Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

Background/Aims: In 2019, the American Society for Gastrointestinal Endoscopy (ASGE) established clinical predictors for choledocholithiasis. Our study was designed to evaluate these predictors within the Korean clinical context, establish cutoff values, and develop a predictive model. Methods: This retrospective study analyzed patients who underwent laparoscopic cholecystectomy. The relationships between choledocholithiasis and predictors including age, blood tests, and imaging findings were assessed through univariate and multivariate logistic regression analyses. We established Korean cutoff values for these predictors and developed a scoring system for choledocholithiasis using a multivariate logistic regression. The performance of this scoring system was then compared with that of the 2019 ASGE guidelines through a receiver operating characteristic curve. Results: We established Korean cutoff values for age (>70 years), alanine aminotransferase (>26.5 U/L), aspartate aminotransferase (>28.5 U/L), gamma-glutamyl transferase (GGT; >82.5 U/L), alkaline phosphatase (ALP; >77.5 U/L), and total bilirubin (>0.95 mg/dL). In the multivariate analysis, only age >70 years, GGT >77.5 U/L, ALP >77.5 U/L, and common bile duct dilatation remained significant. We then developed a new Korean risk stratification model from the multivariate analysis, with an area under the curve of 0.777 (95% confidence interval, 0.75 to 0.81).Our model was stratified into the low-risk, intermediate-risk, and high-risk groups with the scores being <1.0, 1.0–5.5, and >5.5, respectively. Conclusions Predictors of choledocholithiasis in cholecystectomy patients and their cutoff values in Korean should be adjusted and further studies are needed to develop appropriate guidelines.

Background/Aims: In 2019, the American Society for Gastrointestinal Endoscopy (ASGE) established clinical predictors for choledocholithiasis. Our study was designed to evaluate these predictors within the Korean clinical context, establish cutoff values, and develop a predictive model. Methods: This retrospective study analyzed patients who underwent laparoscopic cholecystectomy. The relationships between choledocholithiasis and predictors including age, blood tests, and imaging findings were assessed through univariate and multivariate logistic regression analyses. We established Korean cutoff values for these predictors and developed a scoring system for choledocholithiasis using a multivariate logistic regression. The performance of this scoring system was then compared with that of the 2019 ASGE guidelines through a receiver operating characteristic curve. Results: We established Korean cutoff values for age (>70 years), alanine aminotransferase (>26.5 U/L), aspartate aminotransferase (>28.5 U/L), gamma-glutamyl transferase (GGT; >82.5 U/L), alkaline phosphatase (ALP; >77.5 U/L), and total bilirubin (>0.95 mg/dL). In the multivariate analysis, only age >70 years, GGT >77.5 U/L, ALP >77.5 U/L, and common bile duct dilatation remained significant. We then developed a new Korean risk stratification model from the multivariate analysis, with an area under the curve of 0.777 (95% confidence interval, 0.75 to 0.81).Our model was stratified into the low-risk, intermediate-risk, and high-risk groups with the scores being <1.0, 1.0–5.5, and >5.5, respectively. Conclusions Predictors of choledocholithiasis in cholecystectomy patients and their cutoff values in Korean should be adjusted and further studies are needed to develop appropriate guidelines.

Background/Aims: In 2019, the American Society for Gastrointestinal Endoscopy (ASGE) established clinical predictors for choledocholithiasis. Our study was designed to evaluate these predictors within the Korean clinical context, establish cutoff values, and develop a predictive model. Methods: This retrospective study analyzed patients who underwent laparoscopic cholecystectomy. The relationships between choledocholithiasis and predictors including age, blood tests, and imaging findings were assessed through univariate and multivariate logistic regression analyses. We established Korean cutoff values for these predictors and developed a scoring system for choledocholithiasis using a multivariate logistic regression. The performance of this scoring system was then compared with that of the 2019 ASGE guidelines through a receiver operating characteristic curve. Results: We established Korean cutoff values for age (>70 years), alanine aminotransferase (>26.5 U/L), aspartate aminotransferase (>28.5 U/L), gamma-glutamyl transferase (GGT; >82.5 U/L), alkaline phosphatase (ALP; >77.5 U/L), and total bilirubin (>0.95 mg/dL). In the multivariate analysis, only age >70 years, GGT >77.5 U/L, ALP >77.5 U/L, and common bile duct dilatation remained significant. We then developed a new Korean risk stratification model from the multivariate analysis, with an area under the curve of 0.777 (95% confidence interval, 0.75 to 0.81).Our model was stratified into the low-risk, intermediate-risk, and high-risk groups with the scores being <1.0, 1.0–5.5, and >5.5, respectively. Conclusions Predictors of choledocholithiasis in cholecystectomy patients and their cutoff values in Korean should be adjusted and further studies are needed to develop appropriate guidelines.

Background/Aims: In 2019, the American Society for Gastrointestinal Endoscopy (ASGE) established clinical predictors for choledocholithiasis. Our study was designed to evaluate these predictors within the Korean clinical context, establish cutoff values, and develop a predictive model. Methods: This retrospective study analyzed patients who underwent laparoscopic cholecystectomy. The relationships between choledocholithiasis and predictors including age, blood tests, and imaging findings were assessed through univariate and multivariate logistic regression analyses. We established Korean cutoff values for these predictors and developed a scoring system for choledocholithiasis using a multivariate logistic regression. The performance of this scoring system was then compared with that of the 2019 ASGE guidelines through a receiver operating characteristic curve. Results: We established Korean cutoff values for age (>70 years), alanine aminotransferase (>26.5 U/L), aspartate aminotransferase (>28.5 U/L), gamma-glutamyl transferase (GGT; >82.5 U/L), alkaline phosphatase (ALP; >77.5 U/L), and total bilirubin (>0.95 mg/dL). In the multivariate analysis, only age >70 years, GGT >77.5 U/L, ALP >77.5 U/L, and common bile duct dilatation remained significant. We then developed a new Korean risk stratification model from the multivariate analysis, with an area under the curve of 0.777 (95% confidence interval, 0.75 to 0.81).Our model was stratified into the low-risk, intermediate-risk, and high-risk groups with the scores being <1.0, 1.0–5.5, and >5.5, respectively. Conclusions Predictors of choledocholithiasis in cholecystectomy patients and their cutoff values in Korean should be adjusted and further studies are needed to develop appropriate guidelines.

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients’ values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Purpose: Heterogeneous human epidermal growth factor receptor 2 (HER2) overexpression in gastric cancer may lead to a misdiagnosis of HER2 status. Accurate assessment of HER2 status is essential for optimal treatment as novel HER2-directed agents are being investigated in various clinical settings. We evaluated the usefulness of HER2 re-assessment following progression on first-line treatment in initially HER2-negative advanced gastric cancer (AGC) patients. Materials and Methods: We enrolled 177 patients with baseline HER2-negative AGC and performed HER2 re-assessment after progression on first-line treatment from February 2012 to June 2016 at Asan Medical Center, Seoul, Korea. The re-assessed HER2 status was analyzed with baseline HER2 status and clinical characteristics. Results: The median age was 54 years (range, 24 to 80 years), and 123 patients (69.5%) were men. Seven patients (4.0%) were HER2-positive on the re-assessment. Patients with baseline HER2 negativity confirmed by a single test (n=100) had a higher HER2-positive re-assessment rate compared to those who had repeated baseline testing (n=77) (5.0% vs. 2.6%). Among the patients with single baseline HER2 testing, the rate was higher in patients with baseline HER2 immunohistochemistry (IHC) 1+ compared to those with IHC 0 (13.4% vs. 3.6%). Conclusion Overall, 4.0% of patients with baseline HER2-negative AGC were HER2-positive on re-assessment, and the HER2-positive re-assessment rate was higher among patients who had a single test at baseline. HER2 re assessment may be considered for initially HER2-negative patients to determine their eligibility for HER2-directed therapy, particularly if their HER2 negativity was determined by a single test, especially if they had a single baseline HER2 IHC 1+ test.