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: Since 1995, the Korean Gastric Cancer Association (KGCA) has been periodically conducting nationwide surveys on patients with surgically treated gastric cancer. This study details the results of the survey conducted in 2023. Materials and Methods: The survey was conducted from March to December 2024 using a standardized case report form. Data were collected on 86 items, including patient demographics, tumor characteristics, surgical procedures, and surgical outcomes. The results of the 2023 survey were compared with those of previous surveys. Results: Data from 12,751 cases were collected from 66 institutions. The mean patient age was 64.6 years, and the proportion of patients aged ≥71 years increased from 9.1% in 1995 to 31.7% in 2023. The proportion of upper-third tumors slightly decreased to 16.8% compared to 20.9% in 2019. Early gastric cancer accounted for 63.1% of cases in 2023.Regarding operative procedures, a totally laparoscopic approach was most frequently applied (63.2%) in 2023, while robotic gastrectomy steadily increased to 9.5% from 2.1% in 2014.The most common anastomotic method was the Billroth II procedure (48.8%) after distal gastrectomy and double-tract reconstruction (51.9%) after proximal gastrectomy in 2023.However, the proportion of esophago-gastrostomy with anti-reflux procedures increased to 30.9%. The rates of post-operative mortality and overall complications were 1.0% and 15.3%, respectively. Conclusions The results of the 2023 nationwide survey demonstrate the current status of gastric cancer treatment in Korea. This information will provide a basis for future gastric cancer research.

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.

Objective: We evaluated the occupational exposure levels of healthcare workers while conducting rotational pressurized intraperitoneal aerosol chemotherapy (RIPAC) using cisplatin in a large animal model. Methods: We performed RIPAC using cisplatin in 6 female pigs and collected surface and air samples during the procedure. Surface samples were obtained from RIPAC devices and personal protective equipment (PPE) by wiping, and air samples were collected around the operating table.All samples were analyzed by inductively coupled plasma–mass spectrometry to detect platinum. Results: Among all surface samples (n=44), platinum was detected in 41 samples (93.2%) but not in all air samples (n=16). Among samples collected from RIPAC devices (n=23), minimum and maximum cisplatin levels of 0.08 and 235.09 ng/cm2 were detected, mainly because of direct aerosol exposure in the abdominal cavity. Among samples collected from healthcare workers’ PPE (n=21), 18 samples (85.7%) showed contamination levels below the detection limit, with a maximum of 0.23 ng/cm2 . There was no significant contamination among samples collected from masks, shoes, or gloves. Conclusion During the RIPAC procedures, there is a potential risk of dermal exposure, as platinum, a surrogate material for cisplatin, was detected at low concentration levels in some surface samples. However, the respiratory exposure risk was not identified, as platinum was not detected in the airborne samples in this study.

Heart failure (HF) is a major cause of mortality and morbidity in South Korea, imposing substantial physical, emotional, and financial burdens on patients and society. Despite the high burden of symptom and complex care needs of HF patients, palliative care and hospice services remain underutilized in South Korea due to cultural, institutional, and knowledge-related barriers. This position statement from the Korean Society of Heart Failure emphasizes the need for integrating palliative and hospice care into HF management to improve quality of life and support holistic care for patients and their families. By clarifying the role of palliative care in HF and proposing practical referral criteria, this position statement aims to bridge the gap between HF and palliative care services in South Korea, ultimately improving patient-centered outcomes and aligning treatment with the goals and values of HF patients.

Background: The World Health Organization has declared the end of the coronavirus disease 2019 (COVID-19) public health emergency. However, this did not indicate the end of COVID-19. Several months after the infection, numerous patients complain of respiratory or nonspecific symptoms; this condition is called long COVID. Even patients with mild COVID-19 can experience long COVID, thus the burden of long COVID remains considerable. Therefore, we conducted this study to comprehensively analyze the effects of long COVID using multi-faceted assessments. Materials and Methods: We conducted a prospective cohort study involving patients diagnosed with COVID-19 between February 2020 and September 2021 in six tertiary hospitals in Korea. Patients were followed up at 1, 3, 6, 12, 18, and 24 months after discharge. Long COVID was defined as the persistence of three or more COVID-19-related symptoms. The primary outcome of this study was the prevalence of long COVID after the period of COVID-19. Results: During the study period, 290 patients were enrolled. Among them, 54.5 and 34.6% experienced long COVID within 6 months and after more than 18 months, respectively. Several patients showed abnormal results when tested for post-traumatic stress disorder (17.4%) and anxiety (31.9%) after 18 months. In patients who underwent follow-up chest computed tomography 18 months after COVID-19, abnormal findings remained at 51.9%. Males (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.05–0.53; P=0.004) and elderly (OR, 1.04; 95% CI, 1.00–1.09; P=0.04) showed a significant association with long COVID after 12–18 months in a multivariable logistic regression analysis. Conclusion Many patients still showed long COVID after 18 months post SARS-CoV-2 infection. When managing these patients, the assessment of multiple aspects is necessary.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a devastating and growing global threat, calling for new antibiotic treatments. In Korea, the challenge of treating CRAB is compounded by high nosocomial acquisition rates and limited availability of novel antibiotics. Minocycline, a semisynthetic tetracycline derivative, has been proposed as a therapeutic option for CRAB infections. Nonsusceptibility to minocycline may occur through the efflux pump, TetB. The prevalence of tetB in A. baumannii has increased, along with higher minocycline minimum inhibitory concentrations (MICs). We aimed to evaluate minocycline susceptibility rates in clinical strains of CRAB, and the association between tetB carriage and minocycline susceptibility across different genotypes. Materials and Methods: Representative CRAB blood isolates were collected from Asan Medical Center, Seoul.Minocycline susceptibility was assessed using the Clinical and Laboratory Standards Institute (CLSI) breakpoint (≤4 mg/L) and the proposed pharmacokinetics (PK)/pharmacodynamics (PD) breakpoint (≤1 mg/L). Tigecycline was used as a comparator, and its susceptibility breakpoint for Enterobacterales defined by EUCAST was applied (≤0.5 mg/L).The presence of tetB was detected by PCR, and multilocus sequence typing (MLST) was performed using seven housekeeping genes. Results: Of the 160 CRAB blood isolates, 83.8% were susceptible to minocycline by the CLSI criteria, and 50.6% were PK-PD susceptible by the PK-PD criteria. The minocycline minimum inhibitory concentration (MIC)50 /MIC90 was 1/8 mg/L. tetB was present in 49% of isolates and was associated with a higher minocycline MIC (MIC50/90 2/8 mg/L vs. 1/2 mg/L). No clear correlation was observed between tetB positivity and tigecycline MIC. Nine MLSTs were identified, with significant differences in tetB carriage rates between the major sequence types. Notably, ST191, associated with non-tetB carriage and greater susceptibility to minocycline, declined over the study period (P=0.004), while ST451, associated with tetB carriage, increased. Conclusion tetB was present in 49% of CRAB isolates and was associated with higher MICs and non-susceptibility by both CLSI and PK-PD criteria. However, absence of tetB was not a reliable predictor of minocycline PK-PD susceptibility. Additionally, shifts over time towards genotypes with reduced minocycline susceptibility were observed. Further research is needed to correlate these findings with clinical outcomes and identify additional resistance mechanisms.

Background/Aims: Self-expandable metallic stents (SEMSs) are widely used as palliative or bridge to surgery treatments in patients with malignant colorectal obstruction (MCO). Stent occlusion is more common with uncovered stents, but stent migration is more common with covered stents. Our purpose was to compare the efficacy and safety of a newly designed covered SEMS with an uncovered proximal flared end (CSEMS-UPF) with that of the conventional uncovered SEMS (UCSEMS) in the treatment of MCO. Methods: This prospective randomized trial was conducted at a tertiary-care academic hospital. We enrolled 87 patients with stage 4 cancer and MCO: colorectal cancer in 60 patients and extracolonic cancer in 27 patients. Insertion of UCSEMS was randomly assigned to 43 patients, and 44 patients received the CSEMS-UPF. The primary outcome was the duration of stent patency after successful placement. The secondary outcomes were the number of patients with technical and clinical success and early and late complications from the stent insertion. Results: The median patency of the stent did not differ between the UCSEMS and CSEMS-UPF groups (484 [231–737] days vs. 216 [66–366] days, P= 0.242). The technical and clinical success rates did not differ significantly between the groups, either (100.0% vs. 93.2%, respectively, P= 0.241; 100.0% vs. 92.7%, respectively, P= 0.112), nor did the early (n = 2 [4.7%] vs. n = 4 [9.8%], P> 0.999) or late (n = 12 [27.9%] vs. n = 15 [36.6%], P> 0.999) stent complication rates differ between the groups. Conclusions The UCSEMS and newly developed CSEMS-UPF are similarly effective treatments for MCO, with no differences in the stent migration or occlusion rates (Clinical trial registration number: NCT02640781).

Background: Infantile hemangioma (IH) is a common benign vascular tumor that occurs during infancy. Oral propranolol is used as a first-line treatment. However, standardized guidelines for evaluating treatment efficacy, particularly the appropriate timing and parameters for Doppler ultrasound (US), have not been established. This study reports on the evaluation of therapeutic efficacy of oral propranolol solution in IH patients using Doppler US, and aims to propose the appropriate timing and parameters for using Doppler US based on this experience. Methods: A retrospective analysis was conducted on 120 patients with IH who were treated with oral propranolol solution and maintained for over 6 months from May 2017 to April 2023. Doppler US evaluation of IH was performed at diagnosis, 1-2 and 6-12 months after treatment initiation, and 6 months post-therapy cessation. A complete response (CR) was identified as a reduction in vascularity along with a decrease in longest diameter (LD) or thickness of 50% or more. Recurrence was evaluated based on increased vascularity or size 6 months after treatment discontinuation. Results: Of 120 patients with IH, 82 females and 38 males were analyzed. IH was first detected at a median age of 12 days (range, 1-240 days), and treatment began at 76 days (range, 27-570 days), continuing for an average of 10.4 months (range, 5-24 months). Initial Doppler US measurements showed an LD of 2.65±1.52 cm and a thickness of 0.79±0.55 cm, with prominent vascularity. After 1-2 months of treatment, LD and thickness decreased by 12.9% and 25.9%, respectively. By 6-12 months, reductions reached 37.2% and 53.6%. CR occurred in 77 patients (64.2%) after 6-12 months of treatment. Eleven patients (9.2%) experienced a recurrence. Conclusion Doppler US is a valuable modality for evaluating the characteristics, treatment response, and recurrence of IH treated with oral propranolol.