Refining gastric cancer staging: examining the interplay between number and anatomical location of metastatic lymph nodes - a retrospective multi-institutional study.

BACKGROUND: The current gastric cancer staging system relies on the number of metastatic lymph nodes (MLNs) for nodal stage determination. However, incorporating additional information such as topographic status may help address uncertainties. This study evaluated the appropriateness of the current staging system and relative significance of MLNs based on their anatomical location. METHODS: Patients who underwent curative gastrectomy for gastric cancer between 2000 and 2019 at six Catholic Medical Center-affiliated hospitals were included. Lymph node-positive patients were classified into the perigastric (stations 1-6, group P) or extragastric (stations 7-12) groups. The extragastric group was further subdivided into the near-extragastric (stations 7-9, group NE) and far-extragastric (stations 10-12, group FE) groups. RESULTS: We analyzed the data of 3,591 patients with positive lymph node metastases. No significant survival differences were found between group P and the extragastric group in each N stage. However, in N1 and N2, group FE showed significantly worse survival than the other groups (p = 0.013 for N1, p < 0.001 for N2), but not in N3. In the subgroup analysis, group FE had a significantly lower overall survival in N2, regardless of the cancer location. CONCLUSIONS: Our large-scale multi-institutional big data analysis confirmed the superiority of the current numerical nodal staging system for gastric cancer. Nonetheless, in N1 and N2 in which there is an upper limit on metastatic nodes, attention should be paid to the potential significance of topographic information for specific nodal stations.

Correction of Spacecraft Magnetic Field Noise: Initial Korean Pathfinder Lunar Orbiter MAGnetometer Observation in Solar Wind.

The Korean Pathfinder Lunar Orbiter (KPLO)-MAGnetometer (KMAG) consists of three triaxial fluxgate sensors (MAG1, MAG2, and MAG3) that measure the magnetic field around the Moon. The three sensors are mounted in the order MAG3, MAG2, and MAG1 inside a 1.2 m long boom, away from the satellite body. Before it arrived on the Moon, we compared the magnetic field measurements taken by DSCOVR and KPLO in solar wind to verify the measurement performance of the KMAG instrument. We found that there were artificial disturbances in the KMAG measurement data, such as step-like and spike-like disturbances, which were produced by the spacecraft body. To remove spacecraft-generated disturbances, we applied a multi-sensor method, employing the gradiometer technique and principal component analysis, using KMAG magnetic field data, and confirmed the successful elimination of spacecraft-generated disturbances. In the future, the proposed multi-sensor method is expected to clean the magnetic field data measured onboard the KPLO from the lunar orbit.

Worse Survival of Patients With T1 Stage II Gastric Cancer Following Radical Gastrectomy.

PURPOSE: Lymph node (LN) metastasis is a crucial factor in the prognosis of patients with gastric cancer (GC) and is known to occur more frequently in cases with an advanced T stage. This study aimed to analyze the survival data of patients with advanced LN metastasis in T1 GC. MATERIALS AND METHODS: From January 2008 to June 2018, 677 patients with pathological stage II GC who underwent radical gastrectomy were divided into an early GC group (EG: T1N2 and T1N3a, n=103) and an advanced GC (AGC) group (AG: T2N1, T2N2, T3N0, T3N1, and T4aN0, n=574). Short- and long-term survival rates were compared between the 2 groups. RESULTS: A total of 80.6% (n=83) of the patients in the EG group and 52.8% (n=303) in the AG group had stage IIA AGC. The extent of LN dissection, number of retrieved LNs, and short-term morbidity and mortality rates did not differ between the 2 groups. The 5-year relapse-free survival (RFS) of all patients was 87.8% and the overall survival was 84.0%. RFS was lower in the EG group than in the AG group (82.2% vs. 88.7%, P=0.047). This difference was more pronounced among patients with stage IIA (82.4% vs. 92.9%, P=0.003). CONCLUSIONS: T1 GC with multiple LN metastases seems to have a worse prognosis compared to tumors with higher T-stages at the same level. Adjuvant chemotherapy is highly recommended for these patients, and future staging systems may require upstaging T1N2-stage tumors.

Is Total Omentectomy Mandatory in T3 and T4a Gastric Cancer for Laparoscopic Distal Gastrectomy?

BACKGROUND: Despite the lack of strong evidence, total omentectomy (TO) remains the recommended procedure for gastric cancer (GC) for T3 or deeper tumors. Partial omentectomy (PO) has recently become a preferred procedure owing to its simplicity during laparoscopic distal gastrectomy (LDG); however, the oncological role of PO needs to be elucidated. METHODS: Overall, 341 patients with T3 or T4a GC who had undergone LDG between 2009 and 2016 were divided into TO (n = 167) and PO (n = 174) groups. Propensity matching was performed with respect to covariance age, sex, T and N stage, tumor size, and degree of tumor differentiation. Clinicopathological characteristics and long-term follow-up data were analyzed for both groups. RESULTS: After successful propensity matching, both groups included 107 patients. In a matched cohort, no significant difference in clinicopathologic features and short-term surgical outcomes was observed between the two groups. Furthermore, no significant difference in relapse-free survival (RFS; p = 0.201) and peritoneal seeding-free survival (PSFS; p = 0.094) was observed. However, tumor recurrence as peritoneal metastasis occurred in 5 (4.7%) patients in the PO group and 13 (12.1%) patients in the TO group. In Cox proportional hazards analysis, omentectomy was not identified as a significant factor for RFS, PSFS, and overall survival; however, advanced N and T4a stage were considered significant factors for RFS and PSFS, respectively. CONCLUSIONS: PO may be adopted during the LDG of T3 or T4a GC without definite gross serosal exposure. More large-scale evidence or prospective study is recommended.

The utility of high-mobility group A2 overexpression for predicting the prognosis of gastric cancer patients and its contribution to poor prognosis via chemoresistance and the propensity for the occurrence of carcinomatosis peritonei.

BACKGROUND: The aim of this study was to elucidate the correlation of high-mobility group protein A2 overexpression with gastric cancer prognosis and compare its prognostic power with that of pre-existing markers. METHODS: Malignant tissues from 396 patients with gastric cancer who underwent gastrectomy from 2008 to 2012 were examined. High-mobility group protein A2 expression was assessed by immunohistochemistry and the sensitivity and specificity for predicting disease progression and overall survival of high-mobility group protein A2 and the prognostic biomarkers p53, Ki-67, human epidermal growth factor receptor 2, cyclooxygenase-2, and epidermal growth factor receptor were compared. RESULTS: A total of 95 samples (24.1%) showed high-mobility group protein A2 overexpression, which was related to advanced stage, undifferentiated histology, and lymphatic and perineural invasion. Additionally, high-mobility group protein A2 overexpression was an independent prognostic factor in multivariate analysis for disease progression and overall survival. Based on Kaplan-Meier survival analysis disease progression and overall survival, the high-mobility group protein A2-overexpressing patients showed worse survival. The recurrence pattern of peritoneal dissemination was more frequently observed in high-mobility group protein A2-positive group. Moreover, chemoresistance was more frequently observed in the high-mobility group protein A2-positive group. High-mobility group protein A2 exhibited a better ability for predicting disease progression and overall survival than other markers, and the prognostic power was enhanced when high-mobility group protein A2 was used with these markers. CONCLUSION: High-mobility group protein A2 overexpression is associated with chemoresistance and a propensity for carcinomatosis peritonei after surgery in patients with gastric cancer. The power to predict the prognosis of patients with gastric cancer can be enhanced with the use of preexisting biomarkers and high-mobility group protein A2.

Trends in laparoscopic anti-reflux surgery: a Korea nationwide study.

BACKGROUND: In 2014, the results derived from the nationwide data of the Korean Anti-reflux Surgery Study (KARS) demonstrated short-term feasibility and safety of anti-reflux surgery. This study aimed to update the longer-term safety and feasibility of laparoscopic anti-reflux surgery up to 1-year follow-up with the KARS nationwide cohort. METHODS: The data of 310 patients with GERD who received anti-reflux surgery up to 2018 were analyzed. Baseline patient characteristics, postoperative symptom resolution, and postoperative complications were evaluated at postoperative 3 months and 1 year using the questionnaire designed by KARS. We divided the patients into two groups according to the operation period (up to and after 2014) to identify changes in the trends of the characteristics of surgical patients and operative qualities. RESULTS: The typical preoperative symptoms were present in 275 patients (91.7%), and atypical symptoms were present in 208 patients (71.0%). Ninety-seven (35.5%) and 124 patients (46.1%) had inadequate PPI responses and hiatal hernia, respectively. At postoperative 1 year, typical and atypical symptoms were either completely or partially controlled in 90.3% and 73.5.0% of patients, respectively. Moderate-to-severe dysphagia, inability to belch, gas bloating, and flatulence at postoperative 1 year were identified in 23.5%, 29.4%, 23.2%, and 22.0% of patients, respectively. The number of surgical patients continuously increased from 2011 to 2018 in Korea. The proportion of patients with hiatal hernia and comorbidities increased (p < 0.01, p = 0.053), and the operation time decreased significantly (p < 0.01) in the late period (2015-2018) as compared with the early period (2011-2014). Symptom control and complication rate were equivalent between the two periods. CONCLUSIONS: Anti-reflux surgery was effective with > 90% of typical symptom resolution and posed a comparable postoperative complication rate with those in Western studies with mid-term to long-term follow-up. This result supports the feasibility and safety of anti-reflux surgery as a treatment for GERD in the Korean population.

3D Printed, Customizable, and Multifunctional Smart Electronic Eyeglasses for Wearable Healthcare Systems and Human-Machine Interfaces.

Personal accessories such as glasses and watches that we usually carry in our daily life can yield useful information from the human body, yet most of them are limited to exercise-related parameters or simple heart rates. Since these restricted characteristics might arise from interfaces between the body and items as one of the main reasons, an interface design considering such a factor can provide us with biologically meaningful data. Here, we describe three-dimensional-printed, personalized, multifunctional electronic eyeglasses (E-glasses), not only to monitor various biological phenomena but also to propose a strategy to coordinate the recorded data for active commands and game operations for human-machine interaction (HMI) applications. Soft, highly conductive composite electrodes embedded in the E-glasses enable us to achieve reliable, continuous recordings of physiological activities. UV-responsive, color-tunable lenses using an electrochromic ionic gel offer the functionality of both eyeglass and sunglass modes, and accelerometers provide the capability of tracking precise human postures and behaviors. Detailed studies of electrophysiological signals including electroencephalogram and electrooculogram demonstrate the feasibility of smart electronic glasses for practical use as a platform for future HMI systems.

Long-Term Outcomes of Laparoscopic versus Open Total Gastrectomy for Advanced Gastric Cancer: A Propensity Score-Matched Analysis.

BACKGROUND: Laparoscopic total gastrectomy (LTG) for advanced gastric cancer (AGC) is a technically and oncologically challenging procedure for surgeons. OBJECTIVES: The aim of this study was to compare the technical safety and long-term oncological feasibility between LTG and open total gastrectomy (OTG) for patients with AGC using a propensity score (PS)-matched analysis. METHODS: Between 2004 and 2014, 185 patients (OTG: 127, LTG: 58) underwent curative total gastrectomy for AGC. PS matching was performed using the patients' clinicopathological factors, and comparisons were made based on surgical outcomes and long-term survival rates. RESULTS: After PS matching, 102 patients (51 patients in each group) were enrolled. The total numbers of retrieved lymph nodes were similar in both groups. The numbers of retrieved lymph nodes around the splenic hilum were similar in both groups. A longer operation time was required for the LTG group than for the OTG group, but less intraoperative bleeding was observed in the LTG group. The overall morbidity and mortality rates of both groups were similar. Between the 2 groups, there was no difference in the 5-year overall survival rate or disease-free survival rate. CONCLUSIONS: For treating proximal AGC, LTG may be a technically and an oncologically safe and feasible method.

Negative Impact of Endoscopic Submucosal Dissection on Short-Term Surgical Outcomes of Subsequent Laparoscopic Distal Gastrectomy for Gastric Cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) for gastric cancer produces an artificial ulcer, and negative effects on the surgical outcomes of additional gastrectomy after ESD are anticipated. The aim of this study is to analyze the effect of ESD on subsequent laparoscopic radical gastrectomy procedures and to compare the surgical results of post-ESD patients with the control group using propensity score (PS) methods. PATIENTS AND METHODS: From 2013 to 2018, 1446 patients underwent totally laparoscopic distal gastrectomy in our center. Among these patients, the clinicopathological factors and short-term surgical outcomes of 107 patients who underwent ESD before surgery (the ESD group) were evaluated. A 1:4 PS matching and inverse probability weighting method was utilized to compare the short-term surgical outcomes of the ESD group with those of a matched control group. RESULTS: A longer operation time was required for the patients who underwent gastrectomy earlier than 24 days after ESD than for the patients who did not. Patients whose ulcer size, due to previous ESD, exceeded 4.6 cm required longer operation times and exhibited more intraoperative blood loss than patients whose ulcer size was small. In the PS matching analysis, patients who underwent distal gastrectomy within 24 days after ESD showed more frequent postoperative morbidity than non-ESD patients. CONCLUSIONS: ESD after laparoscopic distal gastrectomy is largely safe in terms of short-term surgical outcomes, but a short interval between the two procedures and a large ESD scar can make subsequent operation difficult.

ARPNet: Antidepressant Response Prediction Network for Major Depressive Disorder.

Treating patients with major depressive disorder is challenging because it takes several months for antidepressants prescribed for the patients to take effect. This limitation may result in increased risks and treatment costs. To address this limitation, an accurate antidepressant response prediction model is needed. Recently, several studies have proposed models that extract useful features such as neuroimaging biomarkers and genetic variants from patient data, and use them as predictors for predicting the antidepressant responses of patients. However, it is impossible to utilize all the different types of predictors when making a clinical decision on what drugs to prescribe for a patient. Although a machine learning-based antidepressant response prediction model has been proposed to overcome this problem, the model cannot find the most effective antidepressant for a patient. Based on a neural network, we propose an Antidepressant Response Prediction Network (ARPNet) model capturing high-dimensional patterns from useful features. Based on a literature survey and data-driven feature selection, we extract useful features from patient data, and use the features as predictors. In ARPNet, the patient representation layer captures patient features and the antidepressant prescription representation layer captures antidepressant features. Utilizing the patient and antidepressant prescription representation vectors, ARPNet predicts the degree of antidepressant response. The experimental evaluation results demonstrate that our proposed ARPNet model outperforms machine learning-based models in predicting antidepressant response. Moreover, we demonstrate the applicability of ARPNet in downstream applications in use case scenarios.

Emergent gauge field and the Lifshitz transition of spin-orbit coupled bosons in one dimension.

In the presence of strong spin-independent interactions and spin-orbit coupling, we show that the spinor Bose liquid confined to one spatial dimension undergoes an interaction- or density-tuned quantum phase transition similar to one theoretically proposed for itinerant magnetic solid-state systems. The order parameter describes broken Z2 inversion symmetry, with the ordered phase accompanied by non-vanishing momentum which is generated by fluctuations of an emergent dynamical gauge field at the phase transition. This quantum phase transition has dynamical critical exponent z ≃ 2, typical of a Lifshitz transition, but is described by a nontrivial interacting fixed point. From direct numerical simulation of the microscopic model, we extract previously unknown critical exponents for this fixed point. Our model describes a realistic situation of 1D ultracold atoms with Raman-induced spin-orbit coupling, establishing this system as a platform for studying exotic critical behavior of the Hertz-Millis type.

Actual compliance to adjuvant chemotherapy in gastric cancer.

PURPOSE: This study aims to investigate the actual compliance with chemotherapy and analyze several factors affecting the compliance in patients with gastric cancer. METHODS: From February 2012 to December 2014, we collected data of patients with gastric cancer who received adjuvant chemotherapy (TS-1 monotherapy or XELOX: capecitabine/oxaliplatin) in Korea. RESULTS: We collected data of 1,089 patients from 31 institutions. The completion rate and dose reduction rate by age (≥60 years vs. <60 years) were 57.5% vs. 76.8% (P < 0.001) and 17.9% vs. 21.3% (P = 0.354); by body mass index (BMI) (≥23 kg/m2 vs. <23 kg/m2) were 70.2% vs. 63.2% (P = 0.019) and 19.2% vs. 19.9% (P = 0.987), respectively. The compliance by American Society of Anesthesiologists physical status (ASA PS) classification was as follows: completion rate was 74.4%, 62.8%, and 60% (P = 0.001) and the dose reduction rate was 18.4%, 20.7%, and 17.8% (P = 0.946) in ASA PS classification I, II, and III, respectively. The completion rate of TS-1 and XELOX was 65.9% vs. 70.3% (P = 0.206) and the dose reduction rate was 15.7% vs. 33.6% (P < 0.001). Furthermore, the completion rate of chemotherapy by surgical oncologists and medical oncologists was 69.5% vs. 63.2% (P = 0.028) and the dose reduction rate was 17.4% vs. 22.3% (P = 0.035), respectively. CONCLUSION: The compliance was lower in patients who were older than 60 years, had BMI <23 kg/m2, and had higher ASA PS classification. Furthermore, the patients showed higher compliance when they received chemotherapy from surgical oncologists rather than from medical oncologists.

Anatomic variations in the left gastric vein and their clinical significance during laparoscopic gastrectomy.

BACKGROUND: Surgeons normally encounter the left gastric vein (LGV) during laparoscopic gastrectomy (LG) for gastric cancer, and the various anatomic variants of this vessel make the procedure difficult. The objective of this study was to classify anatomic variants of the LGV in the laparoscopic operation field and clarify their clinical significance during LG. METHODS: In total, 405 patients who underwent LG in 2013-2017 for gastric cancer were enrolled in the study. LGV drainage was classified into six types by the anatomic relation of the LGV to the arteries of the celiac axis: Type Ia [LGV runs anteriorly to the common hepatic artery (CHA)], Type Ip (LGV runs posteriorly to CHA), Type II (LGV runs anteriorly to the left gastric artery), Type IIIa [LGV runs anteriorly to the splenic artery (SA)], Type IIIp (LGV runs posteriorly to SA), and Type IV (LGV runs cranially into the proximal portal vein or liver parenchyma). If the LGV was injured during the operation, the patient was included as a member of the injury group (IG). RESULTS: Most patients (n = 391, 96.5%) had a single LGV, whereas 14 (3.5%) patients had double LGVs. Type Ip was the most common of the six drainage types (n = 195, 48.1%). The number of patients in the IG was 49 (13.0%). Types I and III were relatively easily injured when compared with type II (p = 0.025). Patients in the IG had longer operation times, more blood loss, and more lymph node metastases than the non-IG patients. CONCLUSIONS: In most patients, the LGV drains posteriorly to the CHA or anteriorly to the LGA. Gastric surgeons should take great care not to injure the LGV during LG when it is not present on the anterior side of the celiac axis.

Classification of lung nodules in CT scans using three-dimensional deep convolutional neural networks with a checkpoint ensemble method.

BACKGROUND: Accurately detecting and examining lung nodules early is key in diagnosing lung cancers and thus one of the best ways to prevent lung cancer deaths. Radiologists spend countless hours detecting small spherical-shaped nodules in computed tomography (CT) images. In addition, even after detecting nodule candidates, a considerable amount of effort and time is required for them to determine whether they are real nodules. The aim of this paper is to introduce a high performance nodule classification method that uses three dimensional deep convolutional neural networks (DCNNs) and an ensemble method to distinguish nodules between non-nodules. METHODS: In this paper, we use a three dimensional deep convolutional neural network (3D DCNN) with shortcut connections and a 3D DCNN with dense connections for lung nodule classification. The shortcut connections and dense connections successfully alleviate the gradient vanishing problem by allowing the gradient to pass quickly and directly. Connections help deep structured networks to obtain general as well as distinctive features of lung nodules. Moreover, we increased the dimension of DCNNs from two to three to capture 3D features. Compared with shallow 3D CNNs used in previous studies, deep 3D CNNs more effectively capture the features of spherical-shaped nodules. In addition, we use an alternative ensemble method called the checkpoint ensemble method to boost performance. RESULTS: The performance of our nodule classification method is compared with that of the state-of-the-art methods which were used in the LUng Nodule Analysis 2016 Challenge. Our method achieves higher competition performance metric (CPM) scores than the state-of-the-art methods using deep learning. In the experimental setup ESB-ALL, the 3D DCNN with shortcut connections and the 3D DCNN with dense connections using the checkpoint ensemble method achieved the highest CPM score of 0.910. CONCLUSION: The result demonstrates that our method of using a 3D DCNN with shortcut connections, a 3D DCNN with dense connections, and the checkpoint ensemble method is effective for capturing 3D features of nodules and distinguishing nodules between non-nodules.

Safety of Laparoscopic Radical Gastrectomy in Gastric Cancer Patients with End-Stage Renal Disease.

PURPOSE: The surgical outcomes of end-stage renal disease (ESRD) patients undergoing radical gastrectomy for gastric cancer were inferior compared with those of non-ESRD patients. This study aimed to evaluate the short- and long-term surgical outcomes of ESRD patients undergoing laparoscopic gastrectomy (LG) and open gastrectomy (OG) for gastric cancer. MATERIALS AND METHODS: Between 2004 and 2014, 38 patients (OG: 21 patients, LG: 17 patients) with ESRD underwent gastrectomy for gastric cancer. Comparisons were made based on the clinicopathological characteristics, surgical outcomes, and long-term survival rates. RESULTS: No significant differences were noted in the clinicopathological characteristics of either group. LG patients had lower estimated blood loss volumes than OG patients (LG vs. OG: 94 vs. 275 mL, P=0.005). The operation time and postoperative hospital stay were similar in both the groups. The postoperative morbidity for LG and OG patients was 41.1% and 33.3%, respectively (P=0.873). No significant difference was observed in the long-term overall survival rates between the 2 groups (5-year overall survival, LG vs. OG: 82.4% vs. 64.7%, P=0.947). CONCLUSIONS: In ESRD patients, LG yielded non-inferior short- and long-term surgical outcomes compared to OG. Laparoscopic procedures might be safely adopted for ESRD patients who can benefit from the advantages of minimally invasive surgery.

Detection of masses in mammograms using a one-stage object detector based on a deep convolutional neural network.

Several computer aided diagnosis (CAD) systems have been developed for mammography. They are widely used in certain countries such as the U.S. where mammography studies are conducted more frequently; however, they are not yet globally employed for clinical use due to their inconsistent performance, which can be attributed to their reliance on hand-crafted features. It is difficult to use hand-crafted features for mammogram images that vary due to factors such as the breast density of patients and differences in imaging devices. To address these problems, several studies have leveraged a deep convolutional neural network that does not require hand-crafted features. Among the recent object detectors, RetinaNet is particularly promising as it is a simpler one-stage object detector that is fast and efficient while achieving state-of-the-art performance. RetinaNet has been proven to perform conventional object detection tasks but has not been tested on detecting masses in mammograms. Thus, we propose a mass detection model based on RetinaNet. To validate its performance in diverse use cases, we construct several experimental setups using the public dataset INbreast and the in-house dataset GURO. In addition to training and testing on the same dataset (i.e., training and testing on INbreast), we evaluate our mass detection model in setups using additional training data (i.e., training on INbreast + GURO and testing on INbreast). We also evaluate our model in setups using pre-trained weights (i.e., using weights pre-trained on GURO, training and testing on INbreast). In all the experiments, our mass detection model achieves comparable or better performance than more complex state-of-the-art models including the two-stage object detector. Also, the results show that using the weights pre-trained on datasets achieves similar performance as directly using datasets in the training phase. Therefore, we make our mass detection model's weights pre-trained on both GURO and INbreast publicly available. We expect that researchers who train RetinaNet on their in-house dataset for the mass detection task can use our pre-trained weights to leverage the features extracted from the datasets.

Feasibility and Safety of Totally Laparoscopic Radical Gastrectomy for Advanced Gastric Cancer: Comparison with Early Gastric Cancer.

PURPOSE: Totally laparoscopic gastrectomy (TLG) for advanced gastric cancer (AGC) is a technically and oncologically challenging procedure for surgeons. This study aimed to compare the oncologic feasibility and technical safety of TLG for AGC versus early gastric cancer (EGC). MATERIALS AND METHODS: Between 2011 and 2016, 535 patients (EGC, 375; AGC, 160) underwent curative TLG for gastric cancer. Clinicopathologic characteristics and surgical outcomes of both patient groups were analyzed and compared. RESULTS: Patients with AGC required a longer operation time and experienced more intraoperative blood loss than those with EGC did. However, patients from both the AGC and EGC groups demonstrated similar short-term surgical outcomes such as postoperative morbidity (14.4% vs. 13.3%, P=0.626), mortality (0% vs. 0.5%, P=0.879), time-to-first oral intake (2.7 days for both groups, P=0.830), and postoperative hospital stay (10.2 days vs. 10.1 days, P=0.886). D2 lymph node dissection could be achieved in the AGC group (95%), with an adequate number of lymph nodes being dissected (36.0±14.9). In the AGC group, the 3-year overall and disease-free survival rates were 80.5% and 73.7%, respectively. CONCLUSIONS: TLG is as safe and effective for AGC as it is for EGC.

Does Hospital Volume Really Affect the Surgical and Oncological Outcomes of Gastric Cancer in Korea?

PURPOSE: The significance of hospital volume remains inconsistent and controversial. In particular, few studies have examined whether hospital volume is associated with the outcome of gastrectomy for gastric cancer in East Asia. This study examined the effect of hospital volume on the short-term surgical and long-term oncological outcomes of patients undergoing curative gastrectomy for gastric cancer. MATERIALS AND METHODS: Between 2009 and 2011, 1,561 patients underwent curative gastrectomy for gastric cancer at Seoul St. Mary's Hospital (n=1,322) and Bucheon St. Mary's Hospital (n=239). We defined Seoul St. Mary's Hospital as a high-volume center and Bucheon St. Mary's Hospital as a low-volume center. RESULTS: The extent of resection, rate of combined resection, tumor stage, operating time, and hospital stay did not differ significantly between the 2 hospitals. In addition, the hospital volume was not significantly associated with the 30-day morbidity and mortality. When the overall and disease-free survival rates of the patients were stratified according to stage, hospital volume was not significantly associated with prognosis at any stage. CONCLUSIONS: Hospital volume might not be a decisive factor with respect to the surgical and oncological outcomes of patients if well-trained surgeons perform gastrectomy for gastric cancer.

Clinical implication of discrepancies between surgical and pathologic diagnoses of acute appendicitis.

PURPOSE: The postoperative treatment after appendectomy is usually decided on the basis of the surgeons' intraoperative findings. Comparatively, the pathologic diagnosis of appendicitis is confirmed several days after the surgery; therefore, it usually does not affect the postoperative treatment strategy. The aim of this study was to investigate the discrepancies between the surgical and pathologic diagnoses of appendicitis and to identify their clinical implication. METHODS: A retrospective observational study was performed in 1,817 patients who underwent 3-port laparoscopic appendectomy for the final diagnosis of appendicitis. The clinical variables that could estimate the severity of appendicitis and the intensity of postoperative treatment were analyzed and compared according to the surgical and pathologic diagnoses. RESULTS: Of 1,321 cases of surgically simple appendicitis, 254 (29.3%) were pathologically complicated appendicitis. On the other hand, 221 of 496 cases (44.5%) of surgically complicated appendicitis were pathologically simple. Neither the surgical nor the pathologic diagnosis of appendicitis affected the development of postoperative intra-abdominal abscess (P = 0.079 for surgical diagnosis; P = 0.288 for pathologic diagnosis); however, the surgical diagnosis showed more correlation with the severity of disease and the intensity of the treatment pathway than did the pathologic diagnosis. CONCLUSION: There were discrepancies between the surgeons' intraoperative assessment and the pathologists' final histologic diagnosis of appendicitis. The surgeon's classification might be more predictive of the outcome than the pathologist's because only the surgeon's findings are available immediately after surgery.