Consensus statements on endoscopic ultrasound-guided tissue acquisition. Guidelines from the Asian Endoscopic Ultrasound Group.

OBJECTIVES: This consensus was developed by the Asian EUS Group (AEG), who aimed to formulate a set of practice guidelines addressing various aspects of endoscopic ultrasound-guided tissue acquisition (EUS-TA). METHODS: The AEG initiated the development of consensus statements and formed an expert panel comprising surgeons, gastroenterologists, and pathologists. Three online consensus meetings were conducted to consolidate the statements and votes. The statements were presented and discussed in the first two consensus meetings and revised according to comments. Final voting was conducted at a third consensus meeting. The Grading of Recommendations, Assessment, Development, and Evaluation system was adopted to define the strength of the recommendations and quality of evidence. RESULTS: A total of 20 clinical questions and statements regarding EUS-TA were formulated. The committee recommended that fine-needle biopsy (FNB) needles be preferred over conventional fine-needle aspiration (FNA) needles for EUS-TA of subepithelial lesions. For solid pancreatic masses, rapid on-site evaluation is not routinely recommended when FNB needles are used. For dedicated FNB needles, fork-tip and Franseen-tip needles have essentially equivalent performance. CONCLUSION: This consensus provides guidance for EUS-TA, thereby enhancing the quality of EUS-TA.

Randomized trial of contrast-enhanced harmonic guidance versus fanning technique for EUS-guided fine-needle biopsy sampling of solid pancreatic lesions.

BACKGROUND AND AIMS: For EUS-guided fine-needle biopsy sampling (EUS-FNB) of solid pancreatic lesions (SPLs), the role of sampling strategy between targeted biopsy sampling and wide sampling has not been reported. This study aimed to investigate the benefits of the 2 sampling techniques on EUS-FNB using rapid on-site evaluation. METHODS: Patients with SPLs were prospectively enrolled and randomly assigned (1:1) to undergo EUS-FNB using either contrast guidance or the fanning technique. The primary outcome was the total number of passes required to establish a diagnosis, and secondary outcomes were overall diagnostic accuracy and adverse event rates. RESULTS: One hundred eighteen patients were enrolled from February 2019 to January 2021, with 59 patients assigned to each group. There was no significant difference in the total number of passes required to establish a diagnosis between the contrast and fanning groups (median, 1 [interquartile range, 1-1] vs 1 [interquartile range, 1-2], respectively; P = .629). The sensitivity, specificity, and diagnostic accuracy in the contrast group was 100%, 66.7%, and 98.3% and in the fanning group 100%, 100%, and 100%, respectively (P = 1). An SPL <4 cm (odds ratio, 2.47; 95% confidence interval, 1.05-5.81; P = .037) and macroscopic visible core length >1 cm (odds ratio, 2.89; 95% confidence interval, 1.07-7.84; P = .037) were independently associated with increased cytologic and histologic accuracy. CONCLUSIONS: The diagnostic accuracy of EUS-FNB with the fanning technique for SPLs was comparable with the contrast guidance technique. Without additional cost, EUS-FNB with the fanning technique may be preferred for SPLs. (Clinical trial registration number: NCT04924725.).

Tissue diagnosis necessary for small endoscopic ultrasound-suspected gastric gastrointestinal stromal tumors 2 cm or less in size: A prospective study focusing on the endoscopic incisional biopsy.

BACKGROUND AND AIM: The small endoscopic ultrasound (EUS)-suspected gastric gastrointestinal stromal tumors (GISTs), gastric subepithelial tumors at the muscularis propria layer on EUS, are detected frequently. Bite-on-bite forceps biopsy and EUS-guided tissue sampling yield variable results. This study aimed to analyze clinicopathologic features of the small EUS-suspected gastric GISTs 2 cm or less in size and to evaluate the efficacy and safety of the endoscopic incisional biopsy (EIB) for these small tumors. METHODS: This prospective study investigated 70 patients with small EUS-suspected gastric GISTs 2 cm or less in size in two stages. Firstly, 30 patients were recruited for the efficacy and safety evaluation of the EIB. Secondly, 40 patients were randomly assigned to receive either EIB or the bite-on-bite biopsy for comparison of the diagnostic yield, procedure time, and adverse event rate. RESULTS: Combining two study stages, leiomyoma (74%) was diagnosed histologically to outnumber GIST (26%) with a diagnostic rate of 94% for patients receiving EIB. KIT exon 11 mutations (50%) and PDGFRA exon 12 mutations (16%) were detected in the small gastric GISTs. In the direct comparison, the diagnostic yield of EIB and the bite-on-bite biopsy was 85% and 50%, respectively (P = 0.018). There was no statistically significant difference of the mean procedure time or adverse event rate between these two groups. CONCLUSIONS: Leiomyoma is more common than expected among these small tumors. Tissue diagnosis with an effective and safe sampling technique, such as EIB, is necessary for making further clinical decisions.

Endoscopic ultrasound-guided tissue acquisition with or without macroscopic on-site evaluation: randomized controlled trial.

BACKGROUND: The use of macroscopic on-site evaluation (MOSE) to estimate the adequacy of a specimen for histological diagnosis during endoscopic ultrasound (EUS)-guided fine-needle tissue acquisition (FNTA) has recently been advocated. This study aimed to evaluate the diagnostic yield of MOSE compared with conventional EUS-FNTA without rapid on-site evaluation (ROSE). METHODS: This was an international, multicenter, prospective, randomized controlled study. After providing informed consent, consecutive adult patients referred for EUS-FNTA for solid lesions larger than 2 cm were randomized to a MOSE arm or to a conventional arm without ROSE. A designated cytopathologist from each center performed all cytopathological examinations for that center and was blinded to the randomization results. The primary outcome measure was the diagnostic yield, and the secondary outcomes included sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy, and the rate of procedure-related complications. RESULTS: 244 patients (122 conventional, 122 MOSE) were enrolled during the study period. No significant differences between the two arms were found in procedure time or rate of procedure-related adverse events. The diagnostic yield for the MOSE technique (92.6 %) was similar to that for the conventional technique (89.3 %; P  = 0.37), with significantly fewer passes made (median: conventional 3, MOSE 2; P  < 0.001). CONCLUSIONS: EUS-FNTA with the MOSE technique provided a similar diagnostic yield to conventional EUS-FNTA technique in the absence of ROSE but with fewer passes. This technique can be used when ROSE is not available.

Multiple impacts of Naa10p on cancer progression: Molecular functions and clinical prospects.

Nα-acetyltransferase 10 protein (Naa10p) is known as the catalytic subunit of N-terminal acetyltransferases A (NatA) complex, associating with Naa15p to acetylate N-termini of the human proteome. Recent investigations have unveiled additional functions for Naa10p, encompassing lysine ε-acetylation and acetyltransferase-independent activities. Its pleiotropic roles have been implicated in diverse physiological and pathological contexts. Emerging evidence has implicated Naa10p in cancer progression, demonstrating dual attributes as an oncogene or a tumor suppressor contingent on the cancer type and acetyltransferase activity context. In this comprehensive review, we present a pan-cancer analysis aimed at elucidating the intricacies underlying Naa10p dysregulation in cancer. Our findings propose the potential involvement of c-Myc as a modulatory factor influencing Naa10p expression. Moreover, we provide a consolidated summary of recent advancements in understanding the intricate molecular underpinnings through which Naa10p contributes to cancer cell proliferation and metastasis. Furthermore, we delve into the multifaceted nature of Naa10p's roles in regulating cancer behaviors, potentially attributed to its interactions with a repertoire of partner proteins. Through an exhaustive exploration of Naa10p's functions, spanning its acetylation activity and acetyltransferase-independent functionalities, this review offers novel insights with implications for targeted therapeutic strategies involving this pivotal protein in the realm of cancer therapeutics.

Traits of Patients With Pituitary Tumors in Multiple Endocrine Neoplasia Type 1 and Comparing Different Mutation Status.

CONTEXT: Recent studies suggest that the clinical characteristics and biological behavior of pituitary tumors (PITs) in patients with multiple endocrine neoplasia type 1 (MEN1) may not be as aggressive as previously reported. Increased imaging of the pituitary as recommended by screening guidelines identifies more tumors, potentially at an earlier stage. However, it is unknown if these tumors have different clinical characteristics in different MEN1 mutations. OBJECTIVE: To assess characteristics of patients with MEN1 with and without PITs, and compare among different MEN1 mutations. METHODS: Data of patients with MEN1 in a tertiary referral center from 2010 to 2023 were retrospectively analyzed. RESULTS: Forty-two patients with MEN1 were included. Twenty-four patients had PITs, 3 of which were invasive and managed with transsphenoidal surgery. One PIT enlarged during follow-up. Patients with PITs had a higher median age at MEN1 diagnosis than those without PITs. MEN1 mutations were identified in 57.1% of patients, including 5 novel mutations. In patients with PITs, those with MEN1 mutations (mutation+/PIT+ group) had more additional MEN1-associated tumors than those without (mutation-/PIT+ group). The mutation+/PIT+ group had a higher incidence of adrenal tumors and a lower median age at initial manifestation of MEN1 than the mutation-/PIT+ group. The most common neuroendocrine neoplasm was nonfunctional in the mutation+/PIT+ group and insulin-secreting in the mutation-/PIT+ group. CONCLUSION: This is the first study comparing characteristics of patients with MEN1 with and without PITs harboring different mutations. Patients without MEN1 mutations tended to have less organ involvement and it might be reasonable for them to receive less intensive follow-up.

Annexin A1 is associated with gastric cancer survival and promotes gastric cancer cell invasiveness through the formyl peptide receptor/extracellular signal-regulated kinase/integrin beta-1-binding protein 1 pathway.

BACKGROUND: Annexin A1 (AnxA1) has been well-known as a glucocorticoid-regulated anti-inflammatory protein, and it is implicated in tumorigenesis in a tumor type-specific pattern. However, the role of AnxA1 in gastric cancer (GC) is indeterminate, and the underlying mechanism is not clear. The purpose of this study was to evaluate the prognostic significance and associated mechanism of AnxA1 in GC. METHODS: Immunohistochemical staining was employed to analyze 118 GC patients. Both AnxA1 gain-of-function and loss-of-function approaches were performed in GC cells. Western blotting and reverse-transcription polymerase chain reaction were used for assessment of the AnxA1 regulation mechanism in GC cells. An intraperitoneal inoculation model in severe combined immunodeficient mice was used for an in vivo assay. RESULTS: High AnxA1 expression was significantly associated with peritoneal metastasis (P = .009) and serosal invasion (P = .044). Cox multivariate analysis showed that high AnxA1 expression was an independent risk factor for poor overall survival in GC patients (P = .037). AnxA1 expression positively correlated with invasiveness of human GC cells both in vitro and in vivo. AnxA1 could regulate the GC cell invasion through the formyl peptide receptor (FPR)/extracellular signal-regulated kinase/integrin beta-1-binding protein pathway, and all 3 FPRs (FPR1 through FPR3) were involved in the regulation process. CONCLUSIONS: High AnxA1 expression was associated with more serosal invasion, more peritoneal metastasis, and poorer overall survival in GC patients. The current study demonstrated a novel mechanism involving FPRs, extracellular signal-regulated kinases 1 and 2, and integrin beta-1-binding protein 1 by which AnxA1 regulated GC cell invasion.

Suggested cutoff tumor size for management of small EUS-suspected gastric gastrointestinal stromal tumors.

BACKGROUND/PURPOSE: Although the incidence of asymptomatic small gastric submucosal tumors increased gradually with routine medical health examination, there was little clinical evidence for management consensus in these small gastric submucosal tumors including endoscopic ultrasound (EUS)-suspected gastric gastrointestinal stromal tumors (GISTs). We investigated the clinical course of small EUS-suspected gastric GISTs and propose a cutoff value of tumor size for treatment policy. METHODS: In this retrospective study, 50 patients with EUS-suspected gastric GISTs of sizes less than 3 cm were enrolled and were followed up by EUS at least twice over a period of more than 24 months (range 24-101 months). An at least 20% increase of the maximal diameter of the tumors was set as a significant change. RESULTS: Significant changes in tumor size were found during the follow-up in 14 patients (28.0%). The one-dimensional 20% change corresponded well to 50% change in two-dimensional area measurement (correlation coefficient = 0.929). The receiver operating characteristic curve analysis showed that the best cutoff size, associated with tumor progression, was 1.4 cm having an 85.7% sensitivity, 86.1% specificity, and 86.0% accuracy. A larger tumor size (35.7% vs. 2.8%, p = 0.005) and irregular tumor margin on the EUS (71.4% vs. 0, p = 0.004) were two significant factors associated with the progression of tumor growth of small suspected gastric GISTs. CONCLUSION: Small EUS-suspected GISTs, larger than 1.4 cm, with irregular margin were associated with significant progression. This subgroup is suggested to be monitored by more intensive follow-up.

Naa10p promotes cell invasiveness of esophageal cancer by coordinating the c-Myc and PAI1 regulatory axis.

N-α-acetyltransferase 10 protein, Naa10p, is involved in various cellular functions impacting tumor progression. Due to its capacity to acetylate a large spectrum of proteins, both oncogenic and tumor-suppressive roles of Naa10p have been documented. Here, we report an oncogenic role of Naa10p in promoting metastasis of esophageal cancer. NAA10 is more highly expressed in esophageal cancer tissues compared to normal tissues. Higher NAA10 expression also correlates with poorer survival of esophageal cancer patients. We found that NAA10 expression was transcriptionally regulated by the critical oncogene c-Myc in esophageal cancer. Furthermore, activation of the c-Myc-Naa10p axis resulted in upregulated cell invasiveness of esophageal cancer. This increased cell invasiveness was also elucidated to depend on the enzymatic activity of Naa10p. Moreover, Naa10p cooperated with Naa15p to interact with the protease inhibitor, PAI1, and prevent its secretion. This inhibition of PAI1 secretion may derive from the N-terminal acetylation effect of the Naa10p/Naa15p complex. Our results establish the significance of Naa10p in driving metastasis in esophageal cancer by coordinating the c-Myc-PAI1 axis, with implications for its potential use as a prognostic biomarker and therapeutic target for esophageal cancer.

Levofloxacin-based and clarithromycin-based triple therapies as first-line and second-line treatments for Helicobacter pylori infection: a randomised comparative trial with crossover design.

BACKGROUND: The efficacy of a levofloxacin-based regimen as the first-line treatment and a clarithromycin-based regimen as the second-line treatment for Helicobacter pylori infection remains unknown. The aim of this study was to assess the eradication rates of these two regimens using different administration sequences. METHODS: Eligible patients were randomised to receive LAL: levofloxacin (750 mg once a day), amoxicillin (1000 mg twice a day) and lansoprazole (30 mg twice a day) for 7 days, or CAL: clarithromycin (500 mg twice a day), amoxicillin (1000 mg twice a day) and lansoprazole (30 mg twice a day) for 7 days. Patients with positive [(13)C]urea breath test after treatment were retreated with the rescue regimen in a crossover manner for 10 days. RESULT: When used as first-line treatment (n=432), the eradication rates of LAL (n=217) and CAL (n=215) were 74.2 and 83.7% (p=0.015) in the intent-to-treat (ITT) analysis, and 80.1 and 87.4% (p=0.046) in the per-protocol (PP) analysis, respectively. When used as second-line treatment, the eradication rates of LAL (n=26) and CAL (n=40) were 76.9 and 60% (p=0.154) in the ITT analysis, and 80 and 61.5% (p=0.120) in the PP analysis, respectively. The overall eradication rates of CAL followed by LAL were better than the reverse sequence in both the ITT analysis (93% vs 85.3%, p=0.01) and the PP analysis (97.6% vs 92.5%, p=0.019). The eradication rate was significantly lower in the presence of levofloxacin resistance in the LAL group (50% vs 84.4%, p=0.018) and clarithromycin resistance in the CAL group (44.4% vs 90.7%, p=0.002). CONCLUSION: CAL achieved a higher eradication rate than LAL as the first-line treatment, but not as the second-line treatment. The strategy of using CAL as the initial treatment and LAL as the rescue regimen achieved higher eradication rates than the reverse sequence.

Indirect percutaneous core needle biopsy of solid pancreatic or peripancreatic lesions.

Solid pancreatic or peripancreatic lesions comprise a heterogeneous group of diseases that rely on a multimodality imaging approach for subsequent tissue procurement. Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA)/biopsy is an effective and safe method for tissue diagnosis in this region. The failure to obtain adequate tissue for diagnosis under EUS guidance is still a rare but important issue. Percutaneous core needle biopsy (CNB) provides an alternative pathway for adequate specimen acquisition. Because of the deep retroperitoneal location, the percutaneous biopsy of pancreatic or peripancreatic lesions may inevitably pass through visceral organs. The procedure is relatively risky and difficult for general radiologists, particularly beginners, and an adequate knowledge of the abdominal anatomy and biopsy technique is indispensable. In this review, various aspects of percutaneous CNB for solid pancreatic or peripancreatic lesions using different trans-organ approaches are reviewed to increase the chance of successful biopsy.

The surgery and repeat aspiration outcomes of the atypia of undetermined significance/follicular lesion of undetermined significance category in The Bethesda System for Reporting Thyroid Cytopathology.

BACKGROUND/OBJECTIVE: The atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category is one of six diagnostic categories of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). In this study, we report the diagnostic distribution of thyroid fine needle aspiration (FNA) cytology and analyze the outcome of AUS/FLUS cases. METHODS: A total of 29,937 thyroid FNA results, reported between April 2012 and December 2016, were retrieved from the database of a medical center. We reviewed the electronic medical records and analyzed the management of these patients. RESULTS: Overall frequency of AUS/FLUS is 3.1% in our laboratory, which is at the lower limit of the recommended range. Of these, 891 reports of AUS/FLUS from 770 patients were identified. Out of the 770 patients, 367 had surgical intervention. In these 367 patients, final surgical pathology yielded 204 (55.6%) malignancies, 12 indeterminateness (3.3%), and 151 (41.1%) benignity. Among these surgical patients, 113 (30.8%) had received a repeat FNA of the thyroid before thyroid resection. The difference between the malignancy rates among patients who directly received surgery after the first AUS/FLUS diagnosis (132 of 254, 52.0%) and patients having a repeat FNA before surgery (72 of 113, 63.7%) was not statistically significant. CONCLUSION: Our results are in agreement with AUS/FLUS diagnoses in less than 7% of specimens, and confirm that it is appropriate to perform either a repeat thyroid FNA or thyroid lobectomy, with the clinical decision being subject to the standardized management protocols of the second edition of TBSRTC in the AUS/FLUS category.

Analysis of fine-needle aspiration cytology of the salivary gland.

BACKGROUND/PURPOSE: Fine needle aspiration (FNA) cytology has been widely accepted as a safe method for diagnosis of salivary gland lesions. This study investigated the accuracy of FNA cytology of salivary gland lesions by correlation between histology and cytology. METHODS: One hundred and thirty-one archived salivary gland FNA specimens collected between January 1994 and December 2002 from 131 patients were correlated with histopathology findings. The major reasons for false-negative and false-positive results in cytologic diagnosis were determined. RESULTS: Considering the results of histopathology as the diagnostic standard, the sensitivity of FNA cytology in diagnosing malignancy was 74% (17/23) after excluding two cases which had a cytodiagnosis of suspicion of malignancy. Excluding eight cases that had a cytodiagnosis of suspicion of malignancy, the diagnostic specificity was 99% (97/98). There were six false-negative and one false-positive cases. CONCLUSION: This study demonstrated that FNA cytology of the salivary gland is a useful technique for diagnosis of salivary gland lesions. Inadequate labeling of the aspiration sites and insufficient cellularity were the most important factors that resulted in incorrect cytologic interpretation.

Pyruvate kinase M2 promotes pancreatic ductal adenocarcinoma invasion and metastasis through phosphorylation and stabilization of PAK2 protein.

Pyruvate kinase muscle isozymes (PKMs) have crucial roles in regulating metabolic changes during carcinogenesis. A switch from PKM1 to PKM2 isoform was thought to lead to aerobic glycolysis promoting carcinogenesis, and was considered as one of the cancer signatures. However, recent evidence has argued against the existence of PKM isoform switch and related metabolic effects during cancer progression. We compared the effects of PKM1 and PKM2 in cell invasiveness and metastasis of pancreatic ductal adenocarcinoma (PDAC). Both PKM1 and PKM2 expression affected cell migration and invasion abilities of PDAC cells, but only knockdown of PKM2 suppressed metastasis in a xenograft model. By comparing the established PKM2 mutants in the regulation of cell invasion, we found that PKM2 may control cell mobility through its protein kinase and phopho-peptide binding abilities. Further survey for PKM2-associated proteins identified PAK2 as a possible phosphorylation target in PDAC. In vitro binding and kinase assays revealed that PKM2 directly phosphorylated PAK2 at Ser20, Ser141, and Ser192/197. Knockdown of PKM2 decreased PAK2 protein half-life by increasing ubiquitin-dependent proteasomal degradation. Moreover, we identified PAK2 as an HSP90 client protein and the mutation at Ser192/197 of PAK2 reduced PAK2-HSP90 association. Knockdown of PAK2 diminished in vitro cell mobility and in vivo metastatic ability of PKM2 overexpressed PDAC cells. PKM2 and PAK2 protein expression also positively correlated with each other in PDAC tissues. Our findings indicate that PKM2-PAK2 regulation is critical for developing metastasis in PDAC, and suggest that targeting the PKM2/HSP90/PAK2 complex has a potential therapeutic value in this deadly disease.

Nuclear translocation of PKM2/AMPK complex sustains cancer stem cell populations under glucose restriction stress.

Cancer cells encounter metabolic stresses such as hypoxia and nutrient limitations because they grow and divide more quickly than their normal counterparts. In response to glucose restriction, we found that nuclear translocation of the glycolic enzyme, pyruvate kinase M2 (PKM2), helped cancer cells survive under the metabolic stress. Restriction of glucose stimulated AMPK activation and resulted in co-translocation of AMPK and PKM2 through Ran-mediated nuclear transport. Nuclear PKM2 subsequently bound to Oct4 and promoted the expression of cancer stemness-related genes, which might enrich the cancer stem cell population under the metabolic stress. Nuclear PKM2 was also capable of promoting cancer metastasis in an orthotopic xenograft model. In summary, we found that cytosolic AMPK helped PKM2 carry out its nonmetabolic functions in the nucleus under glucose restriction and that nuclear PKM2 promoted cancer stemness and metastasis. These findings suggested a potential new targeting pathway for cancer therapy in the future.

Low accuracy of chromogranin A for diagnosing early-stage pancreatic neuroendocrine tumors.

The aim of the present study was to evaluate the clinical utility of plasma chromogranin A (CgA) in patients diagnosed with early-stage pancreatic neuroendocrine tumors (PNETs) in terms of diagnostic value and treatment response. A total of 35 patients with PNETs were prospectively enrolled from August 2010 to April 2014. Demographic and clinicopathological data were collected, and serial plasma CgA levels were measured. Tumor responses were defined by the Response Evaluation Criteria In Solid Tumors criteria. Pearson's χ2 test was used for the analysis of the association between the plasma CgA level and various factors. Plasma CgA level was significantly associated with the size (P=0.03), metastasis (P=0.02) and tumor stage (P=0.03) of the PNETs. Using 126 U/l as the optimal cutoff value, the sensitivity and specificity were 87.5 and 81.5%, respectively. For localized tumors, the sensitivity of CgA for diagnosing PNETs was relatively low, even following a lowering of the cutoff values (29.6-51.9%). Plasma CgA level was correlated with therapeutic response in those patients with high baseline CgA levels (P=0.025), but not in the patients with low baseline CgA levels (P=0.587). In conclusion, plasma CgA level was associated with tumor size, metastasis and tumor stage in patients with PNET. For early-stage PNETs, CgA exhibited a limited role in diagnosis and treatment response evaluation in the population of the present study.

Clinical features and outcomes of gastric neuroendocrine tumors after endoscopic diagnosis and treatment: A Digestive Endoscopy Society of Tawian (DEST).

Gastric neuroendocrine tumors (GNETs) are a heterogeneous group of neoplasm with varying biological characteristics. This study aimed to investigate the clinical features and outcomes of GNET patients after endoscopic diagnosis and treatment in a multicenter registry. Patients with GNETs confirmed histologically were recruited from 17 hospitals between January 2010 and April 2016 in Taiwan. Clinical, laboratory, radiological, endoscopic, pathological data, treatment strategies, follow-up periods, and survivals were collected retrospectively. Totally 187 (107 female, 80 male) patients were recruited. Mean ( ±â€Šstandard deviation [SD]) age and size of tumors were 63.2-year-old ( ±â€Š14.6) and 2.3-cm ( ±â€Š3.0). World Health Organization (WHO) grading were 93 (49.7%) G1, 26 (13.9%) G2, 40 (21.4%) G3, and 28 (15.0%) unknown. G3 patients were older (mean ±â€ŠSD, 71.6 ±â€Š12.4 vs. 60.9 ±â€Š14.3/56.7 ±â€Š15.4 years), larger (6.1 ±â€Š4.0 vs.1.2 ±â€Š1.3/2.4 ±â€Š2.5 cm), more distally located (35.0% vs. 7.6%/15.4%), lower proportion of superficial lesions (17.5% vs. 61.9%/53.8%) and higher rates of lymphovascular invasion (32.5% vs. 3.2%/7.7%) than G1/G2. There was no nodal or distant organ metastases despite different grading of lesions≦10 mm and those <20 mm limited to mucosa and submucosa layers. GNETs larger than 20 mm with G1, G2, and G3 had lymph node (LN) metastatic rates of 21.4%, 30.0%, and 59.3%, respectively. Survivals were different between grading for those >20 mm (log-rank test P = .02). Male gender (P = .01), deeper invasion (P = .0001), nodal (P < .0001), and distant organ metastases (P = .0001) were associated with worse outcome. In conclusion, treatment strategies for GNET should be decided by grading, size, invasiveness, and LN metastasis risk. Curative endoscopic resection is feasible for G1/2 lesions less than 20 mm and limited to mucosa/submucosa layers without lymphovascular invasion.