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: There are limited long-term clinical outcome data comparing first-generation (1G) versus second-generation (2G) drug-eluting stents (DES) in patients with single-vessel disease (SVD). We sought to compare the efficacy and safety of 1G- and 2G-DES in SVD patients who underwent successful percutaneous coronary intervention (PCI) over 10 years of clinical follow-up. Methods: A total of 2,312 consecutive patients with SVD who underwent PCI with 1G-DES (paclitaxel- or sirolimus-eluting stents, n = 811) or 2G-DES (zotarolimus [Endeavor, Endeavor Resolute]- or everolimus-eluting stents [Promus Element, Xience], n = 1,082) were enrolled.After propensity score matching, 2 matched groups (538 pairs) were generated. Study endpoints included individual and composite clinical outcomes through 10 years. Results: During the 10-year follow-up, the 2G-DES group had lower incidences of myocardial infarction (MI; hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.22–0.92; P = 0.028) and target lesion revascularization (TLR; HR, 0.54; 95% CI, 0.32–0.91; P = 0.021) than the 1G-DES group. Rates of total death, cardiac death, non-target vessel revascularization, stroke, major adverse cardiac events, and major adverse cardiac and cerebrovascular events were similar between groups. Conclusions In our single-center, all-comer registry, 2G-DES were associated with lower incidence rates of MI and TLR compared to 1G-DES in SVD patients over 10 years of followup, indicating a safer and more durable effect than 1G-DES.

The submandibular displacement of a mandibular third molar residual root presents major challenges to oral and maxillofacial surgeons due to the proximity to critical anatomical structures such as the lingual nerve and sublingual artery. Preoperative imaging can approximate the location of the residual tooth root; however, accurately determining its exact position is difficult because of the dynamic nature of the mandible and the difficulty of realtime synchronization of imaging. This study presents the successful extraction of a residual mandibular third molar root in a 67-year-old female patient achieved using a magnetic field-based navigation system. The sublingually-displaced residual root was localized using the navigation system, marked using a virtual implant placement, and positioned by a hand piece using synchronized real-time sensor data. The root was successfully removed with a minimally-invasive approach. No complications occurred postoperatively, and follow-up showed no major issues. Due to the small size of the marker, ease of calibration, and independence from visual obstacles, magnetic field-based navigation systems are a promising tool for the removal of residual roots displaced into adjacent soft tissue.

The submandibular displacement of a mandibular third molar residual root presents major challenges to oral and maxillofacial surgeons due to the proximity to critical anatomical structures such as the lingual nerve and sublingual artery. Preoperative imaging can approximate the location of the residual tooth root; however, accurately determining its exact position is difficult because of the dynamic nature of the mandible and the difficulty of realtime synchronization of imaging. This study presents the successful extraction of a residual mandibular third molar root in a 67-year-old female patient achieved using a magnetic field-based navigation system. The sublingually-displaced residual root was localized using the navigation system, marked using a virtual implant placement, and positioned by a hand piece using synchronized real-time sensor data. The root was successfully removed with a minimally-invasive approach. No complications occurred postoperatively, and follow-up showed no major issues. Due to the small size of the marker, ease of calibration, and independence from visual obstacles, magnetic field-based navigation systems are a promising tool for the removal of residual roots displaced into adjacent soft tissue.

Background: Preeclampsia (PE) is a hypertensive pregnancy disorder linked to placental dysfunction, often involving pathological lesions like acute atherosis, decidual vasculopathy, accelerated villous maturation, and fibrinoid deposition. However, there is no gold standard for the pathological diagnosis of PE and this limits the ability of clinicians to distinguish between PE and non-PE pregnancies. Recent advances in computational pathology have provided the opportunity to automate pathological analysis for diagnosis, classification, prediction, and prediction of disease progression. In this study, we assessed whether computational pathology could be used to identify PE placentas. Methods: A total of 168 placental whole-slide images (WSIs) of patients from Seoul National University Hospital (comprising 84 PE cases and 84 normal controls) were used for model development and internal validation. For external validation of the model, 76 placental slides (including 38 PE cases and 38 normal controls) were obtained from the Boramae Medical Center (BMC). To establish standard criteria for diagnosing PE and distinguishing it from controls using placental WSIs, patch characteristics and quantification of terminal and intermediate villi were employed. In unsupervised learning, K-means clustering was conducted as a feature obtained through an Auto Encoder to extract the ratio of each cluster for each WSI. For supervised learning, quantitative assessments of the villi were obtained using a U-Net-based segmentation algorithm. The prediction model was developed using an ensemble method and was compared with a clinical feature model developed by using placental size features. Results: Using ensemble modeling, we developed a model to identify PE placentas.The model showed good performance (area under the precision-recall curve [AUPRC], 0.771; 95% confidence interval [CI], 0.752–0.790), with 77.3% of sensitivity and 71.1% of specificity, whereas the clinical feature model showed an AUPRC 0.713 (95% CI, 0.694–0.732) with 55.6% sensitivity and 86.8% specificity. External validation of the predictive model employing the BMC-derived set of placental slides also showed good discrimination (AUPRC, 0.725; 95% CI, 0.720–0.730). Conclusion The proposed computational pathology model demonstrated a strong ability to identify preeclamptic placentas. Computational pathology has the potential to improve the identification of PE placentas.

Background and Objectives: Ultimaster™, a third-generation sirolimus-eluting stent using biodegradable polymer, has been introduced to overcome long term adverse vascular events, such as restenosis or stent thrombosis. In the present study, we aimed to evaluate the 12-month clinical outcomes of Ultimaster™ stents in Korean patients with coronary artery disease. Methods: This study is a multicenter, prospective, observational registry across 12 hospitals. To reflect real-world clinical evidence, non-selective subtypes of patients and lesions were included in this study. The study end point was target lesion failure (TLF) (the composite of cardiac death, target vessel myocardial infarction [MI], and target lesion revascularization [TLR]) at 12-month clinical follow up. Results: A total of 576 patients were enrolled between November 2016 and May 2021. Most of the patients were male (76.5%), with a mean age of 66.0±11.2 years. Among the included patients, 40.1% had diabetes mellitus (DM) and 67.9% had acute coronary syndrome (ACS).At 12 months, the incidence of TLF was 4.1%. The incidence of cardiac death was 1.5%, MI was 1.0%, TLR was 2.7%, and stent thrombosis was 0.6%. In subgroup analysis based on the presence of ACS, DM, hypertension, dyslipidemia, or bifurcation, there were no major differences in the incidence of the primary endpoint. Conclusions The present registry shows that Ultimaster™ stent is safe and effective for routine real-world clinical practice in non-selective Korean patients, having a low rate of adverse events at least up to 12 months.

The submandibular displacement of a mandibular third molar residual root presents major challenges to oral and maxillofacial surgeons due to the proximity to critical anatomical structures such as the lingual nerve and sublingual artery. Preoperative imaging can approximate the location of the residual tooth root; however, accurately determining its exact position is difficult because of the dynamic nature of the mandible and the difficulty of realtime synchronization of imaging. This study presents the successful extraction of a residual mandibular third molar root in a 67-year-old female patient achieved using a magnetic field-based navigation system. The sublingually-displaced residual root was localized using the navigation system, marked using a virtual implant placement, and positioned by a hand piece using synchronized real-time sensor data. The root was successfully removed with a minimally-invasive approach. No complications occurred postoperatively, and follow-up showed no major issues. Due to the small size of the marker, ease of calibration, and independence from visual obstacles, magnetic field-based navigation systems are a promising tool for the removal of residual roots displaced into adjacent soft tissue.

Despite the availability of direct-acting antivirals (DAAs) for chronic hepatitis C virus (HCV) infection in Korea, need remains for pangenotypic regimens that can be used in the presence of hepatic impairment, comorbidities, or prior treatment failure. We investigated the efficacy and safety of sofosbuvir–velpatasvir and sofosbuvir–velpatasvir–voxilaprevir for 12 weeks in HCV-infected Korean adults. Methods: This Phase 3b, multicenter, open-label study included 2 cohorts. In Cohort 1, participants with HCV genotype 1 or 2 and who were treatment-naive or treatment-experienced with interferon-based treatments, received sofosbuvir–velpatasvir 400/100 mg/day. In Cohort 2, HCV genotype 1 infected individuals who previously received an NS5A inhibitor-containing regimen ≥ 4 weeks received sofosbuvir–velpatasvir–voxilaprevir 400/100/100 mg/day. Decompensated cirrhosis was an exclusion criterion. The primary endpoint was SVR12, defined as HCV RNA < 15 IU/mL 12 weeks following treatment. Results: Of 53 participants receiving sofosbuvir–velpatasvir, 52 (98.1%) achieved SVR12. The single participant who did not achieve SVR12 experienced an asymptomatic Grade 3 ASL/ALT elevation on day 15 and discontinued treatment. The event resolved without intervention. All 33 participants (100%) treated with sofosbuvir–velpatasvir–voxilaprevir achieved SVR 12. Overall, sofosbuvir–velpatasvir and sofosbuvir–velpatasvir–voxilaprevir were safe and well tolerated. Three participants (5.6%) in Cohort 1 and 1 participant (3.0%) in Cohort 2 had serious adverse events, but none were considered treatment-related. No deaths or grade 4 laboratory abnormalities were reported. Conclusions: Treatment with sofosbuvir–velpatasvir or sofosbuvir–velpatasvir–voxilaprevir was safe and resulted in high SVR12 rates in Korean HCV patients.

Background/Aims: Although endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) and fine needle biopsy (FNB) are widely used for tissue acquisition of pancreatic solid mass, the optimal strategy of this procedure has not been established yet. The aim of this nationwide study was to investigate the current practice patterns of EUS-FNA/FNB for pancreatic solid mass in Korea. Methods: The Policy-Quality Management of the Korean Pancreatobiliary Association (KPBA) developed a questionnaire containing 22 questions. An electronic survey consisting of the questionnaire was distributed by e-mail to members registered to the KPBA. Results: A total of 101 respondents completed the survey. Eighty respondents (79.2%) performed preoperative EUS-FNA/FNB for operable pancreatic solid mass. Acquire needles (60.4%) were used the most, followed by ProCore needles (47.5%). In terms of need size, most respondents (>80%) preferred 22-gauge needles regardless of the location of the mass. Negative suction with a 10-mL syringe (71.3%) as sampling technique was followed by stylet slow-pull (41.6%). More than three needle passes for EUS-FNA/FNB was performed by most respondents (>80%). The frequency of requiring repeated procedure was significantly higher in respondents with a low individual volume (<5 per month, p=0.001). Prophylactic antibiotics were routinely used in 39 respondents (38.6%); rapid on-site pathologic evaluation was used in 6.1%. Conclusions According to this survey, practices of EUS-FNA/FNB for pancreatic solid mass varied substantially, some of which differed considerably from the recommendations present in existing guidelines. These results suggest that the development of evidence-based quality guidelines fitting Korean clinical practice is needed to establish the optimal strategy for this procedure.

Background/Aims: This study aimed to investigate the patterns of preferred endoscopic procedure types and techniques for managing difficult common bile duct (CBD) stones in South Korea. Methods: The Committee of Policy and Quality Management of Korean Pancreatobiliary Association (KPBA) conducted a survey containing 19 questions. Both paper and online surveys were carried out; with the paper survey being conducted during the 2019 Annual Congress of KPBA and the online survey being conducted through Google Forms from April 2020 to February 2021. Results: The response rate was approximately 41.3% (86/208). Sixty-two (73.0%) worked at tertiary hospitals or academic medical centers, and 60 (69.7%) had more than 5 years of endoscopic retrograde cholangiopancreatography experience. The preferred size criteria for large CBD stones were 15 mm (40.6%), 20 mm (31.3%), and 30 mm (4.6%). For managing of large CBD stones, endoscopic papillary large balloon dilation after endoscopic sphincterotomy was the most preferred technique (74.4%). When performing procedures in those with bleeding diathesis, 64 (74.4%) respondents favored endoscopic papillary balloon dilation (EPBD) alone or EPBD with small endoscopic sphincterotomy. Fifty-five respondents (63.9%) preferred the doubleguidewire technique when faced with difficult bile duct cannulation in patients with periampullary diverticulum. In surgically altered anatomies, cap-fitted forward viewing endoscopy (76.7%) and percutaneous transhepatic cholangioscopy (48.8%) were the preferred techniques for Billroth-II anastomosis and total gastrectomy with Roux-en-Y anastomosis, respectively. Conclusions Most respondents showed unifying trends for the management of difficult CBD stones. The current practice patterns could be used as basic data for clinical quality improvements in the management of difficult CBD stones.