Objective: This was a retrospective investigation conducted to evaluate the impact of the coronavirus disease-2019 (COVID-19) pandemic on the treatment and outcomes of patients with ischemic stroke. Methods: Data were collected over one year for the COVID-19 and pre-COVID-19 (control) groups, from May 1, 2020, to April 30, 2021, when COVID-19 was prevalent in Korea, and from May 1, 2018 to April 30, 2019, before the COVID-19 outbreak, respectively. Adult patients diagnosed with acute cerebral infarction at three emergency medical centers during the study period were included. COVID-19-positive patients (i.e., those with COVID-19 symptoms but those who tested positive) were excluded from this study to ensure only the evaluation of delays in stroke treatment due to the pandemic. Results: During the COVID-19 pandemic, of the total of 82,558 patients who visited the emergency centers, 710 were diagnosed with ischemic stroke. The study observed that the pandemic caused process delays for these patients, resulting in longer wait times for brain CT scans (P=0.010, P<0.001) and emergency room stays (P=0.0055, P<0.001) during the COVID-19 period. However, the length of time for administration of tissue plasminogen activator remained relatively constant. Notably, the 28-day mortality rate was considerably higher for patients with COVID-19-related symptoms during the pandemic (13.6% vs 3.1%; P=0.006). A cumulative risk analysis revealed an increased mortality risk for patients with COVID-19 related symptoms (P=0.005). Conclusion This study showed the need to improve emergency care procedures during pandemics to ensure prompt treatment of ischemic stroke. Preparation and resource allocation for ischemic stroke patients with COVID-19 symptoms are crucial.

Objective: This was a retrospective investigation conducted to evaluate the impact of the coronavirus disease-2019 (COVID-19) pandemic on the treatment and outcomes of patients with ischemic stroke. Methods: Data were collected over one year for the COVID-19 and pre-COVID-19 (control) groups, from May 1, 2020, to April 30, 2021, when COVID-19 was prevalent in Korea, and from May 1, 2018 to April 30, 2019, before the COVID-19 outbreak, respectively. Adult patients diagnosed with acute cerebral infarction at three emergency medical centers during the study period were included. COVID-19-positive patients (i.e., those with COVID-19 symptoms but those who tested positive) were excluded from this study to ensure only the evaluation of delays in stroke treatment due to the pandemic. Results: During the COVID-19 pandemic, of the total of 82,558 patients who visited the emergency centers, 710 were diagnosed with ischemic stroke. The study observed that the pandemic caused process delays for these patients, resulting in longer wait times for brain CT scans (P=0.010, P<0.001) and emergency room stays (P=0.0055, P<0.001) during the COVID-19 period. However, the length of time for administration of tissue plasminogen activator remained relatively constant. Notably, the 28-day mortality rate was considerably higher for patients with COVID-19-related symptoms during the pandemic (13.6% vs 3.1%; P=0.006). A cumulative risk analysis revealed an increased mortality risk for patients with COVID-19 related symptoms (P=0.005). Conclusion This study showed the need to improve emergency care procedures during pandemics to ensure prompt treatment of ischemic stroke. Preparation and resource allocation for ischemic stroke patients with COVID-19 symptoms are crucial.

Objective: This was a retrospective investigation conducted to evaluate the impact of the coronavirus disease-2019 (COVID-19) pandemic on the treatment and outcomes of patients with ischemic stroke. Methods: Data were collected over one year for the COVID-19 and pre-COVID-19 (control) groups, from May 1, 2020, to April 30, 2021, when COVID-19 was prevalent in Korea, and from May 1, 2018 to April 30, 2019, before the COVID-19 outbreak, respectively. Adult patients diagnosed with acute cerebral infarction at three emergency medical centers during the study period were included. COVID-19-positive patients (i.e., those with COVID-19 symptoms but those who tested positive) were excluded from this study to ensure only the evaluation of delays in stroke treatment due to the pandemic. Results: During the COVID-19 pandemic, of the total of 82,558 patients who visited the emergency centers, 710 were diagnosed with ischemic stroke. The study observed that the pandemic caused process delays for these patients, resulting in longer wait times for brain CT scans (P=0.010, P<0.001) and emergency room stays (P=0.0055, P<0.001) during the COVID-19 period. However, the length of time for administration of tissue plasminogen activator remained relatively constant. Notably, the 28-day mortality rate was considerably higher for patients with COVID-19-related symptoms during the pandemic (13.6% vs 3.1%; P=0.006). A cumulative risk analysis revealed an increased mortality risk for patients with COVID-19 related symptoms (P=0.005). Conclusion This study showed the need to improve emergency care procedures during pandemics to ensure prompt treatment of ischemic stroke. Preparation and resource allocation for ischemic stroke patients with COVID-19 symptoms are crucial.

Purpose: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have greatly improved survival in EGFR-mutant (EGFRm) non–small cell lung cancer (NSCLC); however, their effects on the tumor microenvironment (TME) are unknown. We assessed the changes induced by neoadjuvant erlotinib therapy (NE) in the TME of operable EGFRm NSCLC. Materials and Methods: This was a single-arm phase II trial for neoadjuvant/adjuvant erlotinib therapy in patients with stage II/IIIA EGFRm NSCLC (EGFR exon 19 deletion or L858R mutations). Patients received up to 2 cycles of NE (150 mg/day) for 4 weeks, followed by surgery and adjuvant erlotinib or vinorelbine plus cisplatin therapy depending on observed NE response. TME changes were assessed based on gene expression analysis and mutation profiling. Results: A total of 26 patients were enrolled; the median age was 61, 69% were female, 88% were stage IIIA, and 62% had L858R mutation. Among 25 patients who received NE, the objective response rate was 72% (95% confidence interval [CI], 52.4 to 85.7). The median disease-free and overall survival (OS) were 17.9 (95% CI, 10.5 to 25.4) and 84.7 months (95% CI, 49.7 to 119.8), respectively. Gene set enrichment analysis in resected tissues revealed upregulation of interleukin, complement, cytokine, transforming growth factor β, and hedgehog pathways. Patients with upregulated pathogen defense, interleukins, and T-cell function pathways at baseline exhibited partial response to NE and longer OS. Patients with upregulated cell cycle pathways at baseline exhibited stable/progressive disease after NE and shorter OS. Conclusion NE modulated the TME in EGFRm NSCLC. Upregulation of immune-related pathways was associated with better outcomes.

Purpose: This subgroup analysis of the Korean subset of patients in the phase 3 LASER301 trial evaluated the efficacy and safety of lazertinib versus gefitinib as first-line therapy for epidermal growth factor receptor mutated (EGFRm) non–small cell lung cancer (NSCLC). Materials and Methods: Patients with locally advanced or metastatic EGFRm NSCLC were randomized 1:1 to lazertinib (240 mg/day) or gefitinib (250 mg/day). The primary endpoint was investigator-assessed progression-free survival (PFS). Results: In total, 172 Korean patients were enrolled (lazertinib, n=87; gefitinib, n=85). Baseline characteristics were balanced between the treatment groups. One-third of patients had brain metastases (BM) at baseline. Median PFS was 20.8 months (95% confidence interval [CI], 16.7 to 26.1) for lazertinib and 9.6 months (95% CI, 8.2 to 12.3) for gefitinib (hazard ratio [HR], 0.41; 95% CI, 0.28 to 0.60). This was supported by PFS analysis based on blinded independent central review. Significant PFS benefit with lazertinib was consistently observed across predefined subgroups, including patients with BM (HR, 0.28; 95% CI, 0.15 to 0.53) and those with L858R mutations (HR, 0.36; 95% CI, 0.20 to 0.63). Lazertinib safety data were consistent with its previously reported safety profile. Common adverse events (AEs) in both groups included rash, pruritus, and diarrhoea. Numerically fewer severe AEs and severe treatment–related AEs occurred with lazertinib than gefitinib. Conclusion Consistent with results for the overall LASER301 population, this analysis showed significant PFS benefit with lazertinib versus gefitinib with comparable safety in Korean patients with untreated EGFRm NSCLC, supporting lazertinib as a new potential treatment option for this patient population.

Objective: The Korean Triage and Acuity Scale (KTAS) is a triage tool for patients in the emergency department (ED). This study aimed to evaluate the ability of the KTAS to predict poor outcomes in South Korean ED patients with a suspected infection. We also compared the effectiveness of KTAS with that of the National Early Warning Score (NEWS) and Modified Early Warning Score (MEWS) in predicting poor outcomes. Methods: We conducted a single-center retrospective study that included adult patients with a suspected infection who were admitted to the ED between January 2019 and December 2019. Patients who received a prescription for antibiotics and associated culture tests in the ED were considered to have an infection. Poor outcomes were evaluated by in-hospital mortality, general ward admission, and intensive care unit (ICU) admission. A receiver operating characteristics (ROC) curve analysis was performed to evaluate and compare KTAS, NEWS, and MEWS. Results: Of the 4,127 patients in the study, in-hospital mortality was reported in 154 (3.7%) patients. The median KTAS was lower in the non-survivors than in the survivors (2.51 vs. 3.35). Multivariate logistic regression analysis showed that the KTAS was associated with in-hospital mortality, ward admission, and ICU admission. The area under the ROC curve (AUROC) values for predicting in-hospital mortality associated with the KTAS, NEWS, and MEWS were 0.776 (95% confidence interval, 0.747-0.803), 0.829 (0.759-0.811) and 0.739 (0.694-0.786), respectively. Conclusion Our results showed that the KTAS was associated with in-hospital mortality, ward admissions, and ICU admissions among ED patients with a suspected infection. Thus, KTAS may be reliable in predicting a poor outcome in ED patients with a suspected infection.

Purpose: The luminal subtype of breast cancer has heterogeneous biological characteristics with respect to the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor-2 (HER2), and Ki-67. We analyzed luminal B breast cancer subcategorized by PR expression and identified clinically relevant prognostic factors. Methods: We collected the clinical and pathologic data of 247 breast cancer patients (stage 1-4) who were diagnosed with luminal B subtype, defined as ER- and/or PR-positive and/or HER2-positive and with a high Ki-67 proliferation index (>14%). We classified them into PR intact and PR low groups according to PR expression pattern. We also analyzed the clinical and pathological data of each group, including age at diagnosis, tumor size, node metastasis, breast and axillary operative method, margin involvement, tumor-node-metastasis (TNM) stage, histological grade, nuclear grade, number of tumors, and expression of ER, PR, Ki-67, and Bcl-2; evaluated recurrence or metastatic characteristics; and analyzed disease-free survival (DFS) and overall survival (OS) in both groups. Results: Among the 247 luminal B breast cancer patients (stage 1-4), 141 were classified into the PR intact group (57.1%) and 106 into the PR low group (42.9%). The PR low group was associated with age >50 years (p=0.001), low Bcl-2 expression (p<0.001), and high proportion of mastectomies (p<0.001). DFS and OS were significantly lower in the PR low group (p=0.025 and 0.024, respectively). Conclusion This study showed that decreased in PR expression (PR low group) in luminal B breast cancer was related to poor prognosis compared to normal PR expression (PR intact group).

Purpose: The biggest concern related to ductal carcinoma in situ (DCIS) is local recurrence and recurrence patterns. The purpose of this study was to investigate the relationship between clinicopathological factors and relapse in patients treated with DCIS. Methods: We reviewed medical records of 104 patients who were diagnosed as DCIS between January 1999 and December 2015 at a single institute. We compared and analyzed clinicopathological factors such as age at diagnosis, preoperative lesions on ultrasonography, preoperative tumor markers, operation methods in the breast, histological grade, nuclear grade, resection margin, comedonecrosis, estrogen receptor/ progesterone receptor expression, human epidermal factor receptor 2eu expression, Ki-67, postoperative implementation of adjuvant hormonal therapy, and radiotherapy by dividing them into recurrent and non-recurrent groups. Results: Seventeen patients (16.3%) of 104 patients relapsed in the ipsilateral or contralateral breast. The median follow-up period of non-relapsed group was 4.9 years (range, 0.5–19.15) and the median follow-up period of relapsed group was 3.5 years (range, 1.4–14.13). Clinicopathological factors that were significantly related to relapse were nuclear grade (p=0.022) and Ki-67 (p=0.025) based on the results of chi-square or Fisher’s exact analysis. In multivariate analysis using logistic regression, Ki-67 (p=0.021) was significantly associated with DCIS relapse. Conclusion This study suggested that the higher Ki-67 over 14% was strongly associated with DCIS relapse.

Objective: Various tools using the length-based method for weight estimation and decisions regarding equipment size have been used in pediatric resuscitation globally. The Korean Pediatric Resuscitation Tape (KPRT) is one such tool that has been developed recently. This study was performed to validate the use of KPRT in Korean children. Methods: Data on the measured weights and the endotracheal tube (ETT) sizes used for children aged 12 years or less, who received general anesthesia, were collected by reviewing medical records from June 2018 to October 2020 at two hospitals in the urban areas of Korea. We compared the weight and ETT size estimated by the KPRT to the actually measured weight and ETT size used for the study population. We also calculated the weight and ETT size using an age-based formula and compared these values to the actual values of the patients. We then analyzed the agreement between these estimated values and the actual values of the children. Results: A total of 1,237 children were included in this study. The intra-class correlation coefficient of agreement between the actual weight and estimated weight by the KPRT was 0.94 compared to 0.93 when estimated by the age-based formula. The weighted kappa coefficient of the agreement between the ETT size actually used, and the size estimated by the KPRT was 0.61 compared to 0.74 when estimated by the age-based formula. The estimated ETT sizes using the KPRT were smaller than the actual size used in children under three years old, whereas it was larger for children aged eight years or more. Conclusion Our study showed that the KPRT was a dependable tool for estimating the weight and ETT size of Korean children. Future studies would be needed to augment the reliability of the KPRT in pediatric resuscitation.

Objective: The HEART score is a fast and simple cardiovascular disease (CVD) prediction tool useful in the emergency department (ED). This study evaluates the predictive value of the HEART score when applying other obesity indices such as waist circumference (WC) or waist-to-height ratio (WHtR) instead of body mass index (BMI). Methods: Data were prospectively collected from the pre-made registry of patients who had visited the ED with chest pain. Based on their final diagnoses and coronary imaging study results, patients were classified as acute coronary syndrome (ACS), non-ACS, significant coronary arterial stenosis (SCS), and non-SCS. We compared the HEART score for each group and modified it with variable obesity indices. Multivariable logistic regression and the area under the curve were calculated to determine the most suitable obesity index for the HEART score in predicting ACS or SCS. In addition, we compared the gender-dependent relationship between obesity and ACS or SCS. Results: Of the total 689 patients examined, 281 were diagnosed with ACS. The odds ratio (OR) of the HEART score for ACS was 12.1. The ORs were 13.2 and 11.2 when the HEART score was modified with WC or WHtR, respectively. Obesity was determined as the meaningful factor to predict ACS (OR: BMI, 2.38; WC, 3.39) and SCS (OR: BMI, 3.07; WC, 4.03) in women but not men. Conclusion The HEART score showed good predictive value regardless of obesity index modification. Furthermore, obesity is associated with CVD in women with chest pain, but not in men.