Clinicopathologic and molecular characterization of stages II-IV gastric cancer with Claudin 18.2 expression.

BACKGROUND: Claudin 18.2 (CLDN18.2) is a promising target for targeted therapies in gastric cancer (GC). This study investigated the prevalence of CLDN18.2 expression in patients with stages II-IV GC or gastroesophageal junction (GEJ) adenocarcinoma and its correlation with clinicopathologic features and other crucial GC biomarkers. METHODS: We enrolled 1000 patients diagnosed with stages II-IV GC after surgical treatment. Immunohistochemistry for CLDN18 (43-14A clone), PD-L1 (22C3 pharmDx), HER2, and FGFR2 was performed. CLDN18.2 positivity was defined as moderate-to-strong (2+/3+) membranous staining in ≥75% of tumor cells. CLDN18.2 expression was compared with biomarker expression, Epstein-Barr virus (EBV) association and microsatellite instability status, and clinicopathologic features. RESULT: CLDN18.2 was positive in 34.4% of the patients. CLDN18.2 positivity was significantly higher in the middle and upper thirds than in the lower third gastric location (P < .001), but there was no correlation with age, sex, or stage (P > .05). CLDN18.2 positivity was rare (2.8%) in mucinous adenocarcinoma but frequent (90.9%) in a majority of gastric carcinomas with lymphoid stroma. CLDN18.2 positivity was higher in EBV-associated (P < .001) and PD-L1-positive (PD-L1 CPS ≥ 5) GC (P = .014) but lower in HER2 positive GC (P = .005). CLDN18.2 positivity was not significantly associated with overall survival and disease-free survival. CONCLUSION: This study provides a comprehensive evaluation of CLDN18.2 status and its correlation with the clinicopathologic characteristics of patients with stages II-IV GC in Korea and with crucial biomarkers. It may be valuable for guiding future drug development, expanding treatment options, and ultimately improving patient outcomes in GC.

Laparoscopic Pylorus Preserving Gastrectomy vs Distal Gastrectomy for Early Gastric Cancer; A Multicenter Randomized Controlled Trial (KLASS-04).

OBJECTIVE: To evaluate the long-term outcomes of laparoscopic pylorus preserving gastrectomy (LPPG) with laparoscopic distal gastrectomy (LDG) for early gastric cancer (EGC). SUMMARY BACKGROUND DATA: PPG is considered as a function preserving surgery for EGC. However, there has been no multicenter randomized controlled trial comparing PPG with DG until now. METHODS: A multicenter randomized controlled trial (KLASS-04) with 256 patients with cT1N0M0 gastric cancer located in the mid portion of the stomach was conducted. The primary endpoint was the incidence of dumping syndrome at postoperative 1 year. Secondary endpoints included survival and recurrence, gallstone formation, nutritional parameters, gastroscopic findings, and quality of life (QOL) for 3 years. RESULTS: In the intention-to-treat analyses, there was no difference in the incidence of dumping syndrome at one year postoperatively (13.2% in LPPG vs. 15.8% in LDG, P=0.622). Gallstone formation after surgery was significantly lower in LPPG than in LDG (2.33% vs. 8.66%, P=0.026). Hemoglobin (+0.01 vs. -0.76 gm/dL, P<0.001) and serum protein (-0.15 vs. -0.35 gm/dL, P=0.002) were significantly preserved after LPPG. However, reflux esophagitis (17.8% vs. 6.3%, P=0.005) and grade IV delayed gastric emptying (16.3% vs. 3.9%, P=0.001) were more common in LPPG. Changes in body weight and postoperative QOL were not significantly different between groups. Three-year overall survival and disease-free survival were not different (1 case of recurrence of in each group, P=0.98). CONCLUSIONS: LPPG can be used as an alternative surgical option for cT1N0M0 gastric cancer in the mid portion of the stomach.

Reconstruction Techniques and Associated Morbidity in Minimally Invasive Gastrectomy for Cancer - Insights from the GastroBenchmark and GASTRODATA databases.

OBJECTIVE/BACKGROUND: Various anastomotic and reconstruction techniques are used for minimally invasive total (miTG) and distal gastrectomy (miDG). Their effects on postoperative morbidity have not been extensively studied. METHODS: MiTG and miDG patients were selected from 9356 oncological gastrectomies performed 2017-2021 in 44 centers. Endpoints included anastomotic leakage (AL) rate and postoperative morbidity tested by multivariable analysis. RESULTS: Three major anastomotic techniques (circular stapled (CS); linear stapled (LS); hand sewn (HS)), and three major bowel reconstruction types (Roux (RX); Billroth I (BI); Billroth II (BII)) were identified in miTG (n=878) and miDG (n=3334). Postoperative complications including AL (5.2% vs. 1.1%), overall (28.7% vs. 16.3%) and major morbidity (15.7% vs. 8.2%), as well as 90-day mortality (1.6% vs. 0.5%) were higher after miTG compared with miDG. After miTG, AL rate was higher after CS (4.3%) and HS (7.9%) compared with LS (3.4%). Similarly, major complications (LS: 9.7%, CS: 16.2%, HS: 12.7%) were lowest after LS. Multivariate analysis confirmed anastomotic technique as predictive factor for AL, overall and major complications. In miDG, AL rate (BI: 1.4%, BII 0.8%, RX 1.2%), overall (BI: 14.5%, BII: 15.0%, RX: 18.7%,) and major morbidity (BI: 7.9%, BII: 9.1%, RX: 7.2%), and mortality (BI: 0%, BII: 0.1%, RY: 1.1%%) were not affected by bowel reconstruction. CONCLUSION: In oncologically suitable situations, miDG should be preferred to miTG, as postoperative morbidity is significantly lower. LS should be a preferred anastomotic technique for miTG in Western Centers. Conversely, bowel reconstruction in DG may be chosen according to surgeon's preference.

Diagnostic accuracy and predictors of alpha-synuclein accumulation in the gastrointestinal tract of Parkinson's disease.

The only characteristic of alpha-synuclein (AS) accumulation in the gastrointestinal (GI) tract of Parkinson's disease (PD) found in pathological studies is the "rostrocaudal gradient," which describes the more frequent presence of AS accumulation in the upper GI tract than in the lower GI tract. This study aimed to determine the diagnostic accuracy and identify predictors of AS accumulation in the GI tract of PD patients. The frequency of AS accumulation in the GI tract was compared between PD patients (N = 97) who underwent radical GI surgery for cancer and individually matched controls (N = 94). We evaluated AS accumulation in the neural structures using phosphorylated AS immunohistochemistry. A multivariable logistic regression analysis was conducted to determine the predictors of AS accumulation in the GI tract of PD patients. The frequency of AS accumulation was significantly higher in PD patients (75.3%) than in controls (8.5%, p-value < 0.001). The sensitivity and specificity of the full-layer evaluation were 75.3% and 91.5%, respectively. When the evaluation was confined to the mucosal/submucosal layer, the sensitivity and specificity were 46.9% and 94.7%, respectively. The rostrocaudal gradient of AS accumulation was found in PD patients. The duration from symptom onset to surgery was significantly longer in PD patients with AS accumulation (4.9 ± 4.9 years) than in PD patients without AS accumulation (1.8 ± 4.1 years, p-value = 0.005). Both disease duration and rostrocaudal gradient independently predicted the presence of AS accumulation in the GI tract of PD patients. Our study suggests PD-related AS accumulation in the GI tract follows a temporally increasing but spatially static progression pattern.

Impact of malnutrition and nutritional support after gastrectomy in patients with gastric cancer.

Malnutrition, characterized by altered body composition and impaired function, is particularly prevalent among gastric cancer patients, affecting up to 60% of them. Malnutrition in these patients can manifest both before and after surgery, due to factors such as gastric outlet obstruction, cancer cachexia, and anatomical changes. Notably, total gastrectomy (TG) presents the most significant nutritional challenges. However, function-preserving gastrectomy, such as pylorus-preserving gastrectomy (PPG) and proximal gastrectomy (PG), have shown promise in improving nutritional outcomes. Effective nutritional risk screening and assessment are vital for identifying patients at risk. Nutritional support not only improves nutritional parameters but also reduces complications, enhances quality of life (QoL) and survival rates. Those unable to maintain more than 50% of the recommended intake for over 7 days are recommended for nutritional support. Common methods of nutritional support include oral nutrition supplements (ONS), enteral nutrition (EN), or parenteral nutrition (PN) depending on the patient's status. Effect of perioperative nutritional support remains controversial. Preoperative interventions including ONS and PN have shown mixed results, with selective benefits in patients with sarcopenia or hypoalbuminaemia, while impact of EN in gastric outlet obstruction patients have been positive. In contrast postoperative support appears to be consistent. Tube feeding after TG has shown improvements, and ONS have been effective in reducing weight loss and improving nutritional biomarkers. PN was also associated with benefits such as weight maintenance and QoL. This review explores the mechanisms, assessment, and clinical impact of malnutrition, emphasizing the importance of nutritional support in gastric cancer patients undergoing gastrectomy.

Distinctive Phenotypic and Microenvironmental Characteristics of Neuroendocrine Carcinoma and Adenocarcinoma Components in Gastric Mixed Adenoneuroendocrine Carcinoma.

This study aimed to conduct an in-depth examination of gene expression and microenvironmental profiles of gastric neuroendocrine carcinoma (NEC) and mixed adeno-NEC (MANEC). Tissue microarrays from 55 patients with gastric MANEC (N = 32) or NEC (N = 23) were analyzed using digital spatial profiling (GeoMx DSP, NanoString Technologies). Representative regions of interest were selected from the adenocarcinoma (ADC) portion (ADC-MANEC) and the NEC portion (NEC-MANEC) of the MANEC cores, and pure NEC (pNEC) cores. All regions of interest were separated into epithelial components and stromal components using the masking procedure in the GeoMx platform, followed by transcriptome analysis. Comparison of gene expression between ADC-MANEC and NEC-MANEC/pNEC identified several differentially expressed genes in the epithelial (including PEG10, MAP1B, STMN3, and AKT3) and stromal (FN1, COL1A1, SPARC, and BGN) components. Gene set enrichment analysis revealed that pathways related to the E2F target and G2M checkpoint were more enriched in NEC-MANEC and pNEC than in ADC-MANEC. Deconvolution analysis showed that the microenvironmental profile varied according to histologic differentiation. In ADC-MANEC, intraepithelial infiltrating immune cells were relatively more numerous, whereas fibroblasts in the stroma were more abundant in NEC-MANEC and pNEC. This study confirmed the distinct expression profile of each histologic component of MANEC according to its tumor vs stromal compartment using the DSP platform. Although each component of MANEC shares the same genetic origin, distinctive phenotypes should not be overlooked when managing patients with MANEC. This study provides a useful validation data set for future studies.

An artificial intelligence system for comprehensive pathologic outcome prediction in early gastric cancer through endoscopic image analysis (with video).

BACKGROUND: Accurate prediction of pathologic results for early gastric cancer (EGC) based on endoscopic findings is essential in deciding between endoscopic and surgical resection. This study aimed to develop an artificial intelligence (AI) model to assess comprehensive pathologic characteristics of EGC using white-light endoscopic images and videos. METHODS: To train the model, we retrospectively collected 4,336 images and prospectively included 153 videos from patients with EGC who underwent endoscopic or surgical resection. The performance of the model was tested and compared to that of 16 endoscopists (nine experts and seven novices) using a mutually exclusive set of 260 images and 10 videos. Finally, we conducted external validation using 436 images and 89 videos from another institution. RESULTS: After training, the model achieved predictive accuracies of 89.7% for undifferentiated histology, 88.0% for submucosal invasion, 87.9% for lymphovascular invasion (LVI), and 92.7% for lymph node metastasis (LNM), using endoscopic videos. The area under the curve values of the model were 0.992 for undifferentiated histology, 0.902 for submucosal invasion, 0.706 for LVI, and 0.680 for LNM in the test. In addition, the model showed significantly higher accuracy than the experts in predicting undifferentiated histology (92.7% vs. 71.6%), submucosal invasion (87.3% vs. 72.6%), and LNM (87.7% vs. 72.3%). The external validation showed accuracies of 75.6% and 71.9% for undifferentiated histology and submucosal invasion, respectively. CONCLUSIONS: AI may assist endoscopists with high predictive performance for differentiation status and invasion depth of EGC. Further research is needed to improve the detection of LVI and LNM.

Safety and feasibility of single-incision laparoscopic distal gastrectomy in overweight and obese gastric cancer patients: a propensity score-matched analysis.

BACKGROUND: The technical challenges and safety concerns of single-incision laparoscopic gastrectomy for overweight and obese gastric cancer patients remain unclear. This study aimed to evaluate the safety and feasibility of single-incision laparoscopic distal gastrectomy (SIDG) compared to multiport laparoscopic distal gastrectomy (MLDG) in overweight and obese gastric cancer patients. METHODS: This study retrospectively analyzed overweight and obese patients (body mass index ≥ 25 kg/m2) and pathologic stage T1 primary gastric adenocarcinoma treated with either SIDG or MLDG. The SIDG and MLDG groups were propensity score matched at a 1:2 ratio using age, sex, height, body weight, American Society of Anesthesiologists classification, year of surgery, pathologic N stage, and anastomosis method as covariates. RESULTS: After 1:2 matching, the study included patients who underwent SIDG (n = 179) and MLDG (n = 358). No significant difference in the number of retrieved lymph nodes was found between the SIDG and MLDG groups (52.8 ± 19.3 vs. 53.9 ± 21.0, P = 0.56). Operation times were significantly shorter in the SIDG group (170.8 ± 60.0 min vs. 186.1 ± 52.6 min, P = 0.004). The postoperative hospital length of stay was comparable between the 2 groups (SIDG: 5.9 ± 3.4 days vs. MLDG: 6.3 ± 5.1 days, P = 0.23), as was postoperative complication rate (SIDG: 13.4% vs. MLDG: 12.8%, P = 0.89). CONCLUSIONS: SIDG was shown to be as safe and feasible as MLDG for overweight and obese gastric cancer patients, with comparable early postoperative complication rates without compromising operation time compared to MLDG.

Identification of New Pathogenic Variants of Hereditary Diffuse Gastric Cancer.

Purpose: Hereditary diffuse gastric cancer (HDGC) presents a significant genetic predisposition, notably linked to mutations in the CDH1 and CTNNA1. However, the genetic basis for over half of HDGC cases remains unidentified. The aim of this study is to identify novel pathogenic variants in HDGC and evaluate their protein expression. Materials and Methods: Among 20 qualifying families, two were selected based on available pedigree and DNA. Whole genome sequencing (WGS) on DNA extracted from blood and whole exome sequencing (WES) on DNA from formalin-fixed paraffin-embedded tissues were performed to find potential pathogenic variants in HDGC. After selection of a candidate variant, functional validation and enrichment analysis were performed. Results: As a result of WGS, three candidate germline mutations (EPHA5, MCOA2, and RHOA) were identified in one family. After literature review and in silico analyses, the RHOA mutation (R129W) was selected as a candidate. This mutation was found in two gastric cancer patients within the family. In functional validation, it showed RhoA overexpression and a higher GTP-bound state in the RhoaR129W mutant. Decreased phosphorylation at Ser127/397 suggested altered YAP1 regulation in the Rho-ROCK pathway. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses linked RhoAR129W overexpression to changed migration/adhesion in MKN1 cell line. However, this RHOA mutation (R129W) was not found in index patients in other families. Conclusion: The RHOA mutation (R129W) emerges as a potential causative gene for HDGC, but only in one family, indicating a need for further studies to understand its role in HDGC pathogenesis fully.

Effector Function Characteristics of Exhausted CD8+ T-cell in Microsatellite Stable and Unstable Gastric Cancer.

Purpose: Gastric cancer exhibits molecular heterogeneity, with the microsatellite instability high (MSI-H) subtype drawing attention for its distinct features. Despite a higher survival rate, MSI-H gastric cancer lack significant benefits from conventional chemotherapy. The immune checkpoint inhibitors (ICIs), presents a potential avenue, but a deeper understanding of the tumor immune microenvironment of MSI-H gastric cancer is essential. Materials and Methods: We explored the molecular characteristics of CD8+ T cell subtypes in three MSI-H and three microsatellite stable (MSS) gastric cancer samples using single-cell RNA sequencing and spatial transcriptome analysis. Results: In MSI-H gastric cancer, significantly higher proportions of effector memory T cell (Tem), exhausted T cell (Tex), proliferative exhausted T cell (pTex), and proliferative T cell were observed, while MSS gastric cancer exhibited significantly higher proportions of mucosal-associated invariant T (MAIT) cell and NKT cell. In MSI-H gastric cancer, Tex and pTex exhibited a significant upregulation of the exhaustion marker LAG3, as well as elevated expression of effector function markers such as IFNG, GZMB, GZMH, and GZMK, compared to those in MSS gastric cancer. The IFN-γ signaling pathway of Tex and pTex was retained compared to those of MSS gastric cancer. The spatial transcriptome analysis demonstrates the IFN-γ signaling pathway between neighboring Tex and malignant cell, showcasing a significantly elevated interaction in MSI-H gastric cancer. Conclusion: Our study reveals novel finding indicating that IFN-γ signaling pathway is retained in Tex and pTex of MSI-H gastric cancer, offering a comprehensive perspective for future investigations into immunotherapy for gastric cancer.

RNA expression of 6 genes from metastatic mucosal gastric cancer serves as the global prognostic marker for gastric cancer with functional validation.

BACKGROUND: Molecular analysis of advanced tumors can increase tumor heterogeneity and selection bias. We developed a robust prognostic signature for gastric cancer by comparing RNA expression between very rare early gastric cancers invading only mucosal layer (mEGCs) with lymph node metastasis (Npos) and those without metastasis (Nneg). METHODS: Out of 1003 mEGCs, all Npos were matched to Nneg using propensity scores. Machine learning approach comparing Npos and Nneg was used to develop prognostic signature. The function and robustness of prognostic signature was validated using cell lines and external datasets. RESULTS: Extensive machine learning with cross-validation identified the prognostic classifier consisting of four overexpressed genes (HDAC5, NPM1, DTX3, and PPP3R1) and two downregulated genes (MED12 and TP53), and enabled us to develop the risk score predicting poor prognosis. Cell lines engineered to high-risk score showed increased invasion, migration, and resistance to 5-FU and Oxaliplatin but maintained sensitivity to an HDAC inhibitor. Mouse models after tail vein injection of cell lines with high-risk score revealed increased metastasis. In three external cohorts, our risk score was identified as the independent prognostic factor for overall and recurrence-free survival. CONCLUSION: The risk score from the 6-gene classifier can successfully predict the prognosis of gastric cancer.

Long-term impact of weight loss in people with class II obesity on the overall burden of disease: Evidence from the National Health Screening Cohort in Korea.

BACKGROUND: Obesity is known to increase overall disease burden but does obesity management actually help reduce disease burden? OBJECTIVES: To investigate the effects of weight loss on disease burden in people with obesity using the National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) in Korea. SETTING: Pure longitudinal observational study using Nationwide cohort database. METHODS: Out of 514,866 NHIS-HEALS cohort, participants with class II obesity in Asia-Pacific region (30 ≤ body mass index [BMI] < 35) who underwent health check-up provided by NHIS during 2003-2004 (index date) were included. All final participants continued to receive a total of 5 biennial health check-ups over the next 10 years without missing. A group-based trajectory model (GBTM) was used to categorize subjects based on 10-year BMI change patterns. The changes of co-morbidities, healthcare resource utilization, and medical cost were analyzed. RESULTS: The final study subjects (9857) were categorized into 3 trajectory clusters based on the pattern of BMI (kg/m2) change: maintenance (57.35%) with an average change of -.02 ± .06, loss (38.65%) with -.04 ± .08, and substantial loss (4.0%) with -.10 ± .18. The annual increases in the number of co-morbidities per subject in each cluster were .18, .18, and .16 (all P < .001), respectively. The increase of healthcare resource utilization over time was lowest for the substantial loss compared to maintenance and loss. With each passing year, the average annual total healthcare cost increased by ₩21,200 ($16.48, P = .034) and ₩10,500 ($8.16, P = .498) in the maintenance and loss, respectively, but decreased by ₩62,500 ($48.59, P = .032) in the substantial loss. CONCLUSIONS: Weight loss in people with obesity was associated with a reduced burden of disease, as evidenced by lower co-morbidity, healthcare resource utilization rate, and decreased medical costs. This study highlights the potential positive long-term impact on Korean society when actively managing weight in individuals with obesity.

Long-Term Outcome of Proximal Gastrectomy for Upper-Third Advanced Gastric and Siewert Type II Esophagogastric Junction Cancer Compared With Total Gastrectomy: A Propensity Score-Matched Analysis.

BACKGROUND: This study aimed to investigate the oncologic long-term safety of proximal gastrectomy for upper-third advanced gastric cancer (AGC) and Siewert type II esophagogastric junction (EGJ) cancer. METHODS: The study enrolled patients who underwent proximal gastrectomy (PG) or total gastrectomy (TG) with standard lymph node (LN) dissection for pathologically proven upper-third AGC and EGJ cancers between January 2007 and December 2018. Propensity score-matching with a 1:1 ratio was performed to reduce the influence of confounding variables such as age, sex, tumor size, T stage, N stage, and tumor-node-metastasis (TNM) stage. Kaplan-Meier survival analysis was performed to analyze oncologic outcome. The prognostic factors of recurrence-free survival (RFS) were analyzed using the Cox proportional hazard analysis. RESULTS: Of the 713 enrolled patients in this study, 60 received PG and 653 received TG. Propensity score-matching yielded 60 patients for each group. The overall survival rates were 61.7 % in the PG group and 68.3 % in the TG group (p = 0.676). The RFS was 86.7 % in the PG group and 83.3 % in the TG group (p = 0.634). The PG group showed eight recurrences (1 anastomosis site, 1 paraaortic LN, 1 liver, 1 spleen, 1 lung, 1 splenic hilar LN, and 2 remnant stomachs). In the multivariate analysis, the operation method was not identified as a prognostic factor of tumor recurrence. CONCLUSION: The patients who underwent PG had a long-term oncologic outcome similar to that for the patients who underwent TG for upper-third AGC and EGJ cancer.

Targeting Stem Cells and Dysplastic Features With Dual MEK/ERK and STAT3 Suppression in Gastric Carcinogenesis.

BACKGROUNDS & AIMS: Precancerous metaplasia progression to dysplasia can increase the risk of gastric cancers. However, effective strategies to specifically target these precancerous lesions are currently lacking. To address this, we aimed to identify key signaling pathways that are upregulated during metaplasia progression and critical for stem cell survival and function in dysplasia. METHODS: To assess the response to chemotherapeutic drugs, we used metaplastic and dysplastic organoids derived from Mist1-Kras mice and 20 human precancerous organoid lines established from patients with gastric cancer. Phospho-antibody array analysis and single-cell RNA-sequencing were performed to identify target cell populations and signaling pathways affected by pyrvinium, a putative anticancer drug. Pyrvinium was administered to Mist1-Kras mice to evaluate drug effectiveness in vivo. RESULTS: Although pyrvinium treatment resulted in growth arrest in metaplastic organoids, it induced cell death in dysplastic organoids. Pyrvinium treatment significantly downregulated phosphorylation of ERK and signal transducer and activator of transcription 3 (STAT3) as well as STAT3-target genes. Single-cell RNA-sequencing data analyses revealed that pyrvinium specifically targeted CD133+/CD166+ stem cell populations, as well as proliferating cells in dysplastic organoids. Pyrvinium inhibited metaplasia progression and facilitated the restoration of normal oxyntic glands in Mist1-Kras mice. Furthermore, pyrvinium exhibited suppressive effects on the growth and survival of human organoids with dysplastic features, through simultaneous blocking of the MEK/ERK and STAT3 signaling pathways. CONCLUSIONS: Through its dual blockade of MEK/ERK and STAT3 signaling pathways, pyrvinium can effectively induce growth arrest in metaplasia and cell death in dysplasia. Therefore, our findings suggest that pyrvinium is a promising chemotherapeutic agent for reprogramming the precancerous milieu to prevent gastric cancer development.

Surgical Outcomes of Laparoscopic-assisted Distal Gastrectomy Versus Totally Laparoscopic Distal Gastrectomy Billroth I for Gastric Cancer.

OBJECTIVE: The present study aimed to compare intraoperative and postoperative outcomes of laparoscopic-assisted distal gastrectomy versus totally laparoscopic distal gastrectomy (TLDG) Billroth I (BI) for gastric cancer and to assess the impact of the initial introduction phase of TLDG BI anastomosis. PATIENTS AND METHODS: The study analyzed the prospectively collected data of patients who underwent laparoscopic distal gastrectomy BI from 2014 to 2021 at Seoul National University Hospital. RESULTS: Among 1116 patients, laparoscopic-assisted distal gastrectomy BI was performed in 566 patients and TLDG BI was performed in 550 patients. The total laparoscopic arm had a faster mean operative time (190 vs 208 min; P < 0.001) and a shorter postoperative hospital stay (7.4 vs 7.9 d; P < 0.001). Local complications were higher in the total laparoscopic group (17.6% vs 9.9%; P = 0.008) during the early introduction phase. CONCLUSION: The total laparoscopic approach for BI reconstruction is safe and effective with faster operative time, shorter hospital stays, and less wound infection, but it may be associated with an increase in postoperative surgical complications and hospital stay in the early introduction phase.

Feasibility and safety of pure single-incision laparoscopic total and proximal gastrectomy for early gastric cancer: propensity score-matched comparison to multiport totally laparoscopic approach.

BACKGROUND: There have been few studies regarding the feasibility and safety of pure single-incision laparoscopic total gastrectomy (SITG) or proximal gastrectomy (SIPG) for early gastric cancer (EGC). The purpose of this study was to analyze the surgical outcome of all consecutive SITG or SIPG cases compared with multiport laparoscopic total gastrectomy (MLTG) or proximal gastrectomy (MLPG) for EGC. METHODS: We analyzed all consecutive SITG or SIPG cases with double-tract reconstruction for ECG, including the initial case, between March 2013 and December 2021. SITG/SIPG was performed on patients without significant systemic comorbidities through a 3-4 cm vertical transumbilical incision. SITG/SIPG was matched to multiport laparoscopic total or proximal gastrectomy (MLTG/MLPG) cases performed in the same period using a 1:3 propensity score matching, including sex, body mass index (BMI), age and type of resection, year of operation, and institution as covariates. We compared perioperative clinicopathological characteristics and early postoperative morbidity within 1 month after surgery between the SITG/SIPG and MLTG/MLPG groups. RESULTS: In total, 21 patients with SITG and 15 patients with SIPG were compared with those with MLTG (n = 264) and MLPG (n = 220). No conversion to an open or multiport approach occurred in the SITG/SIPG group. After matching, operation time was similar between SITG/SIPG and MLTG/MLPG (223.9 ± 63.5 min vs 234.8 ± 68.7 min, P = 0.402). Length of stay was not significantly different between SITG/SIPG and MLTG/MLPG (11.9 ± 15.4 days vs 8.4 ± 5.0 days, P = 0.210). The average number of retrieved lymph nodes was not significantly different between SITG and MLTG (53.1 ± 16.3 vs 63.2 ± 27.5, P = 0.115), but it was significantly higher in SIPG than MLPG (59.6 ± 27.2 vs 46.0 ± 19.7, P = 0.040). The overall complication rate (30.6% vs 25.9%, P = 0.666) and Clavien-Dindo grade III or higher complication rates (13.9% vs 6.5%, P = 0.175) were not significantly different between the SITG/SIPG and MLTG/MLPG groups. CONCLUSION: Cautious adoption of SITG/SIPG procedures for EGC is feasible and safe.

Role of reduction gastrectomy in patients with gastric cancer with a single non-curable factor: Supplementary analysis of REGATTA trial.

Background: REGATTA trial failed to demonstrate the survival benefit of reduction gastrectomy in patients with advanced gastric cancer with a single non-curable factor. However, a significant interaction was found between the treatment effect and tumor location in the subset analysis. Additionally, the treatment effect appeared to be different between Japan and Korea. This supplementary analysis aimed to elucidate the effect of reduction surgery based on tumor location and country. Methods: Multivariable Cox regression analyses in each subgroup were performed to estimate the hazard ratio (HRadj), including the following variables as explanatory variables: country, age, sex, incurable factor, cT, cN, primary tumor, performance status, histological type, and macroscopic type. Results: Patients (95 in Japan and 80 in Korea) were randomized to chemotherapy alone (86 patients) or gastrectomy plus chemotherapy (89 patients). The subgroup analysis according to the country revealed a worse overall survival in gastrectomy plus chemotherapy arm in Japan (hazard ratio: 1.32, 95% confidence interval: 0.85-2.05), but not in Korea (hazard ratio: 0.85.95% confidence interval: 0.52-1.40). Overall survival was better in distal gastrectomy plus chemotherapy compared with chemotherapy alone (hazard ratio = 0.69, 95% confidence interval: 0.42-1.13), and worse in total gastrectomy plus chemotherapy compared with chemotherapy alone (hazard ratio = 1.34, 95% CI: 0.93-1.94), which was more remarkable in Korea than in Japan. Conclusions: Primary chemotherapy is a standard of care for advanced gastric cancer; however, the survival benefits from reduction by distal gastrectomy remained controversial.

Can prospective monitoring improve complication rates after gastrectomy? Experience of Billroth I reconstruction at a high-volume tertiary center.

INTRODUCTION: Prospective database is imperative in surgical outcome monitoring and has shown success in providing a comprehensive complication index to monitor surgical quality. This study aims to review whether prospective monitoring has an effect on postoperative complication rates, especially leakage after Billroth I (BI) anastomosis and to identify risk factors of anastomosis leakage after BI anastomosis. MATERIALS AND METHODS: Patients who underwent distal gastrectomy with BI reconstruction at Seoul National University Hospital between January 2018 and April 2021 were enrolled. Clinicopathological characteristics and perioperative variables were retrieved. The risk factor that was statistically significant in univariate analysis was further analyzed by binomial logistic regression analysis. RESULTS: BI leakage rate in three years has declined by half on a yearly basis from 5.7% to 1.8%. The leakage group patients were predominantly male (100%) when compared to the non-leakage group (67.6%) (p = 0.04). The BMI (25.00 ± 1.42 vs. 24.16 ± 3.15, p = 0.048) and CRP measured on POD#2 (16.47 ± 5.64 vs. 9.99 ± 5.42, p < 0.001) showed significant differences between the two groups. POD#2 CRP greater than 12.7 mg/dL was able to predict risk of anastomosis leak with sensitivity 73.3% and specificity 73.1%. CONCLUSION: Understanding variations in outcomes is important for improvements in surgical care, and through prospective monitoring and intra-departmental feedback, it is possible to reduce complication rates after gastrectomy. This study shows that age, gender and BMI are risk factors to BI leakage and POD#2 CRP greater than 12.7 mg/dL can be used to suspect leakage after BI anastomosis.

Genetic and immune microenvironment characterization of HER2-positive gastric cancer: Their association with response to trastuzumab-based treatment.

BACKGROUND: We aimed to determine the molecular and immune microenvironment characteristics of HER2-positive gastric cancer (GC) related to the patient's response to first-line trastuzumab-based treatment. METHODS: Eighty-three cases of HER2-positive advanced gastric adenocarcinoma patients treated with trastuzumab were enrolled. Targeted deep sequencing and transcriptome analysis were performed on selected 21 cases (exploration cohort) along with two post-treatment samples. The results were compared between patients progressed before 6 months (Group 2) and others (Group 1), and were validated by FISH and immunohistochemistry in total cohort. Tumor-infiltrating immune cells were evaluated using RNA sequencing data and multiplex immunohistochemistry. Progression-free survival (PFS) analysis was performed. RESULTS: Group 1 showed frequent amplification of G1/S cell cycle checkpoint-related genes and upregulated KEGG pathways related to cell proliferation. In contrast, Group 2 had more frequent EGFR, HER3, and MET amplification and higher RNA expression in immune-related KEGG pathways than Group 1. In total cohort, significant predictors of better PFS were cell cycle-related including CCNE1 amplification, Cyclin A and PLK1 overexpression, and decreased Cyclin D3 and HER3 expression (p < 0.05), or immune-related including high density of CD3- CD57+ NK cells and PD-L1 combined positive score ≥5 (p < 0.05). The best prognostic predictors were a combination of Cyclin A, Cyclin E, p21, and HER3 (p < 0.001). CONCLUSION: HER2-positive GC with favorable response to trastuzumab were characterized by cell cycle-related gene alterations and increased CD3- CD57+ NK cell infiltration. These findings would be helpful to the fine modulation of therapeutic strategies for patients with HER2-positive GC.