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Background Petersen's hernia, which occurs after minimally invasive surgery for gastric cancer, can be reduced by defect closure. This study aimed to demonstrate the incidence of bowel obstruction above Clavien–Dindo classification grade III due to Petersen's hernia between the mesenteric fixation method(MEFIX) and the conventional methods during the 5-year follow-up period after laparoscopic gastric cancer surgery. Methods This prospective, single-blind, non-inferiority randomized controlled trial and multicenter study was conducted at hospitals in Korea. Patients with histologically diagnosed gastric cancer of clinical stage I, II, or III who underwent Roux-en-Y or B- II gastrojejunostomy anastomosis after laparoscopic gastrectomy were enrolled in this study. Patients who met the inclusion criteria were randomly assigned to two groups: a CLOSURE group that underwent Petersen's defect closure method and a MEFIX group that underwent the mesenteric fixation method. Discussion This trial is expected to provide high-level evidence showing that the MEFIX method can quickly and easily close Petersen's defect and reduce postoperative complications compared to the conventional method. It is also expected to be applicable not only after gastric cancer surgery but also after bariatric surgery. Trial registration The MEFIX study protocol was registered in htrp://register.clinicaltrials.gov as NCT05105360 (registration date: November 3, 2021)

Background The aim of this multicenter cohort study was to compare the clinical courses between open and laparoscopic Petersen’s hernia (PH) reduction. Method We retrospectively collected the clinical data of patients who underwent PH repair surgery after gastrectomy for gastric cancer from 2015–2018. Forty patients underwent PH reduction operations that were performed by six surgeons at four hospitals. Among the 40 patients, 15 underwent laparoscopic PH reduction (LPH), and 25 underwent open PH reduction (OPH), including 4 patients who underwent LPH but required conversion to OPH. Results We compared the clinical factors between the LPH and OPH groups. In the clinical course, we found no differences in operation times or intraoperative bowel injury, morbidity, or mortality rates between the two groups (p > 0.05). However, the number of days on a soft fluid diet (OPH vs. LPH; 5.8 vs. 3.7 days, p = 0.03) and length of hospital stay (12.6 vs. 8.2 days, p = 0.04) were significantly less in the LPH group than the OPH group. Regarding postoperative complications, the OPH group had a case of pneumonia and sepsis with multi-organ failure, which resulted in mortality. In the LPH group, one patient experienced recurrence and required reoperation for PH. Conclusion Laparoscopic PH reduction was associated with a faster postoperative recovery period than open PH reduction, with a similar incidence of complications. The laparoscopic approach should be considered an appropriate strategy for PH reduction in selected cases.

Introduction Petersen's hernia (PH) is a potentially fatal complication of bowel infarction that is difficult to treat by laparoscopic reduction. Aim To define predictive computed tomography (CT) profiles to identify PH patients who would be suitable for laparoscopic reduction by a comparative analysis between patients treated by laparoscopic and open reduction. Material and methods We retrospectively collected the clinical data of patients (n = 28) who underwent PH reduction surgery after minimally invasive gastrectomy for gastric cancer in the period 2015-2018 at four training hospitals. We examined the preoperative CT scans to identify the indications for laparoscopic PH reduction. Results We compared the laparoscopic reduction group (laparoscopic group, n = 15) and the open reduction group (open group, n = 13). Patients in the laparoscopic group were younger (55.7 ±10.4) than those in the open group (69.3 ±9.1), but there were no differences in clinical or laboratory findings. We found that there were two CT profiles with significant differences between the open and laparoscopic groups: superior mesenteric vein (SMV) narrowing and small bowel dilation. We found that small bowel dilatation was an independent factor on multivariate analysis for laparoscopic PH reduction. Conclusions We found that small bowel dilatation is the most important CT profile for identifying PH patients contraindicated for laparoscopic reduction. Despite the retrospective design of this study, these CT profiles are expected to define the scope of laparoscopic reduction in PH patients and to establish indications for the laparoscopic approach.

The aim of this study was to compare the 1 year incidence of Petersen's hernia between individuals who were treated with the jejunal mesentery fixing (Mefix) method and those with the closure of Petersen's space method.We retrospectively collected clinical data of patients who underwent gastrectomy for gastric cancers with the closure of Petersen's space defect (The procedure time for mesentery fixing (3.7 ± 1.1 mins) was significantly shorter than that for Petersen's space closure (7.5 ± 1.5 mins) (We found no occurrence of Petersen's hernias postoperatively in either group. We also found that the Mefix method was faster and easier to perform than the closure method. The Mefix method is an excellent alternative method to prevent the occurrence of Petersen's hernia after B-II or Roux-en-Y reconstruction.

Purpose Patients who have undergone gastrectomy have unique symptoms that are not appropriately assessed using currently available tools. This study developed and validated a symptom-focused quality of life (QoL) questionnaire for patients who have received gastrectomy for gastric cancer. Materials and Methods Based on a literature review, patient interviews, and expert consultation by the KOrean QUality of life in Stomach cancer patients Study group (KOQUSS), the initial item pool was developed. Two large-scale developmental studies were then sequentially conducted for exploratory factor analyses for content validity and item reduction. The final item pool was validated in a separate cohort of patients and assessed for internal consistency, test-retest reliability, construct validity, and clinical validity.Results The initial questionnaire consisted of 46-items in 12 domains. Data from 465 patients at 11 institutions, followed by 499 patients at 13 institutions, were used to conduct item reduction and exploratory factor analyses. The final questionnaire (KOQUSS-40) comprised 40 items within 11 domains. Validation of KOQUSS-40 was conducted on 413 patients from 12 hospitals. KOQUSS-40 was found to have good model fit. The mean summary score of the KOQUSS-40 was correlated with the EORTC QLQ-C30 and STO22 (correlation coefficients, 0.821 and 0.778, respectively). The KOQUSS-40 score was also correlated with clinical factors, and had acceptable internal consistency (> 0.7). Test-retest reliability was greater than 0.8. Conclusion The KOQUSS-40 can be used to assess QoL of gastric cancer patients after gastrectomy and allows for a robust comparison of surgical techniques in clinical trials.

Background The aims of this study were to investigate the correlation between carbohydrate-rich drinks (CRDs) before gastric cancer surgery and postoperative nutrition laboratory findings and to determine whether CRDs affect the incidence of postoperative complications. Materials and Methods A retrospective study was conducted on 142 patients who underwent radical stomach cancer surgery. The patients were divided into 2 groups (nothing per oral group versus CRD group) according to the intake of CRDs before surgery. We performed statistical analysis using Student t test, the χ2 test, and a binary logistic regression model (SPSS Statistics software, version 24). Results Laboratory analysis of the nutrition status showed a significant increase in serum protein and albumin levels in the CRD group after postoperative day 1 (POD1; P < 0.05). The overall morbidity rate showed no difference between the 2 groups, but pulmonary complications showed significant differences of 1/72 and 9/70 (P = 0.008). In the univariate analysis, there were significantly increased pulmonary complications in patients with higher Eastern Cooperative Oncology Group (ECOG) scores (P = 0.001), existing pulmonary disease (P = 0.003), anastomotic leakage (P = 0.03), and CRD intake (P = 0.008). In the multivariate analysis, CRD intake was the only independent factor. Conclusion We found that administering a CRD is effective in improving albumin and protein levels in the short-term period after surgery but is an independent factor for pulmonary complications after gastrectomy. We recommend that patients with no medications for pulmonary disease and with low ECOG scores can safely ingest CRDs and expect short-term nutritional effects.

Purpose To compare long-term disease-free survival (DFS) between patients receiving tegafur/gimeracil/oteracil (S-1) or capecitabine plus oxaliplatin (CAPOX) adjuvant chemotherapy (AC) for gastric cancer (GC). Materials and Methods This retrospective multicenter observational study enrolled 983 patients who underwent curative gastrectomy with consecutive AC with S-1 or CAPOX for stage II or III GC at 27 hospitals in Korea between February 2012 and December 2013. We conducted propensity score matching to reduce selection bias. Long-term oncologic outcomes, including DFS rate over 5 years (over-5yr DFS), were analyzed postoperatively. Results The median and longest follow-up period were 59.0 and 87.6 months, respectively. DFS rate did not differ between patients who received S-1 and CAPOX for pathologic stage II (P=0.677) and stage III (P=0.899) GC. Moreover, hazard ratio (HR) for recurrence did not differ significantly between S-1 and CAPOX (reference) in stage II (HR, 1.846; 95% confidence interval [CI], 0.693-4.919; P=0.220) and stage III (HR, 0.942; 95% CI, 0.664-1.337; P=0.738) GC. After adjustment for significance in multivariate analysis, pT (4 vs. 1) (HR, 11.667; 95% CI, 1.595-85.351; P=0.016), pN stage (0 vs. 3) (HR, 2.788; 95% CI, 1.502-5.174; P=0.001), and completion of planned chemotherapy (HR, 2.213; 95% CI, 1.618-3.028; P

PURPOSE To compare postoperative complications, long-term survival, and quality of life (QOL) after laparoscopic sentinel node navigation surgery (LSNNS) and laparoscopic standard gastrectomy (LSG). METHODS Five hundred eighty patients with preoperatively diagnosed stage IA gastric adenocarcinoma (≤ 3 cm) were assigned to undergo either LSG or LSNNS. Observers were not blinded to patient grouping. The primary outcome was 3-year disease-free survival (3y-DFS). Secondary outcomes included postoperative complications, QOL, 3-year disease-specific survival (3y-DSS), and 3-year overall survival (3y-OS). RESULTS In total, 527 patients were included in the modified intention-to-treat analysis population for the primary outcome (LSG, 269; LSNNS, 258). Stomach-preserving surgery was performed in 210 patients (81%) in the LSNNS group. During the median follow-up duration, the 3y-DFS rates in the LSG and LSNNS groups were 95.5% and 91.8%, respectively (difference: 3.7%; 95% CI, –0.6 to 8.1). Three patients with recurrence and five with metachronous gastric cancer in the LSNNS group underwent standard surgery. Two patients with distant metastasis in both groups were treated with palliative chemotherapy. The 3y-DSS and 3y-OS rates in the LSG and LSNNS groups were 99.5% and 99.1% ( P = .59) and 99.2% and 97.6% ( P = .17), respectively. Postoperative complications occurred in 19.0% of the LSG group and 15.5% of the LSNNS group ( P = .294). The LSNNS group showed better physical function ( P = .015), less symptoms ( P < .001), and improved nutrition than the LSG group. CONCLUSION LSNNS did not show noninferiority to LSG for 3y-DFS, with a 5% margin. However, the 3y-DSS and 3y-OS were not different after rescue surgery in cases of recurrence/metachronous gastric cancer, and LSNNS had better long-term QOL and nutrition than LSG.

Obesity can hinder laparoscopic procedures and impede oncological safety during laparoscopic cancer surgery. Deep neuromuscular block (NMB) reportedly improves laparoscopic surgical conditions, but its oncological benefits are unclear. We aimed to evaluate whether deep NMB improves the oncologic quality of laparoscopic cancer surgery in obese patients.We conducted a double-blinded, parallel-group, randomized, phase 3 trial at 9 institutions in Korea. Clinical stage I and II gastric cancer patients with a BMI at or above 25 kg m -2 were eligible and randomized 1:1 ratio to the deep or moderate NMB groups, with continuous infusion of rocuronium (0.5-1.0 and 0.1-0.5 mg kg -1 h -1, respectively). The primary endpoint was the number of retrieved lymph nodes (LNs). The secondary endpoints included the surgeon's surgical rating score (SRS) and interrupted events.Between August 2017 and July 2020, 196 patients were enrolled. Fifteen patients were excluded, and 181 patients were finally included in the study. There was no significant difference in the number of retrieved LNs between the deep (N = 88) and moderate NMB groups (N = 93; 44.6 ± 17.5 vs 41.5 ± 16.9, p = 0.239). However, deep NMB enabled retrieving more LNs in patients with a BMI at or above 28 kg/m2 than moderate NMB (49.2 ± 18.6 vs 39.2 ± 13.3, p = 0.026). Interrupted events during surgery were lower in the deep NMB group than in the moderate NMB group (21.6% vs 36.6%; p = 0.034). The SRS was not influenced by NMB depth.Deep NMB provides potential oncologic benefits by retrieving more LNs in patients with BMI at or above 28 kg/m2 during laparoscopic gastrectomy.

IntroductionPatients who underwent curative gastrectomy for gastric cancer are regularly followed-up for the early detection of recurrence and postoperative symptom management. However, there is a lack of evidence with regard to proper surveillance intervals and diagnostic tools. This study aims to evaluate whether frequent surveillance tests have a survival benefit or improve the quality of life in patients who underwent curative resection for advanced gastric cancer.Methods and analysisThe STOFOLUP trial is an investigator-initiated, parallel-assigned, multicentre randomised controlled trial involving 16 hospitals in the Republic of Korea. Patients (n=886) diagnosed with pathological stage II or III gastric adenocarcinoma will be randomised to either the 3-month or the 6-month group at a 1:1 ratio, stratified by trial site and tumour stage. Patients allocated to the 3-month group will undergo an abdominal CT scan every 3 months postoperatively and those allocated to the 6-month group will undergo CT every 6 months. The primary endpoint is 3-year overall survival and the secondary endpoints are quality of life, as assessed using KOrean QUality of life in Stomach cancer patients Study group-40, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and the stomach cancer-specific module (STO22), and nutritional outcomes. Other survival data including data concerning 3-year disease-free survival, recurrence-free survival, gastric cancer-specific survival and postrecurrence survival will also be estimated. The first patient was enrolled on July 2021 and active patient enrolment is currently underway.Ethics and disseminationThis study has been approved by the Institutional Review Board of eight of the participating hospitals (NCC 2021-0085, KBSMC2021-01-059, SMC 2021-01-140, KC21OEDE0082, 4-2021-0281, AJIRB-MED-INT-20-608, 2021-0515 and H-2102-093-1198). This study will be disseminated through peer-reviewed publications, national or international conferences.Trial registration numberNCT04740346.

Background In our previous study, transumbilical endoscopic submucosal dissection (TU-ESD) was revealed to be feasible, but delayed gastric perforation was observed in 30% of ESD sites. In this study, we aimed to verify locations at which it is feasible to perform TU-ESD in the upper gastric body and to demonstrate the safety of TU-ESD in single-basin lymph node dissection (SBLND). Methods In vitro, TU-ESD was performed at three lesion sites (anterior wall, AW; posterior wall, PW; and lesser curvature, LC) in each porcine stomach using an EASIE-R tray (cases = 10). In vivo, TU-ESD was performed with SBLND in 9 pigs. Seven days after the operation, the pigs were sacrificed and examined. Results In the in vitro feasibility study, the TU-ESD time was significantly faster in the PW group (5.9 ± 2.0 min) than in the LC group (8.5 ± 1.5 min) (p

KLASS (the Korean Laparoendoscopic Gastrointestinal Surgery Study) is a time-honored study group that has established laparoscopic surgery for gastrointestinal disease in Korea and has performed some important studies for the rationale of laparoscopic gastrointestinal surgery. A multi-center RCT (randomized controlled trial) to compare the quality of life (QOL) of patients undergoing totally laparoscopic distal gastrectomy (TLDG) and laparoscopy-assisted distal gastrectomy (LADG) for gastric cancer, named as KLASS 07, has been currently prepared in Korea. Patients diagnosed as gastric cancer, with clinical stage IA (T1N0M0) or IB (T1N1M0 / T2N0M0) according to the 7th edition of the Americal Joint Committee on Cancer System, were randomized to receive either TLDG or LADG. For surgical quality control, the surgeons participating in this trial had to have performed at least 50 gastrectomies and at least 30 gastrectomies annually (regardless of open or laparoscopic surgery for gastric cancer). The patients who are allocated to TLDG group undergo intracorporeal anastomosis and those who are assigned to LADG undergo extracorporeal anastomosis for gastrointestinal reconstruction. Thirty-one surgeons from 26 institutions were engaged in this trial. The primary endpoint is 30-day morbidity, and secondary endpoint is QOL assessed by the questionnaire score. The KLASS 07 trial is the first multi-center RCT to investigate whether there are significant and quantifiable differences between the QOL of TLDG and LADG. The findings from this trial are expected to be the critical clues for designing the detailed procedures during laparoscopic surgery for gastric cancer. The protocol of KLASS 07 (CKLASS 01) was registered in http://register.clinicaltrials.gov as NCT03393182 (Date of registration: January 2nd, 2018.).

Background: Adjuvant chemotherapy (AC) regimens tegafur/gimeracil/oteracil (S-1) and capecitabine plus oxaliplatin (CAPOX) have predominated, however, there has been a lack of studies on their differences in efficacy. Methods: We conducted pairwise meta-analyses comparing the efficacy of S-1 and CAPOX regimens for overall survival (OS) and disease-free survival (DFS) in stage II or III GC patients. Results: Three studies were enrolled and analyzed using a forest plot for meta-analysis. Two of them were propensity score matching studies, and the remaining one was a retrospective observational study. In all stages, the five-year OS was not different between the two regimens (HR 0.96, 95% CI 0.78–1.17; p = 0.56). Additionally, the 5-year DFS was not different at any stage (HR 1.00, 95% CI 0.85–1.18; p = 0.21). After omitting the retrospective observational study, the five-year OS (HR 1.40, 95% CI 0.53–3.73) and DFS (HR 1.41, 95% CI 0.57–3.44) of S-1 tended to be better in stage II, and the five-year OS (HR 0.81, 95% CI 0.56–1.16) and DFS (HR 0.85, 95% CI 0.63–1.13) of CAPOX tended to be better in stage III, without statistical significance. Conclusions: In the present meta-analysis, the five-year OS and DFS for stage II or III GC patients were comparable between S-1 and CAPOX regimens as AC.

Laparoscopic endoscopic cooperative surgery (LECS) refers to the endoscopic dissection of the mucosal or submucosal layers with laparoscopic seromuscular resection. We recommend a treatment algorithm for the LECS procedure for gastric benign tumors according to the protruding type. In the exophytic type, endoscopic-assisted wedge resection can be performed. In the endophytic type, endoscopic-assisted wedge resection of the anterior wall is relatively easy to perform, and endoscopic-assisted transgastric resection, laparoscopic-assisted intragastric surgery, or single-incision intragastric resection in the posterior wall and esophagogastric junction (EG Jx) can be attempted. We propose an algorithm for the LECS procedure for early gastric cancer according to the tumor location. The endoscopic submucosal dissection (ESD) procedure can be adapted for all areas of the stomach, and single-incision ESD can be performed in the mid to high body and the EG Jx. In full-thickness gastric resection, laparoscopy-assisted endoscopic full-thickness resection can be adapted for the entire area of the stomach, but it cannot be applied to the pyloric and EG Jx. In conclusion, surgeons need to select the LECS procedure according to tumor type, tumor location, the surgeon's individual experience, and the situation of the institution while also considering the advantages and disadvantages of each procedure.

Recently, endoscopic screening systems have enabled the diagnosis of gastric cancer in the early stages. Early gastric cancer (EGC) is typically characterized by a shallow invasion depth and small size, which can hinder localization of EGC tumors during laparoscopic surgery. Here, we review nine recently reported tumor localization methods for the laparoscopic resection of EGCs. Preoperative dye or blood tattooing has the disadvantage of spreading. Preoperative 3-dimensional computed tomography reconstruction is not performed in real time during laparoscopic gastrectomy. Thus, they are considered to have a low accuracy. Intraoperative portable abdominal radiography and intraoperative laparoscopic ultrasonography methods can provide real-time feedback, but these methods require expertise, and it can be difficult to define the clips in some gastric regions. Despite a few limitations, intraoperative gastrofibroscopy provides real-time feedback with high accuracy. The detection system using an endoscopic magnetic marking clip, fluorescent clip, and radio-frequency identification detection system clip is considered highly accurate and provides real-time feedback; we expect a commercial version of this setup to be available in the near future. However, there is not yet an easy method for accurate real-time detection. We hope that improved devices will soon be developed and used in clinical settings.

4050 Background: A phase III multicenter randomized controlled clinical trial (SEntinel Node ORIented Tailored Approach [SENORITA] trial) has been performed to confirm the oncologic safety of laparoscopic sentinel node navigation surgery (LSNNS) for early gastric cancer (EGC). The results did not show the non-inferiority of LSNNS relative to laparoscopic standard gastrectomy (LSG) in terms of 3-year disease-free survival (DFS), the primary endpoint of the SENORITA trial even though the improved quality of life (QOL) in the LSNNS group. However, the long-term oncologic outcomes of LSNNS have not been compared with conventional surgery. This study was planned to investigate the comparison of LSG and LSNNS for EGC in terms of 5 years survival. Methods: We collected 5-year follow-up data of 527 patients recruited in the SENORITA trial. The overall survival (OS), disease-free survival (DFS), and recurrence pattern were evaluated in full analysis sets of both LSG (n = 269) and LSNNS (n = 258). Results: The mean follow-up period was 58.5 and 57.7 months in LSNNS and LSG groups. There was no statistically significant difference in 5-year OS (p = 0.7403) and DFS (p = 0.0561) between LSG and LSNNS. In terms of DFS, additional five events in the LSG group and 7 in LSNNS occurred after a 3-year follow-up until 5-years. Primary site recurrence in 1 LSNNS, and metachronous gastric cancer occurred in one LSG and two in LSNNS were diagnosed from 3 to 5-year follow-up period. Other organ cancer developed in two vs. three and other deaths occurred in two v s. one in each group, respectively, from 3 to 5-year follow-up. Overall survival events were 6 in LSG and 7 in LSNNS, and disease-specific death events were two patients in both groups until five years. Conclusions: Although the SENORITA trial did not show non-inferiority of LSNNS in the primary endpoint, 3-year DFS relative to LSG, the 5-year DFS and OS did not reveal the statistical difference between the two groups. Considering the benefit of LSNNS regarding the postoperative QOL, LSNNS could be recommended as an alternative treatment option of LSG for EGC. Clinical trial information: NCT01804998.

Few studies have presented evidence pertaining to the adequate minimum number of adjuvant chemotherapy (AC) cycles required to achieve an oncologic benefit for gastric cancer. From January 2012 to December 2013, data from patients who underwent curative radical gastrectomy and consequently received AC for pathologic stage 2 or 3 gastric cancer at 27 institutions in South Korea were analyzed. The study enrolled 925 patients, 661 patients (71.5%) who completed 8 cycles of AC and 264 patients (28.5%) who did not. Compared with the mean disease-free survival (DFS) of the patients who completed 8 AC cycles (69.3 months), the mean DFS of patients who completed 6 AC cycles (72.4 months; p = 0.531) and those who completed 7 AC cycles (63.7 months; p = 0.184) did not differ significantly. However, the mean DFS of the patients who completed 5 AC cycles (48.2 months; p = 0.016) and those who completed 1–4 AC cycles (62.9 months; p = 0.036) was significantly lower than the DFS of those who completed 8 AC cycles. In the multivariate Cox proportional hazards analysis, the mean DFS was significantly affected by advanced stage, large tumor size, positive vascular invasion, and number of completed AC cycles (1–5 cycles: hazard ratio 1.45; 95% confidence interval 1.01–2.08; p = 0.041). The current multicenter observational cohort study showed that the mean DFS for 6 or 7 AC cycles was similar to that for 8 AC cycles as an adjuvant treatment for gastric cancer.

Tegafur/gimeracil/oteracil (S-1) and capecitabine plus oxaliplatin (CAPOX) are standard adjuvant chemotherapies (ACs) administered after gastrectomy to patients with stage II or III gastric cancer. However, the efficacy of AC in elderly patients remains unclear. The objective of this retrospective multicenter cohort study was to compare the efficacies of S-1 and CAPOX AC in patients aged ≥70 years.Nine hundred eighty-three patients who were treated with AC using S-1 (768 patients) or CAPOX (215 patients) were enrolled in this study. Each patient underwent AC after curative gastrectomy for stage II or III gastric cancer at one of 27 hospitals in the Republic of Korea between January 2012 and December 2013. Relapse-free survival (RFS) and overall survival (OS) were analyzed according to AC regimen and age group.Of the 983 patients, 254 (25.8%) were elderly. This group had a similar RFS (P=0.099) but significantly poorer OS (p=0.003) compared with the non-elderly group. Subgroup analysis of the non-elderly group revealed no AC-associated differences in survival. Subgroup analysis of the elderly group revealed significantly better survival in the S-1 group than in the CAPOX group (RFS, P0.001; OS, P0.001). Multivariate analysis revealed that the CAPOX regimen was an independent poor prognostic factor for RFS (hazard ratio [HR], 1.891; 95% confidence interval [CI], 1.072-3.333; P=0.028) and OS (HR, 2.970; 95% CI, 1.550-5.692; P=0.001).This multicenter observational cohort study found significant differences in RFS and OS between S-1 and CAPOX AC among patients with gastric cancer aged ≥70 years.

To analyze the short- and long-term clinical outcomes of 2 reconstruction methods after distal gastrectomy for gastric cancer.Three keywords, "gastric neoplasm," "distal gastrectomy," and "reconstruction," were used to search PubMed. We selected only randomized controlled trial that compared the anastomosis methods. A total of 11 papers and 8 studies were included in this meta-analysis. All statistical analyses were performed using the R software.Among short-term clinical outcomes, a shorter operation time, reduced morbidity, and shorter hospital stay were found for Billroth type I (B-I) than for Roux-en-Y (RNY) reconstruction in the meta-analysis (P0.001, P=0.048, P0.001, respectively). When comparing Billroth type II (B-II) to RNY, the operation time was shorter for B-II than for RNY (P0.019), but there were no differences in morbidity or length of hospital stay (P=0.500, P=0.259, respectively). Regarding long-term clinical outcomes related to reflux, there were significantly fewer incidents of reflux esophagitis, reflux gastritis, and bile reflux (P=0.035, P0.001, P=0.019, respectively) for RNY than for B-I in the meta-analysis, but there was no difference between the 2 methods in residual food (P=0.545). When comparing B-II to RNY, there were significantly fewer incidents of reflux gastritis (P0.001) for RNY than for B-II, but the amount of residual food and patient weight gain showed no difference.B-I had the most favorable short-term outcomes, but RNY was more advantageous for long-term outcomes than for other methods. Surgeons should be aware of the advantages and disadvantages of each type of anastomosis and select the appropriate method.

After curative resection of gastric cancer with D2 lymph node dissection, postoperative adjuvant chemotherapy with S-1 or capecitabine plus oxaliplatin (XELOX) is considered to be standard therapy in Eastern countries. This study aimed to compare the efficacies of adjuvant S-1 and XELOX chemotherapy for gastric cancer patients after D2 dissection based on disease-free survival (DFS). This retrospective observational study was conducted at 29 tertiary hospitals in Korea. Of 1898 patients who underwent curative resection and received adjuvant chemotherapy for gastric cancer between February 2012 and December 2013, 1088 patients who met the eligibility criteria were enrolled in the study. After propensity score-matching, the 3-year disease-free survival rate (DFS) was used to compare efficacies directly between adjuvant XELOX and S-1 chemotherapies for patients with stage 2 or 3 gastric cancer after D2 gastrectomy. The 3-year DFS rates for the S-1 and XELOX groups did not differ significantly among disease stages 2A, 2B, and 3A (all p > 0.05). However, the survival rates for the S-1 group were significantly lower than for the XELOX group for stage 3B (65.8% vs. 68.6%; p = 0.019) and stage 3C (48.4% vs. 66.7%; p = 0.002) gastric cancer. The hazard ratios (HRs) of S-1 chemotherapy for recurrence compared with XELOX for stages 3B and 3C were respectively 2.030 [95% confidence interval (CI), 1.110–3.715; p = 0.022] and 2.732 (95% CI 1.427–5.234; p = 0.002). Adjuvant XELOX chemotherapy was more effective than S-1 for patients with stage 3B or 3C gastric cancer after D2 lymph node dissection.

The impact of gastric remnant volumes (GRVs) after gastrectomy on patients’ quality of life (QOL) has not yet been clarified. The aim of the present study was to compare QOL after gastrectomy between small and large gastric remnant volume patients. We prospectively collected clinical data from 78 consecutive patients who underwent distal gastrectomy with Billroth II gastrojejunostomy for gastric cancer. The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Stomach questionnaire and gastric computed tomography scans were performed. The patients were subdivided into 2 groups by remnant stomach volume (the S group ≤110 mL vs L group >110 mL). The worst scores for most items were observed at postoperative month 1 and usually improved thereafter. There was no difference in the STO22 score except for dysphagia between the S and L groups after gastrectomy (P > .05). The QOL score of dysphagia was different at postoperative 6 months (S vs L, 12.4 vs 22.8, P .05). The remnant gastric volume after partial gastrectomy affects neither functional differences nor QOL after 6 months following appropriate radical surgery.

Background and objectives During minimally invasive surgery (MIS), it is impossible to directly detect marked clips around tumors via palpation. Therefore, we developed a novel method and device using Radio Frequency IDentification (RFID) technology to detect the position of clips during minimally invasive gastrectomy or colectomy. Methods The feasibility of the RFID-based detection system was evaluated in an animal experiment consisting of seven swine. The primary outcome was to successfully detect the location of RFID clips in the stomach and colon. The secondary outcome measures were to detect time (time during the intracorporeal detection of the RFID clip), and accuracy (distance between the RFID clip and the detected site). Results A total of 25 detection attempts (14 in the stomach and 11 in the colon) using the RFID antenna had a 100% success rate. The median detection time was 32.5 s (range, 15-119 s) for the stomach and 28.0 s (range, 8-87 s) for the colon. The median detection distance was 6.5 mm (range, 4-18 mm) for the stomach and 6.0 mm (range, 3-13 mm) for the colon. Conclusions We demonstrated favorable results for a RFID system that detects the position of gastric and colon tumors in real-time during MIS.

We aimed to improve the tumor localization system using radiofrequency identification (RFID) technology used during laparoscopic surgery for gastric and colorectal cancer. To this end, we developed a detection algorithm and designed improvement for the RFID clip. To evaluate the proposed system, a swine-based animal study was conducted, followed by experiments on porcine stomachs and colons using the EASIE-R simulator. The success rates of endoscopic clipping, detection time, and detection accuracy, which is the distance between the detection point and RFID tag, were measured. Results of the in vivo swine animal study showed success in all three clippings and detections of the RFID clips. Results of the 60 RFID endoclip attempts using the EASIE-R simulator showed a total clipping success rate of 85.0% (n = 51/60; stomach, 83.3%, n = 25/30; colon, 86.7%, n = 26/30). The median detection times were 29.2 s for the stomach and 25.5 s for the colon. The median detection accuracy was 4.0 mm for the stomach and 4.5 mm for the colon. We confirmed that the proposed RFID-based system showed improvements over the system of a previous study. This RFID-based system is effective at localizing gastric and colorectal tumors.

Background The curative surgical treatment of gastric cancer in the current laparoscopic surgical era relies on the surgeon's preference, technical difficulties, and concerns regarding outcome have led to the availability of totally laparoscopic distal gastrectomy (TLDG) and laparoscopic-assisted distal gastrectomy (LADG). A consensus on which of the two procedures is preferable is necessary. Therefore, the aim of this study was to evaluate the differences between LADG and TLDG in terms of surgical outcomes, postoperative recovery, pain, and complications. Methods PubMed, Google Scholar, Medline, Embase, and Cochrane databases were explored up to 2017 to evaluate TLDG and LADG. Parameters including surgical outcomes, postoperative recovery, and postoperative complications were subjected to meta-analysis to calculate the odds ratio and weighted mean difference with 95% confidence intervals (c.i.). Results Twenty-five studies (24 non-RCT and 1 RCT) with a total of 4562 gastric cancer patients were included in the meta-analysis. Under reconstruction-matched analysis, overall complications and anastomotic complications were similar for TLDG and LADG. Nevertheless, short-term outcomes such as blood loss, time to first soft diet, hospital stay, analgesic use, and CRP level were favourable for TLDG, while all other surgical outcomes showed no difference. Conclusions TLDG and LADG did not show significant differences in surgical outcomes and postoperative complications, including anastomotic-related morbidity. Therefore, decisive factors in selecting surgical procedures, which previously consisted of surgical outcomes, have been superseded by extra-surgical values such as cosmesis, economics, and patient's quality of life. These factors will be explored in a future multicentre prospective study (KLASS07 trial).

Background: Risks and benefits of laparoscopic sentinel node navigation surgery (LSNNS) compared with laparoscopic standard gastrectomy (LSG) with lymph node dissection (LND) for early gastric cancer (EGC) are unknown. The SENORITA trial investigated the clinical impact of LSNNS for EGC regarding short-term surgical outcomes, long-term survival, and quality of life (QOL). Methods: Patients with preoperatively diagnosed T1N0 gastric adenocarcinoma with a diameter of 3 cm or smaller regardless of histology (except absolute indication for endoscopic resection) were eligible. Patients were randomized to LSG with LND or LSNNS. The primary endpoint was 3-year disease-free survival. Morbidity and mortality within 30 postoperative days were evaluated as secondary endpoints and graded by the Clavien-Dindo classification. Findings: From March 2013 to December 2016, 580 patients were randomized (LSG, 292; LSNNS, 288). Fifty-three patients dropped out before surgery due to various reasons. Surgery was performed for 527 patients (LSG, 269; LSNNS, 258) representing the full analysis set. LSNNS was not performed in 13 patients due to intraoperative findings. LSNNS was performed according to protocol for 245 patients, and detection of sentinel basin was possible for 237 patients (96.7%, 237/245). Stomach-preserving surgery was performed in 210 patients (81.4%. 210/258). Postoperative complications occurred in 51 LSG patients (19.0%) and 40 LSNNS patients (15.5%) (P=0.294). Clavien-Dindo grade III or higher complications occurred in 16 LSG patients (5.9%) and 13 LSNNS patients (5.0%) (P=0.647). Postoperative mortality occurred in one LSG patient. LSNNS was not a risk factor for postoperative morbidity in multivariate analysis except sex. Interpretation: LSNNS for EGC is a safe procedure in terms of postoperative morbidity and mortality when compared with LSG with LND. Results: From March 2013 to December 2016, 580 patients were randomized (LSG, 292; LSNNS, 288). Surgery was performed for 527 patients (LSG, 269; LSNNS, 258) representing the full analysis set. LSNNS was not performed in 13 patients due to intraoperative findings. LSNNS was performed according to protocol for 245 patients, and detection of sentinel basin was possible for 237 patients (96.7%, 237/245). Stomach-preserving surgery was performed in 210 patients (81.4%. 210/258). Postoperative complications occurred in 51 LSG patients (19.0%) and 40 LSNNS patients (15.5%) (P=0.294). Clavien-Dindo grade III or higher complications occurred in 16 LSG patients (5.9%) and 13 LSNNS patients (5.0%) (P=0.647). Postoperative mortality occurred in one LSG patient. LSNNS was not a risk factor for postoperative morbidity in multivariate analysis except sex. Conclusions: LSNNS for EGC is a safe procedure in terms of postoperative morbidity and mortality when compared with LSG with LND. Trial Registration Number: NCT01804998. Funding: National Cancer Center, Republic of Korea (grant number: 1710160-2). Declaration of Interest: The authors declare that they have no conflicts of interest or financial ties to disclose. Ethical Approval: All patients provided written informed consent before the surgery. This study was reviewed and approved by the local institutional review boards of all participating institutions.

4054 Background: Laparoscopic sentinel node navigation surgery (LSNNS) has been suggested as an alternative to laparoscopic standard gastrectomy (LSG) in early gastric cancer patients to improve long-term quality of life (QOL) and nutritional outcomes. Here, we present 3-year results of patient-reported quality of life (QOL) and nutrition, secondary endpoints of SENORITA trial. Methods: SENORITA is a prospective multicenter randomized phase 3 trial. Patients diagnosed with early gastric cancer of 3 cm or less were randomly allocated (1:1) to LSNNS for stomach preservation or LSG. The primary endpoint was 3-year disease-free survival. In this study, we analyzed QOL assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and EORTC stomach module (STO22) and nutritional parameters at 3, 12, 24, and 36 months after surgery. Linear mixed model analyses was used to evaluate differences between the two groups. This trial is registered with ClinicalTrials.gov, NCT01804998. Results: From March 2013 to March 2017, a total of 580 patients were randomly assigned and 527 patients were included in the modified intention-to-treat analysis population (258 in LSNNS and 269 in LSG group). QOL questionnaires were available for 99.4% of patients at baseline and then for 92.2%, 83.2%, 72.8%, and 66.9% at 3, 12, 24, and 36 months after surgery, respectively. The LSNNS group had higher physical function score than the LSG group at all time points (p = 0.002). However, there were no significant differences in other scales of EORTC QLQ-C30. Regarding EORTC QLQ-STO22, pain, eating restriction, anxiety, and taste scores were lower (better QOL) at all time points in the LSNNS group than in the LSG group (p = 0.002, < 0.001, < 0.001, and < 0.001, respectively). The summary score of EORTC QLQ-STO22 was also higher in the LSNNS group representing better QOL (p < 0.001). Body mass index, hemoglobin and total protein were significantly higher in the LSNNS group compared with the LSG group. Conclusions: The LSNNS group had better physical function and less symptoms, including pain, eating restriction, anxiety, and taste change compared with the LSG group. Moreover, the nutritional parameters were better maintained in the LSNNS group than in the LSG group. These findings showed benefits of stomach preserving surgery in LSNNS and can be used to help decision making about treatment for patients with early gastric cancer. Clinical trial information: NCT01804998.

4510 Background: The benefits and hazards of laparoscopic sentinel node navigation surgery (LSNNS), compared with laparoscopic standard gastrectomy (LSG) with lymph node dissection in early gastric cancer (EGC), are unknown. The SENORITA trial investigated the clinical impact of LSNNS in EGC in terms of short-term surgical outcomes, long-term survival and quality of life. Methods: This study is a prospective, multicenter, randomized controlled, non-inferiority trial. Patients with preoperatively diagnosed gastric adenocarcinoma with T1N0 of 3 cm or less in diameter, regardless of histology, except absolute indication for endoscopic resection were eligible. Patients were randomized to LSG or LSNNS using dual tracers. The primary endpoint is 3-year disease-free survival (3yDFS). Planned sample size per arm is 290 patients with the non-inferiority margin of 2.737 in hazard ratio (HR) assuming that LSG achieve 97% 3yDFS, 5% of type 1 error and 80% of power. Three-year recurrence-free survival (3yRFS), overall survival (3yOS) and disease specific death rate (3yDSDR) were evaluated as secondary endpoints. Results: From March 2013 to December 2016, 580 patients were randomized (LSG arm 292 vs. LSNNS arm 288). After 53 patients dropped out before surgery, operation was performed in 527 patients (269 vs. 258), representing the full analysis set. LSG was performed in 266 according to the protocol excluding 3 open conversion. After exclusion of 13 without LSNNS due to various reasons, LSNNS was performed in 245 patients according to the protocol. After median follow up of 47.5 months, 3yDFS were 95.5% and 91.8% (HR 1.901, CI 0.911 – 3.967), respectively. The 3yRFS was 98.9% and 95.2% (p=0.019), and 3yOS was 99.2% and 97.6% (p=0.166), and 3yDSDR was 99.5% and 99.1% (p=0.591), respectively. Conclusion: LSNNS in EGC did not show non-inferiority compared with LSG in terms of 3yDFS. However, 3yOS and 3yDSDR of LSNNS were comparable to LSG by the rescue surgery of recurrence. LSNNS might be an alternative surgical option instead of LSG in selected EGC patients. Clinical trial information: NCT01804998 .

Purpose: Many studies have demonstrated the advantage of maintaining intraoperative deep neuromuscular block (NMB) with sugammadex. This trial is designed to evaluate the impact of muscle relaxation during laparoscopic subtotal gastrectomy on the oncological benefits, particularly in obese patients with gastric cancer. Materials and methods: This is a double-blind, randomized controlled multicenter prospective trial. Patients with clinical stage I–II gastric cancer with a body mass index of 25 and over, who undergo laparoscopic subtotal gastrectomy will be eligible for trial inclusion. The patients will be randomized into a deep NMB group or a moderate NMB group with a 1:1 ratio. A total of 196 patients (98 per group) are required. The primary endpoint is the number of harvested lymph nodes, which is a critical index of the quality of surgery in gastric cancer treatment. The secondary endpoints are surgeon's surgical condition score, patient's sedation score, and surgical outcomes including peak inspiratory pressure, operation time, postoperative pain, and morbidity. Discussion: This is the first study that compares deep NMB with moderate NMB during laparoscopic gastrectomy in obese patients with gastric cancer. We hope to show the oncologic benefits of deep NMB compared with moderate NMB during subtotal gastrectomy. Trial registration number: ClinicalTrials.gov (NCT03196791), date of registration: October 10, 2017.

Background. We investigated the results of quality control study prior to phase III trial of sentinel lymph node navigation surgery (SNNS). Methods. Data were reviewed from 108 patients enrolled in the feasibility study of laparoscopic sentinel basin dissection (SBD) in gastric cancer. Seven steps contain tracer injection at submucosa (step 1) and at four sites (step 2) by intraoperative esophagogastroduodenoscopy (EGD), leakage of tracer (step 3), injection within 3 minutes (step 4), identification of at least one sentinel basin (SB) (step 5), evaluation of sentinel basin nodes (SBNs) by frozen biopsy (step 6), and identification of at least five SBNs at back table and frozen sections (step 7). Results. Failure in step 7 (n=23) was the most common followed by step 3 (n=15) and step 6 (n=13). We did not find any differences of clinicopathological factors between success and failure group in steps 1~6. In step 7, body mass index (BMI) was only the significant factor. The success rate was 97.1% in patients with BMI 2 and 80.3% in those with BMI ≥ 23 kg/m2 (P=0.028). Conclusions. Lower BMI group showed higher success rate in step 7. Surgeons doing SNNS should be cautious when evaluating sufficient number of SBN in obese patients.

Purpose Although standard radical gastrectomy is recommended after noncurative resection of endoscopic submucosal dissection (ESD) for early gastric cancer in most cases, residual tumor and lymph node metastasis have not been identified after surgery. The aim of this study is to evaluate the feasibility of sentinel node navigation surgery after noncurative ESD. Materials and methods This trial is an investigator-initiated, multicenter prospective phase II trial. Patients who underwent ESD for clinical stage T1N0M0 gastric cancer with noncurative resections were eligible. Qualified investigators who completed the prior phase III trial (SENORITA 1) are exclusively allowed to participate. In this study, 2 detection methods will be used: 1) intraoperative endoscopic submucosal injection of dual tracer, including radioisotope and indocyanine green (ICG) with sentinel basins detected using gamma-probe; 2) endoscopic injection of ICG, with sentinel basins detected using a fluorescence imaging system. Standard laparoscopic gastrectomy with lymphadenectomy will be performed. Sample size is calculated based on the inferior confidence interval of the detection rate of 95%, and the calculated accrual is 237 patients. The primary endpoint is detection rate, and the secondary endpoints are sensitivity and postoperative complications. Conclusions This study is expected to clarify the feasibility of laparoscopic sentinel basin dissection after noncurative ESD. If the feasibility is demonstrated, a multicenter phase III trial will be initiated to compare laparoscopic sentinel node navigation surgery versus laparoscopic standard gastrectomy in early gastric cancer after endoscopic resection. Trial registration ClinicalTrials.gov Identifier: NCT03123042.

Purpose The Trastuzumab for gastric cancer (GC) trial identified human epidermal growth factor receptor 2 (HER2) as a predictor of successful treatment with trastuzumab (HER2 receptor targeting agent) among patients with advanced/metastatic GC. To date, the prevalence of HER2 overexpression in the Korean population is unknown. The present study aimed to assess the incidence of HER2 positivity among GC and gastroesophageal (GE) junction cancer samples and the relationship between HER2 overexpression and clinicopathological characteristics in Korean patients. Materials and methods Tumor samples collected from 1,695 patients with histologically proven GC or GE junction enrolled at 14 different hospitals in Korea were examined. After gathering clinicopathological data of all patients, HER2 status was assessed by immunohistochemistry (IHC) at each hospital, and IHC 2+ cases were subjected to silver-enhanced in situ hybridization at 3 central laboratories. Results A total of 182 specimens tested positive for HER2, whereas 1,505 tested negative. Therefore, the overall HER2-positive rate in this study was 10.8% (95% confidence interval=9.3%-12.3%). The HER2-positive rate was higher among intestinal-type cases (17.6%) than among other types, and was higher among patients older than 70 years and 50 years of age, compared to other age groups. Conclusions Our evaluation of the HER2 positivity rate (10.8%) among Korean patients with GC and GE junction indicated the necessity of epidemiological data when conducting studies related to HER2 expression in GC and GE junction.

Curative resection, including gastrectomy, extensive lymph node dissection, and combined resection of invaded organs, is the mainstay of treatment for T4b gastric cancers. We sought to investigate the clinicopathologic features, surgical outcomes, and prognostic factors of curatively resected pathologic T4b gastric cancer with a focus on organs invaded.Data of 243 pT4b gastric cancer patients who underwent curative resection at Korea Cancer Center Hospital from 1991 to 2005 were retrospectively subjected to univariate and multivariate analyses.Overall 5-year survival rate and median survival time were 36.8% and 26 months, respectively. Five-year survival rates were 23.3% in the pancreatic invasion group (n = 67) and 42.1% in the nonpancreatic invasion group (n = 176) (P = 0.002). Regarding operative methods used for pancreatectomy in pancreatic invasion group, 5-year survival rates were 0% in the pancreaticoduodenectomy group (n = 9) and 27.4% in the other pancreatectomies group (n = 58) (P = 0.013). Multivariate analysis revealed that advanced lymph node stages (hazard ratio [HR] 1.637 for N0 vs. N1, HR 2.177 for N0 vs. N2, HR 3.241 for N0 vs. N3a, and HR 4.000 for N0 vs. N3b), encircling type of tumor (HR 1.804), and pancreatic invasion (HR 1.463) were independently unfavorable prognostic factors.In pT4b gastric cancer, pancreatic invasion was found to portend the least favorable prognosis, especially in cases requiring pancreaticoduodenectomy. However, prognoses were more favorable after curative resection in patients without advanced lymph node stages (N2, N3a, and N3b), an encircling type of gastric tumor, or pancreatic invasion. We propose a novel therapeutic strategy for patients with T4b gastric cancer.

e16043Background: The benefits and hazards of laparoscopic sentinel node navigation surgery (LSNNS), compared with laparoscopic standard gastrectomy (LSG) with lymph node dissection (LND) in early ...

Purpose We investigated complications after laparoscopic sentinel basin dissection (SBD) for patients with gastric cancer who were enrolled in a quality control study, prior to the phase III trial of sentinel lymph node navigation surgery (SNNS). Materials and Methods We analyzed prospective data from a Korean multicenter prerequisite quality control trial of laparoscopic SBD for gastric cancer and assessed procedure-related and surgical complications. All complications were classified according to the Clavien-Dindo Classification (CDC) system and were compared with the results of the previously published SNNS trial. Results Among the 108 eligible patients who were enrolled in the quality control trial, 8 (7.4%) experienced complications during the early postoperative period. One patient with gastric resection-related duodenal stump leakage recovered after percutaneous drainage (grade IIIa in CDC). The other postoperative complications were mild and patients recovered with supportive care. No complications were directly related to the laparoscopic SBD procedure or tracer usage, and there were no mortalities. The laparoscopic SBD complication rates and patterns that were observed in this study were comparable to those of a previously reported trial. Conclusions The results of our prospective, multicenter quality control trial demonstrate that laparoscopic SBD is a safe procedure during SNNS for gastric cancer.

Purpose To investigate the current status of adjuvant chemotherapy (AC) regimens in Korea and the difference in efficacy of AC administered by surgical and medical oncologists in patients with stage II or III gastric cancers. Materials and methods We performed a retrospective observational study among 1,049 patients who underwent curative resection and received AC for stage II and III gastric cancers between February 2012 and December 2013 at 29 tertiary referral university hospitals in Korea. To minimize the influence of potential confounders on selection bias, propensity score matching (PSM) was used based on binary logistic regression analysis. The 3-year disease-free survival (DFS) rates were compared between patients who received AC administered by medical oncologists or surgical oncologists. Results Between February 2012 and December 2013 in Korea, the most commonly prescribed AC by medical oncologists was tegafur/gimeracil/oteracil (S-1, 47.72%), followed by capecitabine with oxaliplatin (XELOX, 16.33%). After performing PSM, surgical oncologists (82.74%) completed AC as planned more often than medical oncologists (75.9%), with statistical significance (P=0.036). No difference in the 3-year DFS rates of stage II (P=0.567) or stage III (P=0.545) gastric cancer was found between the medical and surgical oncologist groups. Conclusions S-1 monotherapy and XELOX are a main stay of AC, regardless of whether the prescribing physician is a medical or surgical oncologist. The better compliance with AC by surgical oncologists is a valid reason to advocate that surgical oncologists perform the treatment of AC for stage II or III gastric cancers.

The clinical application of sentinel node biopsies in early gastric cancer is still controversial even though it appears promising. This study was conducted as a prerequisite quality control for surgical standardization of laparoscopic sentinel basin dissection (SBD) prior to the initiation of a phase III trial. Laparoscopic SBD was performed in patients with preoperative stage T1-2N0 and tumor size