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.

Background and Objectives: Primary prevention (PP) implantable cardioverter-defibrillator (ICD) therapy for ischemic cardiomyopathy (ICM) is underused in Asian countries, including South Korea. Both clinical and hospital factors may influence appropriate ICD use. We evaluated whether determinants of PP ICD implantation differ by hospital implantation volume. Methods: In this prospective, multicenter observational registry (blinded for review), patients eligible for PP ICD were enrolled. Factors associated with ICD implantation—clinical characteristics and hospital-level systems—were examined across 4 large-volume hospitals (≥ 15 implants during the study) and 12 small-volume hospitals (< 15). Multivariable logistic regression identified independent predictors. Results: Among 3,083 ICM patients (2,403 men; median age 70 years), PP ICD implantation rates were 10.8% in large-volume and 5.7% in small-volume hospitals. Across groups, male sex and chronic kidney disease independently predicted ICD implantation. Regarding hospital factors, non-monetary incentives for referral were the sole independent predictor in large-volume centers (odds ratio [OR], 3.55; 95% confidence interval [CI], 2.07–6.10;P < 0.001). In small-volume centers, heart failure conferences (OR, 12.73; 95% CI, 1.72–94.37;P = 0.013), structured education systems (OR, 11.72; 95% CI, 2.45–56.12; P = 0.02), and pacemaker clinics (OR, 11.4; 95% CI, 2.24–58.39; P = 0.003) were independently associated with implantation. Conclusions Clinical predictors of PP ICD use were consistent across hospital volumes, but hospital-level determinants differed. Referral incentives characterized large-volume centers, whereas conferences, education systems, and pacemaker clinics were key in smallvolume centers. Tailored institutional strategies by hospital volume may help close the PP ICD underuse gap and improve evidence-based implementation.

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.

Purpose: This study aimed to compare the short-term outcomes and safety profiles of androgen-deprivation therapy (ADT)+abiraterone/prednisone with those of ADT+docetaxel in patients with de novo metastatic hormone-sensitive prostate cancer (mHSPC). Materials and Methods: A web-based database system was established to collect prospective cohort data for patients with mHSPC in Korea. From May 2019 to November 2022, 928 patients with mHSPC from 15 institutions were enrolled. Among these patients, data from 122 patients who received ADT+abiraterone/prednisone or ADT+docetaxel as the primary systemic treatment for mHSPC were collected. The patients were divided into two groups: ADT+abiraterone/prednisone group (n=102) and ADT+docetaxel group (n=20). We compared the demographic characteristics, medical histories, baseline cancer status, initial laboratory tests, metastatic burden, oncological outcomes for mHSPC, progression after mHSPC treatment, adverse effects, follow-up, and survival data between the two groups. Results: No significant differences in the demographic characteristics, medical histories, metastatic burden, and baseline cancer status were observed between the two groups. The ADT+abiraterone/prednisone group had a lower prostate-specific antigen (PSA) progression rate (7.8% vs. 30.0%; p=0.011) and lower systemic treatment discontinuation rate (22.5% vs. 45.0%; p=0.037). No significant differences in adverse effects, oncological outcomes, and total follow-up period were observed between the two groups. Conclusions ADT+abiraterone/prednisone had lower PSA progression and systemic treatment discontinuation rates than ADT+docetaxel. In conclusion, further studies involving larger, double-blinded randomized trials with extended follow-up periods are necessary.

Purpose: Heart failure (HF) and atrial fibrillation (AF) frequently coexist, with over 50% patients with HF having AF, while onethird of those with AF develop HF. Differences in obesity-mediated association between HF and HF-related AF among Asians and Europeans were evaluated. Materials and Methods: Using the Korean National Health Insurance Service-Health Screening (K-NHIS-HealS) cohort and the UK Biobank, we included 394801 Korean and 476883 UK adults, respectively aged 40–70 years. The incidence and risk of HF were evaluated based on body mass index (BMI). Results: The proportion of obese individuals was significantly higher in the UK Biobank cohort than in the K-NHIS-HealS cohort (24.2% vs. 2.7%, p<0.001). The incidence of HF and HF-related AF was higher among the obese in the UK than in Korea. The risk of HF was higher among the British than in Koreans, with adjusted hazard ratios of 1.82 [95% confidence interval (CI), 1.30–2.55] in KNHIS-HealS and 2.00 (95% CI, 1.69–2.37) in UK Biobank in obese participants (p for interaction <0.001). A 5-unit increase in BMI was associated with a 44% greater risk of HF-related AF in the UK Biobank cohort (p<0.001) but not in the K-NHIS-HealS cohort (p=0.277). Conclusion Obesity was associated with an increased risk of HF and HF-related AF in both Korean and UK populations. The higher incidence in the UK population was likely due to the higher proportion of obese individuals.

Purpose: In men with metastatic castration-resistant prostate cancer (mCRPC), new bone lesions are sometimes not properly categorized through a confirmatory bone scan, and clinical significance of the test itself remains unclear. This study aimed to demonstrate the performance rate of confirmatory bone scans in a real-world setting and their prognostic impact in enzalutamide-treated mCRPC. Materials and Methods: Patients who received oral enzalutamide for mCRPC during 2014-2017 at 14 tertiary centers in Korea were included. Patients lacking imaging assessment data or insufficient drug exposure were excluded. The primary outcome was overall survival (OS). Secondary outcomes included performance rate of confirmatory bone scans in a real-world setting. Kaplan-Meier analysis and multivariate Cox regression analysis were performed. Results: Overall, 520 patients with mCRPC were enrolled (240 [26.2%] chemotherapy-naïve and 280 [53.2%] after chemotherapy). Among 352 responders, 92 patients (26.1%) showed new bone lesions in their early bone scan. Confirmatory bone scan was performed in 41 patients (44.6%), and it was associated with prolonged OS in the entire population (median, 30.9 vs. 19.7 months; p < 0.001), as well as in the chemotherapy-naïve (median, 47.2 vs. 20.5 months; p=0.011) and post-chemotherapy sub-groups (median, 25.5 vs. 18.0 months; p=0.006). Multivariate Cox regression showed that confirmatory bone scan performance was an independent prognostic factor for OS (hazard ratio 0.35, 95% confidence interval, 0.18 to 0.69; p=0.002). Conclusion Confirmatory bone scan performance was associated with prolonged OS. Thus, the premature discontinuation of enzalutamide without confirmatory bone scans should be discouraged.

Background: This study aimed to generate a Z score calculation model for coronary artery diameter of normal children and adolescents to be adopted as the standard calculation method with consensus in clinical practice. Methods: This study was a retrospective, multicenter study that collected data from multiple institutions across South Korea. Data were analyzed to determine the model that best fit the relationship between the diameter of coronary arteries and independent demographic parameters. Linear, power, logarithmic, exponential, and square root polynomial models were tested for best fit. Results: Data of 2,030 subjects were collected from 16 institutions. Separate calculation models for each sex were developed because the impact of demographic variables on the diameter of coronary arteries differs according to sex. The final model was the polynomial formula with an exponential relationship between the diameter of coronary arteries and body surface area using the DuBois formula. Conclusion A new coronary artery diameter Z score model was developed and is anticipated to be applicable in clinical practice. The new model will help establish a consensus-based Z score model.

Purpose: Most bee sting injuries are benign, although sometimes they can result in life threatening outcomes, such as anaphylaxis and death. The purpose of this study was to investigate the epidemiologic status of bee sting injuries in Korea and to identify risk factors associated with severe systemic reactions (SSRs). Materials and Methods: Cases were extracted from a multicenter retrospective registry for patients who had visited emergency departments (EDs) for bee sting injuries. SSRs were defined as hypotension or altered mental status upon ED arrival, hospitalization, or death. Patient demographics and injury characteristics were compared between SSR and non-SSR groups. Logistic regression was performed to identify risk factors for bee sting-associated SSRs, and the characteristics of fatality cases were summarized. Results: Among the 9673 patients with bee sting injuries, 537 had an SSR and 38 died. The most frequent injury sites included the hands and head/face. Logistic regression analysis revealed that the occurrence of SSRs was associated with male sex [odds ratio (95% confidence interval); 1.634 (1.133–2.357)] and age [1.030 (1.020–1.041)]. Additionally, the risk of SSRs from trunk and head/ face stings was high [2.858 (1.405–5.815) and 2.123 (1.333–3.382), respectively]. Bee venom acupuncture [3.685 (1.408–9.641)] and stings in the winter [4.573 (1.420–14.723)] were factors that increased the risk of SSRs. Conclusion Our findings emphasize the need for implementing safety policies and education on bee sting-related incidents to protect high-risk groups.

Purpose: To establish a prospective registry for the active surveillance (AS) of prostate cancer (PC) using the Korean Urological Oncology Society (KUOS) database and to present interim analysis. Materials and Methods: The KUOS registry of AS for PC (KUOS-AS-PC) was organized in May 2019 and comprises multiple institutions nationwide. The eligibility criteria were as follows: patients with (1) pathologically proven PC; (2) pre-biopsy prostate-specific antigen (PSA) ≤20 ng/mL; (3) International Society of Urological Pathology (ISUP) grade 1 or 2 (no cribriform pattern 4); (4) clinical T stage ≤T2c; (5) positive core ratio ≤50%; and (6) maximal cancer involvement in the core ≤50%.Detailed longitudinal clinical information, including multi-parametric magnetic resonance imaging and disease-specific outcomes, was recorded. Results: From May 2019 to June 2021, 296 patients were enrolled, and 284 were analyzed. The mean±standard deviation (SD) age at enrollment was 68.7±8.2 years. The median follow-up period was 11.2 months (5.9–16.8 mo). Majority of patients had pre-biopsy PSA ≤10 ng/mL (91.2%), PSA density <0.2 ng/mL 2 (79.7%), ISUP grade group 1 (94.4%), single positive core (65.7%), maximal cancer involvement in the core ≤20% (78.1%), and clinical T stage of T1c or lower (72.9%). Fifty-two (18.3%) discontinued AS for various reasons. Interventions included radical prostatectomy (80.8%), transurethral prostatectomy (5.8%), primary androgen deprivation therapy (5.8%), radiation (5.8%), and focal therapy (1.9%). The mean±SD time to intervention was 8.9±5.2 months. The reasons for discontinuation included pathologic reclassification (59.6%), patient preference (25.0%), and radiologic reclassification (9.6%). Two (4.8%) patients with pathologic Gleason score upgraded to ISUP grade group 4, no biochemical recurrence. Conclusions The KUOS established a successful prospective database of PC patients undergoing AS in Korea, named the KUOS-AS-PC registry.

Background: It has become important to identify and manage risk factors for subclinical atrial fibrillation (AF) with an increase in its detection rate. Thus, this research aimed to investigate whether alcohol consumption contrib‑ utes to the development of subclinical AF. Methods: This prospective study enrolled 467 patients without AF from a multicenter pacemaker registry. The incidence of subclinical AF (episodes of atrial rate > 220 beats per minute without symptoms) was compared between alcohol-drinking and non-drinking groups. Results: During followup (median 18 months), the incidence and risk of long-duration atrial high-rate episodes (AHRE) ≥ 24 h were increased in the alcohol group compared to the non-alcohol group [5.47 vs. 2.10 per 100 personyears, adjusted hazard ratio (HR), 2.83; 95% confidence interval (CI), 1.14–7.04; P = 0.03]. After propensity score match‑ ing, the incidence and risk of long-duration AHRE were higher in the alcohol group (6.97 vs. 1.27 per 100 personyears, adjusted HR, 7.84; 95% CI, 1.21–50.93; P = 0.03). The mean burden of long-duration subclinical AF was higher in the alcohol group than in the non-alcohol group (0.18 vs. 1.61% during follow-up, P = 0.08). Conclusion Alcohol consumption was associated with an increased risk of subclinical AF. Long-duration AHRE inci‑ dence and AHRE burden were higher in alcohol drinkers than in non-drinkers.