Purpose: Radiotherapy (RT) remains a cornerstone of curative treatment for localized and locally advanced prostate cancer. However, dose escalation to improve tumor control is often constrained by the proximity of the rectum, which increases the risk of gastrointestinal (GI) and genitourinary toxicities. Biodegradable rectal spacers inserted between the prostate and rectum have emerged as an effective approach to reduce rectal radiation exposure. This guideline provides evidence-based recommendations on indications, contraindications, procedural standards, and clinical management for biodegradable rectal spacer insertion during prostate cancer RT. Materials and Methods: This guideline was developed by a multidisciplinary expert panel through a systematic review of the literature, analysis of international guidelines (National Comprehensive Cancer Network, European Association of Urology, American Society for Radiation Oncology), and expert consensus among radiation oncologists, radiologists, and urologists with clinical experience in spacer insertion. The strength of each recommendation and the level of evidence were classified according to the modified GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system. Results: Spacer insertion is conditionally recommended (Grade C, Level I) for patients receiving definitive external-beam RT without rectal invasion. It reduces the high-dose rectal irradiation volume (V70–75) by >50%, decreases acute GI toxicity, and helps maintain bowel-related quality of life. However, the benefit for late severe toxicity (grade 2 or higher) remains debated in recent meta-analyses. Contraindications include rectal invasion, anatomical inaccessibility, infection, and material hypersensitivity. Procedures should be performed under local anesthesia in a sterile environment by trained physicians. Short-course antibiotics and simulator-based training, including completion of multiple supervised cases, are advised. Conclusion Biodegradable rectal spacer insertion is clinically validated and effective in reducing acute rectal toxicity. Although pivotal trials demonstrated a favorable procedural safety profile, real-world postmarket data include reports of rare but severe procedural complications. This guideline provides standardized recommendations tailored to Korean clinical practice while remaining consistent with international standards, emphasizing the importance of operator training and careful patient selection.

In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

Purpose: Based on the KEYNOTE-522 study, neoadjuvant pembrolizumab plus chemotherapy has become the standard treatment for early-stage triple-negative breast cancer (TNBC).This study evaluated the real-world efficacy, safety, and predictors of pathologic complete response (pCR) in Korean patients. Methods: We conducted a retrospective cohort study of 174 patients with early-stage TNBC who received the KEYNOTE-522 regimen (neoadjuvant pembrolizumab plus paclitaxel and carboplatin, followed by doxorubicin and cyclophosphamide) at a tertiary cancer center between August 2022 and July 2024. We assessed the primary endpoints, including pCR rate and event-free survival (EFS). We performed univariable and multivariable logistic regression analyses to identify independent predictors of pCR. Results: The median patient age was 50 years (range, 24–74 years). The clinical stages were II and III in 79.3% and 20.1% of patients, respectively, and 10.9% had clinical N3 disease. The overall pCR rate was 62.1%, and the N3 subgroup had a pCR rate of 47.4%. On multivariable analysis, high baseline Ki-67 expression (≥ median, 75%) was significantly associated with pCR (odds ratio, 2.84; 95% confidence interval, 1.45 to 5.66; p = 0.002). At a median followup of 18.4 months, the 12-month EFS rate was 97.4%, with significantly superior outcomes observed in patients who achieved pCR compared with those who did not achieve pCR (100% vs. 93.1%, p = 0.007). The treatment completion rate was 92.0%, and immune-related adverse events occurred in 13.8% of patients. Conclusion In this real-world analysis of one of the largest Asian cohorts of patients with earlystage TNBC treated with neoadjuvant pembrolizumab, the KEYNOTE-522 regimen demonstrated substantial efficacy and manageable toxicity, consistent with the original trial findings.

Common variable immunodeficiency (CVID) is a heterogeneous primary immunodeficiency characterized by reduced levels of immunoglobulin (Ig)G, with or without IgA and/or IgM deficiency, and hypogammaglobulinemia. Clinical manifestations are diverse, ranging from recurrent infections to autoimmune and allergic diseases. While CVID has been rarely reported in the Korean population, particularly in adults, we report 2 adult cases of CVID comorbid with asthma and Behcet’s disease. The first case of a 53-year-old with severe allergic asthma and chronic rhinosinusitis experienced recurrent respiratory infections, stomatitis, and cystitis requiring frequent antibiotic treatment. Laboratory findings indicated a T2-high asthma phenotype, with elevated serum total IgE specific IgE to dog hair and fractional exhaled nitric oxide. Immunological evaluation revealed decreased serum IgG (including IgG1 and IgG2), along with hypogammaglobulinemia. She had been treated with regular anti-IgE antibody therapy and intravenous immunoglobulin replacement therapy (IVIGRT). The second case of a 38-year-old with Behçet’s disease and uveitis had bronchial asthma and rhinitis that were exacerbated by recurrent infections despite standard asthma therapy. Laboratory findings revealed a T2-low phenotype and a marked reduction in serum IgG (including IgG1, IgG2, and IgG4), and hypogammaglobulinemia, consistent with CVID.IVIGRT effectively reduced asthma exacerbations and infection episodes in both cases. These cases highlight the clinical heterogeneity of CVID and its potential overlap with allergic and autoimmune diseases. Immunological evaluation of underlying immunodeficiency should be considered in adult patients with asthma who present with frequent exacerbations and recurrent infections. Early diagnosis and IVIGRT can prevent complications and improve outcomes.

Background: A novel botulinum toxin type A (Protoxin; Protox Inc.) has been developed. Objective: To evaluate the efficacy and safety of the newly developed Protoxin compared to the approved drug onabotulinumtoxinA (OBoNT) in moderate to severe glabellar lines. Methods: Adults with a glabellar line Facial Wrinkle Scale (FWS) score of 2 (moderate) or 3 (severe) were enrolled in the study. Subjects were randomized in a 1:1 ratio to receive either Protoxin or OBoNT. A total of 20 units of botulinum toxin was injected at five sites in the glabellar region (4 units at each site). FWS scores were assessed at baseline and at weeks 4, 8, 12, and 16 post-injection. The primary endpoint was the proportion of subjects at week 4 who had a reduction of 2 or more points in FWS and a final score of 0 (none) or 1 (mild). Results: A total of 274 subjects were randomized, of whom 78.1% were female. At week 4 post-treatment, the improvement rate of glabellar lines was 62.22% in the Protoxin group and 62.96% in the OBoNT group. The lower limit of the two-sided 95% confidence interval (−12.24%) exceeded the −15% margin, confirming the non-inferiority of the new drug. Safety profiles were comparable between the two groups. Conclusion Protoxin demonstrated efficacy and safety profiles comparable to those of OBoNT in the treatment of moderate to severe glabellar lines.

Purpose: Despite the global paradigm emphasizing earlier and more aggressive intervention for youth-onset type 2 diabetes mellitus (T2DM), metformin and insulin are the only drugs approved for Korean adolescents. We investigated the incidence of complications, changes in glycemic control during the transition period, the effect of second-line antidiabetic agents on glycemic control in young adults with youth-onset T2DM. Methods: Eighty-four patients diagnosed with T2DM at Seoul National University Children's Hospital between January 2001 and July 2023, before age 18 (47 males; mean age, 14 years) with available glycated hemoglobin (HbA1c) data from at least 2 distinct ages between 19 and 22 years old were retrospectively enrolled. Results: At the last follow-up (mean age, 24.9 years; median follow-up, 9.6 years), complications were found in 33.7% (nephropathy, 25.3%; eye disease, 20.6%), and 83% required insulin or second-line agents. During the transition period, HbA1c levels decreased from 8.2% at age 19 to 7.7% at age 22 (P<0.01), with greater improvements in females, those diagnosed before age 15, and those with HbA1c levels ≥7% at age 19. HbA1c level decreased significantly at 1 year after the addition of second-line medications (P=0.03) and at the last visit (P=0.03) compared with baseline. Conclusion Glycemic control improved during the transition period among youth-onset T2DM patients. Given the high incidence of complications and the beneficial effects of second-line agents on glycemic control, there is an urgent need to expand the range of approved second-line agents, along with broader insurance coverage in adolescence.

Purpose: Although gastric cancer (GC) exhibits significant genomic heterogeneity, the clinical implications of its immune microenvironment remain poorly understood. Materials and Methods: We retrospectively evaluated patients with GC who underwent gastrectomies between 2011 and 2014. The tumors were analyzed for Epstein–Barr virus (EBV), microsatellite instability-high (MSI-H), tumor-infiltrating lymphocytes (CD3), tumor-associated macrophages (CD68 and CD163), and programmed death-ligand 1 (PD-L1) expression. Tumors were classified using the modified The Cancer Genome Atlas scheme, and their clinical characteristics were compared. Results: A total of 567 patients were classified into EBV (6%), MSI-H (10%), chromosomal instability-like (36%), and genomically stable-like (48%) subtypes. EBV tumors exhibited the highest PD-L1 expression (85%) and immune infiltration by CD3+ T cells (86%), CD68+ macrophages (58%), and CD163+ macrophages (40%). High CD68+ macrophage tumors were associated with advanced stages and worse 5-year disease-free survival (83% vs. 95%; P<0.001);however, this association was not independently significant after adjusting for the tumor-nodemetastasis stage. PD-L1 expression did not significantly affect the survival outcomes. Conclusions GC subtypes have distinct immune microenvironments that influence prognosis. Our findings highlight the prognostic and therapeutic potential of immune profiling in GC.

Background: Hair drying is a routine cosmetic practice; however, excessive heat exposure and non-uniform airflow can compromise cuticle integrity, degrade hair sensory properties, and induce scalp discomfort. This study aimed to (i) identify a practical thermal window that minimizes perturbation of hair fiber surface and quantify late-stage thermal amplification during the drying process using percentage-based analysis. Methods: Temperature-dependent hair fiber surface morphology was examined by scanning electron microscopy (SEM) after controlled exposure to 41°C, 60°C, 80°C, and 90°C using virgin and chemically damaged hair. The drying efficacy was assessed using the surface and internal moisture indices under airflow shaping (test) and uniform airflow (control) conditions. Hair fluttering (maximum angular displacement) was evaluated before and after drying under warm-cool alternating (60°C-80°C) versus constant hot airflow (80°C). Results: SEM revealed temperature-dependent cuticle disruption, with markedly greater surface perturbation at 90°C than at 80°C. Infrared thermography demonstrated pronounced late-stage thermal amplification: at 150 seconds, the surface temperature increased by 295% (from 24.2°C to 72.0°C) at 90°C, compared with 207% (from 24.2°C to 50.7°C) at 80°C. Airflow shaping promoted preferential surface moisture removal (–13.6%) while limiting internal dehydration (–9.4%), whereas the control condition exhibited minimal surface drying (–4.6%) but substantial internal moisture loss (–22.2%). Warm-cool modulation increased hair fluttering by +11.0%, whereas constant hot airflow reduced it (–3.7%). Conclusion These findings indicate that spatial and temporal control of heat delivery represents a clinically relevant design strategy beyond the nominal temperature specification in hair-drying devices.

Background: The discovery and evaluation of reliable biomarkers of vitiligo are important;however, no clinically established serological markers exist for predicting the clinical prognosis of vitiligo. Objective: To investigate the levels of SOX10 and lamin A/C antibodies in the serum of patients diagnosed with vitiligo. Methods: In this multicenter prospective study, blood serum samples were collected from adult vitiligo patients. The levels of SOX10 and lamin A/C antibodies were analyzed by direct sandwich enzyme-linked immunosorbent assay. Antibody levels between the groups were compared according to disease activity and subtype. Results: A total of 80 patients (46 females; median age 60 years) were enrolled, including 56 (70%) with nonsegmental vitiligo and 27 (33.7%) with active disease. Positivity for SOX10 and lamin A/C antibodies was observed in 35.0% and 71.3% of patients, respectively. SOX10 positivity was significantly higher in active vitiligo than in stable vitiligo (59.3% vs. 24.5%; p=0.003), whereas lamin A/C positivity did not show significant difference (77.8% vs. 69.8%; p=0.60).No significant associations were found between SOX10 or lamin A/C status and the subtype, extent, or the presence of antinuclear antibody, anti-thyroid peroxidase, or anti-thyroglobulin (all p>0.05). Conclusion SOX10 antibody could be a potential marker for assessing disease activity in vitiligo. The increased production of SOX10 antibodies in the serum may be due to the underlying death or turnover of SOX10 containing cells under active autoimmune response.

Background: Rosacea is a chronic inflammatory disorder characterized by flushing, erythema, papules/pustules, and telangiectasia. Several clinical studies have investigated the efficacy of botulinum neurotoxin A (BoNT/A) in the treatment of rosacea, but its mechanism of action remains unclear. Objective: This study aims to examine the potential role of BoNT/A in a mouse model of rosacea-like skin lesions induced by the 37-amino acid C-terminal cathelicidin peptide (LL-37). Methods: Mice were randomly divided into 4 groups: Control, LL-37, LL-37 + BoNT/A, and LL-37 + dexamethasone. Results: BoNT/A treatment alleviated skin damage, reduced skin thickness, and decreased mast cell infiltration. Furthermore, BoNT/A improved redness score severity and redness area while enhancing skin barrier function by suppressing transepidermal water loss and increasing skin hydration. At the molecular level, BoNT/A decreased the mRNA levels of interleukin (IL)-6 and tumor necrosis factor-α, which are known as pro-inflammatory cytokines. It also downregulated the expression of pyrin domain-containing protein 3, caspase-1, and IL-1 beta in the LL-37-injected dorsal skin. Furthermore, BoNT/A prevented LL-37-mediated upregulation of neurovascular-associated factors, including CD31, transient receptor potential vanilloid 1, calcitonin-related polypeptide alpha, vascular endothelial growth factor, chymase 1, and tryptase alpha/beta 1. Conclusion These results indicate that BoNT/A effectively alleviates inflammatory and vascular responses in a rosacea mouse model, highlighting its potential as a promising preventive approach for rosacea.