Strategically Designed Bifunctional Polydopamine Enwrapping Polycaprolactone-Hydroxyapatite-Doxorubicin Composite Nanofibers for Osteosarcoma Treatment and Bone Regeneration.

This study presents a new multifunctional nanofibrous drug delivery system to provide effective combination therapy with enormous potential for the treatment of osteosarcoma. We developed a composite nanofiber scaffold comprising poly(ε-caprolactone) (PCL) and hydroxyapatite (HAp)-loaded doxorubicin (DOX) coated with polydopamine (PDA) to combine cancer cell inhibition with bone tissue regeneration. DOX was conjugated with HAp and then mixed with a PCL solution to prepare a PCL/HAp-DOX (labeled PCLDH) nanofiber. Then, in situ polymerization of PDA on the PCLDH occurred to produce the PCLDH@PDA composite nanofiber. The morphology, XRD, FT-IR, wettability, photothermal characteristics, cumulative drug release, and in vitro bioactivities were evaluated. We found that the PDA coating not only enhanced the hydrophilic properties but also controlled drug release. The PCLDH@PDA composite scaffold significantly suppressed the proliferation of bone cancer cells initially and, consequently, improved the adhesion and proliferation of human mesenchymal stem cells (hMSCs). The PDA coating boosted the composite scaffold's bioactivity, as demonstrated through ALP activity, ARS assay, and biomineralization results. This strategy offers a promising dual-function scaffold to treat residual cancer and reconstruct defects after osteosarcoma surgery.

Survey of Information Acquisition and Satisfaction after Bariatric Surgery at a Tertiary Hospital in Korea.

Background: To determine how patients who underwent bariatric surgery at a tertiary hospital in Korea first considered and then decided to get the surgery and identify information gaps among patients and healthcare professionals. Methods: This study included 21 patients who underwent bariatric surgery to treat morbid obesity (body mass index [BMI] ≥35 or ≥30 kg/m2 together with obesity-related comorbidities) between August 2020 and February 2022. A telephone interview was conducted with the patients after at least 6 months had elapsed since the surgery. We asked how the patients decided to undergo bariatric surgery. We also inquired about their satisfaction with and concerns about the surgery. Results: Seventy-one percent of the patients were introduced to bariatric surgery following a recommendation from healthcare professionals, acquaintances, or social media. Most of the patients (52%) decided to undergo bariatric surgery based on recommendations from healthcare professionals in non-surgical departments. Satisfaction with the information provided differed among the patients. Post-surgical concerns were related to postoperative symptoms, weight regain, and psychological illness. Conclusion: Efforts are needed to raise awareness about bariatric surgery among healthcare professionals and the public. Tailored pre- and postoperative consultation may improve quality of life after bariatric surgery.

Does total omentectomy prevent peritoneal seeding for advanced gastric cancer with serosal invasion?

BACKGROUND: Radical gastrectomy is composed of gastrectomy, lymph node dissection, and omentectomy. Total omentectomy (TO) is expected to reduce the incidence of peritoneal recurrence. We aimed to investigate the necessity of TO for advanced gastric cancer (AGC) with serosal invasion. METHODS: We retrospectively reviewed 310 patients who underwent radical gastrectomy with TO and 93 patients who underwent partial omentectomy (PO) for gastric cancer with serosal invasion between August, 2005 and December, 2017. Finally, 91 patients in the PO group and 91 in the TO group were enrolled based on a 1:1 propensity-score matching analysis. We evaluated surgical and oncological outcomes, including 5-year overall and recurrence-free survival rates. RESULTS: There was no statistically significant difference between the two groups in postoperative complications. Recurrence sites showed similar patterns in both groups, including peritoneal recurrence (PO vs. TO, 18.7% vs. 28.6%; p = 0.188). Five-year overall survival was better in the PO group (p = 0.018), while 5-year recurrence-free survival was similar in both groups (p = 0.066). CONCLUSION: TO might not be an essential part of preventing peritoneal recurrence for AGC with serosal invasion. PO could be considered a radical gastrectomy for T4a gastric cancer.

Analysis of risk factors affecting long-term survival in elderly patients with advanced gastric cancer.

BACKGROUND: Factors predicting postoperative complications after gastrectomy for elderly patients with gastric cancer have been analyzed in several previous studies. However, there is limited research available on risk factors related to long-term survival. AIMS: This study aimed to analyze factors affecting long-term survival after curative gastrectomy in elderly patients with advanced gastric cancer. METHODS: This study included patients aged > 75 years with histologically confirmed advanced gastric cancer stage II or greater. Before analysis, risk factors were categorized into four groups: baseline characteristics, underlying diseases, surgical and pathologic factors, and nutritional factors. RESULTS: The mean follow-up duration was 71.0 months. The 5-year overall survival and disease-specific survival rates were 51.5% and 58.3%, respectively. Kaplan-Meier curves showed that patients who were female and overweight had significantly longer survival rates than those who were male and underweight. Elderly patients who underwent a total gastrectomy had poorer survival rates than those who underwent a distal gastrectomy. Multivariate analysis demonstrated that tumor stage, extent of gastrectomy, overweight status and overall complication were independent risk factors for overall survival. DISCUSSION: Our study show that the overweight patients, the extent of gastrectomy, tumor stage and overall complications are significant risk factors affecting long-term survival. CONCLUSIONS: Therefore, surgeons may be cautious in performing total gastrectomy in elderly gastric cancer patients. Additionally, it is important to focus on improving nutritional status and mitigating overall complications.

Comparison of Laparoscopic and Open Gastrectomy for Patients With Gastric Cancer Treated With Neoadjuvant Chemotherapy: A Multicenter Retrospective Study Based on the Korean Gastric Cancer Association Nationwide Survey.

PURPOSE: Despite scientific evidence regarding laparoscopic gastrectomy (LG) for advanced gastric cancer treatment, its application in patients receiving neoadjuvant chemotherapy remains uncertain. MATERIALS AND METHODS: We used the 2019 Korean Gastric Cancer Association nationwide survey database to extract data from 489 patients with primary gastric cancer who received neoadjuvant chemotherapy. After propensity score matching analysis, we compared the surgical outcomes of 97 patients who underwent LG and 97 patients who underwent open gastrectomy (OG). We investigated the risk factors for postoperative complications using multivariate analysis. RESULTS: The operative time was significantly shorter in the OG group. Patients in the LG group had significantly less blood loss than those in the OG group. Hospital stay and overall postoperative complications were similar between the two groups. The incidence of Clavien-Dindo grade ≥3 complications in the LG group was comparable with that in the OG group (1.03% vs. 4.12%, P=0.215). No statistically significant difference was observed in the number of harvested lymph nodes between the two groups (38.60 vs. 35.79, P=0.182). Multivariate analysis identified body mass index (odds ratio [OR], 1.824; 95% confidence interval [CI], 1.029-3.234; P=0.040) and extent of resection (OR, 3.154; 95% CI, 1.084-9.174; P=0.035) as independent risk factors for overall postoperative complications. CONCLUSIONS: Using a large nationwide multicenter survey database, we demonstrated that LG and OG had comparable short-term outcomes in patients with gastric cancer who received neoadjuvant chemotherapy.

Factors Associated With Loss to Follow-up After Laparoscopic Sleeve Gastrectomy: A Single-Center Retrospective Study.

Purpose: After bariatric surgery, postoperative follow-up is important for evaluating long-term outcomes, such as successful weight loss and improvement of metabolic parameters. However, many patients are lost to follow-up within 1 year. This study aimed to identify the follow-up rate of bariatric surgery and predictive factors of loss to follow-up (LTF). Materials and Methods: We retrospectively reviewed the data of 61 patients receiving bariatric surgery for obesity (laparoscopic sleeve gastrectomy; LSG group) and 872 for early gastric cancer (EGC group) from November 2018 to July 2020 in a single center. After 1:1 matching, we compared the LTF rate. In the LSG group, we analyzed the factors associated with LTF. Additionally, we collected weight data in the LTF group by a telephone survey. Results: By 1:1 matching, 47 patients for each group were identified. The LTF rates of the LSG and EGC groups were 34.0% (16 patients) and 2.1% (one patient), respectively (P=0.0003). In the LSG group, the LTF rate increased over the postoperative month. Of the patients, 29.5% who missed a scheduled appointment within one year comprised the LTF group. In the analysis, no significant factors associated with LTF were identified. The only factor with borderline significance was dyslipidemia with medication (P=0.094). Conclusion: The LSG group demonstrated a high LTF rate, although adherence to follow-up was closely related to postoperative outcomes. Therefore, educating patients on the significance of follow-up is important. Particularly, continuous efforts to identify the associated factors and develop a multidisciplinary management protocol after bariatric surgery are necessary.

Safety evaluation of curative gastrectomy for gastric cancer patients who underwent liver transplantation: a comparative study with conventional gastrectomy for gastric cancer patients.

BACKGROUND: We aimed to examine the technical and oncological safety of curative gastrectomy for gastric cancer patients who underwent liver transplantation. METHODS: In this study, we compared the surgical and oncological outcomes of two groups. The first group consisted of 32 consecutive patients who underwent curative gastrectomy for gastric cancer after liver transplantation (LT), while the other group consisted of 127 patients who underwent conventional gastrectomy (CG). In addition, a subgroup analysis was performed to evaluate the impact of the background differences and the surgical outcomes on the involvement of a specialized liver transplant surgery team. RESULTS: The mean operative time was significantly longer in the LT group (p < 0.05). Furthermore, there were more frequent cases of postoperative transfusion in the LT group compared to the CG group (p < 0.05). However, there were no significant differences in the overall complications between the groups (25.00 vs 23.62%, p = 0.874). The 5-year overall survival rates of the LT and CG groups were 76.7% and 90.1%, respectively (p < 0.05). The results of the subgroup analysis demonstrated no statistically significant difference in various early surgical outcomes, such as time to transfusion during surgery, first flatus, time to first soft diet, postoperative complications, hospital stay after surgery, and the number of harvested lymph nodes except for operation time. CONCLUSIONS: Despite one's medical history of undergoing LT, our study demonstrated that curative gastrectomy could be a surgically safe treatment for gastric cancer. However, further study should be conducted to identify the reason gastric cancer patients who underwent liver transplant surgery have lower overall survival rate.

Rapidly Progressing Dysphagia After Thoracic Spinal Cord Injury in a Patient With Ankylosing Spondylitis: A Case Report.

Introduction: Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease affecting the axial skeleton, including the sacroiliac joint, which causes vertebral fusion in the advanced stage. However, reports of anterior cervical osteophytes compressing the esophagus and causing dysphagia in patients with AS are rare. Here, we present the case of a patient with AS and anterior cervical osteophytes who exhibited rapidly progressing dysphagia after thoracic spinal cord injury (SCI). Case Presentation: The patient, a 79-year-old man, was previously diagnosed with AS and had syndesmophytes at C2-C7 without dysphagia for several years. In 2020, he began to experience paraplegia, hypesthesia, and bladder and bowel dysfunction after a fall. He also had T9 SCI American Spinal Injury Association Impairment Scale grade A due to a T10 transverse fracture. Four months after SCI, he developed aspiration pneumonia, and a videofluoroscopic swallowing study indicated dysphagia with epiglottic closing problems due to syndesmophytes at the C2-C3 and C3-C4 levels. He received treatment for dysphagia and VitalStim therapy thrice (once daily); however, the recurrent pneumonia and fever continued. He further underwent bedside physical therapy and functional electrical stimulation once daily. However, he died from atelectasis and exacerbation of sepsis. Discussion and Conclusion: General deterioration of the patient's physical condition due to SCI, sarcopenic dysphagia, and compression of cervical osteophytes seemed to be involved in rapid exacerbation following SCI. Early screening for dysphagia is vital in bedridden patients with AS or SCI. Additionally, assessment and follow-up are important if the number of rehabilitation treatments or the out-of-bed movement activity decreases because of pressure ulcers.

Effect of Laparoscopic Proximal Gastrectomy With Double-Tract Reconstruction vs Total Gastrectomy on Hemoglobin Level and Vitamin B12 Supplementation in Upper-Third Early Gastric Cancer: A Randomized Clinical Trial.

Importance: Patients undergoing proximal gastrectomy (PG) with double-tract reconstruction (DTR) have been reported to have an incidence of reflux esophagitis that is as low as that observed after total gastrectomy (TG). It is unclear whether PG has an advantage over TG for the treatment of patients with upper early gastric cancer (GC). Objective: To evaluate the effect of laparoscopic PG with DTR (LPG-DTR) vs laparoscopic TG (LTG) on levels of hemoglobin and vitamin B12 supplementation required among patients with clinically early GC in the upper third of the stomach (upper-third early GC). Design, Setting, and Participants: This multicenter open-label superiority randomized clinical trial was conducted at 10 institutions in Korea. A total of 138 patients with upper-third cT1N0M0 GC were enrolled between October 27, 2016, and September 9, 2018. Follow-up ended on December 3, 2020. Interventions: Patients were randomized to undergo either LPG-DTR or LTG. Main Outcomes and Measures: The primary co-end points were change in hemoglobin level and cumulative amount of vitamin B12 supplementation at 2 years after LPG-DTR or LTG. The secondary end points included morbidity, postoperative reflux esophagitis, quality of life, overall survival, and disease-free survival. Quality of life outcomes were assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ) 30-item core questionnaire (C30) and the EORTC QLQ stomach cancer-specific questionnaire at 3 months, 12 months, and 24 months. Results: Among 138 patients (mean [SD] age, 60.0 [10.9] years; 87 men [63.0%]; all of Asian race and Korean ethnicity), 68 (mean [SD] age, 56.7 [10.4] years; 39 men [57.4%]) were randomized to receive LPG-DTR and 69 (mean [SD] age, 61.3 [11.3] years; 48 men [69.6%]) were randomized to receive LTG. The mean (SD) changes in hemoglobin levels from baseline to month 24 were -5.6% (7.4%) in the LPG-DTR group and -6.9% (8.3%) in the LTG group, for an estimated difference of -1.3% (95% CI, -4.0% to 1.4%; P = .35). The mean (SD) cumulative amount of vitamin B12 supplementation was 0.4 (1.3) mg in the LPG-DTR group and 2.5 (3.0) mg in the LTG group, for an estimated difference of 2.1 mg (95% CI, 1.3-2.9 mg; P < .001). The late complication rates in the LPG-DTR and LTG groups were 17.6% and 10.1%, respectively (P = .31). The incidence of reflux esophagitis was not different between the LPG-DTR and LTG groups (2.9% vs 2.9%; P = .99). Compared with the LTG group, the LPG-DTR group had better physical functioning scores (85.2 [15.6] vs 79.9 [19.3]; P = .03) and social functioning scores (89.5 [17.9] vs 82.4 [19.4]; P = .03) on the EORTC QLQ-C30. Two-year overall survival (98.5% vs 100%; P = .33) and disease-free survival (98.5% vs 97.1%; P = .54) did not significantly differ between the LPG-DTR vs LTG groups. Conclusions and Relevance: In this study, patients with upper-third early GC who received LPG-DTR required less vitamin B12 supplementation than those who received LTG, with no increase in complication rates and no difference in overall and disease-free survival rates. There was no difference in change in hemoglobin level between groups. In addition, the LPG-DTR group had better physical and social functioning than the LTG group. These findings suggest that LPG-DTR may be as safe as LTG and may be a function-preserving procedure for the treatment of patients with upper-third early GC. Trial Registration: ClinicalTrials.gov Identifier: NCT02892643.

Gastric Neuroendocrine Tumors According to the 2019 World Health Organization Grading System: A Single-Center, Retrospective Study.

Background/Aims: Although gastric neuroendocrine tumors (NETs) are uncommon neoplasms, their prevalence is increasing. The clinical importance of the World Health Organization (WHO) classification of gastric NETs, compared with NETs in other organs, has been underestimated. This study aimed to systematically evaluate the clinical and pathologic characteristics of gastric NETs based on the 2019 WHO classification and to assess the survival outcomes of patients from a single-center with a long-term follow-up. Methods: The medical records of 427 patients with gastric NETs who underwent endoscopic or surgical resection between January 2000 and March 2020 were retrospectively reviewed. All specimens were reclassified according to the 2019 WHO classification. The clinicopathologic characteristics, treatment, and oncologic outcomes of 139 gastric NETs were analyzed. Results: The patients' median age was 53.0 years (interquartile range [IQR], 46.0 to 63.0 years). The median follow-up period was 36.0 months (IQR, 15.0 to 63.0 months). Of the patients, 92, 44, and 3 had grades 1, 2, and 3 NETs, respectively. The mean tumor size significantly increased as the tumor grade increased (p=0.025). Patients with grades 2 and 3 gastric NETs more frequently had lymphovascular invasion (29.8% vs 10.9%, p=0.005) and deeper tissue invasion (8.5% vs 0%, p=0.012) than those with grade 1 tumors. The overall disease-specific survival rate was 100%. Two patients with grades 2-3 gastric NETs experienced extragastric recurrence. Conclusions: Although gastric NETs have an excellent prognosis, grade 2 or grade 3 gastric NETs are associated with a larger size, deeper invasion, and extragastric recurrence, which require active treatment.

Marine plankton exoskeletone-derived hydroxyapatite/polycaprolactone composite 3D scaffold for bone tissue engineering.

3D porous scaffolds based on biodegradable polymers are one of the materials for bone tissue regeneration. In this study, a porous scaffold was prepared using a solvent casting/particulate leaching method that used polycaprolactone (PCL) and hydroxyapatite (OceanBone-HAp) extracted from a marine plankton exoskeleton to achieve excellent bone regeneration. In this study, the morphology and physicochemical properties of the PCL/OceanBone-HAp scaffolds were evaluated using scanning electron microscopy, X-ray diffraction, and porosity analysis. The results confirmed the porous structure of the scaffold and removal of the solvent and porogen particles. In vitro test results revealed superior cell adhesion, proliferation, and viability of PCL/OceanBone-HAp scaffolds compared to PCL scaffolds alone. The enhanced alkaline phosphatase activity and expression of bone morphogenetic protein 2, collagen type I α 1, osteocalcin, and bone sialoprotein in the PCL/OceanBone-HAp scaffolds were confirmed through ALP and real-time polymerase chain reaction assays. Moreover, in vivo experiments using a rabbit calvarial defect model showed that the PCL/OceanBone-HAp scaffold exhibited enhanced bone regeneration compared to the PCL scaffold. Therefore, the PCL/OceanBone-HAp scaffold is a promising scaffold for bone repair.

Enhanced Biocompatibility and Osteogenic Activity of Marine-Plankton-Derived Whitlockite Bone Granules through Bone Morphogenetic Protein 2 Incorporation.

Whitlockite (WH) is a calcium-phosphate-based Mg-containing ceramic with good mechanical properties, rapid resorption, and good osteogenicity. Recently, we successfully synthesized highly porous WH granules using a marine plankton exoskeleton (MP-WH). In the present study, we improved the osteoinductive activity of MP-WH granules by bone morphogenetic protein2 (BMP2) (MP-WH/BMP2). The surface morphology and composition of the fabricated MP-WH/BMP2 granules were characterized using scanning electron microscopy (SEM), X-ray diffraction, and Fourier transform infrared (FT-IR) spectroscopy. The biocompatibility and osteogenic effects were evaluated using human mesenchymal stem cells (hMSCs). BMP2 was absorbed on the surfaces of the MP-WH/BMP2 granules. Immobilized BMP2 was released at a moderate rate over 30 days. hMSCs seeded on MP-WH/BMP2 granules became biocompatible, with a better proliferation and adhesion for MP-WH/BMP2, compared with MP-WH. Bone-specific markers Runx2, type I collagen, osteocalcin, and osteopontin were significantly upregulated following BMP2 incorporation. Similar observations were made regarding the alkaline phosphatase activity. This study suggests that BMP2 incorporation improves the osteoinductive activity of marine-plankton-derived WH granules for bone tissue repair.

Novel temperature-responsive hydrogel injected to the incision site for postoperative pain relief in laparoscopic abdominal surgery: a single-blind, randomized, pivotal clinical trial.

BACKGROUND: A temperature-responsive hydrogel (PF-72; TGel Bio, Inc., Ltd, Seoul, Korea), developed as a sustained drug delivery device, can be mixed with ropivacaine to reduce pain in the incision area. The hydrogel is soluble at low temperatures (2-8 °C) and is converted into a gel at high temperatures (> 30 °C). We aimed to evaluate whether the administration of ropivacaine using PF-72 at incision sites reduces pain until 72 h postoperatively in patients undergoing laparoscopic stomach or colorectal surgery. METHODS: Patients were randomly assigned to the control group (0.75% ropivacaine) or PF-72 group (PF-72 mixed with 0.75% ropivacaine). Before surgical incision closure, 0.75% ropivacaine or PF-72 mixed with 0.75% ropivacaine was injected into the subcutaneous fat and muscle of all incisions. Postoperative pain was evaluated by the Numerical Rating Scale (NRS, 0 = no pain, 10 = most severe pain) for wound pain at 3, 6, 24, 48, and 72 h after the end of surgery. RESULTS: Ninety-nine patients (control, n = 51; PF-72, n = 48) were included in the analysis. The areas under the curve of NRS for wound pain until 72 h in the control group and the PF-72 group were 188.7 ± 46.1 and 135.3 ± 49.9 h, respectively (P < 0.001). The frequency of the administration of rescue analgesics in the general ward was similar between the two groups. CONCLUSION: PF-72 mixed with 0.75% ropivacaine reduced postoperative pain until 72 h in patients undergoing laparoscopic surgery. Although the study population was not large enough for safety evaluation, no adverse events associated with PF-72 were observed.

Marine Plankton-Derived Whitlockite Powder-Based 3D-Printed Porous Scaffold for Bone Tissue Engineering.

Powder-based 3D printing is an excellent technique for the fabrication of complex structural shapes. The outstanding bone remodeling capacity of calcium phosphate bioceramics is a desirable characteristic for such fabrication. Whitlockite (WH) is a calcium phosphate-based ceramic that contains Mg ions and possesses good mechanical properties, rapid resorbability, and promotes osteogenesis. The aim of this study was to fabricate 3D-printed scaffolds using marine plankton-derived WH (MP-WH) powder. The surface morphology and composition of the fabricated scaffolds were characterized by scanning electron microscopy and X-ray diffraction. The biocompatibility and osteogenic effects were evaluated using human mesenchymal stem cells. We successfully obtained a 3D porous scaffold using MP-WH. The MP-WH 3D scaffold showed improved compressive strength compared to the tricalcium phosphate (TCP) 3D scaffold. The in vitro results showed that compared with TCP 3D scaffolds, MP-WH 3D scaffolds were biocompatible and enhanced cell proliferation and adhesion. In addition, alkaline phosphatase activity and real-time polymerase chain reaction assays demonstrated that osteoblast differentiation was improved on the MP-WH scaffold. These results suggest that marine plankton-derived WH is useful for fabricating 3D-printed scaffolds for bone tissue engineering applications.

Comparing surgical and oncologic outcomes between laparoscopic gastrectomy and open gastrectomy in advanced gastric cancer with serosal invasion: A retrospective study with propensity score matching.

PURPOSE: Laparoscopic gastrectomy (LG) has gradually increased for treating advanced gastric cancer (AGC). However, there is a lack of evidence on oncologic safety for AGC, especially with serosal invasion. This study evaluates the surgical and oncologic outcomes between laparoscopic and open gastrectomy (OG) for gastric cancer with serosal invasion. METHODS: We retrospectively reviewed 256 patients who underwent OG and 147 patients who underwent LG for gastric cancer with serosal invasion between August 2005 and December 2017. Finally, 124 patients in the LG group and 124 in the OG group were enrolled according to one-to-one propensity score matching (PSM) analysis. We evaluated surgical and oncological outcomes, including overall survival (OS) and recurrence-free survival (RFS). RESULTS: There were no statistical differences in hospital stay and major complications between the two groups. The retrieved lymph nodes of the LG group were similar to those of OG (40 ± 16.23 vs. 38 ± 14.42, p = 0.306), and it showed a similar operation time compared with the other (164 ± 43.86 vs. 156 ± 37.66, p = 0.063). There was no statistical difference in OS (p = 0.761) and RFS (p = 0.121) for survival analysis between the two groups. CONCLUSION: LG for gastric cancer with serosal invasion is feasible and could be considered as a standard treatment.

Short-Term Outcomes of Laparoscopic Proximal Gastrectomy With Double-Tract Reconstruction Versus Laparoscopic Total Gastrectomy for Upper Early Gastric Cancer: A KLASS 05 Randomized Clinical Trial.

PURPOSE: Laparoscopic proximal gastrectomy with double-tract reconstruction (LPG-DTR) is a function-preserving procedure performed for treating upper early gastric cancer (EGC). However, few studies have compared the outcomes of LPG-DTR with those of laparoscopic total gastrectomy (LTG). This study aimed at comparing the short-term outcomes of LPG-DTR between LTG and upper EGC. MATERIALS AND METHODS: For upper-third EGC, a multicenter, prospective, randomized trial was performed to compare those who underwent LPG-DTR with those who underwent LTG. Short-term outcomes, including clinicopathologic results, morbidity, mortality, and postoperative courses, were evaluated using a full analysis set based on the intention-to-treat principle and the per-protocol set. RESULTS: Of the patients, 138 who fulfilled the criteria were randomized to each group. One patient in the LPG-DTR group withdrew consent. Sixty-eight patients underwent LPG-DTR and 69 underwent LTG. The operative time (LPG-DTR=219.4 minutes; LTG=201.8 minutes; P=0.085), estimated blood loss (LPG-DTR=76.0 mL; LTG=66.1 mL; P=0.413), and the morbidity rate (LPG-DTR=23.5%; LTG=17.4%; P=0.373) between the groups were not significantly different. No mortality occurred in either of the study groups. Two weeks post operation, the Visick scores for postprandial symptoms, including reflux symptoms, were not significantly different between the groups (P=0.749). Laboratory findings on postoperative day 5 were not significantly different between the groups. CONCLUSIONS: The short-term outcomes of LPG-DTR for upper EGC were comparable to those of LTG. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02892643.

Reevaluation of the expanded indications in undifferentiated early gastric cancer for endoscopic submucosal dissection.

BACKGROUND: Although the criteria for the indication of endoscopic submucosal dissection (ESD) for undifferentiated early gastric cancer (UD-EGC) have been recently proposed, accumulating reports on the non-negligible rate of lymph node metastasis (LNM) after indicated ESD raise questions on the reliability of the current criteria. AIM: To investigate the prevalence and risk factors of LNM in UD-EGC cases meeting the expanded indication for ESD. METHODS: We retrospectively reviewed 4780 UD-EGC cases that underwent surgical resection between January 2008 and February 2019 at Asan Medical Center, a tertiary university hospital in Korea. To identify the risk factors of LNM of UD-EGC meeting the expanded criteria for ESD, we performed a case-control study by matching the cases with LNM to those without at a ratio of 1:4. We reviewed the clinical, endoscopic, and histologic features of the cases to identify features with a significant difference according to the presence of LNM. Univariate and multivariate logistic regression analyses were performed to estimate the odds ratios (ORs). RESULTS: Of the 4780 UD-EGC cases, 1240 (25.9%) were identified to meet the expanded indication for ESD. Of the 1240 cases, 14 (1.1%) cases had LNM. Among the various clinical, endoscopic, and histopathological features that were evaluated, mixed histology (tumors consisting of 10%-90% of signet ring cells) had a marginally significant association (P = 0.059) with the risk of LNM. Moreover, diffuse blurring of the muscularis mucosae (MM) underneath the tumorous epithelium, a previously unrecognized histologic feature, had a significant association with the absence of LNM (P = 0.028). Multivariate logistic regression analysis showed that the blurring of MM was the only explanatory variable significantly associated with a reduced risk of LNM (OR: 0.12, 95%CI: 0.02-0.95; P = 0.045). CONCLUSION: The risk of LNM is higher than expected when using the current expanded indication for UD-EGC. Histological evaluation could provide useful clues for reducing the risk of LNM.

Comparison of Standard D2 and Limited Lymph Node Dissection in Elderly Patients with Advanced Gastric Cancer.

BACKGROUND: Knowledge on the optimal extent of lymphadenectomy among elderly patients with advanced gastric cancer is limited. This study was designed to compare standard D2 and limited lymphadenectomy for evaluating the appropriate extent of lymphadenectomy. PATIENTS AND METHODS: We retrospectively reviewed patient's data based on a prospectively collected gastric cancer registry. The inclusion criteria were age above 75 years and histologically confirmed stage II or more advanced gastric cancer. In this study, 103 patients who underwent limited lymph node dissection and 134 patients who underwent standard D2 lymph node dissection were included to evaluate surgical and oncological outcomes using propensity score matching (PSM) analysis. RESULTS: The mean age after PSM was approximately 78 years in both groups. The Charlson Comorbidity Index was 5.81 ± 0.87 and 5.75 ± 0.76, respectively, and 12.5% of the patients in both groups had American Society of Anesthesiologists scores of more than 3. The limited lymphadenectomy group showed a shorter operation time and fewer retrieved lymph. However, other surgical outcomes and pathological data were not significantly different between the groups. No postoperative mortality within 30 days was observed. There were no significant differences in overall complications between the groups. The 3-year overall survival rates of the limited and standard lymphadenectomy groups were 58.3% and 73.6%, respectively. The 3-year recurrence-free survival rate of the limited lymphadenectomy group was lower than that of the standard lymphadenectomy group; however, the difference was not statistically significant. CONCLUSIONS: Standard D2 lymphadenectomy has better oncological outcomes in elderly patients with advanced gastric cancer.

An Enhanced Tree Routing Based on Reinforcement Learning in Wireless Sensor Networks.

In wireless sensor networks, tree-based routing can achieve a low control overhead and high responsiveness by eliminating the path search and avoiding the use of extensive broadcast messages. However, existing approaches face difficulty in finding an optimal parent node, owing to conflicting performance metrics such as reliability, latency, and energy efficiency. To strike a balance between these multiple objectives, in this paper, we revisit a classic problem of finding an optimal parent node in a tree topology. Our key idea is to find the best parent node by utilizing empirical data about the network obtained through Q-learning. Specifically, we define a state space, action set, and reward function using multiple cognitive metrics, and then find the best parent node through trial and error. Simulation results demonstrate that the proposed solution can achieve better performance regarding end-to-end delay, packet delivery ratio, and energy consumption compared with existing approaches.

Parallel and non-parallel cannulated screw fixation complications in femoral neck fractures: A systematic review and meta-analysis.

BACKGROUND: Since its introduction in the early 1960s, the multiple cannulated screw fixation method has been developed for use in femoral neck fractures (FNFs); however, the parallelism of screws remains controversial. MATERIALS AND METHODS: MEDLINE, Embase, and the Cochrane Library were systematically searched for studies published before June 2, 2020, that compared the use of parallel and non-parallel screw fixation for the treatment of FNF. The pooled analysis was designed to identify differences between the two groups and focused on postoperative complications, including fracture nonunion and osteonecrosis of the femoral head (ONFH). RESULTS: Over four studies, we enrolled 445 patients, including 195 patients with fixed FNF with parallel trajectory screws and 250 patients with fixed FNF with non-parallel screws. The pooled analysis showed no difference in the nonunion rates (odds ratio (OR)=0.91; 95% confidence interval (CI), 0.24-3.44; p=0.89) and no significant difference in the incidence of ONFH between parallel and non-parallel screw fixation (OR=0.74; 95% CI: 0.21-2.63; p=0.64). CONCLUSIONS: The results of this meta-analysis reveal that screw parallelism in multiple cannulated screw fixation of FNF has no relationship with either the fracture nonunion rate or the incidence of postoperative ONFH. LEVEL OF EVIDENCE: III; meta-analysis.