Possibility Of Lymph Node Metastasis Research Articles

Potential for Metastasis and Recurrence in Colorectal Carcinoma In Situ: A Retrospective Analysis of 1069 Patients

BackgroundColorectal carcinoma in situ, characterized by cancer limited to the intramucosal layer or known as intraepithelial carcinoma, has conventionally considered to be without any risk of regional lymph node metastasis. However, isolated cases of regional lymph node metastasis, local recurrence, and distant metastasis challenge this assumption. This study aimed to assess the occurrence of regional lymph node metastasis and recurrence of colorectal carcinoma in situ. MethodsA retrospective analysis was conducted in 1069 patients who underwent full-thickness local excision or radical surgery for colorectal carcinoma in situ between January 1994 and December 2020. Histopathological features were assessed by 2 experienced pathologists. In cases of suspected recurrence, evaluation involved abdomen-pelvis and chest computed tomography, or PET-CT. ResultsThe recurrence rate of Tis patients was 0.46%. Among the patients, 9 were diagnosed with regional lymph node metastasis or cancer recurrence. Of these, 4 patients were diagnosed with lymph node metastasis during primary surgery; 2 exhibited regional lymph node metastasis, and 2 presented with both regional and distant lymph node metastases. Regional lymph node metastasis occurred in additional 2 patients after radical surgery for the primary tumor. Distant metastasis was observed in 3 patients: hepatic metastasis in 1, hepatic and pulmonary metastases in another, and small bowel metastasis in the third patient. Among the 5 patients experiencing cancer recurrence, 1 expired due to cancer progression. ConclusionContrary to previous assumptions, colorectal carcinoma in situ can potentially metastasize to lymph nodes and recur. Therefore, careful assessment at the time of diagnosis is crucial, recognizing the possibility of lymph node metastasis or recurrence. This approach is essential for accurately identifying instances of cancer recurrence and ensuring optimal oncological outcomes.

Development and validation of a nomogram for predicting lymph node metastasis in ductal carcinoma in situ with microinvasion: A SEER population-based study.

Ductal carcinoma in situ with microinvasion (DCIS-MI) is a special type of breast cancer. It is an invasive lesion less than 1.0 mm in size related to simple ductal carcinoma in situ (DCIS). Lymph node metastasis (LNM) in DCIS-MI often indicates a poor prognosis. Therefore, the management of lymph nodes plays a vital role in the treatment strategy of DCIS-MI. Since DCIS-MI is often diagnosed by postoperative paraffin section and immunohistochemical detection, to obtain the best clinical benefits for such patients, we aim to establish and verify a nomogram to predict the possibility of lymph node metastasis in DCIS-MI patients and help preoperative or intraoperative clinical decision-making. A retrospective analysis of patients with DCIS-MI in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2019 was performed. The study cohort was randomly divided into a training cohort and a validation cohort at a ratio of 7:3. The risk factors were determined by univariate and multivariate logistic regression analyses in the training cohort, and a nomogram was constructed. The receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the nomogram in the training set and validation set. An independent data cohort was obtained from the Shanghai Jiao Tong University Breast Cancer Database (SJTU-BCDB) for external validation. This study included 3951 female patients from SEER with DCIS-MI, including 244 patients with regional lymph node metastasis, accounting for 6.18% of the total. An independent test set of 323 patients from SJTU-BCDB was used for external validation. According to the multifactorial logistic regression analysis results, age at diagnosis, ethnicity, grade, and surgical modality were included in the prediction model. The areas under the ROC curves (AUCs) were 0.739 (95% CI: 0.702~0.775), 0.732 (95% CI: 0.675~0.788), and 0.707 (95%CI: 0.607-0.807) in the training, validation and external test groups, suggesting that the column line graphs had excellent differentiation. The calibration curves slope was close to 1, and the model's predicted values were in good agreement with the actual values. The DCA curves showed good clinical utility. In this study, we constructed accurate and practical columnar maps with some clinical benefit to predict the likelihood of lymph node metastasis in patients with postoperatively diagnosed DCIS-MI and provide a reference value for specifying treatment strategies.

A discrimination model by machine learning to avoid gastrectomy for early gastric cancer.

Gastrectomy is recommended for patients with early gastric cancer (EGC) because the possibility of lymph node metastasis (LNM) cannot be completely denied. The aim of this study was to develop a discrimination model to select patients who do not require surgery using machine learning. Data from 382 patients who received gastrectomy for gastric cancer and who were diagnosed with pT1b were extracted for developing a discrimination model. For the validation of this discrimination model, data from 140 consecutive patients who underwent endoscopic resection followed by gastrectomy, with a diagnosis of pT1b EGC, were extracted. We applied XGBoost to develop a discrimination model for clinical and pathological variables. The performance of the discrimination model was evaluated based on the number of cases classified as true negatives for LNM, with no false negatives for LNM allowed. Lymph node metastasis was observed in 95 patients (25%) in the development cohort and 11 patients (8%) in the validation cohort. The discrimination model was developed to identify 27 (7%) patients with no indications for additional surgery due to the prediction of an LNM-negative status with no false negatives. In the validation cohort, 13 (9%) patients were identified as having no indications for additional surgery and no patients with LNM were classified into this group. The discrimination model using XGBoost algorithms could select patients with no risk of LNM from patients with pT1b EGC. This discrimination model was considered promising for clinical decision-making in relation to patients with EGC.

Pretreatment carcinoembryonic antigen combined with cancer antigen-125 for predicting lymph node metastasis in endometrial carcinoma: a retrospective cohort study.

To investigate whether the cost-effective, pretreatment tumor markers carcinoembryonic antigen (CEA) and carbohydrate antigen-125 (CA-125) can be used to predict lymph node metastasis (LNM) in endometrioid-type endometrial cancer (EC) and to develop a predictive model. This was a single-center retrospective study of patients with endometrioid-type EC who underwent complete staging surgery between January 2015 and June 2022. We identified the optimal cut-off values of CEA and CA-125 for predicting LNM using receiver operating characteristic (ROC) curves. Stepwise multivariate logistic regression analysis was used to identify independent predictors. A nomogram for predicting LNM was constructed and validated by bootstrap resampling. The optimal cut-off values of CEA and CA-125 were 1.4ng/mL (area under the ROC curve (AUC) 0.62) and 40 U/mL (AUC 0.75), respectively. Multivariate analysis showed that CEA (odds ratio (OR) 1.94; 95% confidence interval (CI) 1.01-3.74) and CA-125 (OR 8.75; 95% CI 4.42-17.31) were independent predictors of LNM. Our nomogram showed adequate discrimination with a concordance index of 0.78. Calibration curves for the probability of LNM showed optimal agreement between the predicted and actual probabilities. The risk of LNM for markers below the cut-offs was 3.6%. The negative predictive value and negative likelihood ratio were 96.6% and 0.26, respectively, with moderate ability to rule out the possibility of LNM. We report a cost-effective method of using pretreatment CEA and CA-125 levels to identify patients with endometrioid-type EC who are at a low risk for LNM, which may guide decision-making regarding aborting lymphadenectomy.

Nomogram for pre-procedural prediction of non-curative endoscopic resection in patients with early gastric cancer

BackgroundNon-curative resection (non-CR) after endoscopic submucosal dissection (ESD) requires additional surgery due to the possibility of lymph node metastasis (LNM). Therefore, it is important to accurately predict the risk of non-CR to avoid unnecessary preoperative procedures. Thus, we aimed to develop and verify a nomogram to predict the risk of non-CR prior to ESD.MethodsPatients who underwent ESD for early gastric cancer (EGC) were divided into CR and non-CR groups based on the present ESD criteria. The pre-procedural factors, such as endoscopic features, radiologic findings, and pathology of the lesion, were compared between the groups to identify the risk factors associated with non-CR. A nomogram was developed using multivariate analysis, and its predictive value was assessed using an external validation group.ResultsAmong 824 patients, 682 were curative (82.7%) and 142 were non-curative (17.3%). By comparing two groups, endoscopic features including redness, whitish mucosal change, fold convergence, and large lesion size; histologic features such as moderately or poorly differentiated or signet ring cell carcinoma; and abnormal CT findings including non-specific lymph node enlargement and fold thickening were identified as significant predictors of non-CR. The nomogram was developed based on these predictors and showed good predictive performance in the external validation, with an area under the curve of 0.87.ConclusionsWe developed a nomogram to predict the risk of non-CR prior to ESD. These predictive factors in addition to the existing ESD criteria can help provide the best treatment option for patients with EGC.

A Nomogram Based on Atelectasis/Obstructive Pneumonitis Could Predict the Metastasis of Lymph Nodes and Postoperative Survival of Pathological N0 Classification in Non-small Cell Lung Cancer Patients

NSCLC patients over 20 years old diagnosed between 2004 and 2015 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. The nomograms were based on risk factors that were identified by Logistic regression. The area under the receiver operating characteristic (ROC) curve (AUC) was performed to confirm the predictive values of our nomograms. Cox proportional hazards analysis and Kaplan-Meier survival analysis were also used in this study. A total of 470,283 patients were enrolled. Atelectasis/obstructive pneumonitis, age, gender, race, histologic types, grade, and tumor size were defined as independent predictive factors; then, these seven factors were integrated to establish nomograms of LNM. The AUC is 0.70 (95% CI: 0.694-0.704). Moreover, the Cox proportional hazards analysis and Kaplan-Meier survival analysis showed that the scores derived from the nomograms were significantly correlated with the survival of pathological N0 classification. Nomograms based on atelectasis/obstructive pneumonitis were developed and validated to predict LNM and the postoperative prognosis of NSCLC.

The Different Evaluative Significance of Enlarged Lymph Nodes on Preoperative CT in the N Stage for Patients with Suspected Subsolid and Solid Lung Cancers

To investigate the clinical value of enlarged mediastinal and/or hilar lymph nodes on CT for patients with lung subsolid and solid nodules. The study was performed on patients who underwent surgical treatment for suspected lung cancer. One hundred seventeen subsolid nodules and 101 solid nodules with enlarged lymph nodes (LNs) were included in the study group. The same number of cases with normal LNs with a balanced distribution of the clinical T stage were randomly selected as the control group for each study group. The pathological statuses of the lymph nodes of these patients proven by histopathology after surgery were collected. Lung solid lesions with enlarged LNs were more prone to lymph node metastasis (37.6% vs. 13.9%, p <0.001). However, there were only two and one metastatic lesions in the subsolid group with and without enlarged LNs, respectively. (2/117 vs. 1/117, p=1.000). No pathological lymph node metastasis was observed in subsolid lesions under clinical stage T1b (cT1b), even though some of them (117/234) with enlarged LNs. The evaluative significance of enlarged LNs on CT is different for subsolid and solid lesions. CT is useful for lymph node evaluation and N staging of solid lesions but may has little value for subsolid lesions. There is a very low possibility of lymph node metastasis occurring in patients with subsolid lesions under cT1b. Enlarged LNs on CT may not be critical in subsequent management and treatment for subsolid nodules.

Endoscopic Treatment of Superficial Gastric Cancer: Present Status and Future.

Although the mortality rates of gastric cancer (GC) are gradually declining, gastric cancer is still the fourth leading cause of cancer-related death worldwide. This may be due to the high rate of patients who are diagnosed with GC at advanced stages. However, in countries such as Japan with endoscopic screening systems, more than half of GCs are discovered at an early stage, enabling endoscopic resection (ER). Especially after the introduction of endoscopic submucosal dissection (ESD) in Japan around 2000, a high en bloc resection rate allowing pathological assessment of margin and depth has become possible. While ER is a diagnostic method of treatment and may not always be curative, it is widely accepted as standard treatment because it is less invasive than surgery and can provide an accurate diagnosis for deciding whether additional surgery is necessary. The curability of ER is currently assessed by the completeness of primary tumor removal and the possibility of lymph node metastasis. This review introduces methods, indications, and curability criteria for ER of EGC. Despite recent advances, several problems remain unsolved. This review will also outline the latest evidence concerning future issues.

A metastatic G2 neuroendocrine tumor smaller than 5 mm: A case report

BackgroundNeuroendocrine tumors (NETs) measuring <10 mm are widely thought to be at low risk of lymph node metastasis. Here we report a case of lymph node metastasis in a patient with a 4-mm NET that was classified as grade 2.Presentation of caseA 32-year-old woman was referred to our hospital after a positive fecal occult blood test. Colonoscopy revealed a 4-mm yellowish submucosal tumor, which was diagnosed as NET of the upper rectum and removed by endoscopic submucosal resection with ligation. Pathological examination of the specimen showed a 4-mm grade 2 NET with a Ki-67 labeling index of 4.4% without lymphatic or venous invasion. In accordance with the European Neuroendocrine Tumor Society guidelines, we performed robotic-assisted laparoscopic low anterior resection with lymph node dissection. Final pathological examination revealed invasion confined to the submucosal layer and metastasis to one lymph node (pT1aN1M0, Stage IIIB). There were no residual tumor cells in the scar after endoscopic submucosal resection with ligation.DiscussionShould G2 neuroendocrine tumors smaller than 5 mm be surgically resected?ConclusionsWe encountered a rare case of a small NET with lymph node metastasis that was treated by robotic-assisted laparoscopic low anterior resection with lymph node dissection. Additional surgery is an option to be considered for grade 2 NET even if it is small because of the possibility of lymph node metastasis.

Endoscopic resection for gastrointestinal tumors (esophageal, gastric, colorectal tumors): Japanese standard and future prospects.

Endoscopic resection (ER) techniques such as polypectomy, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are widely accepted as a less invasive treatment for gastrointestinal (GI) tumors. Since there is a limit to the size that can be resected by EMR and it is often divided, it is not possible to accurately evaluate the degree of cancer progression, and the cancer remains or causes recurrence. ESD is a technology that overcomes these weaknesses. ER techniques are considered for tumors that have a very low possibility of lymph node metastasis and are suitable for en-bloc resection. As ESD became more widespread, the difficulty of treating ESD was gradually resolved by the development of technology and equipment, the curative resection rate increased, and the complication rate decreased. ER techniques have become the standard treatment for early cancer and precancerous lesions in Japan, and the therapeutic indications are expanding day by day. The indications for whether endoscopic treatment can be performed are defined by the guidelines for each organ such as the esophagus, stomach, and colorectum. In the coming aging society, it is also necessary to evaluate the indications for endoscopic treatment and invasive treatment. In addition, recent advances in endoscopic technology are making it possible to remove submucosal tumors that previously required surgery. In this review, we summarize the recent Japanese standard indications of ER for each GI location and future prospects of ER.

A genomic-clinicopathologic Nomogram for the preoperative prediction of lymph node metastasis in gastric cancer

BackgroundPreoperative evaluation of lymph node (LN) state is of pivotal significance for informing therapeutic decisions in gastric cancer (GC) patients. However, there are no non-invasive methods that can be used to preoperatively identify such status. We aimed at developing a genomic biosignature based model to predict the possibility of LN metastasis in GC patients.MethodsWe used the RNA profile retrieving strategy and performed RNA expression profiling in a large GC cohort (GSE62254, n = 300) from Gene Expression Ominus (GEO). In the exploratory stage, 300 GC patients from GSE62254 were involved and the differentially expressed RNAs (DERs) for LN-status were determined using the R software. GC samples in GSE62254 were randomly allocated into a learning set (n = 210) and a verification set (n = 90). By using the Least absolute shrinkage and selection operator (LASSO) regression approach, a set of 23-RNA signatures were established and the signature based nomogram was subsequently built for distinguishing LN condition. The diagnostic efficiency, as well as the clinical performance of this model were assessed using the decision curve analysis (DCA). Metascape was used for bioinformatic analysis of the DERs.ResultsBased on the genomic signature, we established a nomogram that robustly distinguished LN status in the learning (AUC = 0.916, 95% CI 0.833–0.999) and verification sets (AUC = 0.775, 95% CI 0.647–0.903). DCA demonstrated the clinical value of this nomogram. Functional enrichment analysis of the DERs was performed using bioinformatics methods which revealed that these DERs were involved in several lymphangiogenesis-correlated cascades.ConclusionsIn this study, we present a genomic signature based nomogram that integrates the 23-RNA biosignature based scores and Lauren classification. This model can be utilized to estimate the probability of LN metastasis with good performance in GC. The functional analysis of the DERs reveals the prospective biogenesis of LN metastasis in GC.

Deficiency of NEIL3 Enhances the Chemotherapy Resistance of Prostate Cancer.

Acquired treatment resistance is an important cause of death in prostate cancer, and this study aimed to explore the mechanisms of chemotherapy resistance in prostate cancer. We employed castration-resistant prostate cancer (CRPC), neuroendocrine prostate cancer (NEPC), and chemotherapy-resistant prostate cancer datasets to screen for potential target genes. The Cancer Genome Atlas (TCGA) was used to detect the correlation between the target genes and prognosis and clinical characteristics. Nei endonuclease VIII-like 3 (NEIL3) knockdown cell lines were constructed with RNA interference. Prostate cancer cells were treated with enzalutamide for the androgen deprivation therapy (ADT) model, and with docetaxel and cisplatin for the chemotherapy model. Apoptosis and the cell cycle were examined using flow cytometry. RNA sequencing and western blotting were performed in the knockdown Duke University 145 (DU145) cell line to explore the possible mechanisms. The TCGA dataset demonstrated that high NEIL3 was associated with a high T stage and Gleason score, and indicated a possibility of lymph node metastasis, but a good prognosis. The cell therapy models showed that the loss of NEIL3 could promote the chemotherapy resistance (but not ADT resistance) of prostate cancer (PCa). Flow cytometry revealed that the loss of NEIL3 in PCa could inhibit cell apoptosis and cell cycle arrest under cisplatin treatment. RNA sequencing showed that the knockdown of NEIL3 changes the expression of neuroendocrine-related genes. Further western blotting revealed that the loss of NEIL3 could significantly promote the phosphorylation of ATR serine/threonine kinase (ATR) and ATM serine/threonine kinase (ATM) under chemotherapy, thus initiating downstream pathways related to DNA repair. In summary, the loss of NEIL3 promotes chemotherapy resistance in prostate cancer, and NEIL3 may serve as a diagnostic marker for chemotherapy-resistant patients.

A Clinical Nomogram for Predicting Lymph Node Metastasis in Penile Cancer: A SEER-Based Study.

Purpose: We developed a nomogram to predict the possibility of lymph node metastasis in patients with squamous cell carcinoma of the penis.Methods: Identifying patients with squamous cell carcinoma of the penis diagnosed between 2004 and 2015 in the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate analyses were carried out by logistic regression to assess significant predictors associated with lymph node metastasis. A nomogram was established and validated by a calibration plot and receptor operating characteristic curve (ROC) analysis.Results: A total of 1,016 patients with penile squamous cell carcinoma (SCCP) were enrolled in this study. One hundred and ninety-five patients (19%) had lymph node involvement (N1-3). Multivariate analysis showed that age, primary tumor site, grade, tumor size, and T stage were identified as being significantly (p < 0.05) associated with lymph node involvement. All the above factors that showed a statistically significant predictive capability were selected for building the nomogram. This model had a calibration slope of 0.9 and a c-index of 0.776, indicating the good discrimination and effectiveness of the nomogram in predicting lymph node status.Conclusion: Although the prediction model has some limitations, the nomogram revealed the relationship between the clinicopathological characteristics of SCCP patients and the risk of lymph node metastasis. This tool will assist patients in counseling and guide treatment decisions for SCCP patients.

Comparison between endoscopic submucosal resection and surgery for the curative resection of undifferentiated-type early gastric cancer within expanded indications: a nationwide multi-center study

Endoscopic submucosal dissection (ESD) for undifferentiated early gastric cancer (UD EGC) has debate due to the risk of lymph node metastasis. We investigated the outcomes of ESD compared to those of surgery for the UD EGC within expanded indication.We reviewed 971 UD EGC patients performed ESD across 18 hospitals in Korea and 1812 patients who underwent surgical resection in two hospitals between February 2005 and May 2015. Of these cases, we enrolled a curative resected ESD group of 328 patients and surgery group of 383 cases within an expanded indication. Overall outcomes and one-to-one propensity score-matched (218 ESD group vs 218 surgery group cases) outcomes for these two groups were analyzed.Over the 75.6 month median follow-up period for the 711 enrolled cases, recurrences occurred in 22 patients (6.7%) in the ESD group but not in the surgery group. Overall survival (OS) was higher in the surgery group (p = 0.0316) in all cases, but there was no significant difference after propensity score matching (p = 0.069). According to the histologic type in propensity score matching, the OS of signet ring cell carcinoma and poorly differentiated carcinoma patients did not differ between the ESD and surgery groups (p = 0.1189 and p = 0.3087, respectively). In the surgery group involving expanded criteria, lymph node metastasis was found in six cases (1.56%).Although ESD shows comparable outcomes to surgery for the UD EGC within expanded indications, appropriate patient selection is needed for the ESD due to the possibility of lymph node metastasis.

Clinical practice guideline for endoscopic resection of early gastrointestinal cancer.

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Usefulness of sentinel lymph node mapping using indocyanine green and fluorescent imaging in the diagnosis of lymph node metastasis in endometrial cancer

The lymph node status is the most important prognostic factor for endometrial cancer. This study aimed to assess whether sentinel lymph node mapping (SLNM) is applicable in endometrial cancer. A retrospective review of patients with endometrial cancer who were diagnosed and treated in Asan Medical Centre from September 2015 to December 2017 was conducted. One hundred patients underwent robotic (da Vinci®) or laparoscopic surgical treatment, including SLNM with indocyanine green (ICG) fluorescence detection using the Firefly® and NIR/ICG systems. At least one lymph node area was observed in 100% of SLNM cases. Sentinel node detection and frozen biopsy were performed in all cases, and all patients with metastasis were found on SLNM. The sensitivity and negative predictive value were both 100% in the patient-by-patient and station-by-station analyses. SLNM appears to be a feasible method to reduce the morbidity and increase the detection rate in early-stage endometrial carcinoma. What is already known on this subject? There are studies that it is safe to diagnose the possibility of lymph node metastasis through sentinel lymph node mapping in endometrial cancer. What do the results of this study add? In this study, it is shown that the accuracy of sentinel lymph node mapping is 100% accurate. What are the implications of these findings for clinical practise and/or further research? Therefore, total lymphadenectomy will not be necessary for the future.

Persistent Lymph Node Metastasis Post Imatinib Treatment in Low Grade Gastrointestinal Stromal Tumor with PDGFRA Mutation

Background/Aims: Lymph node metastasis has been considered very rare in gastrointestinal stromal tumors (GIST), especially in low grade GIST. Thus, lymphadenectomy is not required routinely as standard of care during surgery for GIST unless there is suspicion for lymph node metastasis. However, herein we present a low grade PDGFRA mutated GIST status post imatinib chemotherapy with nearly complete response in the primary tumor but a persistent lymph node metastasis which significantly affected the management of the patient. Case Report: A 38-year-old male presented with a 11.5 cm epigastric GIST status post imatinib (Gleevec) treatment who underwent partial gastrectomy with tumor excision. The initial biopsy showed epithelioid type GIST with a low mitotic rate and PDGFRA gene mutation detected by genetic analysis. The original tumor had nearly complete response to imatinib with a few possible residual tumor cells identified; however, one lymph node was found to be positive for metastatic GIST with minimal treatment effect present. The patient was managed with continuous imatinib treatment and life-long follow up. Conclusion: This case raises the awareness of the possibility of lymph node metastasis in low grade conventional GIST with PDGFRA mutation. Lymph node examination may need to be considered as standard of care for better management of patients with GIST.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Tu1108 FEASIBILITY OF ENDOLOOP CLOSURE AFTER GASTRIC ENDOSCOPIC SUBMUCOSAL DISSECTION TO PREVENT DELAYED BLEEDING IN PATIENTS RECEIVING ANTITHROMBOTIC THERAPY

Endoscopic submucosal dissection (ESD) has been established as a standard treatment for early gastric cancer without the possibility of lymph node metastasis. However, adverse events, such as post-ESD bleeding occurs approximately 5%. In particular, antithrombotic therapy increases the rate of post-ESD bleeding to about 21-38%. Therefore, effective methods for prevention of post-ESD bleeding are desirable. The aim of this study was to assess the efficacy of endoloop closure (ELC) using endoloops and clips in preventing post-ESD bleeding among patients receiving antithrombotic therapy. This study was a nonrandomized, retrospective, single-center study of 1634 early gastric cancers among 1163 patients who were treated by ESD from March 2016 to January 2019. Patients who were taking antithrombotic agents were reviewed. Antithrombotic agents were defined as antiplatelet agents (low-dose aspirin, cilostazol, thienopyridine derivatives) or anticoagulants (warfarin, direct oral anticoagulants) . Exclusion criteria were follows; (1) other upper gastrointestinal endoscopic intervention within 28 days; (2) with an advanced gastric cancer; (3) who underwent ESD for multiple lesions; (4) another prevention after ESD (covering using polyglycolic acid sheets or clip closure). We divided the patients into two groups; ELC group and control group (no preventive treatment). We compared the post-ESD bleeding rates between the two groups. A total of the 178 patients were included, 37 patients underwent ELC and 141 patients were control. Post-ESD bleeding occurred in 8.1% (3/37) and 22.7% (32/141) in the ELC and control groups, respectively; there was no significant difference between the two groups (p=0.06). However, subgroup analysis showed significant difference. Post-ESD bleeding in the resected specimen less than 40 mm occurred in 0% (0/26) lesions in the ELC group and in 16% (12/75) lesions in the control group (p=0.03). Post-ESD bleeding in multiple antithrombotic agents occurred in 10% (1/10) lesions in the ELC group and 70% (7/10) lesions in the control group (p=0.02). Closure using endoloop and endoclips after gastric ESD would prevent post-ESD bleeding in patients receiving antithrombotic therapy, particularly in those with resected specimen <40 mm and among patients undergoing treatment with multiple antithrombotic agents.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.