Purpose: Heterogeneous human epidermal growth factor receptor 2 (HER2) overexpression in gastric cancer may lead to a misdiagnosis of HER2 status. Accurate assessment of HER2 status is essential for optimal treatment as novel HER2-directed agents are being investigated in various clinical settings. We evaluated the usefulness of HER2 re-assessment following progression on first-line treatment in initially HER2-negative advanced gastric cancer (AGC) patients. Materials and Methods: We enrolled 177 patients with baseline HER2-negative AGC and performed HER2 re-assessment after progression on first-line treatment from February 2012 to June 2016 at Asan Medical Center, Seoul, Korea. The re-assessed HER2 status was analyzed with baseline HER2 status and clinical characteristics. Results: The median age was 54 years (range, 24 to 80 years), and 123 patients (69.5%) were men. Seven patients (4.0%) were HER2-positive on the re-assessment. Patients with baseline HER2 negativity confirmed by a single test (n=100) had a higher HER2-positive re-assessment rate compared to those who had repeated baseline testing (n=77) (5.0% vs. 2.6%). Among the patients with single baseline HER2 testing, the rate was higher in patients with baseline HER2 immunohistochemistry (IHC) 1+ compared to those with IHC 0 (13.4% vs. 3.6%). Conclusion Overall, 4.0% of patients with baseline HER2-negative AGC were HER2-positive on re-assessment, and the HER2-positive re-assessment rate was higher among patients who had a single test at baseline. HER2 re assessment may be considered for initially HER2-negative patients to determine their eligibility for HER2-directed therapy, particularly if their HER2 negativity was determined by a single test, especially if they had a single baseline HER2 IHC 1+ test.

Background: Fractional flow reserve (FFR) based on computed tomography (CT) has been shown to better identify ischemia-causing coronary stenosis. However, this current technology requires high computational power, which inhibits its widespread implementation in clinical practice. This prospective, multicenter study aimed at validating the diagnostic performance of a novel simple CT based fractional flow reserve (CT-FFR) calculation method in patients with coronary artery disease. Methods: Patients who underwent coronary CT angiography (CCTA) within 90 days and invasive coronary angiography (ICA) were prospectively enrolled. A hemodynamically significant lesion was defined as an FFR ≤ 0.80, and the area under the receiver operating characteristic curve (AUC) was the primary measure. After the planned analysis for the initial algorithm A, we performed another set of exploratory analyses for an improved algorithm B. Results: Of 184 patients who agreed to participate in the study, 151 were finally analyzed.Hemodynamically significant lesions were observed in 79 patients (52.3%). The AUC was 0.71 (95% confidence interval [CI], 0.63–0.80) for CCTA, 0.65 (95% CI, 0.56–0.74) for CT-FFR algorithm A (P = 0.866), and 0.78 (95% CI, 0.70–0.86) for algorithm B (P = 0.112). Diagnostic accuracy was 0.63 (0.55–0.71) for CCTA alone, 0.66 (0.58–0.74) for algorithm A, and 0.76 (0.68–0.82) for algorithm B. Conclusion This study suggests the feasibility of automated CT-FFR, which can be performed on-site within several hours. However, the diagnostic performance of the current algorithm does not meet the a priori criteria for superiority. Future research is required to improve the accuracy.

Objectives: Disability weights require regular updates, as they are influenced by both diseases and societal perceptions. Consequently, it is necessary to develop an up-to-date list of the causes of diseases and establish a survey panel for estimating disability weights. Accordingly, this study was conducted to calculate, assess, modify, and validate disability weights suitable for Korea, accounting for its cultural and social characteristics. Methods: The 380 causes of disease used in the survey were derived from the 2019 Global Burden of Disease Collaborative Network and from 2019 and 2020 Korean studies on disability weights for causes of disease. Disability weights were reanalyzed by integrating the findings of an earlier survey on disability weights in Korea with those of the additional survey conducted in this study. The responses were transformed into paired comparisons and analyzed using probit regression analysis. Coefficients for the causes of disease were converted into predicted probabilities, and disability weights in 2 models (model 1 and 2) were rescaled using a normal distribution and the natural logarithm, respectively. Results: The mean values for the 380 causes of disease in models 1 and 2 were 0.488 and 0.369, respectively. Both models exhibited the same order of disability weights. The disability weights for the 300 causes of disease present in both the current and 2019 studies demonstrated a Pearson correlation coefficient of 0.994 (p=0.001 for both models). This study presents a detailed add-on approach for calculating disability weights. Conclusions This method can be employed in other countries to obtain timely disability weight estimations.

Background: Phospholipase C-γ (PLC-γ) plays a crucial role in immune responses and is related to the pathogenesis of various inflammatory disorders. In this study, we investigated the role of PLC-γ and the therapeutic effect of the PLC-specific inhibitor U73122 using orbital fibroblasts from patients with Graves’ orbitopathy (GO). Methods: The expression of phospholipase C gamma 1 (PLCG1) and phospholipase C gamma 2 (PLCG2) was evaluated using polymerase chain reaction in GO and normal orbital tissues/fibroblasts. The primary cultures of orbital fibroblasts were treated with non-toxic concentrations of U73122 with or without interleukin (IL)-1β to determine its therapeutic efficacy. The proinflammatory cytokine levels and activation of downstream signaling molecules were determined using Western blotting. Results: PLCG1 and PLCG2 mRNA expression was significantly higher in GO orbital tissues than in controls (P<0.05). PLCG1 and PLCG2 mRNA expression was significantly increased (P<0.05) in IL-1β, tumor necrosis factor-α, and a cluster of differentiation 40 ligand-stimulated GO fibroblasts. U73122 significantly inhibited the IL-1β-induced expression of proinflammatory molecules, including IL-6, IL-8, monocyte chemoattractant protein-1, cyclooxygenase-2, and intercellular adhesion molecule-1 (ICAM-1), and phosphorylated protein kinase B (p-Akt) and p38 (p-p38) kinase in GO fibroblasts, whereas it inhibited IL-6, IL-8, and ICAM-1, and p-Akt and c-Jun N-terminal kinase (p-JNK) in normal fibroblasts (P<0.05). Conclusion PLC-γ-inhibiting U73122 suppressed the production of proinflammatory cytokines and the phosphorylation of Akt and p38 kinase in GO fibroblasts. This study indicates the implications of PLC-γ in GO pathogenesis and its potential as a therapeutic target for GO.

Objectives: . This study was conducted to evaluate the user satisfaction, efficacy, and safety of round window (RW) vibroplasty using the Vibrant Soundbridge (VSB) in patients with persistent mixed hearing loss after mastoidectomy. Methods: . The study included 27 patients (mean age, 58.7 years; age range, 28–76 years; 11 men and 16 women) with mixed hearing loss after mastoidectomy from 15 tertiary referral centers in Korea. The VSB was implanted at the RW. The Korean translation of the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire and the Korean version of the International Outcome Inventory for Hearing Aids (K-IOI-HA) questionnaire were used to evaluate user satisfaction as the primary outcome. The secondary outcome measures were audiological test results and complication rates. Results: . The mean scores for ease of communication (61.3% to 29.7% to 30.2%), reverberation (62.1% to 43.1% to 37.4%), and background noise (63.3% to 37.7% to 34.3%) subscales of the APHAB questionnaire significantly decreased after VSB surgery. The mean K-IOI-HA scores at 3 and 6 months after surgery were significantly higher than the mean preoperative score (18.6 to 27.2 to 28.1). The postoperative VSB-aided thresholds were significantly lower than the preoperative unaided and hearing aid (HA)-aided thresholds. There was no significant difference between preoperative unaided, preoperative HA-aided, and postoperative VSB-aided maximum phonetically balanced word-recognition scores. None of the 27 patients experienced a change in postoperative bone conduction pure tone average. One patient developed temporary facial palsy and two developed surgical wound infections. Conclusion . RW vibroplasty resulted in improved satisfaction and audiological test results in patients with mixed hearing loss after mastoidectomy, and the complication rate was tolerable.

Objective: The incidence of hip fractures is increasing worldwide with the aging population, causing a challenge to healthcare systems due to the associated morbidities and high risk of mortality. After hip fractures in frail geriatric patients, existing comorbidities worsen and new complications are prone to occur. Comprehensive rehabilitation is essential for promoting physical function recovery and minimizing complications, which can be achieved through a multidisciplinary approach. Recommendations are required to assist healthcare providers in making decisions on rehabilitation post-surgery. Clinical practice guidelines regarding rehabilitation (physical and occupational therapies) and management of comorbidities/complications in the postoperative phase of hip fractures have not been developed. This guideline aimed to provide evidence-based recommendations for various treatment items required for proper recovery after hip fracture surgeries. Methods Reflecting the complex perspectives associated with rehabilitation post-hip surgeries, 15 key questions (KQs) reflecting the complex perspectives associated with post-hip surgery rehabilitation were categorized into four areas: multidisciplinary, rehabilitation, community-care, and comorbidities/complications. Relevant literature from four databases (PubMed, EMBASE, Cochrane Library, and KoreaMed) was searched for articles published up to February 2020. The evidence level and recommended grade were determined according to the grade of recommendation assessment, development, and evaluation method. Results A multidisciplinary approach, progressive resistance exercises, and balance training are strongly recommended. Early ambulation, weigh-bearing exercises, activities of daily living training, community-level rehabilitation, management of comorbidities/complication prevention, and nutritional support were also suggested. This multidisciplinary approach reduced the total healthcare cost. Conclusion This guideline presents comprehensive recommendations for the rehabilitation of adult patients after hip fracture surgery.

Objective: The incidence of hip fractures is increasing worldwide with the aging population, causing a challenge to healthcare systems due to the associated morbidities and high risk of mortality. After hip fractures in frail geriatric patients, existing comorbidities worsen and new complications are prone to occur. Comprehensive rehabilitation is essential for promoting physical function recovery and minimizing complications, which can be achieved through a multidisciplinary approach. Recommendations are required to assist healthcare providers in making decisions on rehabilitation post-surgery. Clinical practice guidelines regarding rehabilitation (physical and occupational therapies) and management of comorbidities/complications in the postoperative phase of hip fractures have not been developed. This guideline aimed to provide evidence-based recommendations for various treatment items required for proper recovery after hip fracture surgeries. Methods Reflecting the complex perspectives associated with rehabilitation post-hip surgeries, 15 key questions (KQs) reflecting the complex perspectives associated with post-hip surgery rehabilitation were categorized into four areas: multidisciplinary, rehabilitation, community-care, and comorbidities/complications. Relevant literature from four databases (PubMed, EMBASE, Cochrane Library, and KoreaMed) was searched for articles published up to February 2020. The evidence level and recommended grade were determined according to the grade of recommendation assessment, development, and evaluation method. Results A multidisciplinary approach, progressive resistance exercises, and balance training are strongly recommended. Early ambulation, weigh-bearing exercises, activities of daily living training, community-level rehabilitation, management of comorbidities/complication prevention, and nutritional support were also suggested. This multidisciplinary approach reduced the total healthcare cost. Conclusion This guideline presents comprehensive recommendations for the rehabilitation of adult patients after hip fracture surgery.

Purpose: We aimed to investigate the prognostic value of serum β2-microglobulin for patients with Burkitt lymphoma (BL) and to propose a risk-stratifying classification system. Materials and Methods: A prospective registry-based cohort study of BL patients treated with dose-intensive or effective dose-adjusted chemotherapies (n=81) was conducted. Survival outcomes were compared based on previously reported risk groups and/or serum β2-microglobulin levels. A risk-stratifying classification system incorporating serum β2-microglobulin levels was proposed and validated in an independent validation cohort (n=60). Results: The median age was 47 years, and 57 patients (70.4%) were male. Patients with high serum β2-microglobulin levels (> 2 mg/L) had significantly worse progression-free survival (PFS) and overall survival (OS) (p < 0.01 for both). Serum β2-microglobulin levels further stratified patients in the low-risk and high-risk groups in terms of PFS (p=0.010 and p=0.044, respectively) and OS (p=0.014 and p=0.026, respectively). Multivariate analyses revealed that a high serum β2-microglobulin level (> 2 mg/L) was independently associated with a shorter PFS (hazards ratio [HR], 3.56; p=0.047) and OS (HR, 4.66; p=0.043). The new classification system incorporating the serum β2-microglobulin level allowed the stratification of patients into three distinct risk subgroups with 5-year OS rates of 100%, 89.5%, and 62.5%. In an independent cohort of BL, the system was validated by stratifying patients with different survival outcomes. Conclusion Serum β2-microglobulin level is an independent prognostic factor for BL patients. The proposed β2-microglobulin–based classification system could stratify patients with distinct survival outcomes, which may help define appropriate treatment approaches for individual patients.

Purpose: We aimed to investigate the prognostic value of serum β2-microglobulin for patients with Burkitt lymphoma (BL) and to propose a risk-stratifying classification system. Materials and Methods: A prospective registry-based cohort study of BL patients treated with dose-intensive or effective dose-adjusted chemotherapies (n=81) was conducted. Survival outcomes were compared based on previously reported risk groups and/or serum β2-microglobulin levels. A risk-stratifying classification system incorporating serum β2-microglobulin levels was proposed and validated in an independent validation cohort (n=60). Results: The median age was 47 years, and 57 patients (70.4%) were male. Patients with high serum β2-microglobulin levels (> 2 mg/L) had significantly worse progression-free survival (PFS) and overall survival (OS) (p < 0.01 for both). Serum β2-microglobulin levels further stratified patients in the low-risk and high-risk groups in terms of PFS (p=0.010 and p=0.044, respectively) and OS (p=0.014 and p=0.026, respectively). Multivariate analyses revealed that a high serum β2-microglobulin level (> 2 mg/L) was independently associated with a shorter PFS (hazards ratio [HR], 3.56; p=0.047) and OS (HR, 4.66; p=0.043). The new classification system incorporating the serum β2-microglobulin level allowed the stratification of patients into three distinct risk subgroups with 5-year OS rates of 100%, 89.5%, and 62.5%. In an independent cohort of BL, the system was validated by stratifying patients with different survival outcomes. Conclusion Serum β2-microglobulin level is an independent prognostic factor for BL patients. The proposed β2-microglobulin–based classification system could stratify patients with distinct survival outcomes, which may help define appropriate treatment approaches for individual patients.

Coronavirus disease 2019 (COVID-19) is a highly contagious viral disease that is caused by the novel virus Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). COVID-19 has become pandemic since December 2019, when the first case developed in Wuhan, China. Patients receiving hemodialysis are more vulnerable to viral transmission because their immune functions are impaired and they receive treatment within a narrow space. Calling on previous experience with Middle East Respiratory Syndrome during the 2015 outbreak, the joint committee of the Korean Society of Nephrology and the Korean Society of Dialysis Therapy quickly formed a COVID-19 task force team to develop a manual before the first index case was diagnosed in the hemodialysis unit. This special article introduces clinical practice guidelines to prevent secondary transmission of COVID-19 within hemodialysis facilities, which were developed to protect patients, healthcare workers, and caregivers from this highly transmissible virus. The areas of infection control covered by these guidelines include standard precautions, performing dialysis therapy for confirmed or suspected cases, performing cohort isolation for contact patients, and disease monitoring and contact surveillance. We hope these guidelines help healthcare workers and hemodialysis patients around the world cope with the COVID-19 pandemic.