Purpose: This study analyzed the pathological complete response (pCR) rates, long-term outcomes, and biological features of human epidermal growth factor receptor 2 (HER2)-zero, HER2-low, and HER2-positive breast cancer patients undergoing neoadjuvant treatment. Methods: This single-center study included 1,667 patients who underwent neoadjuvant chemotherapy from 2008 to 2014. Patients were categorized by HER2 status, and their clinicopathological characteristics, chemotherapy responses, and recurrence-free survival (RFS) rates were analyzed. Results: Patients with HER2-low tumors were more likely to be older (p = 0.081), have a lower histological grade (p < 0.001), and have hormone receptor (HorR)-positive tumors (p < 0.001). The HER2-positive group exhibited the highest pCR rate (23.3%), followed by the HER2-zero (15.5%) and HER2-low (10.9%) groups. However, the pCR rate did not differ between HER2-low and HER2-zero tumors in the HorR-positive or HorR-negative subgroups.The 5-year RFS rates increased in the following order: HER2-low, HER2-positive, and HER2-zero (80.0%, 77.5%, and 74.5%, respectively) (log-rank test p = 0.017). A significant survival difference between patients with HER2-low and HER2-zero tumors was only identified in HorR-negative tumors (5-year RFS for HER2-low, 74.5% vs. HER2-zero, 66.0%; log-rank test p-value = 0.04). Multivariate survival analysis revealed that achieving a pCR was the most significant factor associated with improved survival (hazard ratio [HR], 4.279; p < 0.001).Compared with HER2-zero, the HRs for HER2-low and HER2-positive tumors were 0.787 (p = 0.042) and 0.728 (p = 0.005), respectively. After excluding patients who received HER2-targeted therapy, patients with HER2-low tumors exhibited better RFS than those with HER2-zero (HR 0.784, p = 0.04), whereas those with HER2-positive tumors exhibited no significant difference compared with those with HER2-low tumors (HR, 0.975; p = 0.953). Conclusion Patients with HER2-low tumors had no significant difference in pCR rate compared to HER2-zero but showed better survival, especially in HorR-negative tumors.Further investigation into biological differences is warranted.

Purpose: This study evaluated the postoperative quality of life (QoL) after various types of gastrectomy for gastric cancer. Materials and Methods: A multicenter prospective observational study was conducted in Korea using the Korean Quality of Life in Stomach Cancer Patients Study (KOQUSS)-40, a new QoL assessment tool focusing on postgastrectomy syndrome. Overall, 496 patients with gastric cancer were enrolled, and QoL was assessed at 5 time points: preoperatively and at 1, 3, 6, and 12 months after surgery. Results: Distal gastrectomy (DG) and pylorus-preserving gastrectomy (PPG) showed significantly better outcomes than total gastrectomy (TG) and proximal gastrectomy (PG) with regard to total score, indigestion, and dysphagia. DG, PPG, and TG also showed significantly better outcomes than PG in terms of dumping syndrome and worry about cancer. Postoperative QoL did not differ significantly according to anastomosis type in DG, except for Billroth I anastomosis, which achieved better bowel habit change scores than the others. No domains differed significantly when comparing double tract reconstruction and esophagogastrostomy after PG. The total QoL score correlated significantly with postoperative body weight loss (more than 10%) and extent of resection (P<0.05 for both).Reflux as assessed by KOQUSS-40 did not correlate significantly with reflux observed on gastroscopy 1 year postoperatively (P=0.064). Conclusions Our prospective observation using KOQUSS-40 revealed that DG and PPG lead to better QoL than TG and PG. Further study is needed to compare postoperative QoL according to anastomosis type in DG and PG.

Purpose: Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal complication of gastric cancer (GC). This study aimed to evaluate the clinical characteristics, outcomes, and immunohistochemical profiles of patients with GC-induced PTTM. Materials and Methods: From 2011 to 2023, 8 patients were clinically diagnosed with PTTM associated with GC antemortem. Clinical features and outcomes were reviewed, and immunohistochemical staining for c-erbB-2, MutL protein homolog 1, and programmed cell death ligand-1 was performed. Results: The median patient age was 56 years (range, 34–66 years). In all the patients, the tumors exhibited either ulceroinfiltrative or diffusely infiltrative gross morphology.The median tumor size was 5.8 cm (range, 2.0 cm–15.0 cm). Poorly differentiated adenocarcinoma was the most common histological type (6/8, 75%), followed by signet ring cell carcinoma (1/8, 12.5%) and moderately differentiated adenocarcinoma (1/8, 12.5%).Chest computed tomography revealed ground-glass opacities (7/8, 87.5%) or tree-in-bud signs (2/8, 25.0%) without definite evidence of pulmonary thromboembolism. Disseminated intravascular coagulation was present in 62.5% (5/8) of the patients diagnosed with PTTM.C-erbB-2 was positive in one patient (1/8, 12.5%). One patient who received palliative chemotherapy after developing PTTM survived for 35 days, whereas the other 7 patients who did not receive chemotherapy after developing PTTM survived for 7 days or less after PTTM diagnosis. Conclusions Most patients with GC-induced PTTM had an undifferentiated-type histology, infiltrative morphology, and extremely poor survival. Palliative chemotherapy may benefit patients with GC-induced PTTM; however, further studies are needed to explore the potential of targeted therapy in these patients.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

This review examines the challenges associated with occupational disease surveillance in Korea, particularly emphasizing the limitations of current data sources such as the Industrial Accident Compensation Insurance (IACI) statistics and special health examinations. The IACI system undercounts cases due to its emphasis on severe diseases and restrictions on approvals. Special health examinations, although they cover a broad workforce, are constrained by their annual scheduling, which leads to missed acute illnesses and subclinical conditions. The paper also explores the history of occupational disease surveillance in Korea, highlighting the fragmented and disease-specific approach of earlier systems. The authors introduce the newly established Korea Occupational Disease Surveillance Center (KODSC), a comprehensive nationwide system designed to gather, analyze, and interpret data on occupational diseases through a network of regional centers. By incorporating hospital-based surveillance and focusing on acute poisonings and other sentinel events, the KODSC aims to overcome the limitations of previous systems and promote collaboration with various agencies. Although it is still in the early stages of implementation, the KODSC demonstrates potential for improving data accuracy and contributing valuable insights for public health policy.

Objectives: The success of Helicobacter pylori eradication using clarithromycin-based triple therapy relies on the bacteria being sensitive to clarithromycin. This study evaluated the diagnostic performance of two frequently used polymerase chain reaction (PCR) methods (AllplexTM H. pylori & ClariR Assay [Seegene] and Ezplex® HP-CLA Real-time PCR [SML Genetree]) to detect H. pylori infection and identify point mutations associated with clarithromycin resistance. Methods: Patients who underwent esophagogastroduodenoscopy between August 2023 and April 2024 at Incheon St. Mary’s Hospital were enrolled in this study. The diagnostic performance of the Allplex method was evaluated against the rapid urease test (RUT), culture, and Ezplex HP-CLA methods. Point mutation detection using the Allplex and Ezplex methods was compared with the results of gene sequencing. The rates of H. pylori eradication following Ezplex-based tailored therapy were also analyzed. Results: Eighty-seven gastric biopsy specimens were analyzed. For diagnosing H. pylori infections, Allplex demonstrated kappa values of 0.670 compared with RUT, 0.468 compared with culture, and 0.880 compared with Ezplex. Among the 87 bacterial isolates subjected to gene sequencing to detect clarithromycin resistance-associated point mutations, the Allplex and Ezplex methods demonstrated 74 and 76 concordant results, respectively. The H. pylori eradication rate using Ezplex-based tailored therapy was 90.7%. Conclusions This study demonstrated that both the Allplex and Ezplex methods are helpful for diagnosing H. pylori infections and detecting clarithromycin resistance. Furthermore, the Ezplex method was clinically effective for guiding tailored therapy to yield successful H. pylori eradication.

Background/Aims: This study applied the 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) criteria for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) to patients with Behçet’s disease (BD) to investigate the proportion and clinical implications of the reclassification to the overlap syndrome of BD and AAV (OS-BD-AAV). Methods: We included 280 BD patients presenting with ANCA positivity but without medical conditions mimicking AAV at diagnosis. Demographic data, items from the 2014 revised International Criteria for BD and 2022 American College of Rheumatology and European Alliance of Associations for Rheumatology criteria for AAV, ANCA positivity, and laboratory results were recorded as clinical data at diagnosis. A total score ≥ 5 indicated microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA), whereas a total score ≥ 6 indicated a diagnosis of eosinophilic GPA (EGPA). Results: The overall reclassification rate of OS-BD-AAV was 8.6%. Of the 280 patients, 16 (5.7%) and 8 (2.9%) were reclassified as having OS-BD-MPA and OS-BD-GPA, respectively; none were classified as having OS-BD-EGPA. ANCA, myeloperoxidase-ANCA (P-ANCA), proteinase 3-ANCA (C-ANCA) positivity, hearing loss, and interstitial lung disease (ILD) at diagnosis were more common in patients with OS-BD-AAV than in those without. ANCA positivity and ILD at BD diagnosis contributed to the reclassification of OS-BD-AAV. However, hearing loss was not considered a major contributor to BD due to its possibility of developing as a manifestation of BD. Conclusions To our knowledge, this is the first study to demonstrate the reclassification rate (8.6%) of patients with BD and ANCA results at diagnosis as OS-BD-AAV.

Purpose: Several types of dermal fillers have been recently introduced and used for penile augmentation (PA). However, few studies have compared outcomes after the injection of different fillers. This study aimed to compare the clinical outcomes of hyaluronic acid (HLA), polylactic acid (PLA), and polymethyl methacrylate (PMA) filler injections, which are the most commonly used for aesthetic purposes. Materials and Methods: This prospective study was conducted for 24 weeks after a filler injection by a surgeon between March 2017 and December 2021. Healthy adult men complaining of small penis were enrolled. Penile girth, satisfaction, and injection-associated adverse events (AEs) were assessed at baseline and 4, 12, and 24 weeks after injection. Results: Of the 301 men who received filler injections, 125, 134, and 42 received HLA, PLA, and PMA fillers, respectively. The augmentation effect was in the order of PMA, HLA, and PLA, respectively, at 24 weeks (PMA vs. HLA, p<0.001; HLA vs. PLA, p=0.006). Satisfaction levels increased significantly at 24 weeks in all groups (each with p<0.001). However, the increase in satisfaction levels was smaller in the PMA group (PMA vs. HLA or PLA, p<0.05, for both penile appearance and sexual life). No serious or systemic AEs were recorded. Filler injection-associated local AEs in the HLA, PLA, and PMA groups occurred in 9 (7.2%), 16 (11.9%), and 6 (14.3%) men, respectively. There was no significant difference in AEs among the groups (p=0.299). Conclusions The augmentative effect was greater in the PMA group than in the HLA and PLA groups, whereas the increase in satisfaction levels was smaller in the PMA group. Our study demonstrated the clinical course of different types of fillers and suggests that the filler type should be selected after detailed counseling considering individual characteristics and preferences.

Purpose: The purpose of this study was to compare the effectiveness of pericapsular nerve group (PENG) block with periarticular multimodal drug injection (PMDI) on postoperative pain management and surgical outcomes in patients who underwent total hip arthroplasty (THA). We hypothesized that PENG block with PMDI would exhibit superior effects on postoperative pain control after THA compared to PMDI alone. Materials and Methods: From April 2022 to February 2023, 58 patients who underwent THA were randomly assigned into two groups: PENG block with PMDI group (n=29) and PMDI-only group (n=29). Primary outcomes were postoperative numeric rating scale (NRS) at rest and during activity at 6, 24, and 48 hours postoperatively. Secondary outcomes were postoperative complications (nausea and vomiting), Richards-Campbell Sleep Questionnaire (RCSQ) score, length of hospital stay, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, Harris Hip Score (HHS), and total morphine usage after surgery. Results: There was no significant difference in postoperative pain for either resting NRS or active NRS. Postoperative nausea and vomiting, RCSQ score, length of hospital stay, WOMAC index, HHS, and total morphine usage exhibited no significant differences between the two groups. Conclusion Both groups showed no significant differences in postoperative pain and clinical outcomes, indicating that the addition of PENG block to PMDI does not improve pain management after applying the posterolateral approach of THA. PMDI alone during THA would be an efficient, fast, and safe method for managing postoperative pain. This article was registered with ClinicalTrials.gov (Gov ID: NCT05320913).

Purpose: Pediatric papillary thyroid cancer (PTC) is recommended to perform aggressive surgery to reduce the risk of recurrence.This study was designed to evaluate the concurrent association between multifocality, bilaterality, and the risk of recurrence in pediatric PTC. Materials and Methods: This retrospective cohort study included pediatric patients (age <19 years) who underwent total thyroidectomy for PTC between 1996 and 2014 in a single tertiary center. Clinicopathological parameters were analyzed to evaluate the prevalence of multifocality, bilaterality, recurrence, and their association. Results: We analyzed 58 pediatric patients with PTC. There was no factor related to the presence of multifocality or bilaterality in multivariate analysis. Also, in univariate analysis, multifocality and bilaterality were not independent risk factors of each other’s presentation (p=0.061 and p=0.061, respectively). Recurrence was observed in 19 (32.8%) patients. In multivariate analysis of recurrence, clear cell subtype, multifocality, and gross extrathyroidal extension (ETE) were independent risk factors (p=0.027, p=0.035, and p=0.038, respectively). Most recurrences (68.4%) happened during the first 4 years of follow-up after the initial thyroidectomy. Conclusion Multifocality and bilaterality were not independent risk factors of each other’s presentation; however, multifocality was the risk factor for recurrence in pediatric PTC. For pediatric PTC, close monitoring for recurrence within the initial 4 years is recommended, particularly in patients with clear cell subtype, multifocality, and gross ETE.