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: 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: 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.

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.

Purpose: To investigate the characteristics of HER2-positive breast cancer according to HER2 low (2+) or high (3+) classification using immunohistochemistry (IHC). Methods: Data were collected from 205 HER2-positive breast cancer patients in the final assay, regardless of IHC or in situ hybridization (ISH). We thus classified patients into two groups: HER2 2+/low and HER2 3+/high based on the IHC assay. We subsequently compared the clinical and pathological characteristics between groups. Results: The median patient age was 49 years in the HER2 2+/low group and 53 years in the HER2 3+/high group. We observed a significantly lower Allred score for estrogen receptor (ER) and progesterone receptor (PR) (0-6) (p<0.001), less lymphatic invasion (LI), (p=0.010), neural invasion (p=0.041), higher Ki-67 (p=0.001), and lower Bcl-2 (p<0.001) in the HER2 3+/high group than in the HER2 2+/low group. Lymph node recurrence was more frequently observed in the HER2 2+/low group than in HER2 3+/high group (p=0.005). Disease-free survival (DFS) was better in the HER2 3+/high group than in the HER2 2+/low group (p=0.028), but there were no significant differences in overall survival between the groups (p=0.233). Conclusion The HER2 3+/high group was associated with lower ER and PR expression, less LI, higher Ki-67, and lower Bcl-2 than that in HER2 2+/low group in HER2-positive breast cancer. Furthermore, compared to the HER2 2+/low group, the HER2 3+/high group had an improved DFS.

Purpose: To investigate the characteristics of HER2-positive breast cancer according to HER2 low (2+) or high (3+) classification using immunohistochemistry (IHC). Methods: Data were collected from 205 HER2-positive breast cancer patients in the final assay, regardless of IHC or in situ hybridization (ISH). We thus classified patients into two groups: HER2 2+/low and HER2 3+/high based on the IHC assay. We subsequently compared the clinical and pathological characteristics between groups. Results: The median patient age was 49 years in the HER2 2+/low group and 53 years in the HER2 3+/high group. We observed a significantly lower Allred score for estrogen receptor (ER) and progesterone receptor (PR) (0-6) (p<0.001), less lymphatic invasion (LI), (p=0.010), neural invasion (p=0.041), higher Ki-67 (p=0.001), and lower Bcl-2 (p<0.001) in the HER2 3+/high group than in the HER2 2+/low group. Lymph node recurrence was more frequently observed in the HER2 2+/low group than in HER2 3+/high group (p=0.005). Disease-free survival (DFS) was better in the HER2 3+/high group than in the HER2 2+/low group (p=0.028), but there were no significant differences in overall survival between the groups (p=0.233). Conclusion The HER2 3+/high group was associated with lower ER and PR expression, less LI, higher Ki-67, and lower Bcl-2 than that in HER2 2+/low group in HER2-positive breast cancer. Furthermore, compared to the HER2 2+/low group, the HER2 3+/high group had an improved DFS.

Objective: Many previous studies have reported relationships between particulate matter < 10 μm (PM10) and asthma in emergency department (ED) settings, but few have examined its effect on cerebrovascular diseases. We evaluate the “Lag effect” between PM10 and asthma, chronic obstructive pulmonary disease (COPD), myocardial infarction (MI), and ischemic and hemorrhagic stroke among patients that visited an ED. Methods: This study was retrospectively conducted on 96,077 patients that visited one of the 137 EDs in Seoul, Incheon, and Gyeonggi Province in South Korea in 2017. Medical information and 10th revision International Classification of Disease codes were obtained from the National Emergency Department Information System and PM10 levels from AirKorea. We used Poisson regression analysis to evaluate the lag effects of PM10 on diseases of interest. “Lag day 0” was defined as the day when PM10 > 80 μg/m3, and the PM10 values on the 5 following days were recorded. To assess the cumulative effects of PM10, we calculated relative risk (RR) by analyzing the cumulative effects over 6 days (lag days 0 to 5). Results: Asthma, COPD, and ischemic stroke patients (< 65 years old) showed a positive correlation between PM10 (asthma on lag day 5: RR, 2.587; 95% confidence interval [CI], 2.001-3.344; COPD on lag day 4: RR, 3.727; 95% CI, 2.988-4.650; and ischemic stroke on lag day 4: RR, 1.573; 95% CI, 1.168-2.118). MI in those≥65 showed the highest RR on lag day 1 (RR, 1.471; 95% CI, 1.042-2.077). Hemorrhagic stroke was not found to be significantly correlated with PM10 in either age group. Conclusion An increase in PM10 is associated with ED visits by patients<65 years old with asthma, COPD, or ischemic stroke, and with MI for those≥65 years.