Feasibility of intraoperative pathologic examination for sentinel lymph nodes during sentinel node navigation surgery in early gastric cancer: results of pathologic protocol for SENORITA trial

BACKGROUND

During sentinel node navigation surgery in patients with gastric cancer, intraoperative pathologic examination of sentinel nodes is crucial in determining the extent of surgery. In this study, we evaluated the feasibility and accuracy of intraoperative pathologic protocols using data from a prospective, multicenter, randomized trial.

METHODS

A retrospective analysis was conducted using data from the SEntinel Node ORIented Tailored Approach trials from 2013 to 2016. All sentinel lymph nodes were evaluated during surgery with hematoxylin-eosin (HE) staining using a representative section at the largest plane for lymph nodes. For permanent histologic evaluation, sentinel basin nodes were stained with HE and cytokeratin immunohistochemistry in formalin-fixed, paraffin-embedded (FFPE) sections and examined with HE for three deeper-step sections at 200-μm intervals. The failure rate of identification by frozen section and the metastasis rate in non-sentinel basins were investigated.

RESULTS

Of the 237 patients who underwent sentinel node basin dissection, 30 had lymph node metastases on permanent pathology. Thirteen patients had macrometastasis confirmed in frozen sections as well as FFPE sections (failure rate: 0%). Patients with negative sentinel nodes in frozen sections but micrometastasis in FFPE sections had no lymph node recurrence during the follow-up period (0%, 0/6). However, in cases with tumor-positive nodes in frozen sections, metastases in non-sentinel basins were detected in the paraffin blocks (8.3%, 2/24).

CONCLUSIONS

The single-section HE staining method is sufficient for detecting macrometastasis via intraoperative pathological examination. If a negative frozen-section result is confirmed, sentinel basin dissection can be performed safely. Otherwise, standard surgery is required.

Prognostic and predictive impact of sex in locally advanced microsatellite instability high gastric or gastroesophageal junction cancer: An individual patient data pooled analysis of randomized clinical trials

BACKGROUND

Surgery plus peri-operative/adjuvant chemotherapy is the standard of care for locally advanced GC/GEJC, though with unsatisfactory results. dMMR/MSI-high tumors have better prognosis and scant benefit from chemotherapy as compared to pMMR/MSS ones. The differential outcome of therapies in terms of safety and efficacy according to sex is still debated in GC/GEJC patients.

METHODS

We previously performed an individual patient data pooled analysis of MAGIC, CLASSIC, ITACA-S, and ARTIST trials including GC/GEJC patients treated with surgery alone or surgery plus peri-operative/adjuvant chemotherapy to assess the value of MSI status. We performed a secondary analysis investigating the prognostic and predictive role of sex (female versus male) in the pooled analysis dataset in the overall population and patients stratified for MSI status (MSI-high versus MSS/MSI-low). Disease-free (DFS) and overall survival (OS) were calculated.

RESULTS

Patients with MSI-high tumors had improved survival as compared to MSS/MSI-low ones irrespective of sex, whereas in those with MSS/MSI-low tumors, females had numerically longer OS and DFS (5-year OS was 63.2% versus 57.6%, HR 0.842; p = 0.058, and 5-year DFS was 55.8% versus 50.8%, HR 0.850; p = 0.0504 in female versus male patients). The numerical difference for the detrimental effect of chemotherapy in MSI-high GC was higher in females than males, while the significant benefit of chemotherapy over surgery alone was confirmed in MSS/MSI-low GC irrespective of sex.

CONCLUSIONS

This pooled analysis including four randomized trials highlights a relevant impact of sex in the prognosis and treatment efficacy of MSI-high and MSS/MSI-low non-metastatic GC/GEJC.

Clinical Efficacy of Laparoscopic Sentinel Node Navigation Surgery for Stomach Preservation in Patients With Early Gastric Cancer: 5-year Results of the SENORITA Trial

OBJECTIVE

This study aimed to compare laparoscopic standard gastrectomy (LSG) and laparoscopic sentinel node navigation surgery (LSNNS) for EGC in terms of 5-year long-term oncologic outcomes.

SUMMARY BACKGROUND DATA

The oncological safety of LSNNS for early gastric cancer (EGC) has not been confirmed. Three-year disease-free survival (DFS), which is the primary endpoint of the phase III multicenter randomized controlled clinical trial (SEntinel Node ORIented Tailored Approach [SENORITA] trial), did not show the non-inferiority of LSNNS relative to LSG.

METHODS

The SENORITA trial, a multicenter randomized clinical trial, was designed to show that LSNNS is non-inferior to LSG in terms of 3-year DFS. In the present study, we collected 5-year follow-up data from 527 patients recruited in the SENORITA trial as the full analysis set (FAS). Disease-free survival (DFS), overall survival (OS), disease-specific survival (DSS), and recurrence patterns were evaluated using the FAS of both LSG (n=269) and LSNNS (n=258).

RESULTS

The 5-year DFS was not significantly different between the LSG and LSNNS groups (P=0.0561). During the 5-year follow-up, gastric cancer-related events, such as metachronous cancer, were more frequent in the LSNNS group than in the LSG group. However, ten recurrent cancers in the remnant stomach of both groups were curatively resected by additional gastrectomy and one by additional endoscopic resection. Two of the 198 patients who underwent local resection for stomach preservation based on the LSNNS results developed distant metastasis. However, there was no statistically significant difference in the 5-year OS and DSS (P=0.7403 and P=0.9586, respectively) between the two groups.

CONCLUSION

The 5-year DFS, DSS and OS did not differ significantly between the two groups. Considering the benefits of LSNNS on postoperative quality of life, LSNNS could be recommended as an alternative treatment option for EGC.

Unravelling interobserver variability in gastrointestinal glandular neoplasia: a contemporary study of US and Korean pathologists

AIMS

Interobserver variability in the assessment of gastric neoplasia biopsies between most Western and Eastern (predominantly represented by Japanese in the literature) pathologists has been documented. It is unknown if such variability exists between the US and Korean pathologists in the current era.

METHODS

Ten gastrointestinal (GI) pathologists from the USA (n=5) and South Korea (n=5) evaluated 100 scanned images of gastric (n=50) and colorectal (n=50) neoplasia biopsies and answered multiple questionnaires. Consensus was defined as the answer chosen by the majority. Cohen's (κc) and Fleiss' kappa (κf) values were calculated between the consensus of the two groups and among the raters, respectively.

RESULTS

Both groups reached a consensus in the majority of cases (74%-100%) with slight to perfect intergroup (κc=0.049-1.000) and no to substantial intragroup (κf=-0.083 to 0.660) agreements. For gastric neoplasia, Korean pathologists relied heavily on cytoarchitectural atypia, whereas the US pathologists focused on stromal invasion when diagnosing adenocarcinoma. For colorectal neoplasia, the Korean pathologists identified concurrent intramucosal carcinoma when diagnosing invasive adenocarcinoma, while the presence of desmoplasia was a prerequisite for the diagnosis of invasive adenocarcinoma for the US pathologists.

CONCLUSIONS

For GI neoplasia biopsy interpretation, the diagnostic approach of Korean pathologists is similar to that of Eastern/Japanese pathologists. Consensus outperformed kappa statistics in capturing the magnitude of inter-rater and intergroup reliability, highlighting the potential benefit of consensus meetings to decrease the gap between Western and Eastern diagnostic approaches.

Tumour infiltrating lymphocytes and survival after adjuvant chemotherapy in patients with gastric cancer: post-hoc analysis of the CLASSIC trial

BACKGROUND

Only a subset of gastric cancer (GC) patients with stage II-III benefits from chemotherapy after surgery. Tumour infiltrating lymphocytes per area (TIL density) has been suggested as a potential predictive biomarker of chemotherapy benefit.

METHODS

We quantified TIL density in digital images of haematoxylin-eosin (HE) stained tissue using deep learning in 307 GC patients of the Yonsei Cancer Center (YCC) (193 surgery+adjuvant chemotherapy [S + C], 114 surgery alone [S]) and 629 CLASSIC trial GC patients (325 S + C and 304 S). The relationship between TIL density, disease-free survival (DFS) and clinicopathological variables was analysed.

RESULTS

YCC S patients and CLASSIC S patients with high TIL density had longer DFS than S patients with low TIL density (P = 0.007 and P = 0.013, respectively). Furthermore, CLASSIC patients with low TIL density had longer DFS if treated with S + C compared to S (P = 0.003). No significant relationship of TIL density with other clinicopathological variables was found.

CONCLUSION

This is the first study to suggest TIL density automatically quantified in routine HE stained tissue sections as a novel, clinically useful biomarker to identify stage II-III GC patients deriving benefit from adjuvant chemotherapy. Validation of our results in a prospective study is warranted.

Stomach tissue classification using autofluorescence spectroscopy and machine learning

BACKGROUND AND OBJECTIVES

Determination of stomach tumor location and invasion depth requires delineation of gastric histological structure, which has hitherto been widely accomplished by histochemical staining. In recent years, alternative histochemical evaluation methods have been pursued to accelerate intraoperative diagnosis, often by bypassing the time-consuming step of dyeing. Owing to strong endogenous signals from coenzymes, metabolites, and proteins, autofluorescence spectroscopy is a favorable candidate technique to achieve this aim.

MATERIALS AND METHODS

We investigated stomach tissue slices and block specimens using a fast fluorescence imaging scanner. To obtain histological information from broad and structureless fluorescence spectra, we analyzed tens of thousands of spectra with multiple machine-learning algorithms and built a tissue classification model trained with dissected gastric tissues.

RESULTS

A machine-learning-based spectro-histological model was built based on the autofluorescence spectra measured from stomach tissue samples with delineated and validated histological structures. The scores from a principal components analysis were employed as input features, and prediction accuracy was confirmed to be 92.0%, 90.1%, and 91.4% for mucosa, submucosa, and muscularis propria, respectively. We investigated the tissue samples in both sliced and block forms using a fast fluorescence imaging scanner.

CONCLUSION

We successfully demonstrated differentiation of multiple tissue layers of well-defined specimens with the guidance of a histologist. Our spectro-histology classification model is applicable to histological prediction for both tissue blocks and slices, even though only sliced samples were trained.

Clinical Practice Guideline for Gastritis in Korea

Gastritis is a disease characterized by inflammation of the gastric mucosa. It is very common and has various classification systems such as the updated Sydney system. As there is a lot of evidence that Helicobacter pylori infection is associated with the development of gastric cancer and that gastric cancer can be prevented by eradication, H. pylori gastritis has been emphasized recently. The incidence rate of gastric cancer in Korea is the highest in the world, and due to the spread of screening endoscopy, atrophic gastritis and intestinal metaplasia are commonly diagnosed in the general population. However, there have been no clinical guidelines developed in Korea for these lesions. Therefore, this clinical guideline has been developed by the Korean College of Helicobacter and Upper Gastrointestinal Research for important topics that are frequently encountered in clinical situations related to gastritis. Evidence-based guidelines were developed through systematic review and de novo processes, and eight recommendations were made for eight key questions. This guideline needs to be periodically revised according to the needs of clinical practice or as important evidence about this issue is published in the future.

A Standardized Pathology Report for Gastric Cancer: 2nd Edition

The first edition of 'A Standardized Pathology Report for Gastric Cancer' was initiated by the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists and published 17 years ago. Since then, significant advances have been made in the pathologic diagnosis, molecular genetics, and management of gastric cancer (GC). To reflect those changes, a committee for publishing a second edition of the report was formed within the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. This second edition consists of two parts: standard data elements and conditional data elements. The standard data elements contain the basic pathologic findings and items necessary to predict the prognosis of GC patients, and they are adequate for routine surgical pathology service. Other diagnostic and prognostic factors relevant to adjuvant therapy, including molecular biomarkers, are classified as conditional data elements to allow each pathologist to selectively choose items appropriate to the environment in their institution. We trust that the standardized pathology report will be helpful for GC diagnosis and facilitate large-scale multidisciplinary collaborative studies.

A standardized pathology report for gastric cancer: 2nd edition

The first edition of 'A Standardized Pathology Report for Gastric Cancer' was initiated by the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists and published 17 years ago. Since then, significant advances have been made in the pathologic diagnosis, molecular genetics, and management of gastric cancer (GC). To reflect those changes, a committee for publishing a second edition of the report was formed within the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. This second edition consists of two parts: standard data elements and conditional data elements. The standard data elements contain the basic pathologic findings and items necessary to predict the prognosis of GC patients, and they are adequate for routine surgical pathology service. Other diagnostic and prognostic factors relevant to adjuvant therapy, including molecular biomarkers, are classified as conditional data elements to allow each pathologist to selectively choose items appropriate to the environment in their institution. We trust that the standardized pathology report will be helpful for GC diagnosis and facilitate large-scale multidisciplinary collaborative studies.

Clinical efficacy of laparoscopic sentinel node navigation surgery for early gastric cancer: Five-year results of SENORITA trial

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Background: A phase III multicenter randomized controlled clinical trial (SEntinel Node ORIented Tailored Approach [SENORITA] trial) has been performed to confirm the oncologic safety of laparoscopic sentinel node navigation surgery (LSNNS) for early gastric cancer (EGC). The results did not show the non-inferiority of LSNNS relative to laparoscopic standard gastrectomy (LSG) in terms of 3-year disease-free survival (DFS), the primary endpoint of the SENORITA trial even though the improved quality of life (QOL) in the LSNNS group. However, the long-term oncologic outcomes of LSNNS have not been compared with conventional surgery. This study was planned to investigate the comparison of LSG and LSNNS for EGC in terms of 5 years survival. Methods: We collected 5-year follow-up data of 527 patients recruited in the SENORITA trial. The overall survival (OS), disease-free survival (DFS), and recurrence pattern were evaluated in full analysis sets of both LSG (n = 269) and LSNNS (n = 258). Results: The mean follow-up period was 58.5 and 57.7 months in LSNNS and LSG groups. There was no statistically significant difference in 5-year OS (p = 0.7403) and DFS (p = 0.0561) between LSG and LSNNS. In terms of DFS, additional five events in the LSG group and 7 in LSNNS occurred after a 3-year follow-up until 5-years. Primary site recurrence in 1 LSNNS, and metachronous gastric cancer occurred in one LSG and two in LSNNS were diagnosed from 3 to 5-year follow-up period. Other organ cancer developed in two vs. three and other deaths occurred in two v s. one in each group, respectively, from 3 to 5-year follow-up. Overall survival events were 6 in LSG and 7 in LSNNS, and disease-specific death events were two patients in both groups until five years. Conclusions: Although the SENORITA trial did not show non-inferiority of LSNNS in the primary endpoint, 3-year DFS relative to LSG, the 5-year DFS and OS did not reveal the statistical difference between the two groups. Considering the benefit of LSNNS regarding the postoperative QOL, LSNNS could be recommended as an alternative treatment option of LSG for EGC. Clinical trial information: NCT01804998.

Laparoscopic Sentinel Node Navigation Surgery for Stomach Preservation in Patients With Early Gastric Cancer: A Randomized Clinical Trial

PURPOSE

To compare postoperative complications, long-term survival, and quality of life (QOL) after laparoscopic sentinel node navigation surgery (LSNNS) and laparoscopic standard gastrectomy (LSG).

METHODS

Five hundred eighty patients with preoperatively diagnosed stage IA gastric adenocarcinoma (≤ 3 cm) were assigned to undergo either LSG or LSNNS. Observers were not blinded to patient grouping. The primary outcome was 3-year disease-free survival (3y-DFS). Secondary outcomes included postoperative complications, QOL, 3-year disease-specific survival (3y-DSS), and 3-year overall survival (3y-OS).

RESULTS

In total, 527 patients were included in the modified intention-to-treat analysis population for the primary outcome (LSG, 269; LSNNS, 258). Stomach-preserving surgery was performed in 210 patients (81%) in the LSNNS group. During the median follow-up duration, the 3y-DFS rates in the LSG and LSNNS groups were 95.5% and 91.8%, respectively (difference: 3.7%; 95% CI, -0.6 to 8.1). Three patients with recurrence and five with metachronous gastric cancer in the LSNNS group underwent standard surgery. Two patients with distant metastasis in both groups were treated with palliative chemotherapy. The 3y-DSS and 3y-OS rates in the LSG and LSNNS groups were 99.5% and 99.1% (P = .59) and 99.2% and 97.6% (P = .17), respectively. Postoperative complications occurred in 19.0% of the LSG group and 15.5% of the LSNNS group (P = .294). The LSNNS group showed better physical function (P = .015), less symptoms (P < .001), and improved nutrition than the LSG group.

CONCLUSION

LSNNS did not show noninferiority to LSG for 3y-DFS, with a 5% margin. However, the 3y-DSS and 3y-OS were not different after rescue surgery in cases of recurrence/metachronous gastric cancer, and LSNNS had better long-term QOL and nutrition than LSG.

Smad4 and p53 synergize in suppressing autochthonous intestinal cancer

Background

Smad4 and p53 mutations are the most common mutations in human colorectal cancers (CRCs). We evaluated whether and how they are synergistic in intestinal carcinogenesis using novel autochthonous mouse models.

Method

To recapitulate human CRCs, we generated Villin‐Cre;Smad4^F/F;Trp53^F/F mice. We then compared the intestinal phenotype of Villin‐Cre;Smad4^F/F;Trp53^F/F mice (n = 40) with Villin‐Cre;Smad4^F/F (n = 30) and Villin‐Cre;Trp53^F/F mice (n = 45).

Results

Twenty‐week‐old Villin‐Cre;Smad4^F/F;Trp53^F/F mice displayed spontaneous highly proliferative intestinal tumors, and 85% of mice developed adenocarcinomas. p21 was downregulated in the intestinal mucosa in Villin‐Cre;Smad4^F/F;Trp53^F/F mice than in Villin‐Cre;Smad4^F/F and Villin‐Cre;Trp53^F/F mice. Villin‐Cre;Smad4^F/F;Trp53^F/F mice displayed multistep intestinal tumorigenesis and Wnt activation. Long‐term CWP232291 (small‐molecule Wnt inhibitor) treatment of Villin‐Cre;Smad4^F/F;Trp53^F/F mice suppressed intestinal tumorigenesis and progression. CWP232291 treatment downregulated cancer stem cell (CSC) tumor markers including CD133, Lgr‐5, and Sca‐1. CWP232291 treatment reduced the CSC frequency. Small‐molecule Wnt inhibitors reduced intestinal CSC populations and inhibited their growth, along with Bcl‐X_L downregulation. Furthermore, BH3I‐1, a Bcl‐X_L antagonist, increasingly inhibited intestinal CSCs than bulk tumor cells.

Conclusion

Smad4 loss and p53 loss are synergistic in autochthonous intestinal carcinogenesis, by downregulating p21 and activating Wnt/β‐catenin pathway.

A Comprehensive and Comparative Review of Global Gastric Cancer Treatment Guidelines

Countries differ in their treatment expertise and research results regarding gastric cancer; hence, treatment guidelines are diverse based on evidence and medical situations. A comprehensive and comparative review of each country’s guidelines is imperative to understand the similarities and differences among countries. We reviewed and compared five gastric cancer treatment guidelines in terms of endoscopic, surgical, perioperative, and palliative systemic treatment based on evidence levels and recommendation grades, as well as the postoperative follow-up strategies for each guideline. The Korean, Chinese, and European guidelines provided evidence and grading of the recommendations. The United States guidelines suggested categories for evidence and consensus. The Japanese guidelines suggested evidence and recommendations only for systemic treatment. The Korean and Japanese guidelines described endoscopic treatment, surgery, and lymphadenectomy in detail. The Chinese, United States, and European guidelines more intensively considered perioperative chemotherapy. In particular, the indications for chemotherapy and the regimens recommended by each guideline differed slightly. Considering their medical situations, each guideline had some diversity in terms of adopting evidence, which resulted in heterogeneous recommendations. This review will help medical personnel to comprehensively understand the diversity in gastric cancer treatment guidelines for each country in terms of evidence and recommendations.

Development and validation of deep learning classifiers to detect Epstein-Barr virus and microsatellite instability status in gastric cancer: a retrospective multicentre cohort study

BACKGROUND

Response to immunotherapy in gastric cancer is associated with microsatellite instability (or mismatch repair deficiency) and Epstein-Barr virus (EBV) positivity. We therefore aimed to develop and validate deep learning-based classifiers to detect microsatellite instability and EBV status from routine histology slides.

METHODS

In this retrospective, multicentre study, we collected tissue samples from ten cohorts of patients with gastric cancer from seven countries (South Korea, Switzerland, Japan, Italy, Germany, the UK and the USA). We trained a deep learning-based classifier to detect microsatellite instability and EBV positivity from digitised, haematoxylin and eosin stained resection slides without annotating tumour containing regions. The performance of the classifier was assessed by within-cohort cross-validation in all ten cohorts and by external validation, for which we split the cohorts into a five-cohort training dataset and a five-cohort test dataset. We measured the area under the receiver operating curve (AUROC) for detection of microsatellite instability and EBV status. Microsatellite instability and EBV status were determined to be detectable if the lower bound of the 95% CI for the AUROC was above 0·5.

FINDINGS

Across the ten cohorts, our analysis included 2823 patients with known microsatellite instability status and 2685 patients with known EBV status. In the within-cohort cross-validation, the deep learning-based classifier could detect microsatellite instability status in nine of ten cohorts, with AUROCs ranging from 0·597 (95% CI 0·522-0·737) to 0·836 (0·795-0·880) and EBV status in five of eight cohorts, with AUROCs ranging from 0·819 (0·752-0·841) to 0·897 (0·513-0·966). Training a classifier on the pooled training dataset and testing it on the five remaining cohorts resulted in high classification performance with AUROCs ranging from 0·723 (95% CI 0·676-0·794) to 0·863 (0·747-0·969) for detection of microsatellite instability and from 0·672 (0·403-0·989) to 0·859 (0·823-0·919) for detection of EBV status.

INTERPRETATION

Classifiers became increasingly robust when trained on pooled cohorts. After prospective validation, this deep learning-based tissue classification system could be used as an inexpensive predictive biomarker for immunotherapy in gastric cancer.

FUNDING

German Cancer Aid and German Federal Ministry of Health.

PRODIGY: A Phase III Study of Neoadjuvant Docetaxel, Oxaliplatin, and S-1 Plus Surgery and Adjuvant S-1 Versus Surgery and Adjuvant S-1 for Resectable Advanced Gastric Cancer

Adjuvant chemotherapy after D2 gastrectomy is standard for resectable locally advanced gastric cancer (LAGC) in Asia. Based on positive findings for perioperative chemotherapy in European phase III studies, the phase III PRODIGY study (ClinicalTrials.gov identifier: NCT01515748) investigated whether neoadjuvant docetaxel, oxaliplatin, and S-1 (DOS) followed by surgery and adjuvant S-1 could improve outcomes versus standard treatment in Korean patients with resectable LAGC.

Long-term quality of life and nutritional results after laparoscopic sentinel node navigation surgery versus laparoscopic standard gastrectomy for early gastric cancer: Secondary outcomes of a multicenter, randomized phase 3 trial (SENORITA)

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Background: Laparoscopic sentinel node navigation surgery (LSNNS) has been suggested as an alternative to laparoscopic standard gastrectomy (LSG) in early gastric cancer patients to improve long-term quality of life (QOL) and nutritional outcomes. Here, we present 3-year results of patient-reported quality of life (QOL) and nutrition, secondary endpoints of SENORITA trial. Methods: SENORITA is a prospective multicenter randomized phase 3 trial. Patients diagnosed with early gastric cancer of 3 cm or less were randomly allocated (1:1) to LSNNS for stomach preservation or LSG. The primary endpoint was 3-year disease-free survival. In this study, we analyzed QOL assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and EORTC stomach module (STO22) and nutritional parameters at 3, 12, 24, and 36 months after surgery. Linear mixed model analyses was used to evaluate differences between the two groups. This trial is registered with ClinicalTrials.gov, NCT01804998. Results: From March 2013 to March 2017, a total of 580 patients were randomly assigned and 527 patients were included in the modified intention-to-treat analysis population (258 in LSNNS and 269 in LSG group). QOL questionnaires were available for 99.4% of patients at baseline and then for 92.2%, 83.2%, 72.8%, and 66.9% at 3, 12, 24, and 36 months after surgery, respectively. The LSNNS group had higher physical function score than the LSG group at all time points (p = 0.002). However, there were no significant differences in other scales of EORTC QLQ-C30. Regarding EORTC QLQ-STO22, pain, eating restriction, anxiety, and taste scores were lower (better QOL) at all time points in the LSNNS group than in the LSG group (p = 0.002, < 0.001, < 0.001, and < 0.001, respectively). The summary score of EORTC QLQ-STO22 was also higher in the LSNNS group representing better QOL (p < 0.001). Body mass index, hemoglobin and total protein were significantly higher in the LSNNS group compared with the LSG group. Conclusions: The LSNNS group had better physical function and less symptoms, including pain, eating restriction, anxiety, and taste change compared with the LSG group. Moreover, the nutritional parameters were better maintained in the LSNNS group than in the LSG group. These findings showed benefits of stomach preserving surgery in LSNNS and can be used to help decision making about treatment for patients with early gastric cancer. Clinical trial information: NCT01804998.

Risk factors for lymph node metastasis in early gastric cancer without lymphatic invasion after endoscopic submucosal dissection

BACKGROUND

Lymphatic invasion (LI) is a potent risk factor for lymph node metastasis (LNM) in early gastric cancer (EGC) after endoscopic submucosal dissection (ESD). However, there are also other risk factors for LNM. Hence, to identify the need for additional surgery in some case of EGC without LI, the present study aimed to identify the risk factors for LNM in patients with EGC without LI.

METHODS

Data from 2284 patients diagnosed with EGC who underwent curative surgery at National Cancer Center in Korea from January 2012 to May 2019 were collected. The clinicopathological characteristics of patients with EGC without LI were compared on the basis of LNM status.

RESULTS

There were 339 (17.1%) and 1648 (82.9%) patients with and without LI respectively. Among these patients with and without LI, 118 (34.8%) and 91 (5.5%) patients presented with LNM, respectively. In patients with EGC without LI, tumor size larger than 3 cm (OR = 2.12, 95% CI = 1.22-3.68; p = 0.007), submucosal invasion (OR = 4.14, 95% CI = 2.57-6.65; p < 0.001), and undifferentiated histologic type (OR = 2.33, 95% CI = 1.45-3.76; p < 0.001) were significant risk factors for LNM. Rates of LNM in patients meeting absolute, expanded, and beyond expanded criteria without LI were 0%, 1.5% (OR = 3.27, 95% CI = 0.18-59.41; p = 0.423), and 7.3% respectively. When the expanded criteria were divided into four subtypes patients with EGC, without LI within each subtype did not show significant risk of incidence of LNM compared to the absolute criteria.

CONCLUSIONS

The current expanded criteria for endoscopic resection (ER) are tolerable in cases without LI, even though minimal risk LNM exists. Therefore, additional surgery may not be needed for patients meeting expanded criteria for ER.

Evaluation of Lymph Node Metastasis Among Adults With Gastric Adenocarcinoma Managed With Total Gastrectomy

IMPORTANCE

It is unclear whether proximal gastrectomy (PG) can replace total gastrectomy (TG), even in cases of advanced gastric carcinoma.

OBJECTIVES

To evaluate the oncologic safety of PG based on the lymph node (LN) metastasis rate and develop a selection diagram for PG eligibility.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, a retrospective analysis of a prospective database of gastric carcinoma surgery was performed including procedures that took place between December 1, 2000, and December 31, 2015, in the National Cancer Center, Korea, a high-volume carcinoma center with a structured database and accurate long-term follow-up. Among 9952 patients who underwent surgery for gastric carcinoma, 2347 underwent TG. Six-hundred fifty-five (564 in a second statistical analysis) had gastric carcinoma in the upper third of the stomach. The inclusion criteria were age 18 to 85 years, histologically proven adenocarcinoma (any size or differentiation) located in the upper third of the stomach, curative R0 TG performed, and postoperative follow-up for at least 3 years. Exclusion criteria included Borrmann type 4 carcinoma, T4 category, use of neoadjuvant chemotherapy, and a history of other carcinomas. Data analysis was performed from December 1, 2019, to May 30, 2020.

EXPOSURES

Total gastrectomy and LN dissection.

MAIN OUTCOMES AND MEASURES

The primary end point was the rate of LN metastasis at LN stations 4d, 5, and 6, which are usually not dissected during PG.

RESULTS

Among the 655 study patients, the mean (SD) age was 57.7 (11.9) years, and 462 (70.5%) were men. Only those with poorly differentiated cT3 category carcinomas had an increased incidence of LN metastasis at stations 4d (2 of 32 [6.3%]) and 11d (T3N0: 2 of 22 [9.1%], T3N1: 3 of 27 [11.1%]), independent of tumor size. For cT1-T3N0/1M0 category carcinomas, the incidence of station 5 LN metastasis was 0, irrespective of tumor size and differentiation. The LN metastasis rate at stations 4d and 6 for cT1-T3N0/1M0 differentiated tumors was also 0. Tumor size greater than or equal to 4.1 cm was associated with significantly increased LN metastasis compared with tumors less than 4.1 cm (40.0% vs 20.4%, P = .001).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that PG can be safely performed for cT1-T2N0/1M0 tumors less than 4.1 cm in diameter that are located in the upper third of the stomach. The cT3N0/1M0-differentiated tumors less than 4.1 cm may also be eligible for PG, whereas poorly differentiated cT3 tumors and any cT4 or cN2/3 diseases require TG.

Clinicopathologic Features of Submucosal Papillary Gastric Cancer Differ from Those of Other Differentiated-Type Histologies

Background/Aims

Papillary gastric cancer (GC) is classified as differentiated adenocarcinoma, together with well-differentiated (WD) and moderately differentiated (MD) adenocarcinoma. This study evaluated the risk of lymph node metastasis (LNM) in submucosal (SM) invasive papillary GC compared with other differentiated early GC types.

Methods

This retrospective study involved three tertiary hospitals and enrolled 1,798 lesions with differentiated SM invasive GC treated with curative gastrectomy between March 2001 and December 2012. All pathology slides were reviewed, and clinicopathologic findings associated with LNM, including tumor size, location, gross type, ulceration, depth and width of SM invasion, and lymphovascular invasion (LVI), were analyzed.

Results

The proportion of SM papillary GC was 2.8% (n=51). SM papillary GC was associated with larger tumor size and deeper and wider SM invasion than other differentiated GC types. LNM was significantly higher in the papillary type than in the MD and WD types. LNM was found in 27.5% of SM papillary GC patients (WD 9.0%, MD 21.2%). LVI was the only significant risk factor for LNM in SM papillary GC. The depth or width of SM invasion was not associated with LNM in papillary GC. Lower third location or elevated gross appearance was significantly associated with LVI.

Conclusions

SM papillary GC had the highest LNM rate, with features different from those of other differentiated SM invasive GCs. The treatment strategy for SM papillary GC should be carefully approached, especially for lesions located in the lower third or of the elevated gross type.

Recent updates and current issues of sentinel node navigation surgery for early gastric cancer

With the increase in the incidence of early gastric cancer (EGC), several endoscopic and laparoscopic approaches, such as endoscopic submucosal dissection and function-preserving gastrectomy, have been accepted as standard treatments. Sentinel node navigation surgery (SNNS) is an ideal surgical option for preservation of most parts of the stomach and consequent maintenance of normal gastric function to improve quality of life in patients with EGC. Although many previous studies and clinical trials have demonstrated the safety and feasibility of the sentinel node concept in gastric cancer, the clinical application of SNNS is debatable. Several issues regarding technical standardization and oncological safety need to be resolved. Recently several studies to resolve these problems are being actively performed, and SNNS might be an important surgical option in the treatment of gastric cancer in the future.

Non-exposure Simple Suturing Endoscopic Full-thickness Resection with Sentinel Basin Dissection in Patients with Early Gastric Cancer: the SENORITA 3 Pilot Study

Purpose

Recently, non-exposure simple suturing endoscopic full-thickness resection (NESS-EFTR) was developed to prevent tumor exposure to the peritoneal cavity. This study aimed to evaluate the feasibility of NESS-EFTR with sentinel basin dissection for early gastric cancer (EGC).

Materials and Methods

This was the prospective SENORITA 3 pilot. From July 2017 to January 2018, 20 patients with EGC smaller than 3 cm without an absolute indication for endoscopic submucosal dissection were enrolled. The sentinel basin was detected using Tc^99m-phytate and indocyanine green, and the NESS-EFTR procedure was performed when all sentinel basin nodes were tumor-free on frozen pathologic examination. We evaluated the complete resection and intraoperative perforation rates as well as the incidence of postoperative complications.

Results

Among the 20 enrolled patients, one dropped out due to large tumor size, while another underwent conventional laparoscopic gastrectomy due to metastatic sentinel lymph nodes. All NESS-EFTR procedures were performed in 17 of the 18 other patients (94.4%) without conversion, and the complete resection rate was 83.3% (15/18). The intraoperative perforation rate was 27.8% (5/18), and endoscopic clipping or laparoscopic suturing or stapling was performed at the perforation site. There was one case of postoperative complications treated with endoscopic clipping; the others were discharged without any event.

Conclusions

NESS-EFTR with sentinel basin dissection is a technically challenging procedure that obtains safe margins, prevents intraoperative perforation, and may be a treatment option for EGC after additional experience.

Trial Registration

ClinicalTrials.gov Identifier: NCT03216174

Evaluation of Submucosal or Lymphovascular Invasion Detection Rates in Early Gastric Cancer Based on Pathology Section Interval

PURPOSE

The guidelines for pathological evaluation of early gastric cancer (EGC) recommend wider section intervals for surgical specimens (5-7 mm) than those for endoscopically resected specimens (2-3 mm). Studies in surgically resected EGC specimens showed not negligible lymph node metastasis risks in EGCs meeting the expanded criteria for endoscopic submucosal dissection (ESD).

MATERIALS AND METHODS

This retrospective study included 401 EGC lesions with an endoscopic size of ≤ 30 mm detected in 386 patients. Pathological specimens obtained by ESD or surgery were cut into 2-mm section intervals for reference. Submucosal or lymphovascular invasion (LVI) was evaluated arbitrarily in 4- or 6-mm section intervals. McNemar's tests compared the differences between submucosal and LVI.

RESULTS

Submucosal invasion was detected in 29.2% (117/401) and LVI in 9.5% (38/401) at 2-mm interval. The submucosal invasion detection rates in 4-mm intervals decreased to 88.0% or 90.6% (both P<0.001), while the LVI detection rates decreased to 86.8% or 57.9% (P=0.025 and P<0.001, respectively). In 6-mm intervals, the submucosal and LVI detection rates decreased further to 72.7-80.3% (P<0.001 for all three sets) and 55.3-63.2% (P<0.001 for all three sets), respectively. Among 150 out-of-indication cases at 2-mm interval, 4-10 (2.7%-6.7%) at 4-mm intervals, and 10-17 (6.7%-11.3%) at 6-mm intervals were misclassified as lesions meeting the curative resection criteria due to the underestimation of submucosal or LVI.

CONCLUSIONS

After ESD, the 2-mm wide section interval was suitable for the pathological evaluation of focal submucosal or LVI. Thus, if an EGC lesion meets the expanded criteria for the ESD specimen pathological evaluation, it could be safely followed up.

Deep learning-based unsupervised morphological subtyping in histopathology images of gastric cancer

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Background: Gastric cancer subtyping system such as Lauren classification is widely used in clinical practice since it is an independent prognostic factor, and also provides the basis for individualized treatment. However, Lauren classification showed low reproducibility because it is based on qualitative method. Thus, a more reproducible system has been required. In this study, we explore the concordance between a cancer detection model (CDM)-based unsupervised subtyping and a current classification system. Methods: We focused on Lauren classification since it has relatively simple major subtypes: intestinal and diffuse types. 88 resection cases of gastric cancer are collected. Two experienced gastrointestinal pathologists evaluated each case independently by Lauren’s criteria. 200 cancer region image patches per case and its features extracted by the CDM were clustered into five groups via k-means clustering. We then defined the ratio of the number of patches in each cluster group as the case-level feature. Cases are clustered into two groups via k-means clustering using the features. We named this case-level clustering result as a deep learning-based subtyping (DLS), hereafter. Results: DLS showed a high correlation with Lauren classification: intestinal and diffuse subtype. The kappa scores between the pathologists and algorithm (0.765 and 0.796) were higher than between pathologists (0.700). The cluster centers corresponding to intestinal and diffuse types were [44.6, 21.5, 47.5, 63.7, 22.7] and [35.5, 148.2, 4.0, 9.0, 2.3], respectively. Further review of the patches contributing to the second feature (21.5 and 148.2) confirmed that they demonstrate typical morphological characteristics of diffuse type. Conclusions: Our analysis showed that the morphological characteristics of Lauren classification were inherent in gastric cancer detection task and WSIs can be subtyped by the data-driven, and unsupervised manner. Furthermore, DLS was more reliable than human from the concordance results. This suggests that the DLS can supplement current classification systems or be a new subtyping system. [Table: see text]

Family History of Gastric Cancer and Helicobacter pylori Treatment

BACKGROUND

Helicobacter pylori infection and a family history of gastric cancer are the main risk factors for gastric cancer. Whether treatment to eradicate H. pylori can reduce the risk of gastric cancer in persons with a family history of gastric cancer in first-degree relatives is unknown.

METHODS

In this single-center, double-blind, placebo-controlled trial, we screened 3100 first-degree relatives of patients with gastric cancer. We randomly assigned 1838 participants with H. pylori infection to receive either eradication therapy (lansoprazole [30 mg], amoxicillin [1000 mg], and clarithromycin [500 mg], each taken twice daily for 7 days) or placebo. The primary outcome was development of gastric cancer. A prespecified secondary outcome was development of gastric cancer according to H. pylori eradication status, assessed during the follow-up period.

RESULTS

A total of 1676 participants were included in the modified intention-to-treat population for the analysis of the primary outcome (832 in the treatment group and 844 in the placebo group). During a median follow-up of 9.2 years, gastric cancer developed in 10 participants (1.2%) in the treatment group and in 23 (2.7%) in the placebo group (hazard ratio, 0.45; 95% confidence interval [CI], 0.21 to 0.94; P = 0.03 by log-rank test). Among the 10 participants in the treatment group in whom gastric cancer developed, 5 (50.0%) had persistent H. pylori infection. Gastric cancer developed in 0.8% of participants (5 of 608) in whom H. pylori infection was eradicated and in 2.9% of participants (28 of 979) who had persistent infection (hazard ratio, 0.27; 95% CI, 0.10 to 0.70). Adverse events were mild and were more common in the treatment group than in the placebo group (53.0% vs. 19.1%; P<0.001).

CONCLUSIONS

Among persons with H. pylori infection who had a family history of gastric cancer in first-degree relatives, H. pylori eradication treatment reduced the risk of gastric cancer. (Funded by the National Cancer Center, South Korea; ClinicalTrials.gov number, NCT01678027.).

Predictive value of E-cadherin and EpCAM for detection of metastatic lymph node in early gastric cancer

Objective

There has been a demand for a tumor-specific marker for metastatic lymph nodes in sentinel navigation surgery for gastric cancer. The aim of this study is to analyze protein expression in both primary tumors and metastatic lymph nodes in early gastric cancer patients.

Methods

We collected primary tumors and metastatic lymph nodes from 71 patients who underwent curative gastrectomy and pathologically diagnosed with T1N1 or T1N2 (8th Union for International Cancer Control 8th edition/American Joint Committee on Cancer staging system) gastric cancer. Immunohistochemistry was used to determine the expression of six cell membrane proteins, including carcinoembryonic antigen (CEA), E-cadherin, epithelial cell adhesion molecule (EpCAM), P-cadherin, CD44v6, and c-erbB2 in the patient samples.

Results

The expression of CEA, E-cadherin, EpCAM, P-cadherin, CD44v6 and c-erbB2 in the evaluable primary tumor samples was 75.4%, 97.1%, 100%, 89.9%, 11.1% and 7.2%, respectively. Among cases wherein both the primary tumor and metastatic lymph nodes were evaluable, double positivity (expression in both primary tumor and metastatic lymph nodes) was observed for CEA, E-cadherin, EpCAM, P-cadherin, CD44v6 and c-erbB2 in 53.2%, 97.9%, 98.1%, 76.6%, 0 and 6.8% of the cases, respectively. The proportion of metastatic lymph nodes positive for CEA, E-cadherin, EpCAM, P-cadherin, CD44v6 and c-erbB2 was 71.4%, 100%, 98.1%, 83.7%, 0, and 75%, respectively in primary tumors positive for the same markers.

Conclusions

E-cadherin and EpCAM had an overlap of 100% and 98.1% between the primary tumor and metastatic lymph nodes, respectively. Thus, E-cadherin and EpCAM are potential molecular markers to detect metastatic lymph nodes in patients with early gastric cancer.

Factors associated with metastasis in superior mesenteric vein lymph node in subtotal gastrectomy for gastric cancer: Retrospective case control study

Objective

The revised Japanese treatment guideline for gastric cancer recommends dissection of the superior mesenteric vein lymph node (No. 14v LN) if there is metastasis in infrapyloric lymph node (No. 6 LN). However, it is still controversial whether LN dissection is necessary. The aim of this study was to investigate the factors associated with metastasis in No. 14v LN.

Methods

Patients who underwent D2 lymphadenectomy between 2003 and 2010 were included. We excluded patients who underwent total gastrectomy, had multiple lesions, or had missing data about the status of metastasis in the LNs that were included in D2 lymphadenectomy. Clinicopathologic characteristics and the metastasis in regional LNs were compared between patients with No. 14v LN metastasis (14v+) and those without (14v−).

Results

Five hundred sixty patients were included in this study. Univariate analysis showed that old age, larger tumor size, tumor location, differentiation, lymphatic invasion, venous invasion, perineural invasion, T classification, and N classification were related to metastasis in No. 14v LN. Multivariate analysis showed differentiation (P=0.027) and N classification (P<0.001) were independent related factors. Metastasis in infrapyloric lymph node (No. 6 LN) and proxiaml splenic lymph node (No. 11p LN) was independently associated with metastasis in No. 14v LN.

Conclusions

Differentiation and N classification were independent factors associated with No. 14v LN metastasis, and No. 6 and No. 11p LN metastasis were independent risk factors for No. 14v LN metastasis.

The Suggestion of Revised Criteria for Endoscopic Resection of Differentiated-Type Submucosal Gastric Cancer

BACKGROUND

Early gastric cancer that meets the expanded criteria for endoscopic resection (ER) is expected to be associated with a negligible risk for lymph node metastasis (LNM); however, recent studies have reported LNM in submucosal gastric cancer patients who met the existing criteria. In this study, we develop the revised criteria for ER of submucosal gastric cancer with the aim of minimizing LNM.

METHODS

We analyzed the clinicopathological data of 2461 patients diagnosed with differentiated, submucosal gastric cancer who underwent surgery at three tertiary hospitals between March 2001 and December 2012, and re-analyzed the pathological slides of all patients. The depth of submucosal invasion was measured histopathologically in two different ways (the classic and alternative methods) to obtain accurate data.

RESULTS

Of the enrolled subjects, 306 (17.0%) had LNM. The width of submucosal invasion correlated well with the LNM. We defined the depth and width of submucosal infiltration associated with the lowest incidence of LNM. None of the 254 subjects developed LNM when the following criteria were met: tumor diameter ≤ 3 cm, submucosal invasion depth < 1000 μm (as measured using the alternative method), submucosal invasion width < 4 mm, no lymphovascular invasion, and no perineural invasion; however, LNM was observed in 2.7% of subjects (6/218) who met the existing criteria.

CONCLUSIONS

We revised the criteria for ER by adopting the alternative method to measure the depth of submucosal invasion and adding the width of such invasion. Our criteria better predicted LNM than the current criteria used to select ER to treat submucosal gastric cancer.

Individual Patient Data Meta-Analysis of the Value of Microsatellite Instability As a Biomarker in Gastric Cancer

PURPOSE

In the CLASSIC and MAGIC trials, microsatellite instability (MSI)-high status was a favorable prognostic and potential negative predictive factor for neoadjuvant/adjuvant chemotherapy in resectable gastric cancer (GC). Given the low prevalence of MSI-high status in GC and its association with other positive prognostic variables, large data sets are needed to draw robust evidence of its prognostic/predictive value.

PATIENTS AND METHODS

We performed a multinational, individual-patient-data meta-analysis of the prognostic/predictive role of MSI in patients with resectable GC enrolled in the MAGIC, CLASSIC, ARTIST, and ITACA-S trials. Prognostic analyses used multivariable Cox models (MVM). The predictive role of MSI was assessed both in an all-comer population and in MAGIC and CLASSIC trials by MVM testing of the interaction of treatment (chemotherapy plus surgery v surgery) with MSI.

RESULTS

MSI status was available for 1,556 patients: 121 (7.8%) had MSI-high status; 576 were European, and 980 were Asian. In MSI-high versus MSI-low/microsatellite stable (MSS) comparisons, the 5-year disease-free survival (DFS) was 71.8% (95% CI, 63.8% to 80.7%) versus 52.3% (95% CI, 49.7% to 55.1%); the 5-year overall survival (OS) was 77.5% (95% CI, 70.0% to 85.8%) versus 59.3% (95% CI, 56.6% to 62.1%). In MVM, MSI was associated with longer DFS (hazard ratio [HR], 1.88; 95% CI, 1.28 to 2.76; P < .001) and OS (HR, 1.78; 95% CI, 1.17 to 2.73; P = .008), as were pT, pN, ethnicity, and treatment. Patients with MSI-low/MSS GC benefitted from chemotherapy plus surgery: the 5-year DFS compared with surgery only was 57% versus 41% (HR, 0.65; 95% CI, 0.53 to 0.79), and the 5-year OS was 62% versus 53% (HR, 0.75; 95% CI, 0.60 to 0.94). Conversely, those with MSI-high GC did not: the 5-year DFS was 70% versus 77% (HR, 1.27; 95% CI, 0.53 to 3.04), and the 5-year OS was 75% versus 83% (HR, 1.50; 95% CI, 0.55 to 4.12).

CONCLUSION

In patients with resectable primary GC, MSI is a robust prognostic marker that should be adopted as a stratification factor by clinical trials. Chemotherapy omission and/or immune checkpoint blockade should be investigated prospectively in MSI-high GCs according to clinically and pathologically defined risk of relapse.

Effect of Helicobacter pylori eradication and high-density lipoprotein on the risk of de novo gastric cancer development

BACKGROUND AND AIMS

The effect of Helicobacter pylori eradication on de novo gastric cancer is controversial, although meta-analyses suggest a reduction in gastric cancer after eradication. The effect of high-density lipoprotein (HDL) on gastric cancer has been rarely reported.

METHODS

In this large retrospective cohort study, participants underwent endoscopy and H pylori testing from 2003 to 2011 and underwent follow-up endoscopy and H pylori testing until 2013. H pylori infection was detected using a rapid urease test or histologic test. The H pylori eradication group was defined as successful eradication, whereas the H pylori persistent group was defined as noneradication or eradication failure. The risk of cancer was measured with hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Among 10,328 healthy subjects (5951 men; mean age, 48.7 years), 31 gastric cancers were detected during a median follow-up of 5.5 years. De novo gastric cancer developed in 21 of 3508 subjects (.6%) in the noneradication group, 4 of 2050 subjects (.2%) in the successful eradication group, and 6 of 4770 participants (.13%) in the absence of H pylori group. In the adjusted analysis, H pylori eradication decreased de novo gastric cancer risk (HR, .29; 95% CI, .10-.86) compared with the persistent group. The risk of de novo gastric cancer in absence of H pylori was also much lower compared with the persistent group (HR, .24; 95% CI, .09-.60). Low serum HDL increased the risk of de novo gastric cancer (HR, 2.67; 95% CI, 1.14-6.16).

CONCLUSIONS

Successful H pylori eradication reduced de novo gastric cancer, whereas low HDL increased its risk.

CDX1 Expression Induced by CagA-Expressing Helicobacter pylori Promotes Gastric Tumorigenesis

Intestinal-type gastric cancer often results from Helicobacter pylori infection through intestinal metaplasia, a transdifferentiated premalignant phenotype. Because H. pylori virulence factor CagA has been associated with aberrant expression of the transcription factor CDX1, which regulates intestinal differentiation, we explored its relationship with H. pylori infection and function during gastric carcinogenesis in normal gastric epithelial cells and gastric cancer cell lines. Infection of HFE 145 cells with CagA⁺ H. pylori increased expression of CDX1, as well as the epithelial-to-mesenchymal transition (EMT) markers Snail and Slug, increased invasion and migration, but those effects were not found in HFE 145 cells infected with CagA-deficient H. pylori. CDX1 overexpression increased expression of the intestinal markers Villin, sucrose isomaltase (SI), and MUC2, induced spheroid formation, and enhanced expression of the stem cell markers CD44, SOX2, Oct4, and Nanog, while CDX1 knockdown inhibited proliferation and intestinal stemness. Treatment of CDX1-expressing cells with metformin, an antidiabetic drug known to decrease the risk of gastric cancer, decreased expression of EMT and stemness markers, and reduced spheroid formation. In a murine xenograft model, combining metformin or shCDX1 with cisplatin reduced tumor growth, increased caspase-3 cleavage, and reduced expression of CD44 and MMP-9 to a greater degree than cisplatin alone. Patients with more advanced intestinal metaplasia staging exhibited higher CDX1 expression than those with earlier intestinal metaplasia staging (P = 0.039), and those with H. pylori tended to have more CDX1 expression than noninfected patients (P = 0.061). Finally, human tissue samples with higher CDX1 levels showed prominent CD44/SOX2 expression. Our findings indicate CagA⁺ H. pylori-induced CDX1 expression may enhance gastric cancer tumorigenesis and progression, and support therapeutic targeting of CDX1 in gastric cancer. IMPLICATIONS: This study shows that CDX1 contributes to the tumorigenesis and progression of gastric cancer and suggests the potential of targeting CDX1 to treat this malignancy.

Monitoring circulating tumor DNA by analyzing personalized cancer-specific rearrangements to detect recurrence in gastric cancer

Circulating tumor DNA (ctDNA) has emerged as a candidate biomarker for cancer screening. However, studies on the usefulness of ctDNA for postoperative recurrence monitoring are limited. The present study monitored ctDNA in postoperative blood by employing cancer-specific rearrangements. Personalized cancer-specific rearrangements in 25 gastric cancers were analyzed by whole-genome sequencing (WGS) and were employed for ctDNA monitoring with blood up to 12 months after surgery. Personalized cancer-specific rearrangements were identified in 19 samples. The median lead time, which is the median duration between a positive ctDNA detection and recurrence, was 4.05 months. The presence of postoperative ctDNA prior to clinical recurrence was significantly correlated with cancer recurrence within 12 months of surgery (P = 0.029); in contrast, no correlation was found between cancer recurrence and the presence of preoperative ctDNA, suggesting the clinical usefulness of postoperative ctDNA monitoring for cancer recurrence in gastric cancer patients. However, the clinical application of ctDNA can be limited by the presence of ctDNA non-shedders (42.1%, 8/19) and by inconsistent postoperative ctDNA positivity.

Fragments of tumor DNA, or circulating tumor DNA (ctDNA), in blood can help predict stomach cancer recurrence within 12 months of surgery. Kyeong-Man Hong at the National Cancer Center, in Goyang-si, South Korea, and colleagues, carried out whole genome sequencing of stomach tumor samples from 25 patients to identify personalized cancer-specific rearranged DNA sequences. When they used this information to monitor ctDNA in blood samples obtained after surgical removal of the tumor, they found a significant correlation between the presence of ctDNA and cancer recurrence. In most cases, ctDNA was detected around four months prior to clinical recurrence, highlighting the potential usefulness of ctDNA monitoring. The lack of correlation between ctDNA levels and tumor size suggests that further research into the factors determining ctDNA levels is needed.

Inter-observer Reproducibility in the Pathologic Diagnosis of Gastric Intraepithelial Neoplasia and Early Carcinoma in Endoscopic Submucosal Dissection Specimens: A Multi-center Study

PURPOSE

The diagnostic criteria of gastric intraepithelial neoplasia (IEN) are controversial across the world. We investigated how many discrepancies occur in the pathologic diagnosis of IEN and early gastric carcinoma in endoscopic submucosal dissection (ESD) specimens, and evaluated the reasons of the discordance.

Materials and Methods

We retrospectively reviewed 1,202 ESD specimens that were originally diagnosed as gastric IEN and early carcinoma at 12 institutions.

RESULTS

The final consensus diagnosis of carcinoma were 756 cases, which were originally 692 carcinomas (91.5%), 43 high-grade dysplasias (5.7%), 20 low-grade dysplasias (2.6%), and 1 others (0.1%), respectively. High- and low-grade dysplasia were finally made in 63 and 342 cases, respectively. The diagnostic concordance with the consensus diagnosis was the highest for carcinoma (91.5%), followed by low-grade dysplasia (86.3%), others (63.4%) and high-grade dysplasia (50.8%). The general kappa value was 0.83, indicating excellent concordance. The kappa values of individual institutions ranged from 0.74 to 1 and correlated with the proportion of carcinoma cases. The cases revised to a final diagnosis of carcinoma exhibited both architectural abnormalities and cytologic atypia. The main differential points between low- and high-grade dysplasias were the glandular distribution and glandular shape. Additional features such as the glandular axis, surface maturation, nuclear stratification and nuclear polarity were also important.

CONCLUSION

The overall concordance of the diagnosis of gastric IEN and early carcinoma in ESD specimens was excellent. It correlated with the proportion of carcinoma cases, demonstrating that the diagnostic criteria for carcinoma are more reproducible than those for dysplasia.

MSI-GC-01: Individual patient data (IPD) meta-analysis of microsatellite instability (MSI) and gastric cancer (GC) from four randomized clinical trials (RCTs)

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Background: In CLASSIC and MAGIC, MSI was a good prognostic factor, and adjuvant/perioperative chemotherapy had null/detrimental effect. Given the low prevalence of MSI in GCs and its association with other good prognostic variables, larger datasets are needed to draw more robust evidences on its specific prognostic/predictive impact. Methods: This was a multinational IPD meta-analysis of resectable GC pts enrolled in MAGIC, CLASSIC, ARTIST, ITACA-S. Data on pts’ demographics (age, sex, and race), primary site (stomach versus junctional), histotype (intestinal vs. other), T/N stage (7th TNM), treatment received (multimodal therapy vs. surgery alone) and MSI were pooled. Univariable and multivariable associations with disease-free survival (DFS)/overall survival (OS) were assessed. The predictive role of MSI according to treatment received was assessed overall and in the 2 RCTs with a surgery alone arm (MAGIC+CLASSIC). Results: We pooled 1,552 pts with available MSI status: 121 (7,8%) were MSI, 572 Caucasian/980 Asian. In MSI versus MSS subgroups, 5-y DFS was 71.8% (95% CI: 63.8-80.7%) versus 52.3% (49.6-55.0%) (HR = 0.50, 95% CI 0.35-0.72; p < 0.001); 5-y OS 77.4% (69.9-85.8%) versus 59.2% (56.6-62.0%) (HR = 0.50, 95% CI 0.34-0-74; p < 0.001). In multivariable analyses, MSI was independently associated with DFS (HR = 0.48 [0.33-0.70]; p < 0.001) and OS (HR = 0.48 [0.29-0.81]; p = 0.005), as T/N/race/treatment. Conclusions: In resectable primary GC, MSI is an independent good prognostic marker that should be adopted as stratification factor in future RCTs. Chemotherapy omission and/or immune checkpoint blockade should be prospectively investigated in MSI-high GCs according to the clinically-defined risk of relapse. [Table: see text]

Risk Factors for Lymph Node Metastasis in Undifferentiated-Type Gastric Carcinoma

Undifferentiated-type carcinoma has a high incidence of lymph node metastasis. The independent risk factors for lymph node metastasis in undifferentiated-type carcinoma are invasion depth, tumor size, lymphovascular invasion, and presence of ulcer. In the cases that meet the curative resection criteria, no lymph node metastasis was observed in the Japanese studies, but some metastases were observed in Korean studies. After performing curative endoscopic submucosal dissection, the survival rate is similar to that of gastrectomy. The discrepancy between endoscopy and pathology is high in undifferentiated-type carcinoma. The tumor size in endoscopy is a significant risk factor for non-curative resection, and when the tumor size is small, the non-curative resection rate is significantly reduced. Lymphovascular invasion can be assessed in pathologic examination and D2-40 stain is helpful. The presence of ulcer should be determined by pathology, but ulcer's omission in pathology report makes the analysis difficult. Undifferentiatedtype carcinomas with differentiated-type components show higher lymph node metastasis rate than that of pure undifferentiatedtype carcinomas. The lymph node metastasis rate of signet ring cell type is lower than that of other undifferentiated-type carcinomas and is similar to differentiated-type carcinomas. The application of these additional histologic findings may improve the indication of endoscopic submucosal dissection.

Association of current Helicobacter pylori infection and metabolic factors with gastric cancer in 35,519 subjects: A cross-sectional study

Background

The effect of current infection of Helicobacter pylori on gastric cancer has rarely been studied in a large population. We investigated the association of current H. pylori infection and metabolic factors with gastric cancer in a large population.

Methods

Persons who made their first visit to the National Cancer Center for a health examination, including endoscopy and H. pylori testing using gastric tissue between 2003 and 2013, were included. The association of H. pylori with gastric cancer was estimated using odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Among 35,519 people, 113 gastric cancer and 158 gastric dysplasia cases were detected. In the adjusted analysis, gastric cancer was associated with current H. pylori infection (OR, 2.39; 95% CI, 1.53-3.74), age (OR, 1.06; 95% CI 1.04-1.08), first-degree relatives with gastric cancer (OR, 2.08; 95% CI, 1.30-3.32) and hyperglycaemia (OR, 1.66; 95% CI, 1.04-2.65), whereas it was inversely associated with high-density lipoprotein (HDL) (OR, 0.49; 95% CI, 0.22-0.94). In the subanalysis, gastric cancer was associated with first-degree relatives with gastric cancer (OR, 3.23; 95% CI, 1.39-7.50) in the absence of H. pylori, whereas it was associated with hyperglycaemia (OR, 1.98; 95% CI, 1.16-3.39) in the presence of H. pylori.

Conclusions

Gastric cancer was associated with current H. pylori infection, hyperglycaemia, and low HDL levels in a large population.

Phase I trial of intravenous Ad5CRT in patients with liver metastasis of gastrointestinal cancers

We conducted a phase 1 trial for single-dose intravenous Ad5CRT, a replication-defective adenovirus vector expressing HSVtk (herpes simplex virus thymidine kinase) modulated by a specific trans-splicing ribozyme that targets human telomerase reverse transcriptase (hTERT)-encoding RNAs. Dose-limiting toxicities (DLTs) were evaluated in 15 patients at dose levels of 0.1-2 × 10¹² virus particles. Patients well tolerated study treatment. During the DLT evaluation period, none of the 15 patients developed any grade 4 toxicities or treatment discontinuation that was related to agents investigated by this trial. The most frequent treatment-related adverse event was fever/chill (26.7%). Of the 18 patients, no patients achieved a partial or complete response, and the median progression-free survival for 18 patients was 1.1 months (95% CI, 1.0-1.3) and the results suggest no clinical benefit from this treatment. Ad5CRT's circulating virus half-life was approximately 10 min. Maximum tolerated dose was 2 × 10¹² virus particles. Single-dose intravenous Ad5CRT was feasible and well tolerated in patients with gastrointestinal cancer liver metastasis. Ad5CRT did not provide meaningful clinical benefit, and the reason for the lack of efficacy was not entirely clear because no pharmocodynamic assessment was made.

Prevalence and Implications of Bone Marrow Involvement in Patients with Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Background/Aims

Mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach is an uncommon disease. Bone marrow involvement is reported even in patients with only a mucosal lesion. We evaluated the prevalence and risk factors of marrow involvement and its implications for diagnosis and treatment.

Methods

In total, 132 patients who were diagnosed with gastric MALT lymphoma at the National Cancer Center in Korea between January 2001 and December 2016 were enrolled in the study. The patient data were collected and analyzed retrospectively.

Results

Of the 132 patients, 47 (35.6%) were male, with a median age of 52 years (range, 17 to 81 years). The median follow-up duration was 48.8 months (range, 0.5 to 169.9 months). Helicobacter pylori infection was detected in 82 patients (62.1%). Most patients (80.3%) had stage IE1 according to the modified Ann Arbor staging system. Ninety-two patients underwent bone marrow evaluation, and four patients (4.3%) had marrow involvement. Of these patients, one presented with abdominal lymph node involvement, while the other three had stage IE1 disease if marrow involvement was disregarded. All three patients had no significant symptoms and were monitored after local treatment without evidence of disease aggravation.

Conclusions

Bone marrow involvement was found in 4.3% of the patients with gastric MALT lymphoma. Bone marrow examination may be deferred because marrow involvement does not change the treatment options or outcome in gastric MALT lymphoma confined to the stomach wall.

Body mass index and mortality in patients with gastric cancer: a large cohort study

BACKGROUND

The effects of obesity on prognosis in gastric cancer are controversial.

AIMS

To evaluate the association between body mass index (BMI) and mortality in patients with gastric cancer.

METHODS

A single-institution cohort of 7765 patients with gastric cancer undergoing curative gastrectomy between October 2000 and June 2016 was categorized into six groups based on BMI: underweight (< 18.5 kg/m²), normal (18.5 to < 23 kg/m²), overweight (23 to < 25 kg/m²), mildly obese (25 to < 28 kg/m²), moderately obese (28 to < 30 kg/m²), and severely obese (≥ 30 kg/m²). Hazard ratios (HRs) for overall survival (OS) and disease-specific survival (DSS) were calculated using Cox proportional hazard models.

RESULTS

We identified 1279 (16.5%) all-cause and 763 (9.8%) disease-specific deaths among 7765 patients over 83.05 months (range 1.02-186.97) median follow-up. In multivariable analyses adjusted for statistically significant clinicopathological characteristics, preoperative BMI was associated with OS in a non-linear pattern. Compared with normal-weight patients, underweight patients had worse OS [HR 1.42; 95% confidence interval (CI) 1.15-1.77], whereas overweight (HR 0.84; 95% CI 0.73-0.97), mildly obese (HR 0.77; 95% CI 0.66-0.90), and moderately obese (HR 0.77; 95% CI 0.59-1.01) patients had better OS. DSS exhibited a similar pattern, with lowest mortality in moderately obese patients (HR 0.58; 95% CI 0.39-0.85). Spline analysis showed the lowest all-cause mortality risk at a BMI of 26.67 kg/m².

CONCLUSION

In patients undergoing curative gastric cancer surgery, those who were overweight or mildly-to-moderately obese (BMI 23 to < 30 kg/m²) preoperatively had better OS and DSS than normal-weight patients.

The distribution pattern of metastatic lymph nodes after non-curative endoscopic resection in early gastric cancer

BACKGROUND AND OBJECTIVES

Additional surgery should be done after non-curative endoscopic resection (ER) in early gastric cancer (EGC) due to the risk of lymph node metastasis (LNM). However, the distribution pattern of LNM in these patients is complicated and unpredictable. The aim of this study is to identify any different distribution patterns of LNM in patients with EGC who underwent additional surgery after non-curative (ER) comparing to those without ER.

METHODS

Patients who underwent surgery for EGC between 2001 and 2016 were included. Enrolled patients were divided into two groups, those who underwent additional surgery after non-curative ER and those who underwent direct surgery without a history of ER. Demographics, tumor characteristics and LNM distribution pattern were analyzed.

RESULTS

Among 4295 patients with EGC, 404 patients had a history of preoperative ER, and 3891 patients did not. After the application of exclusion criteria, 23 (7.1%) of 322 patients undergoing additional surgery had LNM. The additional surgery group showed less LNM, fewer nodal stations and more restricted distribution pattern of LNM.

CONCLUSIONS

The distribution pattern of LNM in EGC is complicated. However, more restricted locoregional LNM could be expected in cases of additional surgery after non-curative ER than after direct surgery.

KMT2C Mutations in Diffuse-Type Gastric Adenocarcinoma Promote Epithelial-to-Mesenchymal Transition

PURPOSE

Lauren diffuse-type gastric adenocarcinomas (DGAs) are generally genomically stable. We identified lysine (K)-specific methyltransferase 2C (KMT2C) as a frequently mutated gene and examined its role in DGA progression.

EXPERIMENTAL DESIGN

We performed whole exome sequencing on tumor samples of 27 patients with DGA who underwent gastrectomy. Lysine (K)-specific methyltransferase 2C (KMT2C) was analyzed in DGA cell lines and in patient tumors.

RESULTS

KMT2C was the most frequently mutated gene (11 of 27 tumors [41%]). KMT2C expression by immunohistochemistry in tumors from 135 patients with DGA undergoing gastrectomy inversely correlated with more advanced tumor stage (P = 0.023) and worse overall survival (P = 0.017). KMT2C shRNA knockdown in non-transformed HFE-145 gastric epithelial cells promoted epithelial-to-mesenchymal transition (EMT) as demonstrated by increased expression of EMT-related proteins N-cadherin and Slug. Migration and invasion in gastric epithelial cells following KMT2C knockdown increased by 47- to 88-fold. In the DGA cell lines MKN-45 and SNU-668, which have lost KMT2C expression, KMT2C re-expression decreased expression of EMT-related proteins, reduced cell migration by 52% to 60%, and reduced cell invasion by 50% to 74%. Flank xenografts derived from KMT2C-expressing DGA organoids, compared with wild-type organoids, grew more slowly and lost their infiltrative leading edge. EMT can lead to the acquisition of cancer stem cell (CSC) phenotypes. KMT2C re-expression in DGA cell lines reduced spheroid formation by 77% to 78% and reversed CSC resistance to chemotherapy via promotion of DNA damage and apoptosis.

CONCLUSIONS

KMT2C is frequently mutated in certain populations with DGA. KMT2C loss in DGA promotes EMT and is associated with worse overall survival.

Three-year interval for endoscopic screening may reduce the mortality in patients with gastric cancer

BACKGROUND

Endoscopic screening has been adopted in South Korea for the national screening of gastric cancer (GC). This study aimed to assess the effect on overall survival of GC patients and determine the optimal endoscopic screening interval.

METHODS

The baseline characteristics and overall survival of GC patients treated at the National Cancer Center, Korea, between 2010 and 2016 were compared between those without a history of endoscopic evaluation (group N) and those in whom the interval between the last endoscopic evaluations and diagnosis of GC was ≤ 1, 1-2, 2-3, 3-4, or > 4 years (groups 1-5, respectively).

RESULTS

A total of 2362 patients met the criteria for the study (1060 in group N and 1302 in groups 1-5). More patients in groups 1-5 were diagnosed with stage I GC (83.7, 83.7, 71.8, 78.2, and 71.6%, respectively) than in group N (62.4%, P < 0.001) and were treated endoscopically (38.8, 33.8, 24.7, 21.8, and 15.5%, respectively, vs. 13.5%; P < 0.001). Group 2 had less-advanced tumor stages (P = 0.001) and was more likely to have received endoscopic treatments (P = 0.026) than group 3. Hazard ratios for death were significantly lower in groups 2 (0.45; 95% confidence interval [CI], 0.32-0.64) and 3 (0.57; 95% CI, 0.33-0.98) than in group N; the decrease was not significant in group 4 (0.49, 95% CI, 0.20-1.20).

CONCLUSIONS

Endoscopic screening every 3 years may reduce the mortality of GC patients, though screenings at least every 2 years may benefit patients with less-advanced stages.

Helicobacter pylori Therapy for the Prevention of Metachronous Gastric Cancer

BACKGROUND

Patients with early gastric cancers that are limited to gastric mucosa or submucosa usually have an advanced loss of mucosal glandular tissue (glandular atrophy) and are at high risk for subsequent (metachronous) development of new gastric cancer. The long-term effects of treatment to eradicate Helicobacter pylori on histologic improvement and the prevention of metachronous gastric cancer remain unclear.

METHODS

In this prospective, double-blind, placebo-controlled, randomized trial, we assigned 470 patients who had undergone endoscopic resection of early gastric cancer or high-grade adenoma to receive either H. pylori eradication therapy with antibiotics or placebo. Two primary outcomes were the incidence of metachronous gastric cancer detected on endoscopy performed at the 1-year follow-up or later and improvement from baseline in the grade of glandular atrophy in the gastric corpus lesser curvature at the 3-year follow-up.

RESULTS

A total of 396 patients were included in the modified intention-to-treat analysis population (194 in the treatment group and 202 in placebo group). During a median follow-up of 5.9 years, metachronous gastric cancer developed in 14 patients (7.2%) in the treatment group and in 27 patients (13.4%) in the placebo group (hazard ratio in the treatment group, 0.50; 95% confidence interval, 0.26 to 0.94; P=0.03). Among the 327 patients in the subgroup that underwent histologic analysis, improvement from baseline in the atrophy grade at the gastric corpus lesser curvature was observed in 48.4% of the patients in the treatment group and in 15.0% of those in the placebo group (P<0.001). There were no serious adverse events; mild adverse events were more common in the treatment group (42.0% vs. 10.2%, P<0.001).

CONCLUSIONS

Patients with early gastric cancer who received H. pylori treatment had lower rates of metachronous gastric cancer and more improvement from baseline in the grade of gastric corpus atrophy than patients who received placebo. (Funded by the National Cancer Center, South Korea; ClinicalTrials.gov number, NCT02407119 .).

Predictive test for chemotherapy response in resectable gastric cancer: a multi-cohort, retrospective analysis

BACKGROUND

Adjuvant chemotherapy after surgery improves survival of patients with stage II-III, resectable gastric cancer. However, the overall survival benefit observed after adjuvant chemotherapy is moderate, suggesting that not all patients with resectable gastric cancer treated with adjuvant chemotherapy benefit from it. We aimed to develop and validate a predictive test for adjuvant chemotherapy response in patients with resectable, stage II-III gastric cancer.

METHODS

In this multi-cohort, retrospective study, we developed through a multi-step strategy a predictive test consisting of two rule-based classifier algorithms with predictive value for adjuvant chemotherapy response and prognosis. Exploratory bioinformatics analyses identified biologically relevant candidate genes in gastric cancer transcriptome datasets. In the discovery analysis, a four-gene, real-time RT-PCR assay was developed and analytically validated in formalin-fixed, paraffin-embedded (FFPE) tumour tissues from an internal cohort of 307 patients with stage II-III gastric cancer treated at the Yonsei Cancer Center with D2 gastrectomy plus adjuvant fluorouracil-based chemotherapy (n=193) or surgery alone (n=114). The same internal cohort was used to evaluate the prognostic and chemotherapy response predictive value of the single patient classifier genes using associations with 5-year overall survival. The results were validated with a subset (n=625) of FFPE tumour samples from an independent cohort of patients treated in the CLASSIC trial (NCT00411229), who received D2 gastrectomy plus capecitabine and oxaliplatin chemotherapy (n=323) or surgery alone (n=302). The primary endpoint was 5-year overall survival.

FINDINGS

We identified four classifier genes related to relevant gastric cancer features (GZMB, WARS, SFRP4, and CDX1) that formed the single patient classifier assay. In the validation cohort, the prognostic single patient classifier (based on the expression of GZMB, WARS, and SFRP4) identified 79 (13%) of 625 patients as low risk, 296 (47%) as intermediate risk, and 250 (40%) as high risk, and 5-year overall survival for these groups was 83·2% (95% CI 75·2-92·0), 74·8% (69·9-80·1), and 66·0% (60·1-72·4), respectively (p=0·012). The predictive single patient classifier (based on the expression of GZMB, WARS, and CDX1) assigned 281 (45%) of 625 patients in the validation cohort to the chemotherapy-benefit group and 344 (55%) to the no-benefit group. In the predicted chemotherapy-benefit group, 5-year overall survival was significantly improved in those patients who had received adjuvant chemotherapy after surgery compared with those who received surgery only (80% [95% CI 73·5-87·1] vs 64·5% [56·8-73·3]; univariate hazard ratio 0·47 [95% CI 0·30-0·75], p=0·0015), whereas no such improvement in 5-year overall survival was observed in the no-benefit group (72·9% [66·5-79·9] in patients who received chemotherapy plus surgery vs 72·5% [65·8-79·9] in patients who only had surgery; 0·93 [0·62-1·38], p=0·71). The predictive single patient classifier groups (chemotherapy benefit vs no-benefit) could predict adjuvant chemotherapy benefit in terms of 5-year overall survival in the validation cohort (p_interaction=0·036 in univariate analysis). Similar results were obtained in the internal evaluation cohort.

INTERPRETATION

The single patient classifiers validated in this study provide clinically important prognostic information independent of standard risk-stratification methods and predicted chemotherapy response after surgery in two independent cohorts of patients with resectable, stage II-III gastric cancer. The single patient classifiers could complement TNM staging to optimise decision making in patients with resectable gastric cancer who are eligible for adjuvant chemotherapy after surgery. Further validation of these results in prospective studies is warranted.

FUNDING

Ministry of ICT and Future Planning; Ministry of Trade, Industry, and Energy; and Ministry of Health and Welfare.

Effect of total number of harvested lymph nodes on survival outcomes after curative resection for gastric adenocarcinoma: findings from an eastern high-volume gastric cancer center

BACKGROUND

Greater lymph node retrieval in gastric cancer improves staging accuracy and may improve survival from increased clearance of nodal micrometastasis. This retrospective cohort study investigated if more lymph nodes removed in gastric cancer increases survival and if such effect is stage-specific due to differential risks of nodal micrometastasis and systemic disease.

METHODS

The prospectively collected database of curatively resected gastric cancer patients in National Cancer Center, South Korea between 2000 and 2009 was reviewed. Disease-free survival (DFS) and overall survival (OS) for all patients and for each stage according to number of lymph nodes examined (1-30, 31-45, > 45) were analyzed.

RESULTS

Of 4049 patients, 96.6% and 98.4% underwent D2 (perigastric and extragastric) lymphadenectomy and had ≥ 15 lymph nodes examined. Mean number of nodes examined was 43. Five-year OS & DFS rates were 83.3% and 80.7%. Patients with > 45 nodes examined had significantly lower DFS (p = 0.002) and OS (p = 0.007) compared to those with 1-30 and 31-45 nodes. However, proportion of patients with > 45 nodes examined increased with stage (p = 0.0005). Per stage, there was no significant difference in DFS and OS according to number of nodes examined except for stage IIIA favoring more nodes (p = 0.018 and p = 0.044, respectively). Similar trend was seen in stage IIB. Number of examined nodes positively correlated with number of pathologic nodes for all patients (r = 0.144, p < .001) but not for stage IIB and IIIA. Number of nodes examined was a significant survival predictor in stage IIIA.

CONCLUSION

Greater lymph node harvest showed improved survival in intermediate-stage gastric cancer.

Effect of biopsy site on detection of gastric cancer high-risk groups by OLGA and OLGIM stages

BACKGROUND/AIMS

The operative link for gastritis assessment (OLGA) and operative link on gastric intestinal metaplasia assessment (OLGIM) staging systems are recommended to assess the severity of gastritis, but the optimal biopsy sites have not been clearly defined. We aimed to investigate whether the scoring of the OLGA and OLGIM stages was affected by the use of different biopsy sites.

METHODS

Between 2014 and 2015, to determine OLGA and OLGIM stages, seven biopsy samples were obtained from the antrum (lesser and greater curvatures [LG] of the antrum and lesser curvature of the angle) and corpus (LG and anterior and posterior walls [AP]) in 247 patients diagnosed with gastritis, gastric adenoma, or adenocarcinoma. The OLGA and OLGIM stages were scored using four different protocols: antrum + angle + corpus LG, antrum + angle + corpus AP, antrum + corpus LG, and antrum + corpus AP. High-risk group included patients who had OLGA or OLGIM stages III and IV.

RESULTS

For the OLGA stage, the angle + antrum + corpus LG protocol placed more patients in the high-risk group (64.4%) than the angle + antrum + corpus AP (55.5%, P < .001), antrum+corpus LG (59.5%, P = .031), and antrum + corpus AP (47.8%, P < .001) protocols. Likewise, for the OLGIM stage, the angle + antrum + corpus LG protocol placed more patients in the high-risk group (48.6%) than the angle + antrum + corpus AP (46.2%, P = .134), antrum + corpus LG (36.8%, P < .001), and antrum + corpus AP (37.2%, P < .001) protocols.

CONCLUSIONS

To prevent underestimation of OLGA and OLGIM stages, it is necessary to include an angle biopsy, and to obtain corpus biopsy specimens from lesser and greater curvature sites rather than from anterior and posterior wall sites.

Factors to improve the interobserver agreement for gastric atrophy and intestinal metaplasia: consensus of definition and criteria

AIMS

Intestinal metaplasia and atrophy of the gastric mucosa are associated with Helicobacter pylori infection and are considered premalignant lesions. The updated Sydney system is used for these parameters, but experienced pathologists and consensus processes are required for interobserver agreement. We sought to determine the influence of the consensus process on the assessment of intestinal metaplasia and atrophy.

METHODS AND RESULTS

Two study sets were used: consensus and validation. The consensus set was circulated and five gastrointestinal pathologists evaluated them independently using the updated Sydney system. The consensus of the definitions was then determined at the first consensus meeting. The same set was recirculated to determine the effect of the consensus. The second consensus meeting was held to standardise the grading criteria and the validation set was circulated to determine the influence. Two additional circulations were performed to assess the maintainance of consensus and intraobserver variability. Interobserver agreement of intestinal metaplasia and atrophy was improved through the consensus process (intestinal metaplasia: baseline κ = 0.52 versus final κ = 0.68, P = 0.006; atrophy: baseline κ = 0.19 versus final κ = 0.43, P < 0.001). Higher interobserver agreement in atrophy was observed after consensus regarding the definition (pre-consensus: κ = 0.19 versus post-consensus: κ = 0.34, P = 0.001). There was improved interobserver agreement in intestinal metaplasia after standardisation of the grading criteria (pre-standardisation: κ = 0.56 versus post-standardisation: κ = 0.71, P = 0.010).

CONCLUSIONS

This study suggests that interobserver variability regarding intestinal metaplasia and atrophy may result from lack of a precise definition and fine criteria, and can be reduced by consensus of definition and standardisation of grading criteria.

Non-exposure simple suturing endoscopic full-thickness resection (NESS-EFTR) versus laparoscopic wedge resection: a randomized controlled trial in a porcine model

BACKGROUND

Current endoscopic full-thickness resection (EFTR) methods produce transmural communication and expose the tumor to the peritoneum. An EFTR method with a simple suturing technique that does not expose the gastric mucosa to the peritoneum (non-exposure simple suturing, NESS) was recently developed. To date, there have been no prospective studies that compare EFTR with laparoscopic wedge resection in human or animal. The aim of this study was to compare outcomes between NESS-EFTR and laparoscopic wedge resection (LWR) using the linear staplers in a randomized animal study.

METHODS

NESS-EFTR includes steps of laparoscopic seromuscular suturing, EFTR of the inverted stomach wall, and endoscopic mucosal suturing with endoloops and clips. Sixteen pigs underwent NESS-EFTR (n = 8) or LWR (n = 8). The resected locations were the cardia, fundus, upper body anterior and greater curvature, antrum lesser and greater curvature side. The pigs were killed 3 weeks after surgery. Rates of successful complete resection (en-bloc resection with clear margins), successful closure, and complications were evaluated.

RESULTS

The complete resection rates in the NESS-EFTR and LWR groups were 100 and 75%, respectively (P = 0.467). All wounds were successfully closed in both groups. Resected tissues were significantly larger in the LWR group (mean ± SD: 8.0 ± 0.8 cm vs. 4.4 ± 0.5 cm, P < 0.001). Procedure time was significantly shorter in the LWR group (31.7 ± 10.0 min vs. 118.1 ± 23.4 min, P < 0.001). Early deaths due to complications only occurred in the LWR group (a leakage at cardia and a stenosis at the antrum lesser curvature side).

CONCLUSIONS

Incomplete resection and complications were occurred in only LWR group. NESS-EFTR was feasible and safe in animal.

Sporadic Early-Onset Diffuse Gastric Cancers Have High Frequency of Somatic CDH1 Alterations, but Low Frequency of Somatic RHOA Mutations Compared With Late-Onset Cancers

BACKGROUND & AIMS

Early-onset gastric cancer, which develops in patients younger than most gastric cancers, is usually detected at advanced stages, has diffuse histologic features, and occurs more frequently in women. We investigated somatic genomic alterations associated with the unique characteristics of sporadic diffuse gastric cancers (DGCs) from younger patients.

METHODS

We conducted whole exome and RNA sequence analyses of 80 resected DGC samples from patients 45 years old or younger in Korea. Patients with pathogenic germline mutations in CDH1, TP53, and ATM were excluded from the onset of this analysis, given our focus on somatic alterations. We used MutSig2CV to evaluate the significance of mutated genes. We recruited 29 additional early-onset Korean DGC samples and performed SNP6.0 array and targeted sequencing analyses of these 109 early-onset DGC samples (54.1% female, median age, 38 years). We compared the SNP6.0 array and targeted sequencing data of the 109 early-onset DGC samples with those from diffuse-type stomach tumor samples collected from 115 patients in Korea who were 46 years or older (late onset) at the time of diagnosis (controls; 29.6% female, median age, 67 years). We compared patient survival times among tumors from different subgroups and with different somatic mutations. We performed gene silencing of RHOA or CDH1 in DGC cells with small interfering RNAs for cell-based assays.

RESULTS

We identified somatic mutations in the following genes in a significant number of early-onset DGCs: the cadherin 1 gene (CDH1), TP53, ARID1A, KRAS, PIK3CA, ERBB3, TGFBR1, FBXW7, RHOA, and MAP2K1. None of 109 early-onset DGC cases had pathogenic germline CDH1 mutations. A higher proportion of early-onset DGCs had mutations in CDH1 (42.2%) or TGFBR1 (7.3%) compared with control DGCs (17.4% and 0.9%, respectively) (P < .001 and P = .014 for CDH1 and TGFBR1, respectively). In contrast, a smaller proportion of early-onset DGCs contained mutations in RHOA (9.2%) than control DGCs (19.1%) (P = .033). Late-onset DGCs in The Cancer Genome Atlas also contained less frequent mutations in CDH1 and TGFBR1 and more frequent RHOA mutations, compared with early-onset DGCs. Early-onset DGCs from women contained significantly more mutations in CDH1 or TGFBR1 than early-onset DGCs from men. CDH1 alterations, but not RHOA mutations, were associated with shorter survival times in patients with early-onset DGCs (hazard ratio, 3.4; 95% confidence interval, 1.5-7.7). RHOA activity was reduced by an R5W substitution-the RHOA mutation most frequently detected in early-onset DGCs. Silencing of CDH1, but not RHOA, increased migratory activity of DGC cells.

CONCLUSIONS

In an integrative genomic analysis, we found higher proportions of early-onset DGCs to contain somatic mutations in CDH1 or TGFBR1 compared with late-onset DGCs. However, a smaller proportion of early-onset DGCs contained somatic mutations in RHOA than late-onset DGCs. CDH1 alterations, but not RHOA mutations, were associated with shorter survival times of patients, which might account for the aggressive clinical course of early-onset gastric cancer. Female predominance in early-onset gastric cancer may be related to relatively high rates of somatic CDH1 and TGFBR1 mutations in this population.

Clinical impact of microsatellite instability in patients with stage II and III gastric cancer: Results from the CLASSIC trial

4022

Background: The clinical implications of microsatellite instability (MSI) in gastric cancer are unclear. We investigated the usefulness of MSI status as a predictor of prognosis and responsiveness to adjuvant chemotherapy in patients with stage II and III gastric cancer. Methods: Tumor specimens and clinical information were collected from patients enrolled in the CLASSIC trial, a randomized controlled study of capecitabine plus oxaliplatin-based adjuvant chemotherapy. Five mononucleotide markers were used to assess tumor MSI status. Results: Of 592 specimens, 36 (6.1%) were MSI-high (MSI-H), whereas others were MSI-low or microsatellite-stable (MSS). Among 286 patients not treated with adjuvant therapy, those with MSI-H tumors had a better 5-year disease-free survival rate than did those with MSI-low/MSS tumors (hazard ratio adjusted by age, sex, tumor grade, disease stage, tumor location: 0.244 [95% confidence interval, 0.069–0.867]; p = 0.0292). Among 306 patients who received adjuvant chemotherapy, MSI-H status did not correlate with better disease-free survival (adjusted hazard ratio: 0.561 [95% confidence interval, 0.190–1.654]; p = 0.2946). Benefits from adjuvant chemotherapy differed by MSI status; although adjuvant chemotherapy improved disease-free survival among patients with MSI-low/MSS (adjusted hazard ratio: 0.634 [95% confidence interval, 0.485–0.828]; p = 0.0008), no benefit was observed in the MSI-H group (adjusted hazard ratio: 1.877 [95% confidence interval, 0.284–12.390]; p = 0.5130). Conclusions: Among patients with stage II and III gastric cancer, a MSI-H status correlated with a favorable prognosis, and adjuvant chemotherapy benefited those with MSI-L/MSS tumors but not those with MSI-H tumors.

Survival benefit of additional surgery after noncurative endoscopic resection in patients with early gastric cancer

BACKGROUND AND AIMS

Excellent long-term outcome is expected for early gastric cancers (EGCs) after endoscopic submucosal dissection (ESD). However, if ESD is considered noncurative at the pathologic evaluation, additional surgery is recommended. We evaluated whether long-term outcome is compromised if additional surgery is not performed for EGCs that are out-of-indication.

METHODS

We retrospectively analyzed a cohort of patients with EGC not meeting ESD indications whose initial treatment was either ESD (n = 219) or surgery (n = 1799). Among them, 127 patients who underwent additional surgery after initial ESD and 67 patients who did not were matched using propensity scores to patients who initially underwent standard surgery, at a 1:1 ratio. Overall mortality and gastric cancer recurrence were compared.

RESULTS

The overall mortality and gastric cancer recurrence rates were not significantly different between the 127 patients who underwent initial ESD with additional surgery and the corresponding initial standard surgery patients. However, the overall mortality of the 67 patients who underwent ESD without additional surgery (5-year mortality, 26.0%; 95% CI, 13.5%-49.9%) was higher than that of the matched initial standard surgery patients (5-year mortality, 14.5%; 95% CI, 6.3%-33.6%; P = .04). Gastric cancer recurrence was also higher in ESD patients without additional surgery (5-year recurrence, 17.0%; 95% CI, 7.6%-37.8%) than in the matched initial surgery group (0%; P = .002). In multivariate analyses, ESD without additional surgery was a significant risk factor for overall mortality and gastric cancer recurrence.

CONCLUSIONS

Additional surgery should be encouraged after non-curative ESD to obtain long-term outcomes comparable with those of initial standard surgery. (Clinical trial registration number: NCC2015-0093.).