Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Objectives: . Although mandibular advancement device (MAD) treatment is effective for obstructive sleep apnea (OSA), some concerns remain regarding its potential therapeutic impact and side effects. Thus, we developed a novel MAD that auto-titrates depending on its position in patients with OSA. We conducted a clinical trial to determine the efficacy of an auto-titrating mandibular advancement device (AMAD) for treating OSA. Methods: . Fourteen patients diagnosed with OSA participated in this study. Polysomnography (PSG) was performed at the beginning of the clinical trial, and after 3 months of treatment, PSG with AMAD in situ was conducted. Results: . The mean scores for the Epworth Sleepiness Scale (ESS) and STOP-Bang were 8.21±4.21 and 5.00±1.00, respectively. After 3 months of AMAD treatment, the STOP-Bang scores improved to 3.75±1.06; however, the ESS scores did not show a significant change. Additionally, we observed statistically significant improvements in several respiratory parameters in the PSG data following AMAD treatment. These included reductions in the apnea-hypopnea index (AHI) (from 32.85±21.71 to 12.93±10.70), supine AHI (from 45.91±23.58 to 15.59±12.76), and lateral AHI (from 13.94±10.95 to 5.49±7.40). Improvements were also noted in the lowest O2 saturation (from 79.71±6.22 to 84.00± 5.71), total arousal number (from 191.14±112.07 to 86.57±48.80), and arousal index (from 33.76±21.00 to 15.05± 8.42). However, there were no significant changes in total sleep time, sleep efficiency, or mean oxygen saturation. Additionally, no major side effects were observed during treatment, specifically related to tooth or jaw pain. Conclusion . Our clinical trial found that AMAD improved PSG parameters and reduced the incidence of common side effects. Therefore, AMAD may be an effective alternative treatment for OSA.

Objectives: . Although mandibular advancement device (MAD) treatment is effective for obstructive sleep apnea (OSA), some concerns remain regarding its potential therapeutic impact and side effects. Thus, we developed a novel MAD that auto-titrates depending on its position in patients with OSA. We conducted a clinical trial to determine the efficacy of an auto-titrating mandibular advancement device (AMAD) for treating OSA. Methods: . Fourteen patients diagnosed with OSA participated in this study. Polysomnography (PSG) was performed at the beginning of the clinical trial, and after 3 months of treatment, PSG with AMAD in situ was conducted. Results: . The mean scores for the Epworth Sleepiness Scale (ESS) and STOP-Bang were 8.21±4.21 and 5.00±1.00, respectively. After 3 months of AMAD treatment, the STOP-Bang scores improved to 3.75±1.06; however, the ESS scores did not show a significant change. Additionally, we observed statistically significant improvements in several respiratory parameters in the PSG data following AMAD treatment. These included reductions in the apnea-hypopnea index (AHI) (from 32.85±21.71 to 12.93±10.70), supine AHI (from 45.91±23.58 to 15.59±12.76), and lateral AHI (from 13.94±10.95 to 5.49±7.40). Improvements were also noted in the lowest O2 saturation (from 79.71±6.22 to 84.00± 5.71), total arousal number (from 191.14±112.07 to 86.57±48.80), and arousal index (from 33.76±21.00 to 15.05± 8.42). However, there were no significant changes in total sleep time, sleep efficiency, or mean oxygen saturation. Additionally, no major side effects were observed during treatment, specifically related to tooth or jaw pain. Conclusion . Our clinical trial found that AMAD improved PSG parameters and reduced the incidence of common side effects. Therefore, AMAD may be an effective alternative treatment for OSA.

Objectives: . Although mandibular advancement device (MAD) treatment is effective for obstructive sleep apnea (OSA), some concerns remain regarding its potential therapeutic impact and side effects. Thus, we developed a novel MAD that auto-titrates depending on its position in patients with OSA. We conducted a clinical trial to determine the efficacy of an auto-titrating mandibular advancement device (AMAD) for treating OSA. Methods: . Fourteen patients diagnosed with OSA participated in this study. Polysomnography (PSG) was performed at the beginning of the clinical trial, and after 3 months of treatment, PSG with AMAD in situ was conducted. Results: . The mean scores for the Epworth Sleepiness Scale (ESS) and STOP-Bang were 8.21±4.21 and 5.00±1.00, respectively. After 3 months of AMAD treatment, the STOP-Bang scores improved to 3.75±1.06; however, the ESS scores did not show a significant change. Additionally, we observed statistically significant improvements in several respiratory parameters in the PSG data following AMAD treatment. These included reductions in the apnea-hypopnea index (AHI) (from 32.85±21.71 to 12.93±10.70), supine AHI (from 45.91±23.58 to 15.59±12.76), and lateral AHI (from 13.94±10.95 to 5.49±7.40). Improvements were also noted in the lowest O2 saturation (from 79.71±6.22 to 84.00± 5.71), total arousal number (from 191.14±112.07 to 86.57±48.80), and arousal index (from 33.76±21.00 to 15.05± 8.42). However, there were no significant changes in total sleep time, sleep efficiency, or mean oxygen saturation. Additionally, no major side effects were observed during treatment, specifically related to tooth or jaw pain. Conclusion . Our clinical trial found that AMAD improved PSG parameters and reduced the incidence of common side effects. Therefore, AMAD may be an effective alternative treatment for OSA.

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.

Purpose: The treatment of male breast cancer (MBC) has been extrapolated from female breast cancer (FBC) because of its rarity despite their different clinicopathologic characteristics. We aimed to investigate the distribution of intrinsic subtypes based on immunohistochemistry, their clinical impact, and treatment pattern in clinical practice through a multicenter study in Korea. Materials and Methods: We retrospectively analyzed clinical data of 248 MBC patients from 18 institutions across the country from January 1995 to July 2016. Results: The median age of MBC patients was 63 years (range, 25 to 102 years). Among 148 intrinsic subtype classified patients, 61 (41.2%), 44 (29.7%), 29 (19.5%), and 14 (9.5%) were luminal A, luminal B, human epidermal growth factor receptor 2, and triple-negative breast cancer, respectively. Luminal A subtype showed trends for superior survival compared to other subtypes. Most hormone receptor-positive patients (166 patients, 82.6%) received adjuvant endocrine treatment. Five-year completion of adjuvant endocrine treatment was associated with superior disease-free survival (DFS) in patients classified with an intrinsic subtype (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04 to 0.49; p=0.002) and in all patients (HR, 0.16; 95% CI, 0.05 to 0.54; p=0.003). Conclusion Distribution of subtypes of MBC was similar to FBC and luminal type A was most common. Overall survival tended to be improved for luminal A subtype, although there was no statistical significance. Completion of adjuvant endocrine treatment was associated with prolonged DFS in intrinsic subtype classified patients. MBC patients tended to receive less treatment. MBC patients should receive standard treatment according to guidelines as FBC patients.

Purpose: Germline mutations in DNA damage repair (DDR) genes such as BRCA2 have been associated with prostate cancer (PC) risk but has not been thoroughly evaluated for metastatic prostate cancer (mPC) in Asian men. This study attempts to evaluate frequency of DDR mutations in the largest cohort of Koreans. Materials and Methods: We recruited 340 patients with mPC unselected for family history of cancer and compared to 495 controls. Whole genome sequencing was applied to assess germline pathogenic/likely pathogenic variants (PV/LPVs) in 26 DDR genes and HOXB13, including 7 genes (ATM, BRCA1/2, CHEK2, BRIP1, PALB2, and NBN) associated with hereditary PC. Comparisons to published Caucasian and Japanese cohorts were performed. Results: Total of 28 PV/LPVs were identified in 30 (8.8%) patients; mutations were found in 13 genes, including BRCA2 (15 men [4.41%]), ATM (2 men [0.59%]), NBN (2 men [0.59%], and BRIP1 (2 men [0.59%]). Only one patient had HOXB13 mutation (0.29%). A lower rate of overall germline variant frequency was observed in Korean mPC compared to Caucasians (8.8% vs. 11.8%), but individual variants notably differed from Caucasian and geographically similar Japanese cohorts. PV/LPVs in DDR genes tended to increase gradually with higher Gleason scores (GS 7, 7.1%; GS 8, 7.5%; GS 9–10, 9.9%). Conclusions BRCA2 was the most frequently mutated gene common to different cohorts supporting its importance, but differences in variant distribution in Korean mPC underscore the need for ethnic-specific genetic models. Future ethnic-specific analyses are warranted to verify our findings.

Purpose: As pancreaticojejunostomy (PJ) is a challenging anastomosis, an education program is needed to train young surgeons to perform PJ. This study evaluated the effects of simulation-based training of open PJ using pancreas and intestine silicone models. Methods: Five videos pancreatobiliary clinical fellows who did not perform PJ participated in this study. After watching the master video created by a senior pancreatobiliary surgeon, each trainee performed the PJ using silicone models and recorded them 10 times using a video camera. Of these videos, 5 were randomly duplicated due to the validation of the scoring system. The scoring system developed consisted of 20 scores. Three pancreatobiliary professors scored their performance by watching videos. Results: The mean procedure time of the 5 trainees was 25.4 minutes (range, 23.5–27.3 minutes) in the first video and 15.8 minutes (range, 13.8–19.1 minutes) in the 10th video. The mean score was 12.6 (range, 5–19) and 18.3 (range, 15–20) in the first and 10th videos, respectively. The scores were similar among the duplicated videos for each supervisor. Conclusion This education system would help pancreatobiliary trainees to overcome learning curves efficiently without ethical issues related to animal models or direct practice to human patients.