Purpose: Endoscopic submucosal dissection (ESD) has become a standard minimally invasive treatment for selected patients with early gastric cancer (EGC). This study presents the first nationwide survey of patients with EGC treated with ESD in 2023, conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research. Materials and Methods: Data were retrospectively collected from participating referral centers across Korea using a standardized case report form covering patient characteristics, tumor features, procedural details, histopathological findings, and clinical outcomes.Descriptive and comparative analyses were conducted to summarize nationwide ESD practice patterns and outcomes. Results: Data from 5,460 ESD cases from 5,250 patients across 27 institutions were analyzed. The mean age was 67.4 years, with 74.1% males. Multiple synchronous lesions were identified in 3.7%. Most lesions were located in the lower third of the stomach (64.0%), and differentiated-type adenocarcinomas accounted for 87.8%. The en bloc and complete resection rates were 99.2% and 91.4%, respectively. Curative resection was achieved in 80.5%, whereas local non-curative resection (L-NCR) and surgical non-curative resection (S-NCR) were identified in 2.8% and 16.7%, respectively. Additional surgery was performed more frequently in patients with S-NCR than in those with L-NCR (59.3% vs. 24.7%). The bleeding and perforation rates were 3.6% and 0.9%, respectively, and were mostly managed conservatively or endoscopically. The median length of hospitalization was 4.0 days. Conclusions This first nationwide survey provides a comprehensive overview of the current practice of EGC treatment using ESD in Korea, demonstrating high technical success and safety, and establishing a baseline dataset for future longitudinal research.

Background/Aims: Gastroesophageal reflux disease (GERD) after peroral endoscopic myotomy (POEM) is a significant challenge. Disruption of the lower esophageal sphincter during POEM and dysfunction of the crural diaphragm, which contributes to esophagogastric junction pressure, may lead to GERD after POEM. We aim to identify predictors of GERD after POEM and focus on physiological parameters of esophagogastric junction pressure in patients with achalasia before POEM. Methods: We retrospectively analyzed a prospectively collected database of patients who underwent POEM between July 2016 and August 2023. Ninety-two patients with achalasia who underwent high-resolution manometry and endoscopy before and after POEM were included. Results: Forty-nine (53.3%) patients were diagnosed with GERD. Patient demographics, achalasia subtypes, prior treatments, myotomy length, and myotomy orientation were not associated with GERD after POEM. Loss of inspiratory augmentation before POEM was associated with GERD after POEM (P < 0.05). GERD occurred more frequently in patients with a shorter intra-abdominal lower esophageal sphincter length before POEM. Type III esophagogastric junction morphology in the GERD group (37.1%) was more common than that in the non-GERD group (15.8%). Loss of inspiratory augmentation occurred more frequently in patients with type III esophagogastric junction pressure morphology. Conclusion Loss of inspiratory augmentation may predict GERD after POEM.

Purpose: Alectinib has been approved for anaplastic lymphoma kinase (ALK)–positive non–small cell lung cancer (NSCLC) at 300 mg twice daily in Japan, lower than global standard of 600 mg twice daily. This study evaluated the clinical relevance of the reduced dose by comparing outcomes between the two doses. Materials and Methods: This study included patients with advanced ALK-positive NSCLC who received alectinib at Samsung Medical Center, Korea. The progression-free survival (PFS), overall survival, cumulative incidence of central nervous system (CNS) progression, and safety profiles were retrospectively reviewed and compared. Results: Among 306 patients, 32 and 274 received alectinib at either 300 or 600 mg twice daily, respectively. The 300 mg group showed a slight but not significant advantage in PFS (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.44 to 1.51; p=0.51) and overall survival (HR, 0.51; 95% CI, 0.20 to 1.21; p=0.13). Superior outcome with 300 mg was remarkable in patients with lower body weight (≤ 60 kg), but diminished in patients with higher body weights. Patients with baseline brain metastasis in the 300 mg group exhibited a slight increase in incidence of CNS failure (HR, 1.76; 95% CI, 0.53 to 5.8; p=0.36). Although the safety profiles were mostly mild, adverse events were more frequent in the 600 mg group, 50% of which requiring dose reduction. Conclusion Alectinib at 300 mg twice daily seems an acceptable dose in East Asians with ALK-positive NSCLC. Notably, our data favor 300 mg twice daily in patients with lower body weight and no baseline brain metastasis, considering the more tolerable safety profiles and the potential to reduce medical costs.

Purpose: Adjuvant pembrolizumab improved disease-free survival (DFS) and overall survival (OS) versus placebo in participants with renal cell carcinoma (RCC) at increased risk of recurrence after nephrectomy in the global phase 3 KEYNOTE-564 study. This post hoc subgroup analysis evaluated the efficacy and safety of adjuvant pembrolizumab in East Asian (Japan, South Korea, and Taiwan) participants enrolled in KEYNOTE-564. Materials and Methods: Eligible participants were randomly assigned 1:1 to receive adjuvant pembrolizumab 200 mg or placebo intravenously every 3 weeks for ≤ 17 cycles. The primary endpoint was DFS by investigator assessment. OS was a key secondary endpoint. Safety was a secondary endpoint. Results: The East Asian subgroup included 126 participants (pembrolizumab, n=58; placebo, n=68). Median follow-up was 62.1 months (range, 49.6 to 73.0 months). Hazard ratio for DFS with pembrolizumab versus placebo was 0.70 (95% confidence interval 0.41 to 1.20). Median DFS was not reached with pembrolizumab versus 58.8 months with placebo; estimated 48-month rate was 61.3% versus 51.2%. Hazard ratio for OS was 0.47 (95% confidence interval, 0.15 to 1.49). Median OS was not reached with pembrolizumab and placebo; estimated 48-month rate was 94.8% versus 91.2%. Treatment-related adverse events occurred in 70.7% of participants (29.3% grade 3 or 4) receiving pembrolizumab and 36.8% of participants (0.0% grade 3 or 4) receiving placebo. No pembrolizumab-related deaths occurred. Conclusion In the KEYNOTE-564 East Asian subgroup, adjuvant pembrolizumab provided DFS and OS benefits versus placebo and had a safety profile consistent with the global results. These results further support pembrolizumab as adjuvant treatment for East Asian patients with RCC at increased risk of recurrence after nephrectomy.

Purpose: Considering the current lack of consensus on post–poly(adenosine diphosphate-ribose) polymerase inhibitor (PARPi) treatment strategies, this study aimed to evaluate the efficacy of subsequent therapy and compare the outcomes of regimes in patients with recurrent ovarian cancer after PARPi treatment. Materials and Methods: This multi-center retrospective cohort study analyzed data on patients diagnosed with ovarian cancer between January 2012 and June 2023 who had previously used PARPi after first- to fourth-line platinum-based chemotherapy. The primary endpoint was progression-free survival (PFS), which was the interval between recurrence after using PARPi and subsequent recurrence in the case of recurrence. Results: Of 318 patients, 147/318 (46.2%) recurred after the PARPi maintenance. Patients were categorized into groups based on subsequent therapy except non-treated (11/147, 7.5%): platinum-based chemotherapy (89/147, 60.5%), non-platinum-based chemotherapy (21/147, 14.3%), other treatments (26/147, 17.7%), and the median PFS (mPFS) for each group were 7.3, 4.8, and 11.4 months, respectively. Among the platinum-based chemotherapy group, the gemcitabine+carboplatin regimen demonstrated a longer mPFS (10.1 months) than the other regimens (6.6 months, p=0.019). In non-platinum-based chemotherapy, no statistically significant differences were observed among the regimens. And, in the other therapy group, where the proportion of patients with oligometastasis was as high as 88.5%, no significant differences were observed among the therapies, including other modalities. Conclusion In the subsequent chemotherapy of recurrent ovarian cancer after platinum-based chemotherapy and PARPi, the gemcitabine+carboplatin regimen demonstrated a potential to delay recurrence more effectively compared to other therapies.

Purpose: Atypical hyperplasia (AH) management remains controversial due to variable malignant disease progression rates. While Western studies report 10% to 25% upgrade rates, data from Asian populations, particularly from referral academic centers, are limited. We aimed to identify predictive factors for malignant upgrade in Korean women with AH at academic hospitals. Methods: This retrospective multi-institutional study analyzed 340 patients diagnosed with AH on initial biopsy who underwent subsequent excision at five Korean academic hospitals from 2000 to 2022. Malignant upgrade was defined as ductal carcinoma in situ or invasive cancer on the final pathology. Multivariate logistic regression was used to identify independent predictors of upgrades. Results: Among 340 patients (319 atypical ductal hyperplasia, 20 atypical lobular hyperplasia, and 1 mixed), 128 (37.6%) experienced a malignant upgrade, 98 (76.6%) to ductal carcinoma in situ, and 30 (23.4%) to invasive cancer. In multivariate analysis, multifocal atypia (odds ratio [OR], 25.61; 95% confidence interval [CI], 11.20–58.55; P<0.001) and Breast Imaging-Reporting and Data System 4c-5 lesions (OR, 11.02; 95% CI, 1.43–84.86; P=0.021) were significant predictors. Multifocal atypia showed an 84.4% upgrade rate. Core needle biopsy had higher upgrade rates than vacuum-assisted biopsy (45.2% vs. 20.0%; P<0.001). The upgrade rates decreased from 50% to 25% over the study period (P<0.05). Conclusion The 37.6% upgrade rate in this tertiary referral cohort exceeded that in Western reports, with multifocal atypia emerging as the strongest predictor. These findings support immediate excision for multifocal atypia while allowing individualized management for unifocal lesions with favorable imaging in Korean tertiary care settings.

Accurate and early identification of stroke and large vessel occlusion (LVO) in emergency settings is essential for improving patient outcomes and ensuring the efficient allocation of medical resources. This clinical practice guideline systematically reviews domestic and international literature and conducts meta-analyses to evaluate the utility and diagnostic accuracy of stroke assessment tools used in prehospital emergency medical services (EMS). We developed a guideline based on evidence from systematic reviews and meta-analyses via a de novo process. A systematic literature review was conducted to evaluate the usefulness of diagnostic EMS assessment tools for diagnosing stroke and LVO. Overall, 70 non-randomized control studies were selected for this study. A meta-analysis was conducted with a subgroup analysis to distinguish between patients with stroke and those with LVO. EMS tools demonstrated high sensitivity but low specificity for diagnosing stroke. In the prehospital setting, using validated EMS stroke assessment tools is recommended for the early identification of stroke and LVO. Upon hospital arrival, stroke specialists should conduct further evaluation and triage to confirm the diagnosis and guide appropriate management. Delays in diagnosing LVO are frequently unacceptable. While experts advocate for the use of EMS assessment tools to facilitate early identification of LVO, these tools alone lack adequate sensitivity. Therefore, further diagnostic evaluations and consultation with stroke specialists upon hospital arrival are recommended.

Objectives: Endoscopic submucosal dissection (ESD) has become a standard minimally invasive treatment for selected patients with early gastric cancer (EGC). This study presents the first nationwide survey of patients with EGC treated with ESD in 2023, conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research. Methods: Data were retrospectively collected from participating referral centers across Korea using a standardized case report form covering patient characteristics, tumor features, procedural details, histopathological findings, and clinical outcomes. Descriptive and comparative analyses were conducted to summarize nationwide ESD practice patterns and outcomes. Results: Data from 5460 ESD cases from 5250 patients across 27 institutions were analyzed. The mean age was 67.4 years, with 74.1% males. Multiple synchronous lesions were identified in 3.7%. Most lesions were located in the lower third of the stomach (64.0%), and differentiated-type adenocarcinomas accounted for 87.8%. The en bloc and complete resection rates were 99.2% and 91.4%, respectively. Curative resection was achieved in 80.5%, whereas local non-curative resection (L-NCR) and surgical non-curative resection (S-NCR) were identified in 2.8% and 16.7%, respectively. Additional surgery was performed more frequently in patients with S-NCR than in those with L-NCR (59.3% vs. 24.7%). The bleeding and perforation rates were 3.6% and 0.9%, respectively, and were mostly managed conservatively or endoscopically. The median length of hospitalization was 4.0 days. Conclusions This first nationwide survey provides a comprehensive overview of the current practice of EGC treatment using ESD in Korea, demonstrating high technical success and safety, and establishing a baseline dataset for future longitudinal research.

Background: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis and lacks clinical biomarkers. Exosomes are extracellular vesicles that facilitate cell–cell communication by distributing macromolecules, such as small RNAs (smRNAs). We assessed the potential of exosome-derived small RNAs (Ex-smRNAs) as PDAC biomarkers. Methods: Peripheral blood was collected from 51 patients with PDAC and 15 control individuals. Exosomes were isolated using an aqueous two-phase system. Ex-smRNAs were analyzed using smRNA sequencing. smRNA-mediated target gene regulation was verified via The Cancer Genome Atlas analysis and in vitro transfection and wound-healing assays using PDAC organoids. Results: The total Ex-smRNA count was substantially reduced in patients with PDAC compared with that in control individuals. The levels of microRNAs (miRNAs) miR-125a-5p, miR-30e-5p, miR-16-2-3p, miR-98-5p, and the let-7 family were significantly suppressed, whereas that of miR-6731-5p was significantly elevated. Let-7c-5p and miR-98-5p were found to interact with the long non-coding RNA OLMALINC to regulate their common target genes, BACH1 and CCND1, thus controlling PDAC proliferation and migration. The expressions of CARS1-AS1 and miR-142-5p were upregulated in treatment-responsive patients.Multivariable Cox regression analyses, adjusting for potential prognostic factors such as sex, Eastern Cooperative Oncology Group performance status, and tumor size and stage, revealed that CARS1-AS1 (adjusted hazard ratio [HR] 0.33; 95% confidence interval [CI], 0.15–0.73; P = 0.0061) and miR-142-5p (adjusted HR 0.79; 95% CI, 0.61–1.01; P = 0.0581) were associated with improved overall survival. Conclusions We identified potential Ex-smRNA biomarkers involved in PDAC progression and prognosis that reflect key molecular alterations in PDAC and may serve as clinically relevant biomarkers for disease monitoring.