Impact of Body Mass Index on Survival Depending on Sex in 14,688 Patients with Gastric Cancer in a Tertiary Hospital in South Korea

Background/Aims@#The incidence and prognosis of gastric cancer (GC) shows sex difference.This study aimed to evaluate the effect of body mass index (BMI) on GC survival depending on sex. @*Methods@#The sex, age, location, histology, TNM stages, BMI, and survival were analyzed in GC patients from May 2003 to February 2020 at the Seoul National University Bundang Hospital. @*Results@#Among 14,688 patients, there were twice as many males (66.6%) as females (33.4%).However, under age 40 years, females (8.6%) were more prevalent than males (3.1%). Cardia GC in males showed a U-shaped distribution for underweight (9.6%), normal (6.4%), overweight (6.1%), obesity (5.6%), and severe obesity (9.3%) but not in females (p=0.003). Females showed decreased proportion of diffuse-type GC regarding BMI (underweight [59.9%], normal [56.8%], overweight [49.5%], obesity [44.8%], and severe obesity [41.7%]), but males did not (p<0.001). Both sexes had the worst prognosis in the underweight group (p<0.001), and the higher BMI, the better prognosis in males, but not females. Sex differences in prognosis according to BMI tended to be more prominent in males than in females in subgroup analysis of TNM stages I, II, and III and the operative treatment group. @*Conclusions@#GC-specific survival was affected by BMI in a sex-dependent manner. These differences may be related to genetic, and environmental, hormonal factors; body composition; and muscle mass (Trial registration number: NCT04973631).

Postoperative major bleeding risk in patients using oral antiplatelets and/or anticoagulants after laparoscopic gastric cancer surgery

Purpose@#The use of antiplatelet and/or anticoagulant therapies has become common. In rare cases, these therapies may increase the risk of dangerous postoperative bleeding. We investigated the association of antiplatelets and/or anticoagulants with postoperative major bleeding risk in laparoscopic gastric cancer surgery. @*Methods@#We retrospectively enrolled 3,663 gastric cancer patients (antiplatelet/anticoagulant group, 518; control group, 3,145) who had undergone laparoscopic surgery between January 2012 and December 2017. To minimize selection bias, 508 patients in each group were matched using propensity score matching (PSM) method. The primary outcome was postoperative major bleeding. Secondary outcomes were intraoperative, postoperative transfusion and early complications. @*Results@#After PSM, postoperative major bleeding occurred in 10 (2.0%) and 3 cases (0.6%) in the antiplatelets/ anticoagulants and control groups, respectively (P = 0.090). Intraoperative and postoperative transfusions were not significantly different between 2 groups (2.4% vs. 1.4%, P = 0.355 and 5.5% vs. 4.3%, P = 0.469). Early complications developed in 58 (11.4%) and 43 patients (8.5%) in the antiplatelets/anticoagulants and control groups, respectively (P = 0.142). The mean amounts of intraoperative and postoperative transfusions were not significantly different between the groups (366.67 ± 238.68 mL vs. 371.43 ± 138.01 mL, P = 0.962; 728.57 ± 642.25 mL vs. 508.09 ± 468.95 mL, P = 0.185). In multivariable analysis, male (P = 0.008) and advanced stage (III, IV) (P = 0.024) were independent significant risk factors for postoperative major bleeding. @*Conclusion@#Preoperative antiplatelets and/or anticoagulants administration did not significantly increase the risk of postoperative major bleeding after laparoscopic gastric cancer surgery.

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.

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. Reevaluation 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 reevaluation. 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.

The Clinicopathological Features of Mixed Carcinoma in 7,215Patients with Gastric Cancer in a Tertiary Hospital in South Korea

Background/Aims@#There are few reports regarding mixed carcinoma, defined as a mixture of glandular and poorly cohesive components, in patients with gastric cancer (GC). The aim of this study was to evaluate the proportion and characteristics of mixed carcinoma in GC patients. @*Methods@#A total of 7,215 patients diagnosed with GC at Seoul National University Bundang Hospital were enrolled from March 2011 to February 2020. GC was divided into four groups (wellmoderately differentiated GC, poorly differentiated GC, poorly cohesive carcinoma, and mixed carcinoma). The proportion of each GC type and the clinicopathological features were analyzed and divided into early GC and advanced GC. @*Results@#The proportion of mixed carcinoma was 10.9% (n=787). In early GC, submucosal invasion was the most common in poorly differentiated (53.7%), and mixed carcinoma ranked second (41.1%). Mixed carcinoma showed the highest proportion of lymph node metastasis in early GC (23.0%) and advanced GC (78.3%). In advanced GC, the rate of distant metastasis was 3.6% and 3.9% in well-moderately differentiated GC and mixed carcinoma, respectively, lower than that in poorly differentiated GC (6.4%) and poorly cohesive carcinoma (5.7%), without statistical significance. @*Conclusions@#Mixed carcinoma was associated with lymph node metastasis compared to other histological GC subtypes. And it showed relatively common submucosal invasion in early GC, but the rates of venous invasion and distant metastasis were lower in advanced GC. Further research is needed to uncover the mechanism underlying these characteristics of mixed carcinoma (Trial registration number: NCT04973631).

Development and Validation of Models to Predict Lymph Node Metastasis in Early Gastric Cancer Using Logistic Regression and Gradient Boosting Machine Methods / Journal of the Korean Cancer Association, 대한암학회지

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.

The Incidence and Risk Factors for Metachronous Gastric Cancer in the Remnant Stomach after Gastric Cancer Surgery

Background/Aims@#Less invasive surgical treatment is performed in East Asia to preserve postoperative digestive function and reduce complications such as postgastrectomy syndromes, but there is an issue of metachronous gastric cancer (GC) in the remaining stomach. This study aimed to analyze the incidence of metachronous GC and its risk factors in patients who had undergone partial gastrectomy. @*Methods@#A total of 3,045 GC patients who had undergone curative gastric partial resection at Seoul National University Bundang Hospital were enrolled and analyzed retrospectively for risk factors, including age, sex, smoking, alcohol, Helicobacter pylori status, family history of GC, histological type, and surgical method. @*Results@#Metachronous GC in the remaining stomach occurred in 35 of the 3,045 patients (1.1%): 23 in the distal gastrectomy group (18 with Billroth-I anastomosis, five with Billroth-II anastomosis), seven in the proximal gastrectomy (PG) group, and five in the pylorus-preserving gastrectomy (PPG) group. Univariate and multivariate Cox regression analyses showed that age ≥60 years (p=0.005) and surgical method used (PG or PPG, p<0.001) were related risk factors for metachronous GC, while male sex and intestinal type histology were potential risk factors. @*Conclusions@#Metachronous GC was shown to be related to older age and the surgical method used (PG or PPG). Regular and careful follow-up with endoscopy should be performed in the case of gastric partial resection, especially in patients with male sex and intestinal type histology as well as those aged ≥60 years undergoing the PG or PPG surgical method.

Transient Mutism Related to Capecitabine-Induced Acute Toxic Leukoencephalopathy

Capecitabine, a precursor of 5-fluorouracil (5-FU), is a well-tolerated and safe chemotherapy that has been used to treat breast, pancreatic, and colorectal cancers. Albeit rare, both 5-FU and capecitbine have been reported to be associated with acute central nervous system toxicity, including cerebellar dysfunction, posterior reversible encephalopathy syndrome, and transient leukoencephalopathies. Here we present a case of 32-year-old female, demonstrating transient mutism related to capecitabine induced acute toxic leukoencephalopathy.

Does bisphenol-A affect alteration of gut microbiome after bariatric/metabolic surgery?: a comparative metagenomic analysis in a long-term high-fat diet induced-obesity rat model

Purpose@#Bisphenol A (BPA) is a widely used environmental contaminant that is associated with type 2 diabetes mellitus and a shift of gut microbial community. However, little is known about the influence of BPA on gut microbial changes related to bariatric surgery. We investigated whether long-term exposure to dietary BPA causing alterations of gut microbiome occurred after bariatric surgery.  @*Methods@#Six-week-old male Wistar rats were fed either a high- fat diet (HFD) or HFD + BPA for 40 weeks. Then sleeve gastrectomy (SG) or Roux-en Y gastric bypass (RYGB) was performed in each diet group and observed for 12 weeks postoperatively. Fecal samples were collected at the 40th weeks and 12th postoperative weeks. Using 16S ribosomal RNA gene sequencing analysis on fecal samples, a comparative metagenomic analysis on gut microbiome composition was performed.  @*Results@#Long-term exposure to HFD with BPA showed higher body weight change and higher level of fasting blood sugar after 40 weeks-diet challenge than those of the HFD only group. After bariatric surgeries, mean body weight of the HFD with BPA group was significantly higher than the HFD only group, but there was no difference between the SG and RYGB groups. The metagenomic analyses demonstrated that long-term exposure to dietary BPA did not affect significant alterations of gut microbiome before and after bariatric surgery, compared with the HFD groups.  @*Conclusion@#Our results highlighted that BPA was a risk factor for obesity and may contribute to glucose intolerance, but it did not affect alterations of gut microbiome after bariatric/metabolic surgery.

Low Doses of Baclofen Induced Nonconvulsive Status Epilepticus in a Patient with Chronic Kidney Disease

Baclofen, a gamma-aminobutyric acid B agonist, is frequently used in the treatment of various neurologic diseases including spasticity, dystonia and trigeminal neuralgia. This drug usually acts at the presynaptic motor neuron to induce an antispastic response. Oral baclofen toxicity is extremely rare, but is often reported to affect patients with renal disease. Here, we report a patient with chronic kidney disease who was treated with relatively low doses of baclofen (5 mg twice per day) and experienced nonconvulsive status epilepticus.

Usefulness of articulating laparoscopic instruments during laparoscopic gastrectomy for gastric adenocarcinoma

Purpose@#Conventional straight-shaped laparoscopic surgical instruments have limitations that, unlike robotic surgery, the wrist joint cannot be used. This study aimed to analyze the short-term safety and feasibility of ArtiSential (Livsmed), a new articulating laparoscopic instrument, which obviates the limitations of conventional laparoscopic surgery and allows the wrist joint to be used freely over 360° as in robotic surgery. @*Methods@#The study included patients who underwent conventional laparoscopy or laparoscopy with the ArtiSential instrument. Patients who underwent laparoscopic gastrectomy for primary gastric adenocarcinoma in our institution were retrospectively reviewed. The groups were propensity score matched in a 1:1 ratio. Primary endpoint was incidence of early postoperative complication (postoperative 30-day morbidity and mortality) and secondary endpoints were operative outcomes. @*Results@#A total of 327 patients (147 of the conventional group and 180 of the ArtiSential group) were propensity score matched. After propensity score matching was performed, each group comprised of 122 patients. Both groups were comparable with regard to operation time, estimated blood loss, number of retrieved lymph nodes, and length of hospital stay. The ArtiSential group had a faster time to a fluid diet (2.6 ± 1.3 days vs. 2.3 ± 0.6 days, p = 0.015). There was no statistically significant difference in early postoperative complications between the two groups (the conventional group, 23.0%; the ArtiSential group, 26.2%; p = 0.656) @*Conclusion@#The current study showed that the use of ArtiSential is a safe and feasible option without increasing operation time, length of hospital stay, and intraoperative bleeding.

Comparing the short-term outcomes and cost between solo single-incision distal gastrectomy and conventional multiport totally laparoscopic distal gastrectomy for early gastric cancer: a propensity score-matched analysis

Purpose@#Single-incision laparoscopic distal gastrectomy (SIDG) requires experienced camera operators for a stable image. Since it is difficult for skilled camera operators to participate in all SIDG, we began performing solo surgery using mechanical camera holders. We aimed to compare the short-term outcomes and cost between solo SIDG and conventional multiport laparoscopic distal gastrectomy (MLDG) for early gastric cancer (EGC). @*Methods@#From January 2014 to December 2016, a total of 938 consecutive patients underwent laparoscopic gastrectomy for EGC. Solo SIDG (n = 99) and MLDG patients (n = 198) were selected and 1:2 propensity score matching was done to compare the quality of operation and cost-effectiveness. All solo SIDG was performed by a surgeon using a camera holder, without any assistant. @*Results@#Mean operation time (120 ± 35.3 vs. 178 ± 53.4 minutes, P = 0.001) and estimated blood loss (24.6 ± 47.4 vs. 46.7 ± 66.5 mL, P = 0.001) were significantly lower in the solo SIDG group. Hospital stay, use of analgesics, and postoperative inflammatory markers (WBC, CRP) were similar between the 2 groups. The early (<30 days) complication rate in solo SIDG and MLDG groups was 21.2% and 23.7%, respectively (P = 0.240); the late (≥30 days) complication rate was 7.1% and 11.1%, respectively (P = 0.672). The manpower cost of solo SIDG was significantly lower than that of MLDG (P = 0.001). @*Conclusion@#This study demonstrated that solo SIDG performed by experienced laparoscopic surgeons is safe and feasible for EGC. Solo SIDG is expected to be a promising potential treatment for EGC.

Actual compliance rate of Enhanced Recovery After Surgery protocol in laparoscopic distal gastrectomy

Purpose@#The Enhanced Recovery After Surgery (ERAS) protocol enhances recovery rate after laparoscopic distal gastrectomy (LDG). An ERAS protocol has been applied to most patients who underwent LDG at our center. In this study, we determined the actual compliance rate of the ERAS protocol and analyzed the risk factors for noncompliance. @*Methods@#Medical records of 1,013 patients who underwent LDG from March 2016 to December 2017 were reviewed retrospectively. The compliance group (A) included 327 patients who were discharged within four days postoperatively. The noncompliance group (B) comprised 686 patients who were not discharged within four days postoperatively. @*Results@#The compliance rate of the ERAS protocol was 32.3%. Potential compliance rate was 53.2%. Most common reasons for noncompliance were fever (n = 115) and ileus (n = 111). The 30-day emergency room visit rate was significantly lower in group A than that in group B (p = 0.006). Median age, American Society of Anesthesiologists (ASA) physical status classification, operation time, and pathologic stage were significantly higher in group B than those in group A (p < 0.001, p < 0.001, p = 0.005, and p < 0.001, respectively). Risk factors for noncompliance were ASA classification of ≥III (odds ratio [OR], 2.251; p = 0.007), age of ≥70 years (OR, 1.572; p = 0.004), operation time of ≥180 minutes (OR, 1.475; p = 0.003), and pathologic stage of ≥III (OR, 2.224; p < 0.001). @*Conclusion@#The current ERAS protocols should be applied to patients without risk factors.

PD-L1 Testing in Gastric Cancer by the Combined Positive Score of the 22C3 PharmDx and SP263 Assay with Clinically Relevant Cut-offs / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#We provide a comparison between 22C3 pharmDx and SP263 assay, for evaluating programmed death ligand 1 (PD-L1) expression in advanced gastric cancer (GC) patients. @*Materials and Methods@#The PD-L1 immunohistochemistry by 22C3 pharmDx and SP263 assays was performed in the center of the tumor (CT) and invasive margin (IM) in 379 GC tissues using tissue microarrays and interpreted as combined positive score (CPS) and tumor proportion score (TPS). Of the total samples, 55 samples were independently reviewed by five pathologists. @*Results@#The two assays showed a high correlation in both the CPS and TPS. At a CPS ≥ 1 cut-off, 219 (57.8%) and 231 (60.9%) GCs were positive for PD-L1 with the 22C3 and SP263 assays, and at ≥ 10 cut-off, 37 (9.8%) and 36 (9.5%) GCs were positive, respectively. The overall percent agreement (OPA) was greater than 90% with CPS ≥ 1 and ≥ 10 cut-offs, and TPS ≥ 1% and ≥ 10% cut-offs. There was higher OPA between the two assays with a CPS cut-off ≥ 10 (99.2%) than ≥ 1 (94.7%). The percent agreement between the CT and IM was higher with a CPS cut-off ≥ 10 (92.9%) than ≥ 1 (77.6%). Patient with positive expression at CPS ≥ 5 cut-off had a significantly better outcomes in both assays. Interobserver variability among five pathologists was higher than the assay variability. @*Conclusion@#Two assays for PD-L1 expression in GC showed high agreement. These results provide guidance for selecting eligible patients with GC for pembrolizumab treatment.

Clinicopathologic Characteristics of Young Gastric Cancer Patients: Diagnostic Staging Accuracy and Survival

Purpose@#The purpose of this study was to investigate the clinicopathologic characteristics of young gastric cancer patients and analyze the risk factors for stage underestimation and survival. @*Methods@#Relevant data of 5029 patients who underwent surgery for gastric cancer at Seoul National University Bundang Hospital between 2003 to 2014 were collected. Patients were divided based on age (younger group and older group). Clinical stages were compared to pathologic stages for accuracy, and risk factors for underestimation were analyzed using univariate and multivariate analysis regression. Overall survival and cancer-specific survival were analyzed using the Kaplan-Meier method. @*Results@#A total of 4396 patients were eligible for inclusion. The younger group was an independent risk factor for nodal metastasis (RR=1.44, 95% CI 1.06~1.95) and an independent risk factor for clinical N-stage underestimation (RR=1.50, 95% CI=1.14~1.98). However, there was no significant difference in 5-year cancer-specific survival for both age groups (92.2% vs 90.2%, p=0.306). @*Conclusion@#In conclusion, intra-operative investigation of T-stage with standard operation should be done in young gastric cancer patients as they have a higher incidence of lymph node metastasis, with greater frequency of stage underestimation.

Clinicopathologic Characteristics of Young Gastric Cancer Patients: Diagnostic Staging Accuracy and Survival

Purpose@#The purpose of this study was to investigate the clinicopathologic characteristics of young gastric cancer patients and analyze the risk factors for stage underestimation and survival. @*Methods@#Relevant data of 5029 patients who underwent surgery for gastric cancer at Seoul National University Bundang Hospital between 2003 to 2014 were collected. Patients were divided based on age (younger group and older group). Clinical stages were compared to pathologic stages for accuracy, and risk factors for underestimation were analyzed using univariate and multivariate analysis regression. Overall survival and cancer-specific survival were analyzed using the Kaplan-Meier method. @*Results@#A total of 4396 patients were eligible for inclusion. The younger group was an independent risk factor for nodal metastasis (RR=1.44, 95% CI 1.06~1.95) and an independent risk factor for clinical N-stage underestimation (RR=1.50, 95% CI=1.14~1.98). However, there was no significant difference in 5-year cancer-specific survival for both age groups (92.2% vs 90.2%, p=0.306). @*Conclusion@#In conclusion, intra-operative investigation of T-stage with standard operation should be done in young gastric cancer patients as they have a higher incidence of lymph node metastasis, with greater frequency of stage underestimation.

Long-term Outcomes of Laparoscopic Versus Open Transhiatal Approach for the Treatment of Esophagogastric Junction Cancer

PURPOSE: The laparoscopic transhiatal approach (LA) for adenocarcinoma of the esophagogastric junction (AEJ) is advantageous since it allows better visualization of the surgical field than the open approach (OA). We compared the surgical outcomes of the 2 approaches. MATERIALS AND METHODS: We analyzed 108 patients with AEJ who underwent transhiatal distal esophagectomy and gastrectomy with curative intent between 2003 and 2015. Surgical outcomes were reviewed using electronic medical records. RESULTS: The LA and OA were performed in 37 and 71 patients, respectively. Compared to the OA, the LA was associated with significantly shorter duration of postoperative hospital stay (9 vs. 11 days, P=0.001), shorter proximal resection margins (3 vs. 7 mm, P=0.004), and extended operative times (240 vs. 191 min, P=0.001). No significant difference was observed between the LA and OA for intraoperative blood loss (100 vs. 100 mL, P=0.392) or surgical morbidity rate (grade≥II) for complications (8.1% vs. 23.9%, P=0.080). Two cases of anastomotic leakage occurred in the OA group. The number of harvested lymph nodes was not significantly different between the LA and OA groups (54 vs. 51, P=0.889). The 5-year overall and 3-year relapse-free survival rates were 81.8% and 50.7% (P=0.024) and 77.3% and 46.4% (P=0.009) for the LA and OA groups, respectively. Multivariable analyses revealed no independent factors associated with overall survival. CONCLUSIONS: The LA is feasible and safe with short- and long-term oncologic outcomes similar to those of the OA.

Long-term Survival Outcomes of Laparoscopic Gastrectomy for Advanced Gastric Cancer: Five-year Results of a Phase II Prospective Clinical Trial

PURPOSE: Despite an increased acceptance of laparoscopic gastrectomy (LG) in early gastric cancer (EGC), there is insufficient evidence for its oncological safety in advanced gastric cancer (AGC). This is a prospective phase II clinical trial to evaluate the feasibility of LG with D2 lymph node dissection (LND) in AGC. MATERIALS AND METHODS: The primary endpoint was set as 3-year disease-free survival (DFS). The eligibility criteria were as follows: 20-80 years of age, cT2N0-cT4aN3, American Society of Anesthesiologists score of 3 or less, and no other malignancy. Patients were enrolled in this single-arm study between November 2008 and May 2012. Exclusion criteria included cT4b or M1, or having final pathologic results as EGC. All patients underwent D2 lymphadenectomy. Three-year DFS rates were estimated by the Kaplan-Meier method. RESULTS: A total of 157 patients were enrolled. The overall local complication rate was 10.2%. Conversion to open surgery occurred in 11 patients (7.0%). The mean follow-up period was 55.0±20.4 months (1–81 months). The cumulative 3-year DFS rates were 76.3% for all stages, and 100%, 89.3%, 100%, 88.0%, 71.4%, and 35.3% for stage IB, IIA, IIB, IIIA, IIIB, and IIIC, respectively. Recurrence was observed in 37 patients (23.6%), including hematogenous (n=6), peritoneal (n=13), locoregional (n=1), distant node (n=8), and mixed recurrence (n=9). CONCLUSIONS: In addition to being technically feasible for treatment of AGC in terms of morbidity, LG with D2 LND for locally advanced gastric cancer showed acceptable 3-year DFS outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01441336

Implementation of a resident night float system in a surgery department in Korea for 6 months: electronic medical record-based big data analysis and medical staff survey

PURPOSE: To evaluate superiority of a night float (NF) system in comparison to a traditional night on-call (NO) system for surgical residents at a single institution in terms of efficacy, safety, and satisfaction. METHODS: A NF system was implemented from March to September 2017 and big data analysis from electronic medical records was performed for all patients admitted for surgery or contacted from the emergency room (ER). Parameters including vital signs, mortality, and morbidity rates, as well as promptness of response to ER calls, were compared against a comparable period (March to September 2016) during which a NO system was in effect. A survey was also performed for physicians and nurses who had experienced both systems. RESULTS: A total of 150,000 clinical data were analyzed. Under the NO and NF systems, a total of 3,900 and 3,726 patients were admitted for surgery. Mortality rates were similar but postoperative bleeding was significantly higher in the NO system (0.5% vs. 0.2%, P = 0.031). From the 1,462 and 1,354 patients under the NO and NF systems respectively, that required surgical consultation from the ER, the time to response was significantly shorter in the NF system (54.5 ± 70.7 minutes vs. 66.8 ± 83.8 minutes, P < 0.001). Both physicians (90.4%) and nurses (91.4%) agreed that the NF system was more beneficial. CONCLUSION: This is the first report of a NF system using big data analysis in Korea, and potential benefits of this new system were observed in both ward and ER patient management.

Risk factors for atypical lymph node metastasis in gastric cancer

PURPOSE: The present study aimed to evaluate atypical lymph node metastasis rates according to tumor depth, size, and location in patients with gastric cancer.METHODS: A total of 727 gastric adenocarcinoma patients, with metastasis to 1 or 2 lymph nodes, who underwent radical gastrectomy with curative intent from May 2003 to May 2017, were enrolled in this study. The characteristics of atypical (skip or transversal) metastases were evaluated according to the following risk factors: longitudinal versus circumferential location, size, and T stage of the tumor.RESULTS: The rates of skip and transversal metastases were 8.4% and 15.5%, respectively. Skip metastases were present throughout, regardless of the primary tumor location. On the contrary, transversal metastases of gastric cancer were most frequently observed in the lower third region (19.5%, P=0.002). When the size of the tumor is large (>4 cm), transversal metastasis was found to be significantly more common (P=0.035), compared with skip metastasis, which was less common (P=0.011). There was no significant correlation between atypical metastases and tumor depth.CONCLUSION: Lower and larger tumors were more likely to have transversal metastases compared with others; however, skip metastases were less common in large tumors.