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.

Efficacy of Hyperthermic Pressurized Intraperitoneal Aerosol Chemotherapy in an In Vitro Model Using a Human Gastric Cancer AGS Cell Line and an Abdominal Cavity Model.

PURPOSE: Peritoneal carcinomatosis (PC) presents a major challenge in the treatment of late-stage, solid tumors, with traditional therapies limited by poor drug penetration. We evaluated a novel hyperthermic pressurized intraperitoneal aerosol chemotherapy (HPIPAC) system using a human abdominal cavity model for its efficacy against AGS gastric cancer cells. MATERIALS AND METHODS: A model simulating the human abdominal cavity and AGS gastric cancer cell line cultured dishes were used to assess the efficacy of the HPIPAC system. Cell viability was measured to evaluate the impact of HPIPAC under 6 different conditions: heat alone, PIPAC with paclitaxel (PTX), PTX alone, normal saline (NS) alone, heat with NS, and HPIPAC with PTX. RESULTS: Results showed a significant reduction in cell viability with HPIPAC combined with PTX, indicating enhanced cytotoxic effects. Immediately after treatment, the average cell viability was 66.6%, which decreased to 49.2% after 48 hours and to a further 19.6% after 120 hours of incubation, demonstrating the sustained efficacy of the treatment. In contrast, control groups exhibited a recovery in cell viability; heat alone showed cell viability increasing from 90.8% to 94.4%, PIPAC with PTX from 82.7% to 89.7%, PTX only from 73.3% to 74.8%, NS only from 90.9% to 98.3%, and heat with NS from 74.4% to 84.7%. CONCLUSIONS: The HPIPAC system with PTX exhibits a promising approach in the treatment of PC in gastric cancer, significantly reducing cell viability. Despite certain limitations, this study highlights the system's potential to enhance treatment outcomes. Future efforts should focus on refining HPIPAC and validating its effectiveness in clinical settings.

MUC16 as a serum-based prognostic indicator of prometastatic gastric cancer.

Metastatic gastric cancer (GC) presents significant clinical challenges due to its poor prognosis and limited treatment options. To address this, we conducted a targeted protein biomarker discovery study to identify markers predictive of metastasis in advanced GC (AGC). Serum samples from 176 AGC patients (T stage 3 or higher) were analyzed using the Olink Proteomics Target panels. Patients were retrospectively categorized into nonmetastatic, metastatic, and recurrence groups, and differential protein expression was assessed. Machine learning and gene set enrichment analysis (GSEA) methods were applied to discover biomarkers and predict prognosis. Four proteins (MUC16, CAIX, 5'-NT, and CD8A) were significantly elevated in metastatic GC patients compared to the control group. Additionally, GSEA indicated that the response to interleukin-4 and hypoxia-related pathways were enriched in metastatic patients. Random forest classification and decision-tree modeling showed that MUC16 could be a predictive marker for metastasis in GC patients. Additionally, ELISA validation confirmed elevated MUC16 levels in metastatic patients. Notably, high MUC16 levels were independently associated with metastatic progression in T3 or higher GC. These findings suggest the potential of MUC16 as a clinically relevant biomarker for identifying GC patients at high risk of metastasis.

Distinctive phenotypic and microenvironmental characteristics of neuroendocrine carcinoma and adenocarcinoma component 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-neuroendocrine carcinoma (MANEC). Tissue microarrays from 55 patients with gastric MANEC (N=32) or NEC (N=23) were analysed using digital spatial profiling (GeoMx® DSP). Representative regions of interest (ROIs) were selected from the adenocarcinoma portion (ADC-MANEC) and neuroendocrine carcinoma portion (NEC-MANEC) of the MANEC cores, and pure NEC (pNEC) cores. All ROIs were separated into epithelial components and stromal components by the masking procedure in 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, while fibroblasts in the stroma were more abundant in NEC-MANEC and pNEC. This study confirmed the distinct expression profile of each histological component of MANEC according to its tumour versus 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 dataset for future studies.

Comparative analysis of different surgical approaches for recurrent inguinal hernia: a single-center observational study.

Purpose: Managing recurrent inguinal hernias is complex, and choosing the right surgical approach (laparoscopic vs. open) is vital for patient outcomes. This study compared the outcomes of using the same vs. different surgical approaches for initial and subsequent hernia repairs. Methods: We retrospectively analyzed patients who underwent recurrent inguinal hernia repair at Seoul National University Bundang Hospital between January 2014 and May 2023. Patients were divided into the "concordant" and "discordant" groups, comprising patients who underwent same and different approaches in both surgeries, respectively. Preoperative baseline characteristics, index surgery data, postoperative outcomes, and recurrence rates were analyzed and compared. Results: In total, 131 patients were enrolled; the concordant and discordant groups comprised 31 (open, n = 19; laparoscopic, n = 12) and 100 patients (open to laparoscopic, n = 68; laparoscopic to open, n = 32), respectively. No significant differences were observed in the mean operation time (50.5 ± 21.7 minutes vs. 50.2 ± 20.0 minutes, P = 0.979), complication rates (6.5% vs. 14.0%, P = 0.356), or 36-month cumulative recurrence rates (9.8% vs. 9.8%; P = 0.865). The mean postoperative hospital stay was significantly shorter in the discordant than in the concordant group (1.8 ± 0.7 vs. 1.4 ± 0.6, P = 0.003). Conclusion: Most recurrent inguinal hernia repairs were performed using the discordant surgical approach. Overall, concordance in the surgical approach did not significantly affect postoperative outcomes. Therefore, the selection of the surgical approach based on the patient's condition and surgeon's preference may be advisable.

Hyperthermic pressurized intraperitoneal aerosol drug delivery system in a large animal model: a feasibility and safety study.

BACKGROUND: We developed a novel drug delivery system called hyperthermic pressurized intraperitoneal aerosol chemotherapy (HPIPAC) that hybridized Hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC). The present study aims to assess the feasibility and safety of HPIPAC system in a large animal survival model. METHODS: Eleven pigs (eight non-survival models and three survival models) were used in the experiment. The heat module in the HPIPAC controller circulates hyperthermic CO2 in a closed-loop circuit and creates gas-based dry intraperitoneal hyperthermia. Three 12 mm trocars were placed on the abdomen. The afferent CO2 tube wound with heat generating coil was inserted into a trocar, and the efferent tube was inserted into another trocar. Heated CO2 was insufflated and circulated in a closed circuit until the intra-abdominal and peritoneal surface temperature reached 42 °C. 100 ml of 5% dextrose in water was nebulized for 5 min and the closed-loop circulation was resumed for 60 min at 42 °C. Tissue biopsies were taken from several sites from the pigs in the survival model. RESULTS: The average change in core temperature of the pigs was 2.5 ± 0.08 °C. All three pigs displayed no signs of distress, and their vital signs remained stable, with no changes in their diet. In autopsy, inflammatory and fibrotic responses at the biopsy sites were observed without serious pathologic findings. CONCLUSIONS: We successfully proved the feasibility and safety of our novel HPIPAC system in an in-vivo swine survival model.

The Effects of Etchant on via Hole Taper Angle and Selectivity in Selective Laser Etching.

This research focuses on the manufacturing of a glass interposer that has gone through glass via (TGV) connection holes. Glass has unique properties that make it suitable for 3D integrated circuit (IC) interposers, which include low permittivity, high transparency, and adjustable thermal expansion coefficient. To date, various studies have suggested numerous techniques to generate holes in glass. In this study, we adopt the selective laser etching (SLE) technique. SLE consists of two processes: local modification via an ultrashort pulsed laser and chemical etching. In our previous study, we found that the process speed can be enhanced by changing the local modification method. For further enhancement in the process speed, in this study, we focus on the chemical etching process. In particular, we try to find a proper etchant for TGV formation. Here, four different etchants (HF, KOH, NaOH, and NH4F) are compared in order to improve the etching speed. For a quantitative comparison, we adopt the concept of selectivity. The results show that NH4F has the highest selectivity; therefore, we can tentatively claim that it is a promising candidate etchant for generating TGV. In addition, we also observe a taper angle variation according to the etchant used. The results show that the taper angle of the hole is dependent on the concentration of the etchant as well as the etchant itself. These results may be applicable to various industrial fields that aim to adjust the taper angle of holes.

Sex-dependent different clinicopathological characterization of Epstein-Barr virus-associated gastric carcinoma: a large-scale study.

BACKGROUND: Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) has been reported to account for approximately 5-16% of all GCs with good prognosis compared to EBV-negative GC. We evaluated the clinicopathological characteristics of EBVaGC including survival rate in South Korea. METHODS: A total of 4,587 patients with GC who underwent EBV in situ hybridization (EBV-ISH) were prospectively enrolled at the Seoul National University Bundang Hospital from 2003 to 2021. Age, sex, smoking status, cancer type and stage, tumor size and location, histological type, molecular features and survival information were analyzed. RESULTS: A total of 456 patients with GC (9.9%) were positive for EBV. The EBVaGC group displayed a higher proportion of males (P < 0.001), a predominant presence in the proximal stomach (P < 0.001), a higher proportion of undifferentiated cancer (P < 0.001), and a lower cancer stage (P = 0.004) than the EBV-negative group. Cox multivariate analyses revealed age (hazard ratio [HR] = 1.025, P < 0.001), tumor size (HR = 1.109, P < 0.001), and cancer stage (stage2 HR = 4.761, P < 0.001; stage3 HR = 13.286, P < 0.001; stage4 HR = 42.528, P < 0.001) as significant risk factors for GC-specific mortality, whereas EBV positivity was inversely correlated (HR = 0.620, P = 0.022). Furthermore, the EBVaGC group displayed statistically significant survival advantages over the EBV-negative cancer group in terms of both overall (P = 0.021) and GC-specific survival (P = 0.007) on the Kaplan-Meier survival curve. However, this effect was evident only in males. CONCLUSIONS: EBVaGC patients showed better prognoses despite their association with proximal location and poorly differentiated histology in male, probably due to the difference in immunity between males and females.

Genomic and Transcriptomic Characterization of Gastric Cancer with Bone Metastasis.

PURPOSE: Bone metastasis (BM) adversely affects the prognosis of gastric cancer (GC). We investigated molecular features and immune microenvironment that characterize GC with BM compared to GC without BM. MATERIALS AND METHODS: Targeted DNA and whole transcriptome sequencing were performed using formalin-fixed paraffin-embedded primary tumor tissues (gastrectomy specimens) of 50 GC cases with distant metastases (14 with BM and 36 without BM). In addition, immunohistochemistry (IHC) for mucin-12 and multiplex IHC for immune cell markers were performed. RESULTS: Most GC cases with BM had a histologic type of poorly cohesive carcinoma and showed worse overall survival (OS) than GC without BM (p < 0.05). GC with BM tended to have higher mutation rates in TP53, KDR, APC, KDM5A, and RHOA than GC without BM. Chief cell-enriched genes (PGA3, PGC, and LIPF), MUC12, MFSD4A, TSPAN7, and TRIM50 were upregulated in GC with BM compared to GC without BM, which was correlated with poor OS (p < 0.05). However, the expression of SERPINA6, SLC30A2, PMAIP1, and ITIH2 were downregulated in GC with BM. GC with BM was associated with PIK3/AKT/mTOR pathway activation, whereas GC without BM showed the opposite effect. The densities of helper, cytotoxic, and regulatory T cells did not differ between the two groups, whereas the densities of macrophages were lower in GC with BM (p < 0.05). CONCLUSION: GC with BM had different gene mutation and expression profiles than GC without BM, and had more genetic alterations associated with a poor prognosis.

Analysis of Characteristics and Risk Factors of Patients with Single Gastric Cancer and Synchronous Multiple Gastric Cancer among 14,603 Patients.

Background/Aims: Synchronous multiple gastric cancer (SMGC) accounts for approximately 6% to 14% of gastric cancer (GC) cases. This study aimed to identify risk factors for SMGC. Methods: A total of 14,603 patients diagnosed with GC were prospectively enrolled. Data including age, sex, body mass index, smoking, alcohol consumption, family history, p53 expression, microsatellite instability, cancer classification, lymph node metastasis, and treatment were collected. Risk factors were analyzed using logistic regression analysis between a single GC and SMGC. Results: The incidence of SMGC was 4.04%, and that of early GC (EGC) and advanced GC (AGC) was 5.43% and 3.11%, respectively. Patients with SMGC were older (65.33 years vs 61.75 years, p<0.001) and more likely to be male. Lymph node metastasis was found in 27% of patients with SMGC and 32% of patients with single GC. Multivariate analysis showed that SMGC was associated with sex (male odds ratio [OR], 1.669; 95% confidence interval [CI], 1.223 to 2.278; p=0.001), age (≥65 years OR, 1.532; 95% CI, 1.169 to 2.008; p=0.002), and EGC (OR, 1.929; 95% CI, 1.432 to 2.600; p<0.001). Survival rates were affected by Lauren classification, sex, tumor size, cancer type, distant metastasis, and venous invasion but were not related to the number of GCs. However, the survival rate of AGC with SMGC was very high. Conclusions: SMGC had unique characteristics such as male sex, older age, and EGC, and the survival rate of AGC, in which the intestinal type was much more frequent, was very good (Trial registration number: NCT04973631).

Single-port intragastric wedge resection using the tunnel method: a novel surgical approach for treating endophytic gastric subepithelial tumors.

BACKGROUND: Intragastric wedge resection is an effective method for treating endophytic gastric subepithelial tumors (SETs). However, retracting the stomach wall to the umbilicus is difficult in certain patients. In response, we developed a novel surgical technique for single-port intragastric wedge resection, which we termed the "tunnel method." METHODS: A transumbilical incision is made, and a wound retractor is applied. After diagnostic laparoscopy, a gastrostomy is made on the greater curvature, lower body. Another small wound retractor is inserted into the gastrostomy, and extracted through the transumbilical incision, creating a tunnel from the gastrostomy site to the umbilicus. Articulating laparoscopic instruments are inserted via the tunnel, and intragastric wedge resection is performed. We collected and analyzed the clinicopathologic and operative data of patients who underwent intragastric wedge resection via the tunnel method. RESULTS: Twenty-seven patients who underwent single-port intragastric wedge resection via the tunnel method in a single tertiary referral hospital were included in this study. The mean age of the patients was 54.6 ± 11.4 years, body mass index was 26.5 ± 3.4 kg/m2. Twenty-four (88.9%) patients had tumors located in the upper third of the stomach. The average operative time was 65.0 ± 24.2 min. None of the patients experienced Clavien-Dindo grade IIIa or higher postoperative complications. The average postoperative hospital stay length was 2.5 ± 0.8 days. Thirteen gastrointestinal stromal tumors, nine leiomyomas, and one neuroendocrine carcinoma, schwannoma, lipoma, spindle cell proliferative lesion, and fibrotic lesion were pathologically diagnosed. The average tumor size was 2.6 ± 1.3 cm. All cases had negative resection margins. CONCLUSIONS: Single-port intragastric wedge resection by the tunnel method is a feasible and safe approach for treating endophytic gastric SETs.

The Shorr Versus Modified Ultrafast Papanicolaou Method for Intraoperative Diagnosis of Peritoneal Washing Cytology in Advanced Gastric Cancer: A Phase II Study.

PURPOSE: According to the American Joint Committee on Cancer cancer staging system, positive peritoneal washing cytology (PWC) indicates stage IV gastric cancer. However, rapid intraoperative diagnosis of PWC has no established reliable method. This study evaluated and compared the diagnostic accuracy of the Shorr and the modified ultrafast Papanicolaou (MUFP) methods for intraoperative PWC. MATERIALS AND METHODS: This study included patients with gastric cancer who were clinically diagnosed with stage cT3 or higher. The Shorr and MUFP methods were performed on all PWC specimens, and the results were compared with those of conventional Papanicolaou (PAP) staining with carcinoembryonic antigen immunohistochemistry. Sensitivity, specificity, and partial likelihood tests were used to compare the 2 methods. RESULTS: Forty patients underwent intraoperative PWC between November 2019 and August 2021. The average time between specimen reception and slide preparation using Shorr and MUFP methods was 44.4±4.5 minutes, and the average time between specimen reception and pathologic diagnosis was 53.9±8.9 minutes. Eight patients (20.0%) had positive cytology in PAP staining. The Shorr method had a sensitivity of 75.0% and specificity of 93.8%; the MUFP method had 62.5% sensitivity and 100.0% specificity. The area under the curve was 0.844 for Shorr and 0.813 for MUFP. In comparing the C-indices of each method with overall survival, no difference was found among the Shorr, MUFP, and conventional PAP methods. CONCLUSIONS: The Shorr and MUFP methods are acceptable for the intraoperative diagnosis of PWC in advanced gastric cancer.

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.

Feasibility of articulating laparoscopic instruments in laparoscopic gastrectomy using propensity score matching.

Advancements in minimally invasive surgery has led to the development of several surgical instruments, including the ArtiSential®. This new instrument provides a greater range of motion and improved dexterity to laparoscopic procedures, making it an alternative option to traditional straight instruments, and the Da Vinci robot system. The purpose of this study is to compare the postoperative outcomes of a prospective cohort of patients who underwent laparoscopic gastrectomy using articulating instruments with those of a historical cohort of patients who underwent the same procedure using straight instruments. The study was designed as a prospective observational cohort study matched to a retrospective historical cohort using propensity score matching. The primary outcome was the rate of early complications within 90 days of surgery. Other outcomes included the operation time, estimated blood loss, time to first flatus, time to first soft fluid diet, hospital stay, and mortality. After propensity score matching, 41 patients were enrolled in both groups. The mean age was 62.4 ± 12.3 years in the conventional group and 63.5 ± 9.6 years in the artisential group (p = 0.647). Mean operative time was significantly shorter in the artisential group compared to the conventional group (136.1 min vs. 163.9 min, p = 0.032). The time to first soft fluid diet was also significantly shorter in the artisential group (2.2 days vs. 2.8 days, p = 0.030), but there was no significant difference in the time to first flatus and overall hospital stay. The incidence of early complications was lower in the artisential group, but the difference was not significant (24.4% vs 7.3%, p = 0.070). There was no mortality in either group. The use of articulating instruments for laparoscopic gastrectomy did not increase postoperative morbidity compared to straight laparoscopic instruments. The use of articulating instruments may be associated with faster bowel recovery and less early complications.

Study of Through Glass Via (TGV) Using Bessel Beam, Ultrashort Two-Pulses of Laser and Selective Chemical Etching.

Selective laser etching is a promising candidate for the mass production of glass interposers. It comprises two steps: local modification by an ultrashort-pulsed laser and chemical etching of the modified volume. According to previous studies, when an ultrashort-pulsed laser beam is irradiated on the sample, electron excitation occurs, followed by phonon vibration. In general, the electron excitation occurs for less than a few tens of picoseconds and phonon vibration occurs for more than 100 picoseconds. Thus, in order to compare the electric absorption and thermal absorption of photons in the commercial glass, we attempt to implement an additional laser pulse of 213 ps and 10 ns after the first pulse. The modified glass sample is etched with 8 mol/L KOH solution with 110 °C to verify the effect. Here, we found that the electric absorption of photons is more effective than the thermal absorption of them. We can claim that this result helps to enhance the process speed of TGV generation.

Outcome Analysis of Combined Surgical Approaches in Advanced-stage Upper Extremity Breast Cancer-related Lymphedema.

Background: This study aimed to discuss several surgical approaches for advanced-stage breast cancer-related lymphedema and compared their treatment outcomes. Methods: The patients who underwent surgery with International Society of Lymphology stage III lymphedema were included in this study. The three surgical methods used here were (1) suction-assisted lipectomy with lymphovenous anastomosis, (2) autologous breast reconstruction with muscle-sparing transverse rectus abdominis muscle flap combined with inguinal lymph node transfer, and (3) vascularized lymph node transfer with free omental flap. Analysis of the postoperative outcomes in the patients was based on the difference in volume between patients pre- and postoperatively, LYMPH-Q questionnaire, and bioelectrical impedance analysis. Results: Eighty-seven patients with stage IIb or higher disease underwent surgery. 38 patients underwent suction-assisted lipectomy + lymphovenous anastomosis, 23 underwent autologous breast reconstruction with vascularized lymph node transfer + lymphovenous anastomosis, and 26 underwent right gastroepiploic omental vascularized lymph node transfer with lymphovenous anastomosis. The LYMPH-Q questionnaire, which evaluates patients' subjective satisfaction, showed that the autologous breast reconstruction group showed the greatest improvement, whereas in bioimpedance analysis, the omental flap group demonstrated the greatest postoperative improvement compared with preoperative values. However, suction-assisted lipectomy was considered the most effective surgical method for reducing limb volume in patients with high-stage lymphedema accompanied by fibrosis and volume increase. Conclusions: We observed slightly different clinical effects for each surgical method; however, all surgical methods demonstrated a reduction in the degree of edema and an increase in patient satisfaction.

Comprehensive Study of Microsatellite Instability Testing and Its Comparison With Immunohistochemistry in Gastric Cancers.

PURPOSE: In this study, polymerase chain reaction (PCR)-based microsatellite instability (MSI) testing was comprehensively analyzed and compared with immunohistochemistry (IHC) for mismatch repair (MMR) protein expression in patients with gastric cancer (GC). MATERIALS AND METHODS: In 5,676 GC cases, PCR-based MSI testing using five microsatellites (BAT-26, BAT-25, D5S346, D2S123, and D17S250) and IHC for MLH1 were performed. Re-evaluation of MSI testing/MLH1 IHC and additional IHC for MSH2, MSH6, and PMS2 were performed in discordant/indeterminate cases. RESULTS: Of the 5,676 cases, microsatellite stable (MSS)/MSI-low and intact MLH1 were observed in 5,082 cases (89.5%), whereas MSI-high (MSI-H) and loss of MLH1 expression were observed in 502 cases (8.8%). We re-evaluated the remaining 92 cases (1.6%) with a discordant/indeterminate status. Re-evaluation showed 1) 37 concordant cases (0.7%) (18 and 19 cases of MSI-H/MMR-deficient (dMMR) and MSS/MMR-proficient (pMMR), respectively), 2) 6 discordant cases (0.1%) (3 cases each of MSI-H/pMMR and MSS/dMMR), 3) 14 MSI indeterminate cases (0.2%) (1 case of dMMR and 13 cases of pMMR), and 4) 35 IHC indeterminate cases (0.6%) (22 and 13 cases of MSI-H and MSS, respectively). Finally, MSI-H or dMMR was observed in 549 cases (9.7%), of which 47 (0.8%) were additionally confirmed as MSI-H or dMMR by re-evaluation. Sensitivity was 99.3% for MSI testing and 95.4% for MMR IHC. CONCLUSIONS: Considering the low incidence of MSI-H or dMMR, discordant/indeterminate results were occasionally identified in GCs, in which case complementary testing is required. These findings could help improve the accuracy of MSI/MMR testing in daily practice.

Development and Validation of Models to Predict Lymph Node Metastasis in Early Gastric Cancer Using Logistic Regression and Gradient Boosting Machine Methods.

PURPOSE: To identify important features of lymph node metastasis (LNM) and develop a prediction model for early gastric cancer (EGC) using a gradient boosting machine (GBM) method. MATERIALS AND METHODS: The clinicopathologic data of 2556 patients with EGC who underwent gastrectomy were used as training set and the internal validation set (set 1) at a ratio of 8:2. Additionally, 548 patients with EGC who underwent endoscopic submucosal dissection (ESD) as the initial treatment were included in the external validation set (set 2). The GBM model was constructed, and its performance was compared with that of the Japanese guidelines. RESULTS: LNM was identified in 12.6% (321/2556) of the gastrectomy group (training set & set 1) and 4.3% (24/548) of the ESD group (set 2). In the GBM analysis, the top five features that most affected LNM were lymphovascular invasion, depth, differentiation, size, and location. The accuracy, sensitivity, specificity, and the area under the receiver operating characteristics of set 1 were 0.566, 0.922, 0.516, and 0.867, while those of set 2 were 0.810, 0.958, 0.803, and 0.944, respectively. When the sensitivity of GBM was adjusted to that of Japanese guidelines (beyond the expanded criteria in set 1 [0.922] and eCuraC-2 in set 2 [0.958]), the specificities of GBM in sets 1 and 2 were 0.516 (95% confidence interval, 0.502-0.523) and 0.803 (0.795-0.805), while those of the Japanese guidelines were 0.502 (0.488-0.509) and 0.788 (0.780-0.790), respectively. CONCLUSION: The GBM model showed good performance comparable with the eCura system in predicting LNM risk in EGCs.

Comparison of perioperative outcomes between bipolar sealing, ultrasonic shears and a hybrid device during laparoscopic gastrectomy for early gastric cancer: a prospective, multicenter, randomized study.

BACKGROUND: Although EBDs are essential for minimally invasive surgery, well-established prospective randomized studies comparing EBDs are scarce. This study aimed to compare the intraoperative inflammatory response and short-term surgical outcomes among different energy-based devices (EBDs) in laparoscopic distal gastrectomy (LDG). METHODS: Patients with clinical stage I gastric cancer scheduled for LDG at two different medical centers were prospectively randomized into three groups: ultrasonic shears (US), advanced bipolar (BP) and ultrasonic-bipolar hybrid (HB). The C-reactive protein (CRP) level, operation time, intraoperative blood loss (IBL), laboratory tests, cytokines (interleukin (IL)-6 and IL-10), hospital stay, and complication rate were analyzed. A novel semiquantitative measurement method using indocyanine green (ICG) and a near-infrared camera measured the amount of lymphatic leakage. RESULTS: The primary endpoint, the CRP level, was significantly lower in the BP (n = 60) group than in the US (n = 57) or HB (n = 57) group [9.03 ± 5.55 vs. 11.12 ± 5.02 vs. 12.67 ± 6.14, p = 0.001, on postoperative day (POD) 2 and 7.48 vs. 9.62 vs. 9.48, p = 0.026, on POD 4]. IBL was significantly lower in BP than in US or HB (26.3 ± 25.3 vs. 43.7 ± 42.0 vs. 34.9 ± 37.0, p = 0.032). Jackson-Pratt drainage triglycerides were significantly lower in BP than in US (53.6 ± 33.7 vs. 84.2 ± 59.0, p = 0.11; HB: 71.3 ± 51.4). ICG fluorescence intensity, operation time, laboratory results, cytokines, hospital stay, and complication rate were not significantly different among the 3 groups. CONCLUSION: BP showed a lower postoperative CRP level and less IBL than US and HB, suggesting less collateral thermal damage and better sealing function. Surgeons may consider this when selecting EBDs for laparoscopic surgery.