Purpose: This study aimed to investigate the outcomes of laparoscopic gastrectomy in very elderly patients with gastric cancer, who have outlived the average lifespan of the Korean population (men: ${\geq}77years$, women: ${\geq}84years$). Materials and Methods: Between 2004 and 2015, 836 patients with gastric cancer underwent a laparoscopic gastrectomy. They were divided into the elderly group (EldG) and non-elderly group (nEldG). Propensity score matching for covariates of sex, tumor depth, node status, and extent of resection was performed. Clinicopathologic characteristics, and surgical and survival outcomes were compared between the 2 groups. Results: The EldG had a higher American Society of Anesthesiologists (ASA) score and a higher number of comorbidities. There was no significant difference in the post-operative complications, except for pulmonary complications, which were more frequent in the EldG (5/56, 8.9%) than in the nEldG (0/56, 0%). The EldG had a shorter overall survival (OS), but cancer-specific survival was similar for both groups. Among deceased patients, 2 (25%) and 8 patients (50%) died within a year of surgery in the nEldG and EldG, respectively. Univariate and multivariate risk factor analyses for OS showed that age, ASA score, tumor, node, metastasis (TNM) stage, and occurrence of complications were significantly related to deterioration in OS. Conclusions: Laparoscopic gastrectomy can be safely performed in very elderly patients with gastric cancer who have outlived the average lifespan of the Korean population. However, impact of laparoscopic gastrectomy on improving survival is not clear, and careful patient selection is recommended.

Purpose: Exercise intervention after surgery has been found to improve physical fitness and quality of life (QOL). The purpose of this study was to investigate the feasibility and effects of a postoperative recovery exercise program developed specifically for gastric cancer patients (PREP-GC) undergoing minimally invasive gastrectomy. Materials and Methods: Twenty-four patients treated surgically for early gastric cancer were enrolled in the PREP-GC. The exercise program comprised sessions of In-hospital Exercise (1 week), Home Exercise (1 week), and Fitness Improvement Exercise (8 weeks). Adherence and compliance to PREP-GC were evaluated. In addition, body composition, physical fitness, and QOL were assessed during the preoperative period, after the postoperative recovery (2 weeks after surgery), and upon completing the PREP-GC (10 weeks after surgery). Results: Of the 24 enrolled patients, 20 completed the study without any adverse events related to the PREP-GC. Adherence and compliance rates to the Fitness Improvement Exercise were 79.4% and 99.4%, respectively. Upon completing the PREP-GC, patients also exhibited restored cardiopulmonary function and muscular strength, with improved muscular endurance and flexibility (P<0.05). Compared to those in the preoperative period, no differences were found in symptom scale scores measured using the European Organization for Research and Treatment of Cancer (EORTC) Core Quality of Life Questionnaire (QLQ-C30) and Quality of Life Questionnaire-Stomach Cancer-Specific Module (QLQ-STO22); however, higher scores for global health status and emotional functioning were observed after completing the PREP-GC (P<0.05). Conclusions: In gastric cancer patients undergoing minimally invasive gastrectomy, PREP-GC was found to be feasible and safe, with high adherence and compliance. Although randomized studies evaluating the benefits of exercise intervention during postoperative recovery are needed, surgeons should encourage patients to participate in systematic exercise intervention programs in the early postoperative period (Registered at the ClinicalTrials.gov, NCT01751880).

Purpose: Postoperative pancreatic fistula is a serious and fatal complication of gastrectomy for gastric cancer. Blunt trauma to the parenchyma of the pancreas can result from an assistant's forceps compressing and retracting the pancreas, which in turn may result in pancreatic juice leakage. However, no published studies have focused on blunt trauma to the pancreas during laparoscopic surgery. Our aim was to investigate the relationship between compression of the pancreas and pancreatic juice leakage in a swine model. Materials and Methods: Three female pigs were used in this study. The pancreas was gently compressed dorsally for 15 minutes laparoscopically with gauze grasped with forceps. Pancreatic juice leakage was visualized by fluorescence imaging after topical administration of chymotrypsin-activatable fluorophore in real time. Amylase concentrations in ascites collected at specified times was measured. In addition, pancreatic tissue was fixed with formalin, and the histology of the compressed sites was evaluated. Results: Fluorescence imaging enabled visualization of pancreatic juice leaking into ascites around the pancreas. Median concentrations of pancreatic amylase in ascites increased from 46 U/L preoperatively to 12,509 U/L 4 hours after compression. Histological examination of tissues obtained 4 hours after compression revealed necrotic pancreatic acinar cells extending from the surface to deep within the pancreas and infiltration of inflammatory cells. Conclusions: Pancreatic compression by the assistant's forceps can contribute to pancreatic juice leakage. These findings will help to improve the procedure for lymph node dissection around the pancreas during laparoscopic gastrectomy.

Purpose: The modification of the cancer classification system aimed to improve the classical anatomy-based tumor, node, metastasis (TNM) staging by considering tumor biology, which is associated with patient prognosis, because such information provides additional precision and flexibility. Materials and Methods: We previously developed an mRNA expression-based single patient classifier (SPC) algorithm that could predict the prognosis of patients with stage II/III gastric cancer. We also validated its utilization in clinical settings. The prognostic single patient classifier (pSPC) differentiates based on 3 prognostic groups (low-, intermediate-, and high-risk), and these groups were considered as independent prognostic factors along with TNM stages. We evaluated whether the modified TNM staging system based on the pSPC has a better prognostic performance than the TNM 8th edition staging system. The data of 652 patients who underwent gastrectomy with curative intent for gastric cancer between 2000 and 2004 were evaluated. Furthermore, 2 other cohorts (n=307 and 625) from a previous study were assessed. Thus, 1,584 patients were included in the analysis. To modify the TNM staging system, one-grade down-staging was applied to low-risk patients according to the pSPC in the TNM 8th edition staging system; for intermediate- and high-risk groups, the modified TNM and TNM 8th edition staging systems were identical. Results: Among the 1,584 patients, 187 (11.8%), 664 (41.9%), and 733 (46.3%) were classified into the low-, intermediate-, and high-risk groups, respectively, according to the pSPC. pSPC prognoses and survival curves of the overall population were well stratified, and the TNM stage-adjusted hazard ratios of the intermediate- and high-risk groups were 1.96 (95% confidence interval [CI], 1.41-2.72; P<0.001) and 2.54 (95% CI, 1.84-3.50; P<0.001), respectively. Using Harrell's C-index, the prognostic performance of the modified TNM system was evaluated, and the results showed that its prognostic performance was better than that of the TNM 8th edition staging system in terms of overall survival (0.635 vs. 0.620, P<0.001). Conclusions: The pSPC-modified TNM staging is an alternative staging system for stage II/III 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 ($36.0{\pm}14.9$). 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.

Purpose: This study assessed the feasibility of near-infrared (NIR) imaging with indocyanine green (ICG) in investigating the completeness of laparoscopic lymph node (LN) dissection for gastric cancer. Materials and Methods: Patients scheduled for laparoscopic gastrectomy for treating gastric cancer were enrolled in the study. After intraoperative submucosal ICG injection (0.05 mg/mL), LN dissection was performed under conventional laparoscopic light. After dissection, the LN stations of interest were examined under the NIR mode to locate any extra ICG-stained (E) tissues, which were excised and sent for pathologic confirmation. This technique was tested in 2 steps: infra-pyloric LN dissection (step 1) and review of all stations after proper radical node dissection (step 2). Results: In step 1, 15 patients who underwent laparoscopic pylorus-preserving gastrectomy (LPPG) and 15 patients who underwent laparoscopic distal gastrectomy (LDG) were examined. Seven and 2 E-tissues were obtained during LPPG and LDG, respectively. From the retrieved E-tissues, 1 and 0 tissue obtained during LPPG and LDG, respectively, was confirmed as LN. In step 2, 20 patients were enrolled (13 D1+ dissection and 7 D2 dissection). Six E-tissues were retrieved from 5 patients, and 1 tissue was confirmed as LN in the pathologic review. Overall, 15 E-tissues were detected and removed, and 2 tissues were confirmed as LNs in the pathologic review. Both nodes were from LN station #6, with 1 case each in the LDG and LPPG groups. Conclusions: NIR imaging may provide additional node detection during laparoscopic LN dissection for gastric cancer, especially in the infra-pyloric area.

Purpose: This study aimed to evaluate the surgical outcomes and investigate the feasibility of reduced-port laparoscopic gastrectomy using learning curve analysis in a small-volume center. Materials and Methods: We reviewed 269 patients who underwent laparoscopic distal gastrectomy (LDG) for gastric carcinoma between 2012 and 2017. Among them, 159 patients underwent reduced-port laparoscopic gastrectomy. The cumulative sum technique was used for quantitative assessment of the learning curve. Results: There were no statistically significant differences in the baseline characteristics of patients who underwent conventional and reduced-port LDG, and the operative time did not significantly differ between the groups. However, the amount of intraoperative bleeding was significantly lower in the reduced-port laparoscopic gastrectomy group (56.3 vs. 48.2 mL; P<0.001). There were no significant differences between the groups in terms of the first flatus time or length of hospital stay. Neither the incidence nor the severity of the complications significantly differed between the groups. The slope of the cumulative sum curve indicates the trend of learning performance. After 33 operations, the slope gently stabilized, which was regarded as the breakpoint of the learning curve. Conclusions: The surgical outcomes of reduced-port laparoscopic gastrectomy were comparable to those of conventional laparoscopic gastrectomy, suggesting that transition from conventional to reduced-port laparoscopic gastrectomy is feasible and safe, with a relatively short learning curve, in a small-volume center.

Purpose: Despite the fact that there are several reports of single-port laparoscopic distal gastrectomy (SPDG), no analysis of its learning curve has been described in the literature. The aim of this study was to investigate the favorable factors for SPDG and to analyze the learning curve of SPDG. Materials and Methods: A total of 125 cases of SPDG performed from November 2011 to December 2015 were enrolled. All operations were performed by 2 surgeons (surgeon A and surgeon B). The moving average method was used for defining the learning curve. All cases were divided into 10 cases in a sequence, and the mean operative time and estimated blood loss data were extracted from each group. Results: Surgeon A performed 68 cases (female-to-male sex ratio, 91.1%:8.82%), and surgeon B performed 57 cases (female-to-male sex ratio, 61.4%:38.5%). The operative time of surgeon B significantly decreased after 30 cases ($157.8{\pm}38.4$ minutes vs. $118.1{\pm}34.5$ minutes, P=0.003); that of surgeon A did not significantly decrease before and after around 30 cases ($160.8{\pm}51.6$ minutes vs. $173.3{\pm}35.2$ minutes, P=0.6). The subgroup analysis showed that the operative time significantly decreased in the patients with body mass index (BMI) of <$25kg/m^2$ (<$25kg/m^2$:${\geq}25kg/m^2$, $159.3{\pm}41.7$ minutes: $194.25{\pm}81.1$ minutes; P=0.001). Conclusions: Although there was no significant decrease in the operative time for surgeon A, surgeon B reached the learning curve upon conducting 30 cases of SPDG. BMI of <$25kg/m^2$ was found to be a favorable factor for SPDG.

Purpose: This study sought to examine whether near total gastrectomy (nTG) confers a longterm nutritional benefit when compared with total gastrectomy (TG) for the treatment of gastric cancer. Materials and Methods: Patients who underwent nTG or TG for gastric cancer were included (n=570). Using the 1:2 matched propensity score, 25 patients from the nTG group and 50 patients from the TG group were compared retrospectively for oncologic outcomes, including long-term survival and nutritional status. Results: The length of the proximal resection margin, number of retrieved lymph nodes and tumor nodes, metastasis stage, short-term postoperative outcomes, and long-term survival were not significantly different between the groups. The body mass index values, and serum total protein and hemoglobin levels of the patients decreased significantly until postoperative 6 months, and then recovered slightly over time (P<0.05); however, there was no difference in the levels between the groups. The prognostic nutritional index values and serum albumin levels decreased significantly until postoperative 6 months and then recovered (P<0.05); the levels decreased more in the nTG group than in the TG group (P<0.05). The mean corpuscular volumes and serum transferrin levels increased significantly until postoperative 1 year and then recovered slightly over time (P<0.05); however, there was no difference between the groups. Serum vitamin $B_{12}$, iron, and ferritin levels of the patients did not change significantly over time, and no difference existed between the groups. Conclusions: A small remnant stomach after nTG conferred no significant nutritional benefits over TG.

Mixed neuroendocrine-nonneuroendocrine neoplasms (MiNENs) are a group of rare tumors previously known as mixed adenoneuroendocrine carcinomas (MANECs). The neuroendocrine component is high-grade and may consist of small-cell carcinoma or large-cell neuroendocrine carcinoma. The nonneuroendocrine component may consist of adenocarcinoma or squamous cell carcinoma. We report a unique case of a MiNEN with trilineage differentiation: large-cell neuroendocrine carcinoma, squamous cell carcinoma, and adenocarcinoma. The reported patient presented with symptoms of an upper gastrointestinal bleed and was ultimately diagnosed with a MiNEN with trilineage differentiation. This is the first report of this exceedingly rare tumor type to include next-generation sequencing of the 3 separate tumor entities. In addition, we review the current literature and discuss the role of next-generation sequencing in classifying and treating MiNEN tumors.