were curatively treated with ESD or gastrectomy. For patients with EGC-HH, five-year overall survival and recurrence-free survival rates after curative ESD were 97.0% and 94.8%, respectively, which were comparable to those of patients with PuD-EGC. In conclusion, ESD showed favorable long-term outcomes after curative resection and may be an acceptable treatment option for EGC-HH meeting curative endoscopic resection criteria.

Dual-energy CT-based deep learning radiomics can improve lymph node metastasis risk prediction for gastric cancer

OBJECTIVES

To build a dual-energy CT (DECT)-based deep learning radiomics nomogram for lymph node metastasis (LNM) prediction in gastric cancer.

MATERIALS AND METHODS

Preoperative DECT images were retrospectively collected from 204 pathologically confirmed cases of gastric adenocarcinoma (mean age, 58 years; range, 28-81 years; 157 men [mean age, 60 years; range, 28-81 years] and 47 women [mean age, 54 years; range, 28-79 years]) between November 2011 and October 2018, They were divided into training (n = 136) and test (n = 68) sets. Radiomics features were extracted from monochromatic images at arterial phase (AP) and venous phase (VP). Clinical information, CT parameters, and follow-up data were collected. A radiomics nomogram for LNM prediction was built using deep learning approach and evaluated in test set using ROC analysis. Its prognostic performance was determined with Harrell's concordance index (C-index) based on patients' outcomes.

RESULTS

The dual-energy CT radiomics signature was associated with LNM in two sets (Mann-Whitney U test, p < 0.001) and an achieved area under the ROC curve (AUC) of 0.71 for AP and 0.76 for VP in test set. The nomogram incorporated the two radiomics signatures and CT-reported lymph node status exhibited AUCs of 0.84 in the training set and 0.82 in the test set. The C-indices of the nomogram for progression-free survival and overall survival prediction were 0.64 (p = 0.004) and 0.67 (p = 0.002).

CONCLUSION

The DECT-based deep learning radiomics nomogram showed good performance in predicting LNM in gastric cancer. Furthermore, it was significantly associated with patients' prognosis.

KEY POINTS

• This study investigated the value of deep learning dual-energy CT-based radiomics in predicting lymph node metastasis in gastric cancer. • The dual-energy CT-based radiomics nomogram outweighed the single-energy model and the clinical model. • The nomogram also exhibited a significant prognostic ability for patient survival and enriched radiomics studies.

History and future perspectives in Japanese guidelines for endoscopic resection of early gastric cancer

Japanese guidelines for gastric cancer treatment were first published in 2001 for the purpose of showing the appropriate indication for each treatment method, thereby reducing differences in the therapeutic approach among institutions, and so on. With the accumulation of evidence and the development and prevalence of endoscopic submucosal dissection (ESD), the criteria for the indication and curability of endoscopic resection (ER) for early gastric cancer (EGC) have expanded. However, several problems still remain. Although a risk-scoring system (eCura system) for predicting lymph node metastasis (LNM) may help treatment decision in patients who do not meet the curative criteria for ER of EGC, which is referred to as eCura C-2 in the latest guidelines, additional gastrectomy with lymphadenectomy may be excessive for many patients, even those at high risk for LNM. Less-invasive function-preserving surgery, such as non-exposed endoscopic wall-inversion surgery with laparoscopic sentinel node sampling, may overcome this problem. In addition, further less-invasive treatment, such as ER with chemotherapy, should be established for patients who prefer not to undergo additional gastrectomy.

Additional laparoscopic gastrectomy after noncurative endoscopic submucosal dissection for early gastric cancer: A single-center experience

BACKGROUND

The necessity of additional gastrectomy for early gastric cancer (EGC) patients who do not meet curative criteria after endoscopic submucosal dissection (ESD) is controversial.

AIM

To examine the clinicopathologic characteristics of patients who underwent additional laparoscopic gastrectomy after ESD and to determine the appropriate strategy for treating those after noncurative ESD.

METHODS

We retrospectively studied 45 patients with EGC who underwent additional laparoscopic gastrectomy after noncurative ESD from January 2013 to January 2019 at the Cancer Hospital of the Chinese Academy of Medical Sciences. We analyzed the patients’ clinicopathological data and identified the predictors of residual cancer (RC) and lymph node metastasis (LNM).

RESULTS

Surgical specimens showed RC in ten (22.2%) patients and LNM in five (11.1%). Multivariate analysis revealed that positive horizontal margin [odds ratio (OR) = 13.393, 95% confidence interval (CI): 1.435-125, P = 0.023] and neural invasion (OR = 14.714, 95%CI: 1.087-199, P = 0.043) were independent risk factors for RC. Undifferentiated type was an independent risk factor for LNM (OR = 12.000, 95%CI: 1.197-120, P = 0.035). Tumors in all patients with LNM showed submucosal invasion more than 500 µm. Postoperative complications after additional laparoscopic gastrectomy occurred in five (11.1%) patients, and no deaths occurred among patients with complications.

CONCLUSION

Gastrectomy is necessary not only for patients who have a positive margin after ESD, but also for cases with neural invasion, undifferentiated type, and submucosal invasion more than 500 µm. Laparoscopic gastrectomy is a safe, minimally invasive, and feasible procedure for additional surgery after noncurative ESD. However, further studies are needed to apply these results to clinical practice.