Clinical outcomes of early gastric cancer with non-curative resection after pathological evaluation based on the expanded criteria

Korean Practice Guidelines for Gastric Cancer 2024: An Evidence-based, Multidisciplinary Approach (Update of 2022 Guideline)

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area. Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version. Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Management Strategy of Non-curative ESD in Gastric Cancer: Curative Criteria, and the Critical Building Block for Determining Beyond It

Endoscopic submucosal dissection is performed in cases of early gastric cancer, where the risk of lymph node metastasis (LNM) is expected to be negligible, and 12%-21% of these patients are deemed to have undergone non-curative resections based on pathological criteria. In such cases, decisions regarding additional treatments must be made to maximize curability, depending on the anticipated LNM risk. Well-established risk factors for LNM include lymphatic invasion, vascular invasion, deep submucosal invasion, positive vertical margins, and larger tumor size. When pathological factors associated with a clear LNM risk, such as lymphatic or deep submucosal invasion, are present, additional gastrectomy with lymph node dissection should be considered. Conversely, in cases involving only a positive horizontal margin, additional endoscopic treatment may be an effective therapeutic option as opposed to gastrectomy because of the negligible risk of LNM despite the potential risk of residual tumors. Endoscopic resection is particularly advantageous for determining complete resection. In addition to pathological curability, patient-specific factors, such as age and comorbidities, must be considered. Several retrospective cohort studies have shown that the cause of mortality among patients placed only on observation without additional treatment after non-curative resection is generally related to underlying conditions irrelevant to gastric cancer. Thus, it is crucial to assess both GC-specific mortality and all-cause mortality to finalize treatment decisions that help minimize such mortality. Therefore, new treatment algorithms that integrate pathological curability with patient-specific factors must be developed.

Predicting residual neoplasia after a non-curative gastric ESD: validation and modification of the eCura system in the Western setting: the W-eCura score

OBJECTIVE

To evaluate the risk factors for lymph node metastasis (LNM) after a non-curative (NC) gastric endoscopic submucosal dissection (ESD) and to validate and eventually refine the eCura scoring system in the Western setting. Also, to assess the rate and risk factors for parietal residual disease.

DESIGN

Retrospective multicentre multinational study of prospectively collected registries from 19 Western centres. Patients who had been submitted to surgery or had at least one follow-up endoscopy were included. The eCura system was applied to assess its accuracy in the Western setting, and a modified version was created according to the results (W-eCura score). The discriminative capacities of the eCura and W-eCura scores to predict LNM were assessed and compared.

RESULTS

A total of 314 NC gastric ESDs were analysed (72% high-risk resection (HRR); 28% local-risk resection). Among HRR patients submitted to surgery, 25% had parietal disease and 15% had LNM in the surgical specimen. The risk of LNM was significantly different across the eCura groups (areas under the receiver operating characteristic curve (AUC-ROC) of 0.900 (95% CI 0.852 to 0.949)). The AUC-ROC of the W-eCura for LNM (0.916, 95% CI 0.870 to 0.961; p=0.012) was significantly higher compared with the original eCura. Positive vertical margin, lymphatic invasion and younger age were associated with a higher risk of parietal residual lesion in the surgical specimen.

CONCLUSION

The eCura scoring system may be applied in Western countries to stratify the risk of LNM after a gastric HRR. A new score is proposed that may further decrease the number of unnecessary surgeries.

Long-term outcomes of additional surgery versus non-gastrectomy treatment for early gastric cancer after non-curative endoscopic submucosal dissection: a meta-analysis

BACKGROUND

Endoscopic resection is increasingly used in the treatment for early gastric cancer (EGC); however, about 15% of endoscopic submucosal dissection (ESD) cases report non-curative resection. The efficacy of different remedial interventions after non-curative ESD for EGC remains controversial. This meta-analysis aimed to compare the long-term outcomes of additional surgery and non-gastrectomy treatment for EGC patients who underwent non-curative ESD.

METHODS

All relevant studies published up to October 2021 were systematically searched in the PubMed, Web of Science, and Embase databases. The medical subject headings terms "early gastric cancer," "gastrectomy," "endoscopic submucosal dissection," and their related free keywords were used to search relevant articles without restrictions on regions, publication types, or languages. The Newcastle-Ottawa Quality Assessment Scale was used to evaluate the quality of the included studies. Odds ratios (ORs) with 95% confidence intervals (CIs) of 5-year overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS) and hazard ratios (HRs) with 95% CIs of OS were calculated using a random- or fixed-effects model.

RESULTS

This meta-analysis included 17 retrospective cohort studies with 5880 patients, of whom 3167 underwent additional surgery and 2713 underwent non-gastrectomy. We found that patients receiving additional gastrectomy had better 5-year OS (OR = 3.63, 95% CI = 3.05-4.31), DSS (OR = 3.22, 95% CI = 2.22-4.66), and DFS (OR = 4.39, 95% CI = 1.78-10.82) outcomes than those receiving non-gastrectomy treatments. The pooled HR also showed that gastrectomy following non-curative ESD significantly improved OS (HR = 0.40, 95% CI = 0.33-0.48). In addition, elderly patients benefited from additional surgery in consideration of the 5-year OS (HR = 0.54, 95% CI = 0.41-0.72).

CONCLUSIONS

Compared with non-gastrectomy treatments, additional surgery offered better long-term survival outcomes for patients with EGC who underwent non-curative ESD.

Metachronous gastric neoplasm beyond 5 years after endoscopic resection for early gastric cancer

BACKGROUND AND AIMS

The natural course of early gastric cancer (EGC) following endoscopic submucosal dissection (ESD) remains unclear. This study aimed to clarify the long-term clinical outcomes and risk factors of metachronous gastric neoplasm (MGN) 5 years after ESD for EGC.

METHODS

We performed a retrospective analysis of patients who underwent ESD for EGC from July 2005 to October 2015 in Seoul National University Hospital. Long-term clinical outcomes and risk factors of MGN after 5 years post-ESD were evaluated.

RESULTS

Among the 2059 patients who underwent ESD for EGC, 1102 were followed up for > 5 years. MGN developed in 132 patients 5 years after ESD. During the median follow-up period of 85 months, the cumulative incidences of MGN and metachronous gastric cancer were 11.7, 16.9, and 27.0 and 7.6, 10.8, and 18.7% after 5, 7, and 10 years, respectively. In multivariable analysis, male sex (odds ratio 1.770; P = 0.042), severe intestinal metaplasia (odds ratio 1.255; P = 0.000), tumor-positive lateral margin (odds ratio 2.711; P = 0.008), < 5 mm lateral safety margin (odds ratio 1.568; P = 0.050), and synchronous adenoma (odds ratio 2.612; P = 0.001) were positive predictive factors, and successful eradication of Helicobacter pylori (odds ratio 0.514; P = 0.024) was a negative predictive factor for MGN after 5 years post-ESD.

CONCLUSION

The cumulative MGN incidence was high even 5 years post-ESD for EGC. Meticulous long-term endoscopic follow-up is mandatory, especially in male patients with underlying intestinal metaplasia, tumor-positive lateral margins, lateral safety margins of < 5 mm, and synchronous adenomas.

Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Evaluations on laser ablation of ex vivo porcine stomach tissue for development of Ho:YAG-assisted endoscopic submucosal dissection (ESD)

Endoscopic submucosal dissection (ESD) is clinically used to remove early gastric cancer in stomach. The aim of the current study is to examine a therapeutic capacity of pulsed Ho:YAG laser for the development of laser-assisted ESD under various surgical parameters. Ex vivo porcine stomach tissue was ablated with 1-J Ho:YAG pulses at 10 Hz at different number of treatments (NT = 1, 2, and 3) and treatment speeds (TS = 0.5, 1, and 2 mm/s) without and with saline injection. Regardless of saline injection, straight tissue ablation showed that ablation depth increased with increasing NT and decreasing TS. At NT = 3 and TS = 0.5 mm/s, no saline injection yielded the maximum ablation depth (3.4 ± 0.3 mm), partially removing muscularis propria. However, saline injection confined the tissue ablation within a submucosal layer (2.1 ± 0.3 mm). Thermal injury was found to be 0.7~1.1 mm in the adjacent tissue with superficial carbonization. Circular tissue ablation (2 cm in diameter) at NT = 3 and TS = 0.5 mm/s presented that no saline injection yielded a reduction in the lesion area, whereas saline injection maintained the ablated lesion area. Histological analysis revealed that unlike no saline injection, saline injection ablated the entire mucosal layer without perforation in the muscular propria. The pulsed Ho:YAG laser can be a potential surgical tool for clinical ESD to incise a target lesion without adverse perforation. Further investigations will validate the efficacy and safety of the Ho:YAG laser-assisted ESD in in vivo porcine stomach models for clinical translation.