Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.

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: Finasteride and dutasteride are used to treat benign prostatic hyperplasia (BPH) and reduce the risk of developing prostate cancer. Finasteride blocks only the type 2 form of 5-alpha-reductase, whereas dutasteride blocks both type 1 and 2 forms of the enzyme. Previous studies suggest the possibility that dutasteride may be superior to finasteride in preventing prostate cancer. We directly compared the effects of finasteride and dutasteride on the risk of prostate cancer in patients with BPH using a pooled analysis of 15 real-world databases. Materials and Methods: We conducted a multicenter, cohort study of new-users of finasteride and dutasteride. We include patients who were prescribed 5 mg finasteride or dutasteride for the first time to treat BPH and had at least 180 days of prescription. We excluded patients with a history of prostate cancer or a prostate-specific antigen level ≥ 4 ng/mL before the study drug prescription. Cox regression analysis was performed to examine the hazard ratio (HR) for prostate cancer after propensity score (PS) matching. Results: A total of 8,284 patients of new-users of finasteride and 8,670 patients of new-users of dutasteride were included across the 15 databases. In the overall population, compared to dutasteride, finasteride was associated with a lower risk of prostate cancer in both on-treatment and intent-to-treat time-at-risk periods. After 1:1 PS matching, 4,897 patients using finasteride and 4,897 patients using dutasteride were enrolled in the present study. No significant differences were observed for risk of prostate cancer between finasteride and dutasteride both on-treatment (HR=0.66, 95% confidence interval [CI]: 0.44–1.00; p=0.051) and intent-to-treat time-at-risk periods (HR=0.87, 95% CI: 0.67–1.14; p=0.310). Conclusions Using real-world databases, the present study demonstrated that dutasteride was not associated with a lower risk of prostate cancer than finasteride in patients with BPH.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Background: Small cell lung cancer (SCLC) is called ‘smoker’s disease’ because it is strongly associated with smoking and most cases occur in smokers. However, it can also occur in never smokers. We investigated the clinical features of never smokers with SCLC and compared their treatment outcomes with those of smokers with SCLC. Methods: We retrospectively reviewed the clinical data of patients who had proven SCLC and had received chemotherapy at a single cancer center between July 2002 and April 2021. Results: Of 1,643 patients, 1,416 (86.2%) were enrolled in this study. A total of 162 (11.4%) and 1,254 (88.6%) patients were never smokers and smokers, respectively. There were more female never smokers than smokers (n=130; 80.2% vs. 79, 6.3%, p=0.000), and the incidence of ischemic heart disease was lower among never smokers than among smokers (4/1,416, [2.5%] vs. 83/1,416 [6.6%], p=0.036). Never smokers showed less symptoms at diagnosis than smokers (80.9% vs. 87.2%, p=0.037); however, they showed more toxicity after first-line treatment (61.7% vs. 47.8%, p=0.001). The objective response rate (ORR) was significantly higher in never smokers (74.1% vs. 59.6%, p=0.000). In the multivariate analysis, never smoking and second-line treatment were associated with a better ORR. However, progression-free survival and overall survival were not significantly different between never smokers and smokers. Conclusion In conclusion, never smokers accounted for 11.4% of patients with SCLC. They had distinguishing clinical characteristics and showed better chemotherapeutic responses than smokers.

Background: s/Aims: In hepatocellular carcinoma (HCC), which exhibits high mortality and recurrence rates globally, the traits of cancer stem cells (CSCs) that significantly influence recurrence and metastasis are not well understood. CSCs are self-renewing cell types identified in most liquid and solid cancers, contributing to tumor initiation, growth, resistance, recurrence, and metastasis following chemo-radiotherapy or trans-arterial chemoembolization therapy. Methods: CSCs are classified based on the expression of cell surface markers such as CD133, which varies depending on the tumor type. Proteomic analysis of liver cancer cell lines with cancer stem cell potential and HCC cancer cell lines lacking stem cell propensity was conducted to compare and analyze specific expression patterns. Results: Proteomic profiling and enrichment analysis revealed higher expression of the calcium-binding protein S100 family in CD133+ Huh7 cells than in CD133- or wild-type cells. Furthermore, elevated expression of S100 family members was confirmed in an actual CD133+ liver cancer cell line via protein-protein network analysis and quantitative polymerase chain reaction (qPCR). Conclusion The S100 family members are not only new markers of cancer stem cells but will also assist in identifying new treatment strategies for CSC metastasis and tumor advancement.

Background: The diagnosis of tuberculous pleural effusion (TPE) often relies on pleural fluid adenosine deaminase (ADA) levels. The diagnostic utility of ADA, however, is influenced by the prevalence of tuberculosis (TB) in local populations. Malignant pleural effusion (MPE) cases can exhibit moderately elevated ADA levels comparable to those seen in TPE. As population aging potentially impacts ADA levels, global TB incidence is decreasing whereas the burden of malignancy is on the rise. Consequently, epidemiological shifts and temporal changes in ADA distribution complicate the differential diagnosis between TPE and MPE when ADA levels are within the 40–70 IU/L range. Nonetheless, data specific to this subset are scarce. Methods: This retrospective study included consecutive patients aged > 18 years with confirmed TPE and MPE, spanning from 2012 to 2023. ADA levels in pleural fluid were categorized into three groups: < 40 IU/L, 40–70 IU/L, and > 70 IU/L. The study examined annual trends in the frequency of new cases and ADA level distributions over time and identified discriminating factors between TPE and MPE in cases with ADA levels of 40–70 IU/L. Results: In total, 297 TPE and 369 MPE cases were included in this study. Over the study period, the frequency of TPE progressively declined, while that of MPE increased. In the most recent four-year period, new TPE and MPE cases with ADA levels of 40–70 IU/L occurred at comparable numbers. Multivariable analysis identified pleural fluid carcinoembryonic antigen (CEA) levels and the number of focal pleural nodules as independent predictors for MPE. Specifically, the presence of either CEA levels > 15.7 ng/mL or more than eight pleural nodules yielded the highest diagnostic accuracy with a sensitivity of 88%, specificity of 100%, and an area under the curve of 0.95. Conclusion The differential diagnosis between TPE and MPE with pleural ADA levels of 40–70 IU/L has become increasingly critical due to evolving epidemiological patterns and ADA distribution changes over time. Pleural fluid CEA levels and the characteristics of pleural nodules may offer valuable guidance in distinguishing between TPE and MPE within this diagnostic gray zone.

Background: Factors influencing the decline in forced expiratory volume in one second (FEV1 )/forced vital capacity (FVC) for chronic obstructive pulmonary disease (COPD) progression remain uncertain. We aimed to identify risk factors associated with rapid FEV1 / FVC decline in patients with COPD. Methods: This multi-center observational study was conducted from January 2012 to December 2022. Eligible patients were monitored with symptoms, spirometric tests, and treatment patterns over 3 years. Rapid FEV1 /FVC decliners were defined as the quartile of patients exhibiting the highest annualized percentage decline in FEV1 /FVC. Results: Among 1,725 patients, 435 exhibited rapid FEV1 /FVC decline, with an annual change of −2.5%p (interquartile range, −3.5 to −2.0). Rapid FEV1 /FVC decliners exhibited lower body mass index (BMI), higher smoking rates, elevated post-bronchodilator (BD) FEV1 , higher post-BD FEV1 / FVC, and a lower prevalence of Staging of Airflow Obstruction by Ratio (STAR) stage IV. Rapid FEV1 /FVC decline was not linked to the annual exacerbation rate, but there was an association with symptom deterioration and FEV1 decline. In multivariable analyses, low BMI, current smoking, increased modified Medical Research Council dyspnoea score, low post-BD FEV1 , low STAR stage, high forced mid-expiratory flow (FEF 25-75% ), accelerated FEV1 decline, and not initiating dual BD therapy were identified as independent risk factors for rapid FEV1 /FVC decline. Conclusion We identified the risk factors for rapid FEV1 /FVC decline, including BMI, smoking, symptoms deterioration, FEV1 decline, and adherence to standard inhaler treatment. Our findings underscore the potential benefits of maintaining consistent use of long-acting beta-agonist/long-acting muscarinic antagonist even in the presence of worsening symptoms, in attenuating FEV1 /FVC decline.

Background: Despite the necessity of long-term management for fracture risk reduction, adherence to osteoporosis pharmacotherapy remains poor. We investigated the factors influencing adherence to pharmacotherapy among Korean patients with osteoporosis, with a particular focus on treatment with bisphosphonates (BPs). Methods: Data from 725,313 osteoporosis patients newly prescribed BPs or selective estrogen receptor modulators (SERMs) between 2012 and 2014, obtained from the Korean National Health Insurance Service, were analyzed. Adherence was assessed based on compliance and persistence over a two-year period, with factors associated with adherence identified using multivariable logistic regression. Results: Only 14.8% of the patients who started BPs or SERMs sustained medication compliance, with 15.8% persisting with treatment over the two-year follow-up. Compared with BPs, patients receiving SERMs showed better compliance and persistence (odds ratios [ORs], 1.44 and 1.48, respectively; P < 0.001); while patients receiving intravenous administration showed higher compliance and persistence (ORs, 2.08 and 1.76, respectively; P < 0.001) compared with those taking oral medications. Patients placed on a quarterly dosing schedule showed improved compliance and persistence (ORs, 1.55 and 1.31, respectively; P < 0.001) compared with those on other dosing intervals. Male gender, advanced age, living outside metropolitan areas, receiving treatment in non-general hospitals, and a history of previous fractures were associated with poorer two-year adherence. Conclusion This study underscores the complex nature of medication adherence among Korean osteoporosis patients, particularly those treated with BPs. These findings accordingly indicate that medication with more convenient administration regimens and fewer side effects, coupled with suitable follow-up durations, could contribute to enhancing treatment adherence.