Undifferentiated-type component mixed with differentiated-type early gastric cancer is a significant risk factor for endoscopic non-curative resection

Endoscopic Submucosal Dissection Criteria for Differentiated-type Early Gastric Cancer Are Applicable to Mixed-type Differentiated Predominant

BACKGROUND

There is a lack of sufficient evidence on whether mixed-type differentiated predominant early gastric cancer (MD-EGC) can be treated endoscopically by referring to the criteria for differentiated-type early gastric cancer (EGC). This study aims to evaluate the efficacy of endoscopic submucosal dissection (ESD) in MD-EGC.

METHODS

Patients with differentiated-type EGC treated with ESD first from January 2015 to June 2021 were reviewed, including MD-EGC and pure differentiated-type EGC (PD-EGC). Clinical data, including the clinicopathological characteristics, resection outcomes of ESD, and recurrence and survival time, were collected, and the difference between MD-EGC and PD-EGC was tested.

RESULTS

A total of 48 patients (48 lesions) with MD-EGC and 850 patients (890 lesions) with PD-EGC were included. Compared with PD-EGC, MD-EGC had a higher submucosal invasion rate (37.5% vs. 13.7%, P <0.001) and lymphatic invasion rate (10.4% vs. 0.4%, P <0.001). The rates of complete resection (70.8% vs. 92.5%, P <0.001) and curative resection (54.2% vs. 87.4%, P <0.001) in MD-EGC were lower than those of PD-EGC. Multivariate analysis revealed that MD-EGC (OR 4.26, 95% CI, 2.22-8.17, P <0.001) was an independent risk factor for noncurative resection. However, when curative resection was achieved, there was no significant difference in the rates of recurrence ( P =0.424) between the 2 groups, whether local or metachronous recurrence. Similarly, the rates of survival( P =0.168) were no significant difference.

CONCLUSIONS

Despite the greater malignancy and lower endoscopic curative resection rate of MD-EGC, patients who met curative resection had a favorable long-term prognosis.

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.

Effect of Helicobacter pylori eradication evaluated using magnifying endoscopy with narrow-band imaging in mixed-type early gastric Cancer

BACKGROUND

The effect of Helicobacter pylori (H.pylori) eradication therapy on mixed-histological-type gastric cancer remains unclear. This study aimed to clarify the effect of H. pylori eradication therapy on mixed-histological-type early gastric cancer using endoscopic and histological findings.

METHODS

This single-center, retrospective study included patients with mixed-histological-type gastric cancer who underwent endoscopic submucosal dissection at the Cancer Institute Hospital. We compared detailed magnifying endoscopy with narrow-band imaging findings between eradicated and non-eradicated groups of patients with differentiated-type- and undifferentiated-type-predominant cancers. Subsequently, we performed histological evaluations of the non-cancerous epithelium covering differentiated-type components.

RESULTS

A total of 124 patients with mixed-type early gastric cancer were enrolled (eradicated group: 62 differentiated-type-predominant cancer patients and 8 undifferentiated-type-predominant cancer patients; non-eradication group: 40 differentiated-type-predominant cancer patients and 14 undifferentiated-type-predominant cancer patients). Regarding differentiated-type-predominant cancer, differentiated-type findings were detected in all patients in eradicated and non-eradicated groups. The difference in the detection rate of undifferentiated-type findings between both groups was not significant in differentiated-type-predominant cancer patients. In differentiated-type-predominant cancers, the percentage of non-cancerous epithelium covering differentiated-type components was higher in the eradicated group than in the non-eradicated group (median: 60% vs. 40%, p < 0.001).

CONCLUSIONS

Although the pathological findings of differentiated-type-predominant cancer were affected by H. pylori eradication, eradication did not affect the diagnosis of differentiated-type-predominant early gastric cancer using magnifying endoscopy with narrow-band imaging. ME-NBI is useful for the early detection of D-MIX EGCs and diagnosis of histological types during endoscopy, regardless of whether H. pylori eradication therapy has been administered.

Endoscopic submucosal dissection for early gastric cancer: It is time to consider the quality of its outcomes

Endoscopic resection, particularly endoscopic submucosal dissection (ESD), is widely used as a standard treatment modality for early gastric cancer (EGC) when the risk of lymph node metastasis is negligible. Compared with surgical gastrectomy, ESD is a minimally invasive procedure with additional advantages, such as preservation of the entire stomach and maintenance of the patient's quality of life. However, not all patients achieve curative resection after ESD of EGC. Several patients require surgical gastrectomy after ESD to achieve a curative treatment. Additional surgery after ESD, owing to non-curative resection, places considerable emotional and financial burdens on patients. Recently, as the number of endoscopists performing ESD has increased, the rate of non-curative resection after ESD has increased correspondingly. In order to decrease the non-curative resection rate, as well as determine the ideal rate of non-curative resection after ESD, it is time to consider quality indicators for the outcomes of ESD for EGC.

Endoscopic Resection of Early Gastric Cancer and Pre-Malignant Gastric Lesions

Early gastric cancer comprises gastric malignancies that are confined to the mucosa or submucosa, irrespective of lymph node metastasis. Endoscopic resection is currently pivotal for the management of such early lesions, and it is the recommended treatment for tumors presenting a very low risk of lymph node metastasis. In general, these lesions consist of two groups of differentiated mucosal adenocarcinomas: non-ulcerated lesions (regardless of their size) and small ulcerated lesions. Endoscopic submucosal dissection is the technique of choice in most cases. This procedure has high rates of complete histological resection while maintaining gastric anatomy and its functions, resulting in fewer adverse events than surgery and having a lesser impact on patient-reported quality of life. Nonetheless, approximately 20% of resected lesions do not fulfill curative criteria and demand further treatment, highlighting the importance of patient selection. Additionally, the preservation of the stomach results in a moderate risk of metachronous lesions, which underlines the need for surveillance. We review the current evidence regarding the endoscopic treatment of early gastric cancer, including the short-and long-term results and management after resection.

Comparison of clinical and pathological features between early-stage gastric-type and intestinal-type differentiated adenocarcinoma: a retrospective study

BACKGROUND

The clinicopathological features and endoscopic characteristics under magnifying endoscopy with narrow band imaging (ME-NBI) between early-stage gastric-type differentiated adenocarcinoma (GDA) and intestinal-type differentiated adenocarcinoma (IDA) remain controversial.

METHODS

Early gastric adenocarcinomas that underwent endoscopic submucosal dissection (ESD) in Nanjing Drum Tower Hospital between August 2017 and August 2021 were included in the present study. GDA cases and IDA cases were selected based on morphology and immunohistochemistry staining of CD10, MUC2, MUC5AC, and MUC6. Clinicopathological data and endoscopic findings in ME-NBI were compared between GDAs and IDAs.

RESULTS

The mucin phenotypes of 657 gastric cancers were gastric (n = 307), intestinal (n = 109), mixed (n = 181) and unclassified (n = 60). No significant difference was observed in terms of gender, age, tumor size, gross type, tumor location, background mucosa, lymphatic invasion, and vascular invasion between patients with GDA and IDA. GDA cases were associated with deeper invasion than IDA cases (p = 0.007). In ME-NBI, GDAs were more likely to exhibit an intralobular loop patten, whereas IDAs were more likely to exhibit a fine network pattern. In addition, the proportion of none-curative resection in GDAs was significantly higher than that in IDAs (p = 0.007).

CONCLUSION

The mucin phenotype of differentiated early gastric adenocarcinoma has clinical significance. GDA was associated with less endoscopically resectability than IDA.

Construction of a nomogram for preoperative prediction of the risk of lymph node metastasis in early gastric cancer

Background

The status of lymph node metastasis (LNM) in patients with early gastric cancer (EGC) is particularly important for the formulation of clinical treatment. The purpose of this study was to construct a nomogram to predict the risk of LNM in EGC before operation.

Methods

Univariate analysis and logistic regression analysis were used to determine the independent risk factors for LNM. The independent risk factors were included in the nomogram, and the prediction accuracy, discriminant ability and clinical practicability of the nomogram were evaluated by the receiver operating characteristic curve (ROC), calibration curve and clinical decision curve (DCA), and 100 times ten-fold cross-validation was used for internal validation.

Results

33 (11.3%) cases of AGC were pathologically confirmed as LNM. In multivariate analysis, T stage, presence of enlarged lymph nodes on CT examination, carbohydrate antigen 199 (CA199), undifferentiated histological type and systemic inflammatory response index (SIRI) were risk factors for LNM. The area under the ROC curve of the nomogram was 0.86, the average area under the ROC curve of the 100-fold ten-fold cross-validation was 0.85, and the P value of the Hosmer-Lemeshow test was 0.60. In addition, the clinical decision curve, net reclassification index (NRI) and Integrated Discriminant Improvement Index (IDI) showed that the nomogram had good clinical utility.

Conclusions

We found that SIRI is a novel biomarker for preoperative prediction of LNM in EGC, and constructed a nomogram for preoperative prediction of the risk of LNM in EGC, which is helpful for the formulation of the clinical treatment strategies.

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.

Clinicopathological features of endoscopically treated early gastric cancer with lymphovascular infiltration

PURPOSE

Lymphovascular infiltration (LVI) may play a critical role in radicality and prognostic assessment of early gastric cancer (EGC). However, risk factors for LVI in endoscopically resected EGC remain unknown. This study evaluated the clinicopathological characteristics and prognoses of patients who underwent endoscopic resection of EGC to identify potential risk factors of LVI.

METHODS

A cross-sectional study of patients who received gastric endoscopic submucosal dissection between February 1, 2012, and December 31, 2019, at two institutions was conducted. Among 1,462 lesions, 943 met the criteria for radical treatment considering features other than LVI and were included. The lesions were classified based on the presence of LVI. The clinicopathological characteristics of the two groups were compared.

RESULTS

LVI was detected in 17 lesions (1.8%). The positivity rates of LVI were 0.7% (7/903) for intramucosal cancer and 25% (10/40) for submucosally invasive cancer. The LVI positivity rate was significantly higher for mixed-type cancer (lesions containing differentiated and undifferentiated-type carcinoma) than for non-mixed-type cancer (35.3 vs. 2.8%; P < 0.001) and for submucosally invasive cancer than for intramucosal cancer (58.8 vs. 3.2%; P < 0.001). In the multivariate logistic regression analysis, independent risk factors for LVI were mixed-type cancer (odds ratio; 95% confidence interval: 23.9; 5.0-115; P < 0.001) and submucosal invasion (58.7; 16.0-215; P < 0.001).

CONCLUSIONS

Mixed-type cancer and submucosal invasion were risk factors for LVI in endoscopically resected EGC. These factors may play a critical role in the radicality and prognostic assessment of EGC.

The Histopathological Types and Distribution Characteristics of Gastric Mixed Tumors

Objective

The present study aimed to investigate the histopathological types and distribution characteristics of gastric mixed tumors.

Methods

Detailed histological observations, together with related immunohistochemical and genetic tests, were analyzed on 960 surgically resected samples in 6 hospitals with gastric mixed tumors from May 2017 to May 2021 in this retrospective study.

Results

Epithelial-derived tumors accounted for 80.10% (769/960) of the gastric mixed tumor samples studied, and tumors of different tissue origins accounting for 10.83% (104/960), mesenchymal-derived tumors accounting for 6.25% (60/960), neuroendocrine tumors accounting for 2.40% (23/960), and lymphoma accounting for 0.42% (4/960). The histological types of gastric mixed tumors identified as most commonly were epithelial originated, followed by mixed tumors of different tissue originated, then mixed neuroendocrine, lymphoma, and mesenchymal originated in sequence. The histological number of gastric mixed tumors was ≤ 3 in 83.23% (799/960) of cases and > 4 in 16.77% (161/960) of cases. The mixed histological patterns of gastric mixed tumors were divided into three types: those with tumor cells interspersed with each other, those with incomplete fibrous tissue separation, and those without fibrous tissue separation. The gene target characteristics of gastric mixed tumors were the existence of multi-gene mutation, including human epidermalgrowth factor receptor-2 (HER2) gene amplification, key result areas (K-ras) and platelet-derived growth factor receptor alpha (PDGFRA).

Conclusion

Gastric mixed tumors should be adequately sampled, each piece of tissue should be involved in the morphological proportional division of the tumor, and any independent histological component should be written into the pathological examination report.

Relationship between histological mixed-type early gastric cancer and lymph node metastasis: A systematic review and meta-analysis

The clinicopathological features of early gastric cancer (EGC) with mixed-type histology (differentiated and undifferentiated) are incompletely understood, and the capacity of endoscopic submucosal dissection (ESD) to treat mixed-type cancer remains controversial. This systematic review analyzed the rate of lymph node metastasis (LNM) in mixed-type EGC. We gathered articles published up to February 21, 2021, that analyzed the relationship between LNM and mixed-type EGC from Embase, PubMed, and Web of Science. The primary outcome was the LNM rate associated with different histological types of EGC, and the secondary outcomes were the odds ratios (ORs) for LNM risk factors among EGC patients. From the 24 studies included in this meta-analysis, the overall rate of LNM in predominantly differentiated mixed-type (MD) EGC was 12%, whereas the LNM rate in predominantly undifferentiated mixed-type (MU) EGC was 22%. We further divided these studies into 2 groups according to the depth of invasion. In mixed-type mucosal EGC, the pooled LNM rate was 15%; in submucosal EGC, the rate was 33% for MU, which was higher than the rates for pure types (pure differentiated type, 13%; pure undifferentiated type, 21%; p<0.05). The LNM rate of MD was 20%, it was higher than those of the pure differentiated type and nearly the same as pure undifferentiated type. Other pooled statistics showed that submucosal invasion, pure undifferentiated EGC, and mixed-type EGC were independent risk factors for LNM. This meta-analysis showed that MD submucosal EGC has a high rate of LNM and is highly correlated with LNM; thus, the management of MD EGC as purely differentiated EGC according to the indications for ESD is inappropriate, and the mixed type should be added as a parameter in these indications.

Undifferentiated-predominant mixed-type early gastric cancer is more aggressive than pure undifferentiated type: a systematic review and meta-analysis

BACKGROUND

Studies have shown that differentiated-predominant mixed-type early gastric cancer (EGC) is more aggressive than pure differentiated-type EGC. However, the biological behaviour of undifferentiated-predominant mixed-type (MU) EGC and pure undifferentiated-type (PU) EGC are controversial. This study was conducted to compare the biological behaviour of MU EGC and PU EGC.

METHODS

A systematic review and meta-analysis of observational studies was conducted using literature published through PubMed and Embase from inception to 9 November 2021. Inclusion criteria were: (1) a direct or indirect comparison of MU and PU; (2) patients with EGC; (3) a specified outcome of lymph node metastasis (LNM), lymphovascular invasion, submucosal invasion and/or ulcer findings; and (4) the primary lesion was obtained. The literature search, data extraction and quality assessment were performed by two independent reviewers. The meta-analysis was conducted with a random-effect model using the Mantel-Haenszel method.

RESULTS

Twelve publications with 5644 patients were included. Patients with MU EGC had significantly higher risk of LNM (OR 2.28; 95% CI 1.72 to 3.03) and submucosal invasion (OR 2.19; 95% CI 1.90 to 2.52) compared with patients with PU EGC. No difference was found between patients with MU and PU EGC with respect to lymphovascular invasion risk (OR 1.81; 95% CI 0.84 to 3.87). After stratifying the data according to depth of tumour invasion, a significantly higher risk for LNM was associated with intramucosal MU EGC (OR 2.56; 95% CI 1.66 to 3.95) and submucosal MU EGC (OR 2.63; 95% CI 2.06 to 3.06). Submucosal MU EGC also had a significantly higher risk of lymphovascular invasion (OR 2.40; 95% CI 1.79 to 3.21) compared with submucosal PU EGC.

DISCUSSION

Patients with MU EGC had an increased risk of submucosal invasion and LNM compared with patients with PU EGC . MU patients with submucosal EGC also had an increased lymphovascular invasion risk compared with PU patients. Therefore, attention should be focused on the clinical management of patients with MU EGC.

Research on the Histological Features and Pathological Types of Gastric Adenocarcinoma With Mucinous Differentiation

Objective

To discuss the histological features, pathological types, and prognosis of gastric adenocarcinoma with mucinous differentiation.

Methods

Specimens of 189 cases of gastric adenocarcinoma with mucinous differentiation were collected for detailed histomorphology, immunohistochemistry, fluorescence in situ hybridization, and follow-up.

Results

In accordance with the morphological and histological structural features of the cancer cells as well as the area ratio of the mucus, gastric adenocarcinoma with mucinous differentiation was divided into four types, namely pure mucinous carcinoma, intraductal papillary mucinous carcinoma, signet ring cell type mucinous carcinoma, and mixed cell type mucinous carcinoma. Based on the macroscopic types according to Bormann's classification, pure mucinous carcinoma was mostly Type I, intraductal papillary mucinous carcinoma was mostly Type II, signet ring cell type mucinous carcinoma was mostly Type IV, and mixed cell type mucinous carcinoma was mostly Type III. The 5-year survival rate was 69.2, 64.2, 0, and 31.5%, respectively. There was a statistical difference in the lymph node metastasis rate and survival rate of the four carcinoma types. The invasion features of pure mucinous carcinoma entailed penetrating corrosively in a push-in form, without blood vessel or lymphatic metastasis and with few lymphocytes and lymphatic nodules in the marginal area. Thus, there was little lymph node metastasis and invasion of nerves. The HER2 protein expression rate was 40.2% (76/189), the HER2 gene amplification detected by FISH technology was 16.9% (32/189).

Conclusion

The independent histological type, four subtypes, and histopathological classification of gastric mucinous adenocarcinoma are important for the prognosis evaluation and precise treatment of this disease.

Differentiated/undifferentiated mixed type is a prognostic factor for T2/T3 gastric cancer patients

OBJECTIVES

This work aimed to find the association of mixed-type histology and prognosis of T2/T3 GC patients.

METHODS

Eligible T2/T3 gastric cancer patients at our institution were identified. The histological types and risk factors affecting OS were examined. Survival differences were assessed by log-rank tests and Kaplan-Meier curves.

RESULTS

The study identified 972 T2/T3 gastric cancer patients, including 283 differentiated-type patients, 544 undifferentiated-type patients and 145 mixed type. Mixed-type histology was associated with shorter 5-year OS (DT vs UDT vs MT:57.5% vs 44.9% vs 39.6%, P = 0.002). MT histology can be predictive for prognosis of T2/T3 GC patients (HR for OS: 1.386, 95% CI: 1.028-1.868, P = 0.032), and its malignant potential is not inferior to UDT. In the subgroup analysis, MT can potentially be independent risk factor for non-distal GC patients (P = 0.010).

CONCLUSION

This study reported that mixed histology could be regarded as a potential prognostic factor for T2/T3 gastric cancer patients, especially for those with non-distal cancer. MT patients have higher incidence of metastasis and recurrence and had poorer prognosis than those with pure histological type. It is necessary for MT patients to have preoperative pathological examination for accurate histologic classification, so as to make the comprehensive treatment strategies..

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.

Comparison of clinicopathological features and long-term prognosis between mixed predominantly differentiated-type and pure differentiated-type early gastric cancer

Background

Recent studies have shown that mixed predominantly differentiated-type (MD) early gastric cancer (EGC) might have more malignant potential than pure differentiated-type (PD) EGC. However, no study has analyzed all differentiated-type EGC cases treated endoscopically and surgically. This study aimed to compare the differences in clinicopathological features and long-term prognosis between MD- and PD-EGC.

Methods

We evaluated all patients with differentiated-type EGCs who were treated endoscopically and surgically in our hospital between January 2010 and October 2014. The clinicopathological features and long-term prognosis of MD-EGC were compared with those of PD-EGC.

Results

A total of 459 patients with 459 lesions were evaluated in this study; of them, 409 (89.1%) and 50 (10.9%) were classified into the PD and MD groups, respectively. Submucosal invasion was found in 96 (23.5%) patients of the PD group and in 33 (66.0%) patients of the MD group (p < 0.01). The rates of positive lymphatic and vascular invasion and ulceration were significantly higher in the MD group than in the PD group (p < 0.01). The proportion of patients with lymph node metastasis was also significantly higher in the MD group than in the PD group (5 (10%) vs 6 (1.5%), p < 0.01). The 5-year overall and EGC-specific survival rates in the PD group were 88.3 and 99.5%, respectively, while they were 94.0 and 98.0% in the MD group, respectively.

Conclusions

MD-EGC has more malignant potential than PD-EGC. However, the long-term prognosis of MD-EGC is good and is not significantly different from that of PD-EGC when treated appropriately.

Histological diversity and molecular characteristics in gastric cancer: relation of cancer stem cell-related molecules and receptor tyrosine kinase molecules to mixed histological type and more histological patterns

BACKGROUND

Gastric cancers (GCs) are still one of the leading causes of cancer-related mortality. The histological and molecular features of GC may differ widely from area to area within the same tumor. Intratumoral heterogeneity has been considered a major obstacle to an efficient diagnosis and successful molecular treatment.

METHODS

We selected and reevaluated 842 GC cases and analyzed the relationship between numbers or composites of histological patterns within tumors, and clinicopathological parameters in mucosal and invasive areas. In addition, we searched for the GC-associated molecules or molecular subtypes marking histological diversities.

RESULTS

GC cases with more histological numbers or mixed types in invasive areas showed significantly higher T grade and staging, whereas those in mucosal areas did not show any significant associations. GCs with histological diversities showed poorer prognosis and characteristically expressed cancer stem cell-related molecules (CD44, CD133 or ALDH1) and receptor tyrosine kinase molecules (HER2, EGFR or c-MET) as well as Helicobacter pylori infection. Expressions of CD44, HER2, c-MET, laminin 5·2 or retained E-cadherin in mucosal areas were predictive of more histological numbers and mixed types in invasive areas. In addition, the chromosomal instability subtype of GC showed significant associations with more histological numbers and mixed histological type, whereas the genomic stability subtype of GC showed a significant relationship with pure type.

CONCLUSIONS

We displayed the relationship between histological diversity and molecular features in GC, and we hope that the present data can contribute to the early diagnosis and prevention, and effective treatment of GC.

Neutrophil-to-Lymphocyte Ratio Is a Useful Marker for Predicting Histological Types of Early Gastric Cancer

Background: The indications for endoscopic submucosal dissection (ESD) for gastric cancer are based on preoperative histological assessment; however, examination of tissue biopsy is not always reliable as only a limited portion of the lesion can be obtained. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are markers of inflammatory response and are potentially associated with the grade of malignancy in gastric cancer. We aimed to investigate the association between NLR and PLR and the histology of gastric cancer. Methods: This study included 218 patients who underwent ESD for gastric cancer. The relationship between NLR/PLR and histological diagnosis was investigated. Results: Patients with adenocarcinomas showed significantly higher NLR and PLR than those with adenomas (p < 0.001 and p < 0.05, respectively). Further, patients with undifferentiated adenocarcinoma showed a significantly higher NLR (p < 0.05) than those with differentiated adenocarcinoma. Conclusion: This study suggests that NLR could be a useful marker for assessing early gastric cancer.

Mixed histology poses a greater risk for noncurative endoscopic resection in early gastric cancers regardless of the predominant histologic types

OBJECTIVES

Clinicopathologic characteristics and treatment outcomes of mixed-histological-type (MT) early gastric cancers (EGCs) treated with endoscopic submucosal dissection (ESD) have not been sufficiently elucidated. We aimed to clarify them in comparison with pure-histological-type EGCs.

METHODS

We used 3022 consecutive EGCs in 2281 patients treated with ESD from our prospectively maintained database. Cases were stratified into four groups according to the final diagnosis of the resected specimen are as follows: 2780 pure differentiated-type (DT), 127 DT-predominant MT (D-MT), 87 pure undifferentiated-type (UDT), and 28 UDT-predominant MT (U-MT). Clinicopathologic characteristics and treatment outcome were compared between pure DT and D-MT, and between pure UDT and U-MT separately. Risk factors for deep submucosal invasion, lymphovascular invasion, and a final diagnosis of MT were identified using multivariate analysis.

RESULTS

Both D-MT (41.7 vs. 92.0%; P < 0.0001) and U-MT (35.7 vs. 75.9%; P = 0.0002) showed a significantly lower curative resection rate than their pure histologic counterparts. Multivariate analysis revealed that MT was an independent risk factor for deep submucosal (OR 6.55; 95% CI, 4.18-10.14) and lymphovascular (OR 4.74; 95% CI, 2.72-8.29) invasion. Preoperative biopsy results that did not show well-differentiated tubular adenocarcinoma (OR 28.2; 95% CI, 18.9-42.9) were an independent risk factor for a final diagnosis of MT.

CONCLUSIONS

MT poses a greater risk for noncurative resection regardless of the predominant histologic types, reflecting more aggressive malignant potential. Although a biopsy examination rarely shows MT, clinicians should consider the possibility of MT when a biopsy examination does not show well-differentiated tubular adenocarcinoma.

Risk-Scoring System for Prediction of Non-Curative Endoscopic Submucosal Dissection Requiring Additional Gastrectomy in Patients with Early Gastric Cancer

Purpose

When patients with early gastric cancer (EGC) undergo non-curative endoscopic submucosal dissection requiring gastrectomy (NC-ESD-RG), additional medical resources and expenses are required for surgery. To reduce this burden, predictive model for NC-ESD-RG is required.

Materials and Methods

Data from 2,997 patients undergoing ESD for 3,127 forceps biopsy-proven differentiated-type EGCs (2,345 and 782 in training and validation sets, respectively) were reviewed. Using the training set, the logistic stepwise regression analysis determined the independent predictors of NC-ESD-RG (NC-ESD other than cases with lateral resection margin involvement or piecemeal resection as the only non-curative factor). Using these predictors, a risk-scoring system for predicting NC-ESD-RG was developed. Performance of the predictive model was examined internally with the validation set.

Results

Rate of NC-ESD-RG was 17.3%. Independent pre-ESD predictors for NC-ESD-RG included moderately differentiated or papillary EGC, large tumor size, proximal tumor location, lesion at greater curvature, elevated or depressed morphology, and presence of ulcers. A risk-score was assigned to each predictor of NC-ESD-RG. The area under the receiver operating characteristic curve for predicting NC-ESD-RG was 0.672 in both training and validation sets. A risk-score of 5 points was the optimal cut-off value for predicting NC-ESD-RG, and the overall accuracy was 72.7%. As the total risk score increased, the predicted risk for NC-ESD-RG increased from 3.8% to 72.6%.

Conclusions

We developed and validated a risk-scoring system for predicting NC-ESD-RG based on pre-ESD variables. Our risk-scoring system can facilitate informed consent and decision-making for preoperative treatment selection between ESD and surgery in patients with EGC.

Performance of a computer-aided diagnosis system in diagnosing early gastric cancer using magnifying endoscopy videos with narrow-band imaging (with videos)

BACKGROUND AND AIMS

The performance of magnifying endoscopy with narrow-band imaging (ME-NBI) using a computer-aided diagnosis (CAD) system in diagnosing early gastric cancer (EGC) is unclear. Here, we aimed to clarify the differences in the diagnostic performance between expert endoscopists and the CAD system using ME-NBI.

METHODS

The CAD system was pretrained using 1492 cancerous and 1078 noncancerous images obtained using ME-NBI. One hundred seventy-four videos (87 cancerous and 87 noncancerous videos) were used to evaluate the diagnostic performance of the CAD system using the area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). For each item, comparisons were made between the CAD system and 11 experts who were skilled in diagnosing EGC using ME-NBI with clinical experience of more than 1 year at our hospital.

RESULTS

The CAD system demonstrated an AUC of 0.8684. The accuracy, sensitivity, specificity, PPV, and NPV were 85.1% (95% confidence interval [95% CI], 79.0-89.6), 87.4% (95% CI, 78.8-92.8), 82.8% (95% CI, 73.5-89.3), 83.5% (95% CI, 74.6-89.7), and 86.7% (95% CI, 77.8-92.4), respectively. The CAD system was significantly more accurate than 2 experts, significantly less accurate than 1 expert, and not significantly different from the remaining 8 experts.

CONCLUSIONS

The overall performance of the CAD system using ME-NBI videos in diagnosing EGC was considered good and was equivalent to or better than that of several experts. The CAD system may prove useful in the diagnosis of EGC in clinical practice.

Histopathological validation of magnifying endoscopy for diagnosis of mixed-histological-type early gastric cancer

BACKGROUND

The undifferentiated-type (UDT) component profoundly affects the clinical course of early gastric cancers (EGCs). However, an accurate preoperative diagnosis of the histological types is unsatisfactory. To date, few studies have investigated whether the UDT component within mixed-histological-type (MT) EGCs can be recognized preoperatively.

AIM

To clarify the histopathological characteristics of the endoscopically-resected MT EGCs for investigating whether the UDT component could be recognized preoperatively.

METHODS

This was a single-center retrospective study. First, we attempted to clarify the histopathological characteristics of the endoscopically-resected MT EGCs with emphasis on the UDT component. Histopathological examination investigated each lesion’s UDT component: (1) Whole mucosal layer occupation of the UDT component; (2) UDT component exposure to the surface of the mucosa; and (3) existence of a clear border between the differentiated-type and UDT components. Then, preoperative endoscopic images with magnifying endoscopy with narrow-band imaging (ME-NBI) were examined to identify whether the endoscopic UDT component finding was recognizable within the area where it was present in the histopathological examination. The preoperative biopsy results and comparative relationships between endoscopic and histopathological findings were also examined.

RESULTS

In the histopathological examination, the whole mucosal layer occupation of the UDT component and exposure of the UDT component to the mucosal surface were observed in 67.3% (33/49) and 79.6% (39/49) of samples, respectively. A clear distinction of the border between the differentiated-type and UDT components could not be drawn in 65.3% (32/49) of MT lesions. In the endoscopic examination, the preoperative endoscopic images showed that only 24.5% (12/49) of MT EGCs revealed the UDT component within the area where it was present histopathologically. Histopathological UDT predominance was the single significant factor associated with the presence of the endoscopic UDT component finding (61.5% vs 11.1%, P = 0.0009). Only 26.5% (13/49) of the lesions were diagnosed from the pretreatment biopsy as having a UDT component. Combined results of the pretreatment biopsy and ME-NBI showed the preoperative presence of the UDT component in 40.8% (20/49) of MT EGCs.

CONCLUSION

Recognition of a UDT component within MT EGCs is difficult even when pretreatment biopsy and ME-NBI are combined. Endoscopic resection plays a significant role in both treatment and diagnosis.

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.

Undifferentiated-type predominant mixed-type early gastric cancer is a significant risk factor for requiring additional surgeries after endoscopic submucosal dissection

We aimed to clarify the differences in therapeutic outcomes of patients with pure undifferentiated-type and mixed undifferentiated-type cancers who underwent endoscopic submucosal dissection (ESD), and whether pre-treatment diagnosis of mixed undifferentiated-type cancer is associated with requiring additional surgery after ESD. Patients subjected to ESD as initial treatment between May 2005 and March 2017 were enrolled. There were 277 undifferentiated-type cancers (265 patients). Histologically, 258 lesions were pure-type and 19 were mixed-type. We compared therapeutic outcomes and pre-treatment factors (tumour diameter, tumour depth, ulcerative findings, tumour location, and the macroscopic, and histological type of the biopsy specimen) between pure-type and mixed-type lesions, and between cases not requiring additional surgeries and cases requiring additional surgeries. Tumour diameter >20 mm, submucosal invasion, and the presence of ulcerative findings made pre-treatment diagnosis more difficult for mixed-type than for pure-type lesions. In cases requiring additional surgery, pre-treatment diagnosis of mixed-type lesions was significantly more likely than pre-treatment diagnosis of pure-type lesions. For mixed-type lesions, pre-treatment histological diagnosis and careful consideration are necessary to determine indications for ESD to avoid additional surgery after ESD.

Poorly differentiated is more significant than signet ring cell component for lymph node metastasis in mixed-type early gastric cancer: a retrospective study from a large-volume hospital

Objective

The purpose of this study was to explore the role of different undifferentiated components in the lymph node metastasis (LNM) of early mixed gastric cancer.

Methods

A total of 1596 patients with EGC who underwent gastrectomy were divided into four types: pure differentiated (PD), pure poorly differentiated (Poorly D), pure signet ring cell carcinoma (SRC), and mixed. Mixed type was classified into four subtypes: differentiated-predominant type mixed with poorly differentiated component (MD-P), poorly differentiated-predominant type mixed with differentiated component (MP-D), differentiated-predominant type mixed with SRC component (MD-S), and poorly differentiated-predominant type mixed with SRC component (MP-S). We analyzed the clinicopathological differences between all types and the rates of LNM of patients fulfilling endoscopic submucosal dissection (ESD) criteria.

Results

LNM was more common in mixed (21.9%) than in PD (7.5%, P < 0.001) or SRC (11.3%, P < 0.001). When analyzed the subgroups of mixed type, LNM was more frequent in MD-P (15.4%) than in PD (7.5%, P = 0.003). LNM in MD-S (7.4%, P = 1.000) was not higher than in PD. MP-S (24.5%) showed a higher rate of LNM than SRC (11.3%, P < 0.001) rather than Poorly-D (22.7%, P = 0.681). For lesions satisfying ESD criteria, MD-S (0%, P = 1.000), and MD-P (5.9%, P = 0.12) did not have higher rates of LNM than PD (1.4%).

Conclusion

The presence of poorly differentiated component but not SRC increases the LNM rate of mixed type. ESD is recommended for the treatment of MD-S and MD-P consistent with ESD criteria.

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.

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.

Gastric endoscopic submucosal dissection: a systematic review and meta-analysis on risk factors for poor short-term outcomes

OBJECTIVE

Endoscopic submucosal dissection (ESD) is now established as the first option to manage early gastric neoplasms, but its efficacy may vary according to diverse factors. We aimed to systematically identify risk factors for poor short-term outcomes of gastric ESD with the purpose to improve patients' selection and management.

METHODS

Three online databases (MEDLINE, ISI Web of Knowledge and Scopus) were searched (last search on June 2018) for poor outcomes of gastric ESD (deep submucosal invasion, piecemeal/incomplete resection, noncurative resection and local recurrence).

RESULTS

One hundred five studies were included referring to 52.126 ESDs. Undifferentiated histology and upper location (vs lower) were associated with submucosal invasion [odds ratio (OR) = 2.42 [95% confidence interval (CI), 1.62-3.61] and OR = 3.20 (1.04-9.86), respectively] and deep submucosal invasion [OR = 2.98 (2.02-4.39) and OR = 2.35 (1.45-3.81), respectively]. Lesion size greater than 30 mm and ulceration were associated with piecemeal resection [OR = 2.78 (1.17-6.60) and OR = 2.76 (1.23, 6.20), respectively]. Lesion size greater than 30 mm, ulceration, upper location and fibrosis were risk factors for incomplete resection [OR = 3.83 (2.68-5.49), OR = 4.06 (1.62-10.16), OR = 3.71 (2.49-5.54) and OR = 4.46 (1.66-11.96), respectively]. A noncurative resection was more often observed for lesions located in the upper third of the stomach [OR = 1.49 (1.24-1.79)], depressed morphology [OR = 1.49 (1.04-2.12)] and those outside standard criteria [OR = 3.56 (2.31-5.48)]. Older age was significantly linked with local recurrence rates [OR = 3.08 (1.13-5.02)].

CONCLUSION

Several risk factors influence poor efficacy short-term outcomes of gastric ESD that may be used to inform both patients and health providers about the expected efficacy.

Strategy for Curative Endoscopic Resection of Undifferentiated-Type Early Gastric Cancer

Endoscopic resection (ER) of undifferentiated-type early gastric cancer (UD-EGC) has a lower curative resection (CR) rate than differentiated-type EGC. However, if UD-EGC is curatively resected using ER, long-term outcomes can be favorable. Thus, the strategy for CR by ER is important in UD-EGC. To achieve CR in UD-EGC, biological behaviors including tumor growth patterns must be considered. This review aims to describe what is important for curative ER of UD-EGC.

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.

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.

Risk assessment of lymph node metastases in early gastric adenocarcinoma fulfilling expanded endoscopic resection criteria

BACKGROUND AND AIMS

Early gastric cancer (EGC) is known to present a low rate of lymph node metastases (LNMs). Gastrectomy with D2 lymphadenectomy is usually curative for EGC. Endoscopic submucosal dissection (ESD) is a well-accepted treatment modality for lesions that meet the classic criteria: those mucosal differentiated adenocarcinoma measuring 20 mm or less, without ulceration. Expanded criteria for ESD have been proposed based on a null LNM rate from large gastrectomy series from Japan. Patients with LNM have been reported in Western centers, heightening the need for validation of expanded criteria. Our aim was to assess the risk of LNM in gastrectomy specimens of patients with EGC who met the expanded criteria for ESD.

METHODS

We conducted an evaluation of gastrectomy specimens including LNM staging of patients submitted to gastrectomy for EGC in a 39-year retrospective cohort.

RESULTS

A total of 389 surgical specimens were included. From them, 135 fulfilled criteria for endoscopic resection. None of the 31 patients with classic criteria had LNM. From the 104 patients with expanded criteria, 3 had LNM (n = 104 [2.9%], 95% confidence interval, .7%-8.6%), all of them with undifferentiated tumors without ulceration, measuring less than 20 mm.

CONCLUSIONS

There is a small risk of LNM in EGC when expanded criteria for ESD are met. Refinement of the expanded criteria for the risk of LNM may be desirable in a Brazilian cohort. Meanwhile, the decision to complement the endoscopic treatment with gastrectomy will have to take into consideration the individual risk of perioperative morbidity and mortality.