An interesting paper reporting the Chinese expert consensus for sentinel node navigation surgery (SNNS) was recently published in Chinese Journal of Cancer Research(CJCR) (1). Along with the increasing proportion of individuals with early gastric cancer (EGC),clinical interest in minimally invasive function-preserving surgeries such as SNNS,pylorus-preserving and proximal gastrectomy has gradually increased in East Asia (2). However SNNS remains controversial in clinical practice due to the limited evidence and ongoing debate regarding standardized protocols comparing pylorus-preserving and proximal gastrectomy (3). In this context,a Chinese expert consensus for SNNS is meaningful for the advancement of clinical applicability.

Background/Objective: Laparoscopic gastrectomy (LG) and robotic gastrectomy (RG) exhibit similar surgical outcomes in patients with gastric cancer (GC), except for the higher cost associated with RG. Comparative surgical outcome studies after open conversion from laparoscopic (OL) and robotic (OR) gastrectomy in GC are limited. This study aimed to evaluate clinical effectiveness while considering differences in procedural cost. Methods: This retrospective cohort study included a comparative analysis of patients with GC who underwent OL or OR. Inclusion criteria were histologically confirmed adenocarcinoma and curative resection for GC using OL or OR. Exclusion criteria included initially planned open surgery and other laparoscopic or robotic procedures without gastrectomy. Clinicopathological characteristics, as well as short- and long-term surgical outcomes, were compared between groups. Results: Overall, 118 (1.9%) of 6336 LG cases and 10 (2.6%) of 384 RG cases were included (p = 0.3308). Clinicopathological characteristics were statistically comparable between groups. Postoperative complication incidence, evaluated using the Clavien-Dindo classification, was 19.5% and 10% in the OL and OR groups, respectively (p > 0.05). The median hospital stay was 8 and 9.5 days in the OL and OR groups, respectively (p > 0.05). Reasons for open conversion were similar between groups and included adhesion, bleeding, advanced disease, and positive resection margins, among others. Overall 5-year survival was 0.79 (0.72-0.88) and 0.88 (0.67-1.0) in OL and OR, respectively (p = 0.596). Conclusions: Short- and long-term surgical outcomes after OL and OR did not differ statistically. Selection of LG versus RG should be performed with caution.

Background/Objective:Gastric cancer (GC) is a major cause of cancer mortality worldwide. We evaluated whether oral microbiota could be sensitive, specific, and non-invasive markers for early GC detection. Materials and methods:Saliva samples were analyzed using 16S rRNA sequencing, and oral microbial markers were validated using an internal validation dataset. Machine learning was used to identify key genera, and functional associations were inferred using Kyoto Encyclopedia of Genes and Genomes pathway and ortholog analyses. Blood samples were also collected, and plasma cytokines were quantified by enzyme-linked immunosorbent assay (ELISA) for pathway-level interpretations. Results:Eight genera-Lautropia, Megasphaera, Ralstonia, Pseudomonas, Peptostreptococcus, Anaerovorax, Fusobacterium, and Neisseria-were validated as diagnostic microbial markers (area under the receiver operating characteristic curve [AUC] = 0.91). Megasphaera and Ralstonia were enriched in GC, whereas Lautropia was depleted and associated with reduced risk. These genera may be functionally linked to pathways involved in GC progression, including NF-κB, IL-6, STAT3, TGF-β1, and Smad2/3. The proposed classification method effectively identified early-stage and tumor-marker-negative GCs, underscoring its clinical translation potential. Conclusions:Oral microbial markers, including Ralstonia, Megasphaera, and Lautropia, may serve as non-invasive diagnostic markers for GC and may be related to carcinogenic signaling activity.

PURPOSE:The current expanded criteria for endoscopic resection (ER) of early gastric cancer (EGC) include a non-negligible risk of lymph node metastasis (LNM) in submucosal (SM) disease. We had previously proposed revised criteria incorporating the SM invasion width to better stratify LNM risk. In the present study, we aimed to validate whether these revised criteria improved the identification of truly node-negative, differentiated-type pT1b EGC. MATERIAL AND METHODS:This multicenter retrospective study included 712 patients with differentiated-type SM invasive EGC who underwent gastrectomy at 2 tertiary centers between 2016 and 2023. The SM invasion depth and width were re-evaluated, and the diagnostic performance of the conventional, expanded, and revised criteria (tumor size ≤3 cm, SM depth ≤1,000 µm, SM width ≤4 mm, and no lymphovascular/perineural invasion) for predicting LNM was compared. RESULTS:LNM was identified in 16.9% of the patients. An SM invasion width >4 mm was a strong independent predictor of LNM (P<0.001) and demonstrated superior discriminatory ability (area under the receiver operating characteristic curve [AUC], 0.79) in comparison with SM depth (AUC, 0.68) and tumor size (AUC, 0.59). Although the conventional criteria classified 54 cases as curative, the revised criteria classified 83 cases as curative, and no LNM events were observed in both sets of cases. Thus, the revised criteria expanded the potential candidate pool for curative ER by approximately 54% without compromising nodal safety. CONCLUSIONS:SM invasion width can be a significant independent predictor of LNM. The revised criteria, which incorporated SM width, safely expanded the indications for curative ER in patients with differentiated-type SM gastric cancer.

BackgroundPatients undergoing gastrectomy usually experience postgastrectomy syndrome and face difficulties adapting to a regular diet. Human health coaching via a mobile app has recently been applied to patients with chronic metabolic diseases, with significant improvements being observed in clinical outcomes. ObjectiveThis study aimed to compare the quality of life and nutritional outcomes of human health coaching via a mobile app with those of conventional face-to-face counseling in postgastrectomy patients with gastric cancer. MethodsThis was a prospective randomized controlled trial, and patients were enrolled between May 2020 and August 2022. The mobile coaching group received health coaching that provides personalized advice based on self-recorded health data via a mobile app from assigned coaches for 3 months after discharge, and the conventional counseling group underwent dietary consultations with a clinical dietitian 1 and 3 months postoperatively. The primary end point for sample size calculation was the eating restriction score on the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire gastric cancer module 1 month postoperatively. Secondary end points included changes in other subscales of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and gastric cancer module, as well as nutritional outcomes assessed preoperatively and 1, 3, 6, and 12 months postoperatively. ResultsData from 88.9% (160/180) of enrolled patients were analyzed after excluding dropouts. In the mobile coaching group (n=76), 66% (n=50) of patients who used the mobile app for ≥8 weeks were classified as active users. No significant difference in eating restriction 1 month postoperatively was found between the mobile coaching and conventional counseling groups. However, the mobile coaching group reported less dyspnea during the entire period (P=.01), less eating restriction at 6 months (P=.045), and less negative body image 3 months postoperatively (P=.04) than the conventional counseling group (n=84). Exploratory subgroup analyses based on age, sex, and operation type indicated that younger patients (<60 years), female patients, and those who underwent distal gastrectomy had better quality of life from mobile coaching. In the mobile coaching group, exploratory subgroup analyses based on mobile activity showed that active users had a better global health status than inactive users (P=.005). However, no significant differences in body composition or nutritional parameters were observed between the mobile coaching and conventional counseling groups or between active and inactive users in the mobile coaching group. ConclusionsAlthough this trial did not show a significant difference in eating restriction 1 month postoperatively, human coaching via a mobile app was associated with fewer symptoms in some scales compared to conventional counseling in postgastrectomy patients with gastric cancer. The intervention might help patients manage their symptoms and adapt to their diet. Trial RegistrationClinicalTrials.gov NCT04394585; https://clinicaltrials.gov/study/NCT04394585

Modern liquid rocket engine turbopumps implement hybrid bearings, which combine hydrostatic and hydrodynamic fluid film principles, in compact and lightweight units known for their superior reusability, durability, and reliability. This study aims to provide extensive and reliable test data for the purpose of anchoring and benchmarking predictive tools for these bearings. This paper provides comprehensive dynamic response measurements of a rotor weighing 10.40 kg and approximately 60 mm in diameter at the bearing locations. The test rotor is supported on two hybrid journal bearings with a bearing length to bearing diameter ratio of approximately 0.42 and a bearing radial clearance to rotor radius ratio of around 0.0017. The bearings are tested with air, water, and liquid nitrogen, serving as surrogate test fluids for common propellants in liquid rocket engines. Rotor run-up and speed coast-down tests are conducted to measure shaft motion responses. The results clearly demonstrate that the rotordynamic characteristics of the test rotor supported on the hybrid journal bearings largely rely on properties of the test fluids and their feeding conditions. Notably, when air is pressurized into the test bearings, the shaft motion responses differ markedly from those observed with water and liquid nitrogen, primarily due to significantly lower stiffness and damping coefficients. Furthermore, rotor speed coast-down tests for each test fluid exhibit notable differences in coast-down speed over time characteristics, depending on the test fluid properties. The predicted rotor imbalance responses exhibit excellent correlation with the measurement data. The steady increase of demand and growth of the fluid film bearing technology for reusable rocket engines require accurate bearing design tools, the extensive component testing, and the implementation of the technology. The validated and developed bearing predictive models from previous research demonstrate well the characteristics of bearings under various operating fluids conditions. The findings and database presented in this work contribute not only to comprehending the performance of hybrid bearings but also to understanding and enhancing the dynamic characteristics of rotor systems supported by hybrid bearings.

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.

Modern turbomachinery demands simplified components and compact shaft support systems. This study introduces novel hydrostatic journal bearings incorporating multiple tilting pads and fluid feeding features, which are manufactured with Direct Metal Laser Melting (DMLM) technology, an advanced laser powder bed fusion manufacturing process. Two test bearings, fabricated by fusing extremely thin layers of Inconel 718 powder, incorporate fluid external feed pressurization features without the need for recesses. One test bearing features unique internal feeding hole configurations, which combine multiple holes with an angled injection feature, while the other test bearing includes distinctive porous layers on the bearing pad surfaces. This paper provides a comprehensive overview of the design, fabrication process, and static load characteristic measurements of these innovative bearings. A simple static load test rig is used to measure the flow rate, temperature, and stiffnesses of the test bearings while supplying compressed air, water, and liquid nitrogen with increasing static loads. The performance of these bearings is compared with counterparts produced via conventional subtractive manufacturing (CNC machining). In general, the bearings lubricated with liquid nitrogen exhibit a higher load capacity compared to those lubricated with air. This study confirms the static load performance of metal 3D printed hydrostatic journal bearings, marking a significant advancement in the application of additive manufacturing for turbomachinery bearings. The findings offer valuable insights into the potential of additive manufacturing in producing bearings for extreme operating conditions and various lubricants.

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.

Background/Objectives: Delayed gastric emptying (DGE) is a well-known complication of laparoscopic pylorus-preserving gastrectomy (LPPG). Patients who underwent LPPG in the KLASS-04 trial, which was a multicenter prospective randomized control trial comparing LPPG and laparoscopic distal gastrectomy (LDG), showed an unneglectable incidence of long-term DGE compared to patients who underwent LDG. This study aimed to identify the multifactorial risk factors associated with DGE and to analyze the quality of life (QoL) of patients with DGE following LPPG. Methods: DGE was defined as “nearly normal diet residue” at least once in the endoscopic follow-up at 1, 2, and 3 years after the surgery. Clinicopathological features, surgical outcomes, and QoL were compared between the DGE and non-DGE groups. Results: DGE was observed in 21/124 patients (16.3%) who underwent LPPG. Patients without previous abdominal surgery had a higher incidence of DGE in the univariate (32% vs. 4.8%, p = 0.011) and logistic regression analyses (odds ratio: 0.106, 95% confidence interval: 0.014–0.824, p = 0.032). Patients with DGE reported more symptoms of nausea and vomiting (p = 0.004), constipation (p = 0.04), and a dry mouth (p = 0.005). Conclusions: Despite the strict protocol used to avoid well-known risk factors for DGE, such as damage to the hepatic branch of the vagus nerve, infrapyloric artery and vein, and short antral cuff, the LPPG group of the KLASS-04 trial exhibited a considerable incidence of DGE. No clinicopathological or surgical factors, other than the absence of a previous surgical history, were identified as multifactorial risk factors for DGE. However, DGE had a negative impact on the QoL of patients.

Hydrostatic journal bearings (HJBs), employed in highspeed turbomachinery under extreme operating conditions, offer enhanced reliability, durability, load-carrying capacity, and stiffness, even when lubricated with low-viscosity fluids. A significant challenge with these bearings, particularly when deep recesses are involved and compressible fluids are used, is the occurrence of pneumatic hammer instability. This phenomenon poses a substantial risk, potentially leading to catastrophic system failures. The focus of this research is to quantify the influence of orifice diameter and recess depth on pneumatic hammer instability in HJBs. The study employs a predictive model, prioritizing the understanding and mitigation of this instability. Key to this research is the examination of volume and pressure ratios, particularly the recess volume to fluid film volume ratio and the recess pressure to supply pressure ratio. These ratios are fundamentally influenced by the orifice diameter and recess depth, which in turn significantly affect the HJBs’ characteristics and susceptibility to pneumatic hammer instability. The current study reveals that both the load-carrying capacity and flow rate of the bearings increase progressively with the recess pressure ratio. Meanwhile, the bearing stiffness peaks at a specific orifice diameter and recess depth, typically where the recess pressure ratio is around 0.6. Under these conditions, the bearings demonstrate maximum stiffness with minimized risk of instability. This research also proposes a framework for selecting design parameters in HJBs, aiming to maximize stiffness while averting pneumatic hammer instability. The effectiveness of these design strategies is validated through experimental data from two test bearings, each with different recess depths and orifice diameters. This work contributes significantly to the field by offering strategies for optimizing HJBs. It provides a balance between achieving high performance and mitigating the risks associated with pneumatic hammer instability. By careful selection of orifice diameter and recess depth, it is possible to attain maximum bearing performance, effectively circumventing the challenges posed by pneumatic hammer instability.

PURPOSE:The aim of this study is to compare the detection ability of quality of life (QoL) changes and responsiveness of the KOrean QUality of life in Stomach cancer patients Study group (KOQUSS)-40 and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ). MATERIALS AND METHODS:A multicenter prospective observational study was conducted to evaluate QoL changes after various gastrectomies between January 2021 and April 2022. Participants were instructed to complete the KOQUSS-40 and EORTC QLQ-C30/STO22 preoperatively and at 1, 3, 6, and 12 months postoperatively. QoL changes over time and QoL responsiveness were assessed for each questionnaire. RESULTS:Data from 491 patients who underwent curative gastrectomy for gastric cancer at 22 institutions were analyzed. The summary scores of the KOQUSS-40 and EORTC QLQ-STO22 showed significant differences between the total and proximal gastrectomy groups (p=0.044 and p=0.038, respectively), but no difference was observed for the EORTC QLQ-C30. Dysphagia on the KOQUSS-40 was significantly different between the total and proximal gastrectomy groups (p=0.031); however, dysphagia on the EORTC QLQ-STO22 did not differ. The responsiveness of the KOQUSS-40 was similar to that of the EORTC QLQ in patients who experienced ≥ 10% body weight loss, but approximately 10% less in patients receiving adjuvant chemotherapy than the EORTC QLQ. CONCLUSION:KOQUSS-40 has several advantages over EORTC QLQ-C30/STO22 when comparing QoL between the total and proximal gastrectomy groups. The findings provide information for researchers investigating the QoL of patients who have undergone curative gastrectomy for gastric cancer.

Background/Objectives: During laparoscopic pylorus-preserving gastrectomy (LPPG), the preservation of the infra-pyloric artery (IPA) and dissection of the infra-pyloric lymph node (LN) station 6 are essential, underscoring the importance of understanding the anatomical structure of the IPA. This study aimed to investigate anatomical variations in the IPA and surgical outcomes based on data from a multicenter prospective trial. Methods: A post hoc analysis was conducted based on the Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS)-04 trial, in which patients randomly underwent LPPG or laparoscopic distal gastrectomy (LDG). The IPA variations were categorized into three groups: distal, caudal, and proximal. Clinicopathological characteristics and surgical outcomes were analyzed according to the IPA type. Results: Among the 192 patients, the distribution of IPA types was as follows: 45 (23.44%) distal, 74 (38.54%) caudal, and 73 (38.02%) proximal. There were no significant differences in the clinicopathological characteristics between the IPA types. Of the 119 patients who underwent LPPG, a significant difference in operative time was observed based on the IPA type, with a longer duration observed with the distal type compared to that of the proximal type (distal type vs. proximal type: 202.5 (150-275) vs. 170 (105-265) min, p = 0.0300). No significant differences were observed in other surgical outcomes. Conclusions: The distribution of IPA types was more diverse than that reported in previous studies. There was a statistically significant difference in the operating time based on the IPA type. Identifying IPA variations during LPPG may be beneficial for gastric cancer surgeons.

Objective:Laparoscopic distal gastrectomy (LDG) has potential as a surgical treatment option for locally advanced gastric cancer (LAGC). However, there is uncertainty regarding the generalizability of LDG efficacy across diverse patient populations and treatment settings. This study aimed to assess the outcomes of LDG vs. open distal gastrectomy (ODG) in patients with LAGC despite differences in clinical trial populations and treatment environments. Methods:The KLASS-02 and CLASS-01 trials are multicenter, non-inferiority, open-label, randomized controlled trials for patients with LAGC eligible for distal subtotal gastrectomy in Korea and China, respectively. Some 1,050 patients were enrolled in KLASS-02, and 1,056 patients were enrolled in CLASS-01. Individual patient data (IPD) from KLASS-02 and CLASS-01 were pooled and analyzed. Results:There were 900 patients in the LDG group and 920 in the ODG group. Baseline characteristics were well balanced between groups. The LDG group had better short-term and recovery outcomes than the ODG group, although anastomotic leakage was more frequent. For patients who underwent LDG vs. ODG, 5-year overall survival (OS) was 82.7% [95% confidence interval (95% CI), 80.2%-85.2%] vs. 83.3% (95% CI, 80.9%-85.8%) (P=0.706) and 5-year recurrence-free survival (RFS) was 76.9% (95% CI, 74.1%-79.7%) vs. 77.9% (95% CI, 75.2%-80.6%) (P=0.666), respectively, with a median follow-up of 70 months. In the multivariable prognostic IPD meta-analysis, the operative approach was not independently associated with OS [hazard ratio (HR)=1.045, 95% CI, 0.833-1.311; P=0.706] or RFS (HR=1.044, 95% CI, 0.859-1.269; P=0.667) for LDG vs. ODG. In the subgroup analysis, LDG demonstrated a significant association with poorer RFS in the pT4 subgroup (HR=1.377, 95% CI, 1.022-1.760; P=0.034). Conclusions:Despite differences in patient populations, surgical practices, and postoperative treatments between trials, LDG is oncologically safe with the benefit of being minimally invasive for patients with LAGC, except for the pT4 patients. Therefore, LDG could be a good treatment alternative for patients with LAGC; however, caution should be warranted in its application for patients classified as T4.

BACKGROUND:The SENORITA phase III trial demonstrated the effectiveness of laparoscopic sentinel node navigation surgery (LSNNS) in preserving stomach function for patients with early gastric cancer (EGC), although some patients experienced surgical failure or recurrence. The purpose of this study was to analyze patients' clinicopathologic features from the SENORITA trial who were allocated to LSNNS with stomach-preserving surgery but ultimately did not preserve stomach or experienced recurrence. PATIENTS AND METHODS:Patients were categorized into two groups: the failure group (stomach preservation failure or cancer recurrence after LSNNS) and the success group (stomach preservation without recurrence following LSNNS). This study analyzed the detailed clinicopathologic characteristics of patients in the failure group from the SENORITA trial. RESULTS:Among 258 patients who underwent LSNNS, 193 patients (74.8%) achieved stomach preservation, while 65 patients (25.2%) failed to preserve. Intraoperative failure was the most common cause of unsuccessful stomach preservation, occurring in 35 of 65 cases (53.8%). Advanced pathological TNM stage was the only independent risk factor by multivariate analysis, with stage IB and IIA patients showing 5.9- and 45.0-fold higher failure risks. The main causes of failure included sentinel basin detection failure, metastatic lymph nodes, positive tumors at resection margins, and complications. The failure group also included five cases of gastric cancer recurrence following LSNNS. CONCLUSION:Accurate preoperative staging and patient selection are crucial for optimizing LSNNS outcomes. Ensuring precise resection with an adequate number of harvested sentinel basin nodes is essential to succeed the stomach-preserving surgery.

Hydrostatic thrust bearings are required in various turbomachinery systems due to their substantial load capacity and superior rotor axial positioning capabilities, which minimize friction and heat generation. However, when lubricated with compressible fluids, these bearings can experience pneumatic hammer instability especially if the recess volume is significant. This study aims to establish design guidelines and experimentally validate the performance of hydrostatic thrust bearings, with a focus on predicting and mitigating pneumatic hammer instability. The research includes an investigation into the static load characteristics of these bearings when operated with air as the lubricant. The analysis in this paper covers the effects of varying supply pressures, recess depths, and orifice diameters on pneumatic hammer instability, as well as on the load capacity, stiffness, and damping coefficients of the bearings. To validate these findings, experiments are conducted using two test bearings with differing recess depths and orifice diameters. The results from both predictive models and experimental data consistently show that a shallow recess depth is effective in preventing pneumatic hammer instability without notably diminishing the bearing load capacity. Nonetheless, modifying the orifice diameter to control pneumatic hammer instability requires careful design consideration, as it might lead to decreased load capacity and stiffness. This research addresses the challenge of preventing pneumatic hammer instability in hydrostatic thrust bearings through a combined approach of numerical analysis and experimental testing. It contributes significantly to the field by offering practical design recommendations for optimizing recess depth and orifice diameter. These guidelines aim to eliminate pneumatic hammer instability while preserving critical performance aspects of hydrostatic thrust bearings, such as load capacity and stiffness.

Undifferentiated-type (UD-type) gastric cancer is associated with a high frequency of lymph node metastasis (LNM); however, recent reports indicate that LNM frequency varies according to specific histologic components. We conducted a multicenter study to define criteria for distinguishing low- and high-risk histology groups for LNM in UD-type gastric cancers. Histologic components were classified into four types: poorly cohesive signet ring cells (SRC), poorly cohesive non-signet ring cells (non-SRCs), poorly differentiated tubular (PD), and differentiated-type (D-type). Their proportions were measured semi-quantitatively. The proportion of extracellular mucin (EMC) and the predominant histologic components within EMC were also recorded. LNM risk was analyzed based on pathological findings. Overall, 2256 mucosal and 688 submucosal UD-type cancers were analyzed. A higher SRC amount was linked to lower LNM frequency. Non-SRCs showed no association with LNM. Increased PD and D-type were linked to more frequent LNM; however, PD-predominant cases (PD >= 90%) showed paradoxically lower LNM frequency. SRC proportion > 10% was essential for low LNM probability. PD or D-type proportion > 10% is important for high LNM probability. Most compositions with low LNM probability (< 5%) showed a SRC majority (SRC > 50%) and <= 10% of PD or D-type. Pure poorly cohesive carcinomas with > 10% SRC and no PD or D-type were classified as low-risk histology (LNM probability 2.6%-3.4%). We developed a risk assessment method for tumor histology based on the composition of all histologic components and defined criteria to identify low-risk histology for LNM among UD-type cancers.

BACKGROUND:Standard treatment for non-curative endoscopic submucosal dissection (ESD) of early gastric cancer is radical gastrectomy with systematic lymph node dissection. However, the actual incidence of lymph node metastasis was reported to be 5-10%. The aim of this study is to evaluate the feasibility of sentinel basin mapping after non-curative ESD for early gastric cancer. METHODS:This is a multicenter, prospective feasibility study. Patients who underwent ESD for early gastric cancer and had a non-curative resection on final pathology were included. Sentinel basin mapping was performed using one of two methods: (1) endoscopic submucosal injection of a dual tracer, including a radioisotope and indocyanine green (ICG); or (2) fluorescence imaging after ICG injection. Following dissection of the identified sentinel basins, laparoscopic gastrectomy with D1 + lymphadenectomy was performed in all patients. The primary endpoint was the detection rate; secondary endpoints were sensitivity and postoperative complications. RESULTS:A total of 243 patients were enrolled from April 2017 to July 2024, and data from 238 eligible patients were analyzed. The dual tracer and fluorescence imaging with ICG were used in 216 and 22 patients, respectively. The overall detection rate was 97.1% (231/238), and metastatic lymph nodes were observed in 23 patients (9.7%, 23/238). The sensitivity was 69.6% (16/23) with 7 false-negative cases. Univariate analysis to identify risk factors for false-negative events showed that the early study period and institution had a nonsignificant trend. The postoperative complication rate was 10.1%, and the severe complication rate (Clavien-Dindo grade ≥ III) was 2.5%. CONCLUSION:Sentinel basin mapping after non-curative ESD achieved a high detection rate of 97.1%. However, the false-negative rate of 30.4% appears to be unacceptably high from an oncological safety perspective.

Differences in demographics, medical expertise, and patient healthcare resources across countries have led to significant variations in guidelines. In light of these differences, in this review, we aimed to explore and compare the most recent updates to gastric cancer treatment from five guidelines that are available in English. These English-version guidelines, which have been recently published and updated for journal publication, include those published in South Korea in 2024, Japan in 2021, China in 2023, the United States in 2024, and Europe in 2024. The South Korean and Japanese guidelines provide a higher proportion of content to endoscopic and surgical treatments, reflecting their focus on minimally invasive techniques, function-preserving surgeries, and systemic therapy. The Chinese guidelines provide recommendations addressing not only surgical approaches but also perioperative chemotherapy and palliative systemic therapy. Meanwhile, in the United States and European guidelines, a higher proportion of the content is dedicated to perioperative and palliative systemic therapy, aligning with their approaches to advanced-stage disease management. All guidelines address surgical and systemic chemotherapy treatments; however, the proportion and emphasis of content vary based on the patient distribution and treatment approaches specific to each country. With emerging research findings on gastric cancer treatment worldwide, the national guidelines are being progressively revised and updated. Understanding the commonalities and differences among national guidelines, along with the underlying evidence, can provide valuable insights into the treatment of gastric cancer.