Endoscopic submucosal dissection for early gastric cancer with undifferentiated-type histology: A meta-analysis

External Validation of the eCura System for Undifferentiated-Type Early Gastric Cancer with Noncurative Endoscopic Resection

Background/Aims

The eCura system, a scoring model for stratifying the lymph node metastasis risk after noncurative endoscopic resection for early gastric cancer (EGC), has been internally validated, primarily for differentiated-type EGC. We aimed to externally validate this model for undifferentiated-type EGC.

Methods

This multicenter, retrospective cohort study included 634 patients who underwent additional surgery (radical surgery group, n=270) or were followed up without additional treatment (no additional treatment group, n=364) after noncurative endoscopic resection for undifferentiated-type EGC between 2005 and 2015. The lymph node metastasis and survival rates were compared according to the risk categories.

Results

For the radical surgery group, the lymph node metastasis rates were 2.6%, 10.9%, and 14.8% for the low-, intermediate-, and high-risk eCura categories, respectively (p for trend=0.003). For the low-, intermediate-, and high-risk categories in the no additional treatment group, the overall survival (92.7%, 68.9%, and 80.0% at 5 years, respectively, p<0.001) and cancer-specific survival rates (99.7%, 94.7%, and 80.0% at 5 years, respectively, p<0.001) differed significantly. In the multivariate analysis, the hazard ratios (95% confidence interval) in the no additional treatment group relative to the radical surgery group were 3.18 (1.41 to 7.17; p=0.005) for overall mortality and 2.60 (0.46 to 14.66; p=0.280) for cancer-specific mortality in the intermediate-to-high risk category. No such differences were noted in the low-risk category.

Conclusions

The eCura system can be applied to undifferentiated-type EGC. Close follow-up without additional treatment might be considered for low-risk patients, while additional surgery is recommended for intermediate- and high-risk patients.

Endoscopic submucosal dissection versus surgery for patients with undifferentiated early gastric cancer

BACKGROUND AND AIMS

endoscopic submucosal dissection (ESD) is the standard treatment for differentiated early gastric cancer (EGC). However, its expanded indication for undifferentiated EGC is controversial. In this study, the efficacy and safety of ESD versus surgery in patients with undifferentiated EGC were compared.

METHODS

four databases were searched until February 24, 2022, for studies assessing patients with undifferentiated EGC that met an expanded indication for endoscopic resection and who were treated with ESD or surgery. Primary outcomes were all-cause mortality and any recurrence. Secondary outcomes were complete histological resection, local recurrence, metachronous recurrence, synchronous recurrence, distant metastasis, overall complication, and bleeding. All meta-analyses were performed using a random-effects models. Unadjusted (risk ratio [RR]) and adjusted (aRR and hazard ratio [aHR]) estimates with 95 % confidence interval (CI) were calculated.

RESULTS

seven cohort studies were included (n = 2637). The use of ESD was significantly associated with higher all-cause mortality compared to surgery (RR, 2.17; 95 % CI, 1.24-3.81); adjusted all-cause mortality effects were not significant (aRR, 2.28; 95 % CI, 0.95-5.47 and aHR, 1.97; 95 % CI, 0.85-4.53). ESD was associated with a higher risk of any recurrence using unadjusted (RR, 5.24; 95 % CI, 1.49-18.46) and adjusted (aRR, 7.89; 95 % CI, 1.52-40.95 and aHR, 3.73; 95 % CI, 1.17-11.90) estimates. The risk of local recurrence, synchronous recurrence and bleeding were significantly higher for ESD versus surgery. No significant differences were found for other secondary outcomes.

CONCLUSIONS

although ESD is associated with a higher risk of any recurrence, adjusted all-cause mortality is similar during follow-up. Overall complications were similar between ESD and surgery.

Endoscopic Submucosal Dissection vs. Surgery for Superficial Esophageal Squamous Cancer: A Systematic Review and Meta-Analysis

Background

Esophageal cancer is one of the leading causes of morbidity and mortality across the world. Only one systematic review and meta-analysis has attempted to compare the morbidity and mortality outcomes in superficial esophageal squamous cancer patients undergoing endoscopic submucosal dissection (ESD) and esophagectomy (ESO), but with several limitations. This study aimed at comparing the outcomes of hospital stay duration, procedure duration, recurrence, complications, all-cause mortality, short-term survival, and long-term survival in patients with superficial esophageal squamous cancer undergoing ESD and ESO.

Methods

Six databases (Web of Science, PubMed, EMBASE, CENTRAL, Scopus, and MEDLINE) were systematically searched according to PRISMA guidelines for eligible studies. With the available literature, we conducted a random-effect meta-analysis to evaluate weighted effect size and odds ratios to determine the comparative morbidity and mortality outcomes between patients with superficial esophageal squamous cancer undergoing ESD and ESO.

Results

We found 16 eligible studies detailing 5,213 and 8,049 age- and sex-matched patients undergoing ESD and ESO, respectively. Meta-analysis revealed reduced hospital stay (Hedge’s g: -1.22) and procedure duration (g: -4.54) for patients undergoing ESD. We also observed significantly reduced risks for complications (odds ratio: 0.35) and all-cause mortality (OR: 0.56) in patients undergoing ESD. Differences in recurrence (OR: 0.95), short-term outcomes (OR: 1.10), and long-term survival (OR: 0.81) outcomes were not significantly different between ESD and ESO.

Conclusions

This meta-analysis provides evidence concerning the improved morbidity and mortality outcomes in superficial esophageal squamous cancer patients undergoing ESD as compared to ESO. The findings herein may aid in developing clinical awareness and assisting best practice guideline development for managing superficial esophageal squamous cancer.

Registration

PROSPERO, https://www.crd.york.ac.uk/prospero/#searchadvanced, CRD42021286212.

Diffuse-type Gastric Cancer

Gastric cancer is the most prevalent malignant tumor in Korea. Histologically, it is often classified into intestinal-type and diffuse-type. Intestinal-type gastric cancer is known to occur mainly from chronic gastritis caused by Helicobacter pylori (H. pylori) through atrophic gastritis and intestinal metaplasia, a precancerous change of the mucosa, whereas diffuse-type gastric cancer is caused by H. pylori infection, wherein active inflammation of the gastric mucosa occurs without precancerous changes in the mucosa. Compared with intestinal-type gastric cancer, it occurs at a young age, there is no difference in male to female ratio, or tends to occur more in women, and is more aggressive than intestinal-type gastric cancer. Intestinal-type gastric cancer is predominant in East Asian populations such as Koreans and Japanese, whereas diffuse-type gastric cancer has more uniform geographic distribution. In the present manuscript, I have reviewed diffuse-type gastric cancer, distinct from intestinal-type gastric cancer.

Usefulness of artificial intelligence in gastric neoplasms

Recently, studies in many medical fields have reported that image analysis based on artificial intelligence (AI) can be used to analyze structures or features that are difficult to identify with human eyes. To diagnose early gastric cancer, related efforts such as narrow-band imaging technology are on-going. However, diagnosis is often difficult. Therefore, a diagnostic method based on AI for endoscopic imaging was developed and its effectiveness was confirmed in many studies. The gastric cancer diagnostic program based on AI showed relatively high diagnostic accuracy and could differentially diagnose non-neoplastic lesions including benign gastric ulcers and dysplasia. An AI system has also been developed that helps to predict the invasion depth of gastric cancer through endoscopic images and observe the stomach during endoscopy without blind spots. Therefore, if AI is used in the field of endoscopy, it is expected to aid in the diagnosis of gastric neoplasms and determine the application of endoscopic therapy by predicting the invasion depth.

Risk Factors and Prediction Model for Non-curative Resection of Early Gastric Cancer With Endoscopic Resection and the Evaluation

Background and Study Aim: EGC, also known as Early Gastric Cancer is known to lack the lymph node metastasis and confined along the mucosa, which is treated through an endoscopic resection procedure that includes ESD (Endoscopic Submucosal dissection) and EMR (Endoscopic Mucosal Resection). However, some cases underwent residual disease, recurrence, or additional gastrectomy because of non-curative resection. The following research aims to delineate the threat factors causing the non-curative resection as well as develop a predictive model.

Patient and Methods: Effort was taken to collect all the records about the health history of pathologically diagnosed EGC who experienced endoscopic treatment in the Department of Endoscopy, the Capital Medical University, and Beijing Friendship Hospital from January 2012 to January 2020. Patients were grouped into two categories primarily; a curative resection group and finally a non-curative resection group based on the outcomes of the postoperative pathological and immunohistochemical examination results. The statistical methods used included single factor analysis, a multivariate logistic regression analysis and a chi-square test. A nomogram for the prediction of non-curative resection was constructed, which included information on age, gender, resection method, postoperative pathology, tumor size, ulcer, treatment, and infiltration depth. Receiver operating characteristic (ROC) curve analysis and calibration were performed to present the predictive accuracy of the nomogram.

Results: Of 443 patients with 478 lesions who had undergone ESD or EMR for EGCs, 127 were identified as being treated non-curative resection. Older patients (>60 years), a large tumor size (>30 mm), submucosal lesion, piecemeal resection, EMR for treatment and undifferentiated tumor histology were associated with non-curative resection group. Our risk nomogram showed good discriminated performance in internal validation (bootstrap-corrected area under the receiver-operating characteristic curve, 0.881; P < 0.001).

Conclusions: A validated prediction model was developed to identify people who were subject to undergoing a non-curative resection for ESD. The predictive model that we formulated is essential in providing reliable information to guide the decision-making process on the treatment for EGC before undertaking an endoscopic resection.

Establishing Machine Learning Models to Predict Curative Resection in Early Gastric Cancer with Undifferentiated Histology: Development and Usability Study

Background

Undifferentiated type of early gastric cancer (U-EGC) is included among the expanded indications of endoscopic submucosal dissection (ESD); however, the rate of curative resection remains unsatisfactory. Endoscopists predict the probability of curative resection by considering the size and shape of the lesion and whether ulcers are present or not. The location of the lesion, indicating the likely technical difficulty, is also considered.

Objective

The aim of this study was to establish machine learning (ML) models to better predict the possibility of curative resection in U-EGC prior to ESD.

Methods

A nationwide cohort of 2703 U-EGCs treated by ESD or surgery were adopted for the training and internal validation cohorts. Separately, an independent data set of the Korean ESD registry (n=275) and an Asan medical center data set (n=127) treated by ESD were chosen for external validation. Eighteen ML classifiers were selected to establish prediction models of curative resection with the following variables: age; sex; location, size, and shape of the lesion; and whether ulcers were present or not.

Results

Among the 18 models, the extreme gradient boosting classifier showed the best performance (internal validation accuracy 93.4%, 95% CI 90.4%-96.4%; precision 92.6%, 95% CI 89.5%-95.7%; recall 99.0%, 95% CI 97.8%-99.9%; and F1 score 95.7%, 95% CI 93.3%-98.1%). Attempts at external validation showed substantial accuracy (first external validation 81.5%, 95% CI 76.9%-86.1% and second external validation 89.8%, 95% CI 84.5%-95.1%). Lesion size was the most important feature in each explainable artificial intelligence analysis.

Conclusions

We established an ML model capable of accurately predicting the curative resection of U-EGC before ESD by considering the morphological and ecological characteristics of the lesions.

Prediction model for curative endoscopic submucosal dissection of undifferentiated-type early gastric cancer

BACKGROUND

Endoscopic submucosal dissection (ESD) is an effective treatment for early gastric cancer (EGC); however, its curative resection rate is low for undifferentiated-type EGC. We developed and externally validated a prediction model for curative ESD of undifferentiated-type EGC.

METHODS

In this cross-sectional study, we included 448 patients who underwent ESD for undifferentiated-type EGC at 18 hospitals in Korea between 2005 and 2015 in the development cohort and 1342 patients who underwent surgery at two hospitals in the validation cohort. A prediction model was developed using the logistic regression model.

RESULTS

Endoscopic tumor size 1-2 cm (odds ratio [OR], 2.40; 95% confidence interval [CI] 1.54-3.73), tumor size > 2 cm (OR, 14.00; 95% CI 6.81-28.77), and proximal tumor location from the lower to upper third of the stomach (OR, 1.45; 95% CI 1.03-2.04) were independent predictors of non-curative ESD. A six-score prediction model was developed by assigning points to endoscopic tumor size > 2 cm (five points), tumor size 1-2 cm (two points), upper third location (two points), and middle third location (one point). The rate of curative ESD ranged from 70.6% (score 0) to 11.6% (score 5) with an area under the receiver operating characteristic curve (AUC) of 0.720 (95% CI 0.673-0.766). The model also showed good performance in the validation cohort (AUC, 0.775; 95% CI 0.748-0.803).

CONCLUSIONS

This six-score prediction model may help in predicting curative ESD and making informed decisions about the treatment selection between ESD and surgery for undifferentiated-type EGC.

Clinical outcomes of endoscopic resection for undifferentiated intramucosal early gastric cancer larger than 2 cm

BACKGROUND

This study investigated the long-term clinical outcomes of endoscopic resection (ER) for undifferentiated-type (UD) early gastric cancer (EGC), with tumor size > 2 cm as the only non-curative factor.

METHODS

From among 1123 patients who underwent ER for UD EGC at 18 tertiary hospitals in Korea between 2005 and 2014, we identified 216 patients with UD intramucosal EGC > 2 cm, which was completely resected, with negative resection margins, and absence of ulceration and lymphovascular invasion. The patients were divided into the additional surgery (n = 40) or observation (n = 176) groups, according to post-ER management and were followed up for a median duration of 59 months for recurrence and 90 months for overall survival.

RESULTS

Lymph node (LN) or distant metastasis or cancer-related mortality was not observed in the surgery group. In the observation group, two (1.1%) patients developed LN or distant metastasis with a 5-year cumulative risk of 0.7%, and one (0.6%) patient died of gastric cancer. The 5- and 8-year overall survival rates were 94.1% and 89.9%, respectively, in the observation group and 100.0% and 95.2%, respectively, in the surgery group (log-rank P = 0.159). Cox regression analysis did not reveal an association between the observation group and increased mortality.

CONCLUSION

The risk of LN or distant metastasis was not negligible, but as low as 1% for patients undergoing non-curative ER for UD EGC, with tumor size > 2 cm as the only non-curative factor. Close observation may be an alternative to surgery, especially for older patients or those with poor physical status.

Endoscopic Submucosal Dissection versus Surgery for Undifferentiated-Type Early Gastric Cancer: A Systematic Review and Meta-Analysis

Background/Aims

The use of endoscopic submucosal dissection (ESD) for treating undifferentiated-type early gastric cancer is controversial. The objective of this study was to perform a meta-analysis to compare the long-term outcomes of ESD and surgery for undifferentiated-type early gastric cancer.

Methods

The PubMed, Cochrane Library, and EMBASE databases were used to search for relevant studies comparing ESD and surgery for undifferentiated-type early gastric cancer. The methodological quality of the included publications was evaluated using the Risk of Bias Assessment tool for Nonrandomized Studies. The rates of overall survival, recurrence, adverse event, and complete resection were determined. Odds ratios (ORs) and 95% confidence intervals (CIs) were also evaluated.

Results

This meta-analysis enrolled five studies with 429 and 1,236 participants undergoing ESD and surgery, respectively. No significant difference was found in the overall survival rate between the ESD and surgery groups (OR, 2.29; 95% CI, 0.98–5.36; p=0.06). However, ESD was associated with a higher recurrence rate and a lower complete resection rate. The adverse event rate was similar between the two groups.

Conclusions

ESD with meticulous surveillance esophagogastroduodenoscopy may be as effective and safe as surgery in patients with undifferentiated-type early gastric cancer. Further large-scale, randomized, controlled studies from additional regions are required to confirm these findings.

Clinicopathological Features and Prognostic Implication of Gastric Carcinoma with Lymphoid Stroma

Methods

This study included 34 eligible studies and 1757 GCLSs. The clinicopathologic characteristics of GCLS were investigated from eligible studies, and the meta-analysis was performed. In addition, we compared the survival rates between GCLS and non-GCLS.

Results

The estimated rate of GCLS was 0.062 (95% confidence interval (CI) 0.040-0.097). GCLS was significantly correlated with the diffuse type of Lauren's classification, proximal tumor location, less-frequent lymphatic invasion, and lower pTNM stage. However, there was no significant difference in age, sex, tumor differentiation, vascular invasion, perineural invasion, pT stage, lymph node metastasis, and distant metastasis between GCLS and non-GCLS patients. EBV positive rates in GCLS and non-GCLS patients were 0.723 (95% CI 0.643-0.791) and 0.064 (95% CI 0.039-0.103), respectively. HER2 expression in GCLS was significantly lower than that in non-GCLS. GCLS patients had a more favorable prognosis than that of non-GCLS patients (hazard ratio 0.500, 95% CI 0.305-0.821).

Conclusion

GCLS comprised 6.2% of overall GC and more frequent in the proximal portion of the stomach. Since GCLS was associated with better prognosis, the histologic finding can be useful for predicting the patient's prognosis.

Prognostic factors for ESD of early gastric cancers: a systematic review and meta-analysis

Background and study aims  Gastric neoplasms are one of the leading types of cancer in the world and early detection is essential to improve prognosis. Endoscopy is the gold-standard diagnostic procedure and allows adequate treatment in selected cases. Endoscopic submucosal dissection (ESD) has been reported to safely address most early gastric cancers (EGCs), with high curability rates. However, data on prognostic factors related to ESDs of EGCs are conflicting. Therefore, we aimed to systematically review the available literature and to perform a meta-analysis to identify the relevant prognostic factors in this context. Methods  We performed this study according to PRISMA guidelines. Comparative studies assessing the relationship between curative resection or long-term curability rates and relevant prognostic factors were selected. Prognostic factors were demographic data, lesion features (location, morphology of the lesion, size, and depth of invasion), histological findings, Helycobacter pylori (HP) infection, presence of gastric a atrophy and body mass index (BMI). Finally, we also evaluated risk factors related to metachronous gastric neoplasm. Results  The initial search retrieved 2829 records among which 46 studies were included for systematic review and meta-analysis. The total sample comprised 28366 patients and 29282 lesions. Regarding curative resection, pooled data showed no significant influence of sex [odds ratio (OR): 1.15 (0,97, 1.36) P  = 0.10 I 2  = 47 %] , age [OR: 1.00 (0.61, 1.64) P  = 1.00 I 2  = 58 %], posterior vs non-posterior location [OR: 1.35 (0.81, 2.27) P  = 0.25 I 2  = 84 %], depressed vs von-depressed macroscopic type[OR: 1.21 (0.99, 1.49) P  = 0.07 I 2  = 0 %], non-upper vs upper location [OR: 1.41 (0.93, 2.14) P  = 0.10 I 2  = 77 %] and BMI [OR: 0.84 (0.57; 1.26) P  = 0.41 I 2  = 0 %]. Differentiated neoplasms presented greater chance of cure compare to undifferentiated [OR: 0.10 (0.07, 0.15) P  < 0.00001 I 2  = 0 %]. Ulcerated lesions had lower curative rates compared to non-ulcerated [OR: 3.92 (2.81, 5.47) P  < 0.00001 I 2  = 44 %]. Lesions smaller than 20 mm had greater chance of curative resection [OR: 3.94 (3.25, 4.78) P  < 0.00001 I 2  = 38 %]. Bleeding during procedure had lower curative rates compared to non-bleeding [OR: 2.13 (1.56, 2.93) P  < 0.0001 I 2  = 0 %]. Concerning long-term cure, female gender [OR 1.62 (1.33, 1.97) P  < 0.00001 I 2  = 0 %] and the mucosal over SM1 cancers were protective factors [OR: 0.08 (0.02, 0.39) P  = 0.002 I 2  = 86 %]. Gastric atrophy [OR: 0.60 (0.45, 0.81) P  = 0.0006 I 2  = 42 %] and the pepsinogen I/pepsinogen II ratio [OR 2.29 (1.47, 3.57) P  = 0.0002 I 2  = 0 %] were risk factors to metachronous gastric neoplasm. Conclusions  Ulcerated lesions, histology, bleeding and size > 20 mm are prognostic factors concerning curative resection. Regarding long-term cure, female gender and mucosal over SM1 cancer are predictive factors. Gastric atrophy and the pepsinogen ratio are risk factors for metachronous gastric neoplasm.

Combination of endoscopic submucosal dissection and laparoscopic sentinel lymph node dissection in early mucinous gastric cancer: Role of lymph node metastasis

BACKGROUND

Recent evidence showed that combining endoscopic submucosal dissection (ESD) and laparoscopic sentinel lymph node dissection may avoid unnecessary gastrectomy in treating early mucinous gastric cancer (EMGC) patients with risks of positive lymph node metastasis (pLNM).

AIM

To explore the predictive factors for pLNM in EMGC, and to optimize the clinical application of combing ESD and sentinel lymph node dissection in a proper subgroup of patients with EMGC.

METHODS

Thirty-one patients with EMGC who had undergone gastrectomy with lymph node dissection were consecutively enrolled from January 1988 to December 2016. Univariate and multivariate logistic regression analyses were used to estimate the association between the rates of pLNM and clinicopathological factors, providing odds ratio (OR) with 95% confidence interval. And the association between the number of predictors and the pLNM rate was also investigated.

RESULTS

Depth of invasion (OR = 7.342, 1.127-33.256, P = 0.039), tumor diameter (OR = 9.158, 1.348-29.133, P = 0.044), and lymphatic vessel involvement (OR = 27.749, 1.821-33.143, P = 0.019) turned out to be significant and might be the independent risk factors for predicating pLNM in the multivariate analysis. For patients with 1, 2, and 3 risk factors, the pLNM rates were 9.1%, 33.3%, and 75.0%, respectively. pLNM was not detected in seven patients without any of these risk factors.

CONCLUSION

ESD might serve as a safe and sufficient treatment for intramucosal EMGC if tumor size ≤ 2 cm, and when lymphatic vessel involvement is absent by postoperative histological examination. Combining ESD and sentinel lymph node dissection could be recommended as a safe and effective treatment for EMGC patients with a potential risk of pLNM.

Long-term outcomes of endoscopic submucosal dissection versus surgery for treating early gastric cancer of undifferentiated-type

Application of endoscopic submucosal dissection (ESD) for treating undifferentiated-type early gastric cancers (EGCs) remains controversial. Therefore, we aimed to compare long-term outcomes of ESD with those of surgery for patients with undifferentiated-type EGCs by a retrospective study.We retrospectively reviewed data of patients who underwent curative ESD or gastrectomy for undifferentiated-type EGCs between 2010 and 2017. Gastric cancers were undifferentiated-type adenocarcinoma without ulceration confined to the mucosal layer and 2 cm or smaller in size. Demographics, complications, recurrence cancer rates, and survival data were collected and compared.Forty patients who underwent curative ESD and 52 patients who underwent surgery were included. The median follow-up duration was 74.6 months. There was no significant difference of metachronous gastric cancer rate (5.0% vs 3.8%, P = .75) or total cancer recurrence rate (10.0% vs 3.8%, P = .33) between the 2 groups. The 5-year overall survival, disease-free survival, recurrence-free survival rates did not significantly differ between the 2 groups (P = .72, .26, .27 respectively). There were no gastric cancer-related deaths in either group.Long-term outcomes after curative ESD for undifferentiated-type EGCs that met the expanded indication were comparable to that achieved with surgery. ESD without additional surgery is an acceptable choice to treat undifferentiated-type EGCs that meet the curative criteria.

Accuracy of endoscopic size measurements of early gastric signet ring cell carcinoma

BACKGROUND AND AIMS

Indications for endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) are expanding, but signet ring cell carcinoma (SRC) is still unclear because of its unclear boundaries. The purpose of this study was to compare pathologic size and endoscopic size in SRC-type EGC and to find risk factors associated with tumor size underestimation.

METHODS

Medical records of 137 patients diagnosed with SRC-type EGC between January 2009 and December 2016 at our tertiary hospital were reviewed. According to pathologic and endoscopic tumor sizes, they were classified into correct estimation, underestimation, and overestimation groups, and risk factors related to underestimation were analyzed.

RESULTS

Among 137 patients with SRC-type EGC, 77 patients (56.2%) had undergone correct estimation, 43 patients (31.4%) had undergone underestimation, and 17 patients (12.4%) had undergone overestimation. Mean pathologic size (SD) was 20.1 (13.8) mm and mean endoscopic size (SD) was 17.9 (10.1) mm, the correlation coefficients were 0.919 (p < 0.001) , and there was no significant difference between the two groups. Multivariate analysis showed that tumor size more than 20 mm (OR 3.419; 95% CI 1.271-9.194; p = 0.015) and atrophy (OR 6.011; 95% CI 2.311-15.633; p = 0.001) were risk factors for tumor size underestimation.

CONCLUSION

There was no significant difference in pathologic and endoscopic size in SRC-type EGC. Therefore, ESD may be considered as a therapeutic option if the size of the tumor is less than 20 mm and atrophy is not present in the surrounding mucosa.

Endoscopic Submucosal Dissection of Papillary Gastric Adenocarcinoma; Systematic Review

This study evaluated the possibility of endoscopic submucosal dissection (ESD) for early gastric cancer with papillary adenocarcinoma (EGC-PAC). PAC, an uncommon pathologic type of stomach cancer, is classified into differentiated-type histology. However, aggressive features, including a high rate of submucosal invasion, lymphovascular invasion (LVI), and lymph node metastasis (LNM), have been reported in studies with surgical specimens. Treatment outcomes of ESD for EGC-PAC have not been precisely demonstrated. Core databases were sought for the following inclusion criteria: studies of endoscopic resection or surgery of EGC-PAC presenting the following therapeutic indicators; en bloc resection, complete resection, curative resection, recurrence, complications associated with procedures, LVI, or LNM that enabled an analysis of ESD possibility. Overall, 15 studies were included for systematic review. Frequent submucosal invasion and high LVI were noted in EGC-PAC. However, PAC was not significantly associated with LNM. Pooled en bloc resection, complete resection, and curative resection rates were 89.7% (95% confidence interval: 55.3%-98.4%), 85.3% (67.7%-94.2%), and 67% (43%-84.5%), respectively. No LNM was observed if EGC-PAC satisfied the curative resection criteria. ESD seems technically feasible, although a high LVI rate results in a lower rate of curative resection.

Endoscopic Submucosal Dissection of Early Gastric Cancer with Mixed-Type Histology: A Systematic Review

BACKGROUND

Endoscopic submucosal dissection (ESD) criteria are histologically categorized by early gastric cancer (EGC) with differentiated- and undifferentiated-type histology. However, EGC is histologically heterogenous and there have been no separate criteria for EGC with mixed-type histology [EGC-MH; differentiated-type predominant EGC mixed with an undifferentiated component (EGC-MD) or undifferentiated-type predominant EGC mixed with a differentiated component (EGC-MU)]. Moreover, therapeutic outcomes of ESD for EGC-MH have not been clearly described.

AIM

This study aimed to evaluate the feasibility of ESD for EGC-MH.

METHODS

We searched core databases for specific inclusion factors: patients with EGC-MH, intervention of ESD, and at least one of the following outcomes: rate of en bloc, complete, curative resection, recurrence, procedure-related adverse event, lymphovascular invasion (LVI), or lymph node metastasis (LNM) that enabled evaluation of feasibility of ESD.

RESULTS

A total of eight (systematic review) and four studies (meta-analysis) were included. There was no robustness in age, location, or morphology of EGC-MH. Moderately differentiated adenocarcinoma was frequent in pre-ESD biopsy. EGC-MH showed larger size, deeper invasion, and higher rates of LVI/LNM than pure-type EGC. Total en bloc, complete resection, and curative resection rates were 94.6% (95% confidence interval 86.6-97.9%), 77.8% (57.9-89.9%), and 55.1% (50.4-59.6%), respectively. There was no LNM or extra-gastric recurrence after ESD if the EGC-MD met the curative resection criteria. However, the EGC-MD itself was a risk factor for non-curative resection. (Margin positivity was the most common reason.) CONCLUSIONS: Although ESD seems to be technically feasible, inaccurate prediction of lateral or vertical margin leads to lower curative resection rate. Application of more strict indication is needed for EGC-MH.

Possible indication of endoscopic resection in undifferentiated early gastric cancer

Endoscopic resection for early gastric cancer (EGC) without lymph node metastasis may be a valuable treatment option. To date, endoscopic resection for undifferentiated EGC is being investigated. We evaluated the risk of lymph node metastasis in undifferentiated EGC by examining the preoperative endoscopic findings and operated pathologic specimen. The medical records of patients who underwent surgical resection because of undifferentiated EGC between November 2008 and December 2015 were reviewed retrospectively. The risk factors associated with lymph node metastasis and the lymph node metastasis rate in the expanded indication of undifferentiated EGC were evaluated. A total of 376 patients with undifferentiated EGC (233 signet ring cell type and 143 poorly differentiated type) were analyzed. Lymph node metastasis was found in 9.8% of the patients. Among the patients who met the expanded criteria (59 patients), only one patient had lymph node metastasis (signet ring cell type without ulceration and 15 mm in size). The risk factors associated with lymph node metastasis were lesion size >20 mm (OR 3.013), scar deformity (OR 2.248), surface depression (OR 2.360), submucosal invasion (OR 3.427), and lymphovascular invasion (OR 6.296). Before endoscopic resection of undifferentiated EGC, careful selection of patients should be considered. The undifferentiated EGC with size ≥15 mm, scar deformity, surface depression, submucosal invasion, and lymphovascular invasion should be considered surgical resection instead of endoscopic resection.

Common Locations of Gastric Cancer: Review of Research from the Endoscopic Submucosal Dissection Era

Detection of early-stage gastric cancer improves the prognosis of patients. Endoscopic submucosal dissection (ESD) is a curative and stomach-preserving treatment for early gastric cancer (EGC) associated with a low risk of lymph node metastasis. However, several studies have reported missed diagnosis of gastric cancer. Therefore, endoscopists are required to learn accurate diagnostic skills to eliminate endoscopic blind spots. A systematic screening protocol to map the entire stomach without blind spots reduces the risk of missed lesions. Knowledge of the features of EGC or dysplasia is essential to identify suspicious lesion. Information of the common sites of occurrence of EGC can also enable a detailed endoscopic examination to improve detection rates. Previous reports investigating the location of gastric cancers resected by ESD or surgery showed that the antrum and lesser curvature of stomach were predominantly affected. Helicobacter pylori-induced atrophic changes advance from the antrum to the corpus along the lesser curvature, predominantly affecting these areas. Gastric cancers in the antrum and the lower corpus are also commonly missed during screening examination. Therefore, a careful examination of the lower third stomach is warranted to avoid missing synchronous and metachronous gastric lesions. Knowledge of the location of EGC enables accurate endoscopic examination and detection of EGC in early stage.

Pitfalls in the Interpretation of Publications about Endoscopic Submucosal Dissection of Early Gastric Cancer with Undifferentiated-Type Histology

Endoscopic submucosal dissection (ESD) is a standard treatment for patients with gastrointestinal neoplasms with a negligible risk of lymph node metastasis. ESD enables en bloc resection of gastrointestinal neoplasms and organ preservation, thereby, avoiding surgical treatment. Although small (<2 cm) intramucosal early gastric cancer with undifferentiated-type histology (EGC-UH) without ulceration is included in the expanded criteria for ESD, controversies remain due to different biology and characteristics compared to EGC with differentiated-type histology. The authors previously presented studies about the technical feasibility of ESD for these lesions using a meta-analysis and retrospective multicenter analysis. However, many pitfalls were identified in the interpretation of studies analyzing histologic discrepancy, mixed-type histology, criteria-based analysis of therapeutic outcomes, interpretation of curative resection, and long-term clinical outcomes. In this review, the authors discuss pitfalls in the interpretation of publications on ESD for EGC-UH.

A Single-Center Experience of Endoscopic Resection for Early Gastric Cancer with Lymphoid Stroma

Purpose

This study aimed to evaluate immediate outcomes and clinical courses of patients with early gastric carcinoma with lymphoid stroma (GCLS) who underwent endoscopic resection.

Materials and Methods

We retrospectively reviewed the medical records of 40 patients (mean age, 56.9 years; 90.0% male) who underwent endoscopic resection and were pathologically diagnosed with GCLS confined to the mucosa or to the submucosa between March 1998 and December 2017.

Results

Forty GCLS lesions in 40 patients were treated using endoscopic resection. Only 4 (10%) patients received diagnosis of GCLS before endoscopic resection. Fourteen (35.0%) lesions were intramucosal cancers and 26 (65.0%) exhibited submucosal invasion. En bloc resection (97.5%) was achieved for all lesions except one, with no significant complications. The complete resection rate was 85.0% (34 of 40 lesions). After endoscopic resection, 17 patients were referred for surgery and underwent gastrectomy with lymph node (LN) dissection because of deep submucosal invasion (n=16) and misclassification as undifferentiated cancer (n=1). No LN metastasis was determined in the specimens obtained during surgery. During a mean follow-up period of 49.7 months for 23 patients without surgical treatment, no regional LN enlargements, distant metastases, or gastric cancer-related deaths were found, although 1 metachronous lesion (undifferentiated adenocarcinoma, follow-up duration: 7 months) was observed.

Conclusions

In patients with early GCLS, endoscopic resection is technically feasible and has favorable clinical outcomes. Therefore, endoscopic resection might represent an alternative treatment modality in patients with early GCLS with a low likelihood of LN metastasis.

Effect of age on the clinical outcomes of patients with early gastric cancer with undifferentiated-type histology

BACKGROUND

Undifferentiated-type early gastric cancers account for a large proportion of gastric cancers in younger patients. Therefore, the clinical outcomes of endoscopic resection in younger patients are a major concern. We aimed to investigate the influence of age on lymph node metastasis and long-term survival after surgery for undifferentiated-type early gastric cancers.

METHODS

We identified 4,236 patients who underwent surgery for undifferentiated-type early gastric cancers. For each T stage, the correlation between age and lymph node metastasis was analyzed using a multivariate logistic regression. Lymph node metastasis rates were compared between younger (<40 years) and older patients (≥40 years) who fulfilled the expanded criteria for endoscopic resection. The Kaplan-Meier method was used to compare long-term survival between younger and older patients.

RESULTS

Younger age groups (20-29 and 30-39 years) had the highest lymph node metastasis rate within each T stage (5.7% and 5.7% for T1a, 26.3% and 24.1% for T1b, respectively). After adjusting for possible covariates, however, age did not have a significant effect on lymph node metastasis in either T stage (P = .127 for T1a, P = .114 for T1b). Among patients fulfilling the expanded indication for endoscopic resection, younger patients had a slightly higher lymph node metastasis rate compared with older patients (2.7% versus 2.0%), although this difference was not statistically significant. Although younger patients had a significantly better overall survival (P < .001), no significant age-related differences were observed in recurrence-free and disease-specific survival (P = .051 and P = .069) CONCLUSION: Endoscopic resection may be feasible in young patients with undifferentiated-type early gastric cancers because these patients share a similar lymph node metastasis rate and long-term survival outcomes with older patients.

Endoscopic submucosal dissection of early gastric cancer with mixed-type histology: Protocol for a systematic review and meta-analysis

BACKGROUND

Endoscopic submucosal dissection (ESD) is a primary treatment for the early gastric cancer (EGC) who have a negligible risk of lymph node metastasis satisfying specific criteria. These criteria are histologically categorized by EGC with differentiated-type histology (EGC-DH) and undifferentiated-type histology (EGC-UH). However, gastric cancer is histologically heterogenous and there has been no specific criteria for EGC with mixed-type histology (EGC-MH). Moreover, therapeutic outcomes of ESD for EGC-MH have not been clearly described.

METHODS

We will search the core databases (MEDLINE (through PubMed), the Cochrane Library, and Embase) from their inception to November 2018 using pre-established searching strategy by 2 independent evaluators. The P.I.C.O. is as follows; Patients: who have EGC-MH, Intervention: ESD, Comparison: none, Outcome: at least one among the rate of complete resection, curative resection, en bloc resection, recurrence or procedure-related adverse event that enabled an evaluation of feasibility of ESD. All types of study design will be sought and publications in English with full-text will be included. The risk of bias will be assessed using the ROBINS-I tool. Descriptive data synthesis is planned and quantitative synthesis will be used if the included studies are sufficiently homogenous (pooled therapeutic outcomes data with 95% confidence intervals). Publication bias will be assessed with quantitative analyses if more than 10 articles are enrolled.

RESULTS

The results will provide evidence for validity of current ESD criteria in addition to the technical feasibility of ESD for EGC-MH.

CONCLUSION

This study will provide evidence of ESD for EGC-MH.

Endoscopic submucosal dissection of papillary adenocarcinoma of stomach; protocol for a systematic review and meta-analysis

BACKGROUND

Endoscopic submucosal dissection (ESD) is a primary treatment for the early gastric cancer (EGC) who has a negligible risk of lymph node metastasis. Papillary adenocarcinoma (PAC) of stomach is a rare histologic variant of gastric cancer and categorized into EGC with differentiated-histology. However, aggressive features such as higher rate of lymphovascular invasion (LVI) or submucosal invasion have been reported, whereas comparable lymph node metastasis (LNM) rate to the lesions meeting the current ESD criteria also has been reported. This study aimed to evaluate the feasibility of ESD for EGC with PAC.

METHODS

We will search the core databases (MEDLINE (through PubMed), the Cochrane Library, and Embase) from their inception to December 2018 by 2 independent evaluators. The P.I.C.O. is as follows; Patients: who have EGC with PAC, Intervention: ESD or surgery, Comparison: none, Outcome: at least one among the rate of complete resection, curative resection, en bloc resection, recurrence, procedure-related adverse event, LVI or LNM that enabled an evaluation of the feasibility of ESD. All types of study design with full text will be sought and included. The risk of bias will be assessed using the ROBINS-I tool. Descriptive data synthesis is planned, and quantitative synthesis will be used if the included studies are sufficiently homogenous. Publication bias will be assessed with quantitative analyses if more than 10 articles are enrolled.

RESULTS

The results will provide evidence for efficacy and safety of ESD for EGC with PAC.

CONCLUSION

This study will provide evidence of ESD for EGC with PAC.

Cost Effectiveness of Gastric Cancer Screening According to Race and Ethnicity

BACKGROUND & AIMS

There are marked racial and ethnic differences in non-cardia gastric cancer prevalence within the United States. Although gastric cancer screening is recommended in some regions of high prevalence, screening is not routinely performed in the United States. Our objective was to determine whether selected non-cardia gastric cancer screening for high-risk races and ethnicities within the United States is cost effective.

METHODS

We developed a decision analytic Markov model with the base case of a 50-year-old person of non-Hispanic white, non-Hispanic black, Hispanic, or Asian race or ethnicity. The cost effectiveness of a no-screening strategy (current standard) for non-cardia gastric cancer was compared with that of 2 endoscopic screening modalities initiated at the time of screening colonoscopy for colorectal cancer: upper esophagogastroduodenoscopy with biopsy examinations and continued surveillance only if intestinal metaplasia or more severe pathology is identified or esophagogastroduodenoscopy with biopsy examinations continued every 2 years even in the absence of identified pathology. We used prevalence rates, transition probabilities, costs, and quality-adjusted life years (QALYs) from publications and public data sources. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay threshold of $100,000/QALY.

RESULTS

Compared with biennial and no screening, screening esophagogastroduodenoscopy with continued surveillance only when indicated was cost effective for non-Hispanic blacks ($80,278/QALY), Hispanics ($76,070/QALY), and Asians ($71,451/QALY), but not for non-Hispanic whites ($122,428/QALY). The model was sensitive to intestinal metaplasia prevalence, transition rates from intestinal metaplasia to dysplasia to local and regional cancer, cost of endoscopy, and cost of resection (endoscopic or surgical).

CONCLUSIONS

Based on a decision analytic Markov model, endoscopic non-cardia gastric cancer screening for high-risk races and ethnicities could be cost effective in the United States.

Long-term outcomes of endoscopic submucosal dissection in comparison to surgery in undifferentiated-type intramucosal gastric cancer using propensity score analysis

BACKGROUND

The treatment of intramucosal early gastric cancer with undifferentiated-type histologies (UD-EGCs) using endoscopic submucosal dissection (ESD) is controversial. This study aimed to compare the clinical and oncologic long-term outcomes of ESD and surgery for UD-EGCs.

METHODS

A prospectively collected database of patients who underwent ESD or surgery between January 2006 and December 2012 was established. Patients who diagnosed with UD-EGC and satisfied the expanded indications of ESD were included. Clinical data from 111 patients treated with ESD and 382 patients underwent surgery were analyzed, and 1-1 propensity score-matched 81 pairs of patients were also compared.

RESULTS

In both groups, two-thirds of the UD-EGCs had signet ring cell (SRC)-type histology and about 90% of UD-EGCs were flat or depressed types. The mean size of tumors was smaller in ESD group (9.7 vs. 13.2 mm; P < 0.001). After propensity score-matched, case-matching covariates were not significantly different between the groups. Disease-free survival (DFS) was significantly shorter in the ESD group, but overall survival (OS) was not different between the two groups both in overall comparison (DFS; P < 0.001 and OS; P = 0.078) and propensity score-matched analysis (DFS; P < 0.001 and OS; P = 0.850). According to histologic type, OS of SRC histology was not different between the group, both in overall comparison and propensity score-matched analysis (P = 0.286 and P = 0.210). On the other hands, OS of poorly differentiated adenocarcinoma was significantly shorter in ESD group in overall comparison (P = 0.007), but was not as so in propensity score-matched analysis (P = 0.088).

CONCLUSIONS

ESD might be a complementary option for the treatment of UD-EGCs, especially in those with SRC-type histology based on strict expanded indications. Nonetheless, close endoscopic surveillance is required because of a high incidence of intragastric recurrence.

Endoscopic submucosal dissection for undifferentiated-type early gastric cancer: short- and long-term outcomes

BACKGROUND AND AIMS

Application of endoscopic submucosal dissection (ESD) for undifferentiated-type early gastric cancers (EGCs) remains controversial owing to limited data regarding long-term outcomes. We aimed to evaluate the feasibility of ESD for undifferentiated-type EGCs that meet the expanded criteria (EC).

METHODS

We performed a retrospective analysis of 66 patients who underwent ESD for undifferentiated-type EGC between January 2005 and December 2014. We evaluated the rates of en bloc, complete, and curative resections along with overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS).

RESULTS

Of the 66 patients, the EC group included 38 patients and the beyond-EC group included 28 patients. The overall rates of en bloc, complete, and curative resection of the 66 lesions were 92.4% (61/66), 65.2% (43/66), and 48.5% (32/66), respectively. Of the 34 patients with non-curative resection, 18 underwent additional surgery. Local remnant cancer was detected in 1 patient (1/18, 5.6%), and none of the 18 patients had lymph node metastasis. On multivariate analysis, tumors > 2 cm [odd ratio (OR) 6.183, 95% confidence interval (CI) 1.279-29.880, p = 0.023) and submucosal invasion depth (OR 6.226, 95% CI 1.881-20.606, p = 0.003) were independent predictors of incomplete resection. All 26 patients with more than 1 year of follow-up after curative resection survived without any evidence of local or distant recurrences over a median follow-up period of 36 months. The OS, DSS, and RFS rates of patients with curative ESD were 93.8, 100, and 100%, respectively.

CONCLUSIONS

ESD may have favorable long-term outcomes in patients with undifferentiated-type EGC after curative resection.

Risk factors for lymph node metastasis of early gastric cancers in patients younger than 40

This research aims to explore the potential risk factors of lymph node metastasis (LNM) for early gastric cancers in young patients.We retrospectively collected data from 4287 patients who underwent gastrectomy from January 2005 to December 2015 at Linyi People's Hospital. Of these, we enrolled 397 eligible consecutive patients who had early gastric cancer, then divided them into 2 groups according to age (≤40 years and >40 years). The association between the clinicopathological factors and LNM was analyzed by univariate and multivariate analysis.Compared to older patients (>40 years), younger patients (≤40 years) with early gastric cancer had more diffuse and mixed types (51.1% and 37.8% vs 40% and 8.3%, respectively), less proximal gastric cancer (0% vs 33.8%, P < .01) and higher LNM (33.3% vs 13%, P < .01). Univariate analysis showed tumor invasion depth (P < .01), lymphovascular invasion (P < .01), and E-cadherin expression (P = .024) were associated with LNM in the younger cohort. Multivariate analysis revealed that lymphovascular invasion (OR = 17.740, 95% CI: 1.458-215.843) was an independent risk factor for LNM (P = .024). Further analysis showed 3 patients who were within expanded endoscopic resection indications were positive for LNM.Given the high risk of lymph node involvement in young patients with early gastric cancer, both endoscopic and surgical resection procedures should be performed with caution, and active postoperative surveillance is warranted.

Therapeutic Outcomes of Endoscopic Resection of Early Gastric Cancer with Undifferentiated-Type Histology: A Korean ESD Registry Database Analysis

Background/Aims

To assess the therapeutic outcomes of endoscopic resection (ER) of early gastric cancer (EGC) with undifferentiated-type histology.

Methods

Cases of ER of EGC with undifferentiated-type histology in the Korean endoscopic submucosal dissection (ESD) registry database were identified and reviewed. The immediate outcomes, including en bloc resection, complete resection, and curative resection rates, and long-term outcomes, including recurrence and survival rates, were extracted and analyzed.

Results

From 2006 to 2015, 275 EGCs with undifferentiated-type histology from 275 patients were identified. The immediate outcomes were as follows: en bloc resection rate: 92.4%; complete resection rate: 80%; and curative resection rate: 36.4%. Compared to patients with lesions that were beyond the expanded indication, those with expanded indication lesions showed better therapeutic outcomes. There was no difference in immediate outcomes between patients with poorly differentiated adenocarcinoma (PDC) and signet ring cell carcinoma (SRC). However, compared to ER of SRC, ER of PDC had a stronger association with submucosal invasion (41.9% vs. 23.6%, p=0.003). With regard to long-term outcomes, there was no difference between lesions with curative and non-curative resections in the recurrence and mortality rates. These rates also did not differ between PDC and SRC (median follow up: 3.96 years).

Conclusions

ER confined to expanded indication lesions can be considered for treatment of EGC with undifferentiated-type histology.

Prediction model for non-curative resection of endoscopic submucosal dissection in patients with early gastric cancer

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) is a useful method for complete resection of early gastric cancer (EGC). However, there are still some patients who undergo additional gastrectomy after ESD because of non-curative resection. There is no model that can accurately predict non-curative resection of ESD. We aimed to create a model for predicting non-curative resection of ESD in patients with EGC.

PATIENTS AND METHODS

We reviewed the medical records, including all gross findings of EGC, of patients who underwent ESD for EGCs. We divided the patients into a non-curative resection group and a curative resection group. The clinicopathologic characteristics were compared between the groups to identify the risk factors for non-curative resection of ESD. We created a scoring system based on logistic regression modeling and bootstrap validation.

RESULTS

Of 1639 patients who had undergone ESD for EGCs, 272 were identified as being treated non-curatively with ESD. A large tumor size (≥20 mm), tumor location in the upper body of the stomach, the presence of ulcer, fusion of gastric folds, the absence of mucosal nodularity, spontaneous bleeding, and undifferentiated tumor histology were associated with non-curative resection of ESD. Points of risk scores were assigned for these variables based on the β coefficient as follows: tumor size (≥20 mm), 2 points; tumor location in the upper body of the stomach, 1 point; ulcer, 2 points; fusion of gastric folds, 2 points; absence of mucosal nodularity, 1 point; spontaneous bleeding, 1 point; and undifferentiated histology, 2 points. Our risk scoring model showed good discriminatory performance on internal validation (bootstrap-corrected area under the receiver operating characteristic curve, 0.7004; 95% confidence interval, 0.6655-0.7353).

CONCLUSIONS

We developed a validated prediction model that can be used to identify patients who will undergo non-curative resection of ESD. Our prediction model can provide useful information for making decisions about the treatment of EGC before performing ESD.

Endoscopic submucosal dissection of gastric tumors: A systematic review and meta-analysis

AIM: To systematically review the medical literature in order to evaluate the safety and efficacy of gastric endoscopic submucosal dissection (ESD).

METHODS: We performed a comprehensive literature search of MEDLINE, Ovid, CINAHL, and Cochrane for studies reporting on the clinical efficacy and safety profile of gastric ESD.

RESULTS: Twenty-nine thousand five hundred and six tumors in 27155 patients (31% female) who underwent gastric ESD between 1999 and 2014 were included in this study. R0 resection rate was 90% (95%CI: 87%-92%) with significant between-study heterogeneity (P < 0.001) which was partly explained by difference in region (P = 0.02) and sample size (P = 0.04). Endoscopic en bloc and curative resection rates were 94% (95%CI: 93%-96%) and 86% (95%CI: 83%-89%) respectively. The rate of immediate and delayed perforation rates were 2.7% (95%CI: 2.1%-3.3%) and 0.39% (95%CI: 0.06%-2.4%) respectively while rates of immediate and delayed major bleeding were 2.9% (95%CI: 1.3-6.6) and 3.6% (95%CI: 3.1%-4.3%). After an average follow-up of about 30 mo post-operative, the rate of tumor recurrence was 0.02% (95%CI: 0.001-1.4) among those with R0 resection and 7.7% (95%CI: 3.6%-16%) among those without R0 resection. Overall, irrespective of the resection status, recurrence rate was 0.75% (95%CI: 0.42%-1.3%).

CONCLUSION: Our meta-analysis, the largest and most comprehensive assessment of gastric ESD till date, showed that gastric ESD is safe and effective for gastric tumors and warrants consideration as first line therapy when an expert operator is available.

Recent developments and innovations in gastric cancer

Gastric cancer has an important place in the worldwide incidence of cancer and cancer-related deaths. It can metastasize to the lymph nodes in the early stages, and lymph node metastasis is an important prognostic factor. Surgery is a very important part of gastric cancer treatment. A D2 lymphadenectomy is the standard surgical treatment for cT1N+ and T2-T4 cancers, which are potentially curable. Recently, the TNM classification system was reorganized, and the margins for gastrectomy and lymphadenectomy were revised. Endoscopic, laparoscopic and robotic treatments of gastric cancer have progressed rapidly with development of surgical instruments and techniques, especially in Eastern countries. Different endoscopic resection techniques have been identified, and these can be divided into two main categories: endoscopic mucosal resection and endoscopic submucosal dissection. Minimally invasive surgery has been reported to be safe and effective for early gastric cancer, and it can be successfully applied to advanced gastric cancer with increasing experience. Cytoreductive surgery and hyperthermıc intraperıtoneal chemotherapy were developed as a combined treatment modality from the results of experimental and clinical studies. Also, hyperthermia increases the antitumor activity and penetration of chemotherapeutics. Trastuzumab which is a monoclonal antibody interacts with human epidermal growth factor (HER) 2 and is related to gastric carcinoma. The anti-tumor mechanism of trastuzumab is not clearly known, but mechanisms such as interruption of the HER2-mediated cell signaling pathways and cell cycle progression have been reported previously. H. pylori is involved in 90% of all gastric malignancies and Japanese guidelines strongly recommend that all H. pylori infections should be eradicated regardless of the associated disease. In this review, we present innovations discussed in recent studies.

Endoscopic resection of gastric and esophageal cancer

Endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) techniques have reduced the need for surgery in early esophageal and gastric cancers and thus has lessened morbidity and mortality in these diseases. ESD is a relatively new technique in western countries and requires rigorous training to reproduce the proficiency of Asian countries, such as Korea and Japan, which have very high complete (en bloc) resection rates and low complication rates. EMR plays a valuable role in early esophageal cancers. ESD has shown better en bloc resection rates but it is easier to master and maintain proficiency in EMR; it also requires less procedural time. For early esophageal adenocarcinoma arising from Barrett’s, ESD and EMR techniques are usually combined with other ablative modalities, the most common being radiofrequency ablation because it has the largest dataset to prove its success. The EMR techniques have been used with some success in early gastric cancers but ESD is currently preferred for most of these lesions. ESD has the added advantage of resecting into the submucosa and thus allowing for endoscopic resection of more aggressive (deeper) early gastric cancer.