Purpose: Advances in chemotherapeutic and targeted agents have increased pathologic complete response (pCR) rates after neoadjuvant systemic therapy (NST). Vacuum-assisted biopsy (VAB) has been suggested to accurately evaluate pCR. This study aims to confirm the non-inferiority of the 5-year disease-free survival of patients who omitted breast surgery when predicted to have a pCR based on breast magnetic resonance imaging (MRI) and VAB after NST, compared with patients with a pCR who had undergone breast surgery in previous studies. Methods The Omission of breast surgery for PredicTed pCR patients wIth MRI and vacuumassisted bIopsy in breaST cancer after neoadjuvant systemic therapy (OPTIMIST) trial is a prospective, multicenter, single-arm, non-inferiority study enrolling in 17 tertiary care hospitals in the Republic of Korea. Eligible patients must have a clip marker placed in the tumor and meet the MRI criteria suggesting complete clinical response (post-NST MRI size ≤ 1 cm and lesion-to-background signal enhancement ratio ≤ 1.6) after NST. Patients will undergo VAB, and breast surgery will be omitted for those with no residual tumor. Axillary surgery can also be omitted if the patient was clinically node-negative before and after NST and met the stringent criteria of MRI size ≤ 0.5 cm. Survival and efficacy outcomes are evaluated over five years.Discussion: This study seeks to establish evidence for the safe omission of breast surgery in exceptional responders to NST while minimizing patient burden. The trial will address concerns about potential undertreatment due to false-negative results and recurrence as well as improved patient-reported quality of life issues from the omission of surgery. Successful completion of this trial may reshape clinical practice for certain breast cancer subtypes and lead to a safe and less invasive approach for selected patients.

Background: There is a need to update the cardiovascular (CV) Sequential Organ Failure Assessment (SOFA) score to reflect the current practice in sepsis. We previously proposed the modified CV SOFA score from data on blood pressure, norepinephrine equivalent dose, and lactate as gathered from emergency departments. In this study, we externally validated the modified CV SOFA score in multicenter intensive care unit (ICU) patients. Methods: A multicenter retrospective observational study was conducted on ICU patients at six hospitals in Korea. We included adult patients with sepsis who were admitted to ICUs. We compared the prognostic performance of the modified CV/total SOFA score and the original CV/total SOFA score in predicting 28-day mortality. Discrimination and calibration were evaluated using the area under the receiver operating characteristic curve (AUROC) and the calibration curve, respectively. Results: We analyzed 1,015 ICU patients with sepsis. In overall patients, the 28-day mortality rate was 31.2%. The predictive validity of the modified CV SOFA (AUROC, 0.712; 95% confidence interval [CI], 0.677–0.746; P < 0.001) was significantly higher than that of the original CV SOFA (AUROC, 0.644; 95% CI, 0.611–0.677). The predictive validity of modified total SOFA score for 28-day mortality was significantly higher than that of the original total SOFA (AUROC, 0.747 vs. 0.730; 95% CI, 0.715–0.779; P = 0.002). The calibration curve of the original CV SOFA for 28-day mortality showed poor calibration. In contrast, the calibration curve of the modified CV SOFA for 28-day mortality showed good calibration. Conclusion In patients with sepsis in the ICU, the modified SOFA score performed better than the original SOFA score in predicting 28-day mortality.

Background/Aims: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the stomach. We evaluated the clinical outcomes of endoscopic treatment for gastric GISTs. Methods: This is a single center, retrospective study that enrolled 135 cases of gastric subepithelial tumors (SETs) resected by endoscopic procedures and confirmed as GISTs by histopathology from March 2005 to July 2019. The immediate and long-term clinical outcomes were analyzed retrospectively. Results: The mean patient age was 57.9 years, and the mean tumor size was 2.1 cm. Of the tumors, 43.0% were located in the body, followed by the fundus (26.7%) and cardia (17.0%). Most tumors (85.2%) were resected by endoscopic submucosal dissection, followed by endoscopic mucosal resection (6.7%), submucosal tunneling endoscopic resection (5.9%), and endoscopic full-thickness resection (2.2%). Macroperforation occurred in 4.4% and microperforation in 6.7% of the cases. The R0 resection rate was 15.6%. However, the rate of complete resection by the endoscopic view was 90.4%, of which 54.8% of cases were in the very-low-risk group, followed by the low-risk group (28.1%), intermediate-risk group (11.9%), and high-risk group (5.2%). During 36.5 months of follow-up, recurrence was found in four (3.4%) of the 118 patients who were monitored for more than 6 months (low-risk group, 1/37 [2.7%]; intermediate-risk group, 2/11 [18.2%]; high-risk group, 1/6 [16.7%]). Conclusions Endoscopic treatment of a GIST appears to be a feasible procedure in selected cases. However, additional surgery should be considered if the pathologic results correspond to intermediate- or high-risk groups.

Background/Aims: Irreversible electroporation (IRE) is a relatively new ablation method. However, the application of IRE ablation in the treatment of biliary disease has not been attempted. A minimally invasive approach using endoscopic retrograde cholangiopancreatography (ERCP) can be a novel therapeutic modality for IRE ablation. In this study, we aimed to investigate the feasibility of endoscopic IRE for the biliary tract using an animal model. Methods: A new catheter-type electrode was developed for endoscopic IRE ablation of the biliary tract. We performed ERCP and endoscopic IRE ablations in the normal common bile duct of Yorkshire pigs. The experimental setting of IRE was 500 V/cm (50 pulses, 100-µs length). The animals were sacrificed after 24 hr, and the ablated bile duct was examined. Results: Well-demarcated focal color changes were observed on the mucosa of the common bile duct. The depth of change after IRE was confined to the mucosal and submucosal layers. Apoptotic changes in the bile duct were observed only around the IRE ablation area. Immunohistochemistry assay showed cell death in the bile duct along the electrode. Conclusions Endoscopic IRE ablation using ERCP was successfully performed in the common bile duct. It can be a potential option for the treatment of biliary tumors.

Background/Aims: Several attempts have been made to incorporate smart glasses in the medical field. We applied wearable display glasses to show the position of an observer during endoscopy and compared students’ responses between the conventional and new methods. Methods: We surveyed 28 medical students regarding the use of wearable display devices. The students used wearable display glasses to observe an endoscopic procedure and answered the prepared questionnaire. Their collected responses were analyzed for statistical correlations between each variable. Results: The survey of medical students revealed disadvantages including dizziness (dissatisfied and very dissatisfied: 21.5%) and eye fatigue (25% dissatisfied) and advantages including concentration (satisfied and very satisfied: 57.2%) and securing patient rights (71.4%). The students showed more positive than negative reviews regarding the new devices (32.1% vs. 21.5%). Conclusions We investigated the advantages and disadvantages of viewing the endoscope image with new wearable display glasses compared to the conventional method using the survey to record user experience. The results revealed relatively positive responses from the medical students in the survey. If the new device compensates for some shortcomings, its use in the endoscopy room will be feasible.

Background/Aims: Irreversible electroporation (IRE) is a relatively new ablation method. However, the application of IRE ablation in the treatment of biliary disease has not been attempted. A minimally invasive approach using endoscopic retrograde cholangiopancreatography (ERCP) can be a novel therapeutic modality for IRE ablation. In this study, we aimed to investigate the feasibility of endoscopic IRE for the biliary tract using an animal model. Methods: A new catheter-type electrode was developed for endoscopic IRE ablation of the biliary tract. We performed ERCP and endoscopic IRE ablations in the normal common bile duct of Yorkshire pigs. The experimental setting of IRE was 500 V/cm (50 pulses, 100-µs length). The animals were sacrificed after 24 hr, and the ablated bile duct was examined. Results: Well-demarcated focal color changes were observed on the mucosa of the common bile duct. The depth of change after IRE was confined to the mucosal and submucosal layers. Apoptotic changes in the bile duct were observed only around the IRE ablation area. Immunohistochemistry assay showed cell death in the bile duct along the electrode. Conclusions Endoscopic IRE ablation using ERCP was successfully performed in the common bile duct. It can be a potential option for the treatment of biliary tumors.

Background/Aims: Several attempts have been made to incorporate smart glasses in the medical field. We applied wearable display glasses to show the position of an observer during endoscopy and compared students’ responses between the conventional and new methods. Methods: We surveyed 28 medical students regarding the use of wearable display devices. The students used wearable display glasses to observe an endoscopic procedure and answered the prepared questionnaire. Their collected responses were analyzed for statistical correlations between each variable. Results: The survey of medical students revealed disadvantages including dizziness (dissatisfied and very dissatisfied: 21.5%) and eye fatigue (25% dissatisfied) and advantages including concentration (satisfied and very satisfied: 57.2%) and securing patient rights (71.4%). The students showed more positive than negative reviews regarding the new devices (32.1% vs. 21.5%). Conclusions We investigated the advantages and disadvantages of viewing the endoscope image with new wearable display glasses compared to the conventional method using the survey to record user experience. The results revealed relatively positive responses from the medical students in the survey. If the new device compensates for some shortcomings, its use in the endoscopy room will be feasible.

Background: s/Aims: Rebleeding of gastric varices (GVs) after endoscopic variceal obturation (EVO) can be fatal. This study was performed to evaluate the usefulness of computed tomography (CT) for the prediction of rebleeding after EVO GV bleeding. Methods: Patients who were treated with EVO for GV bleeding and underwent CT before and after EVO were included. CT images of the portal phase showing pretreatment GVs and feeding vessels, and nonenhanced images showing posttreatment cyanoacrylate impaction were reviewed. Results: Fifty-three patients were included. Their mean age was 60.6±11.6 years, and 40 patients (75.5%) were men. Alcoholic liver disease was the most frequent underlying liver disease (45.3%). Complete impaction of cyanoacrylate in GVs and feeding vessels were achieved in 40 (75.5%) and 24 (45.3%) of patients, respectively. During the follow-up, GV rebleeding occurred in nine patients, and the cumulative incidences of GV rebleeding at 3, 6, and 12 months were 11.8%, 18.9%, and 18.9%, respectively. The GV rebleeding rate did not differ significantly according to the complete cyanoacrylate impaction in the GV, while it differed significantly according to complete cyanoacrylate impaction in the feeding vessels. The cumulative incidences of GV rebleeding at 3, 6, and 12 months were 22.3%, 35.2%, and 35.2%, respectively, in patients with incomplete impaction in feeding vessels, and there was no rebleeding during the follow-up period in patients with complete impaction in the feeding vessels (p=0.002). Conclusions Abdominal CT is useful in the evaluation of the treatment response after EVO for GV bleeding. Incomplete cyanoacrylate impaction in feeding vessels is a risk factor for GV rebleeding.

Background/Aims: Gastric electrical stimulation (GES) is a feasible modality for the treatment of gastroparesis; however, the presently available device requires invasive surgical implantation for long-term stimulation and repeated surgical procedure after a period of time. This study is aimed at developing a wireless miniature GES device and testing its endoscopic insertion in animal models. Methods: Endoscopic gastric implantation of the GES device was performed on 5 healthy weaner pigs under general anesthesia. We created an endoscopic submucosal pocket and inserted the gastro-electrical stimulator. In vivo gastric slow waves were recorded and measured during electrical stimulation. A multi-channel recorder, called an electrogastrogram, was used to record the gastric myoelectrical activity in the study. Results: The gastric slow waves on the electrogastrogram were more consistent with GES on the gastric tissues compared to no stimulation. The frequency-to-amplitude ratio was also significantly altered after the electrical stimulation. Conclusions GES is feasible with our minimally invasive wireless device. This technique has the potential to increase utilization of GES as a treatment alternative.

BACKGROUND/AIMS: For the clinical application of stem cell therapy, functional enhancement is needed to increase the survival rate and the engraftment rate. The purpose of this study was to investigate functional enhancement of the paracrine effect using stem cells and hepatocyte-like cells and to minimize stem cell homing by using a scaffold system in a liver disease model. METHODS: A microporator was used to overexpress Foxa2 in adipose tissue-derived stem cells (ADSCs), which were cultured in a poly(lactic-co-glycolic acid) (PLGA) scaffold. Later, the ADSCs were cultured in hepatic differentiation medium for 2 weeks by a 3-step method. For in vivo experiments, Foxa2-overexpressing ADSCs were loaded in the scaffold, cultured in hepatic differentiation medium and later were implanted in the dorsa of nude mice subjected to acute liver injury (thioacetamide intraperitoneal injection). RESULTS: Foxa2-overexpressing ADSCs showed greater increases in hepatocyte-specific gene markers (alpha fetoprotein [AFP], cytokeratin 18 [CK18], and albumin), cytoplasmic glycogen storage, and cytochrome P450 expression than cells that underwent the conventional differentiation method. In vivo experiments using the nude mouse model showed that 2 weeks after scaffold implantation, the mRNA expression of AFP, CK18, dipeptidyl peptidase 4 (CD26), and connexin 32 (CX32) was higher in the Foxa2-overexpressing ADSCs group than in the ADSCs group. The Foxa2-overexpressing ADSCs scaffold treatment group showed attenuated liver injury without stem cell homing in the thioacetamide-induced acute liver injury model. CONCLUSIONS: Foxa2-overexpressing ADSCs applied in a scaffold system enhanced hepatocyte-like differentiation and attenuated acute liver damage in an acute liver injury model without homing effects.
Animals ; Cytochrome P-450 Enzyme System ; Cytoplasm ; Dipeptidyl Peptidase 4 ; Fetal Proteins ; Glycogen ; Keratin-18 ; Liver Diseases ; Liver Failure, Acute ; Liver ; Mesenchymal Stromal Cells ; Methods ; Mice ; Mice, Nude ; RNA, Messenger ; Stem Cells ; Survival Rate