Background: Circulating tumor DNA (ctDNA) profiling from peripheral blood allows relatively noninvasive monitoring of solid tumors; however, its utility post-surgery or chemotherapy in colorectal cancer remains underexplored. We evaluated the clinical implications of a ctDNA next-generation sequencing (NGS) panel post-surgery or chemotherapy in patients with colorectal cancer. Methods: We collected samples from 23 patients with colorectal cancer (17 men, median age 65 yrs) at baseline and post-surgery or chemotherapy at the National Cancer Center, Korea, between January 2021 and September 2023. ctDNA was analyzed using an NGS panel including 46 genes, and variant allele frequencies (VAFs) were determined. Followup samples were analyzed using the NGS panel or droplet digital PCR (ddPCR) when probes were available. Clinical status was compared with ctDNA results, and survival was analyzed using a time-dependent Cox model. Results: Mutations were identified in 13 out of 14 patients (92.8%) with stage II/III cancer and in all nine patients (100%) with stage IV cancer. Mutations were detected in KRAS (N = 15, 65%), APC (N = 8, 35%), TP53 (N = 7, 30%), PIK3CA (N = 5, 22%), and RET (N = 4, 17%). A 1% increase in KRAS and TP53 VAFs was associated with 48% and 32% increased mortality risk, respectively. Changes in VAF correlated well with clinical findings. Conclusions The detection of and an increase in KRAS and TP53 VAFs were associated with poor prognosis. ddPCR-based ctDNA monitoring results were comparable to those obtained with the NGS panel. ctDNA monitoring during treatment is clinically informative in managing colorectal cancer.

Background: Respiratory syncytial virus (RSV) prophylaxis using palivizumab effectively reduces RSV-associated morbidity in preterm infants. In Korea, national insurance coverage for palivizumab was implemented in October 2016 for moderate-to-late preterm (MLPT) infants born during the RSV season (October-March) who have older siblings. However, no large-scale studies have investigated the changes in the incidence and risk of severe acute lower respiratory infections (ALRIs) after insurance coverage implementation for MLPT infants. Methods: This large-scale retrospective cohort study used data from the Korean National Health Insurance Service between October 2013 and December 2019. MLPT infants (32 0/7– 35 6/7 weeks of gestation) with older siblings were stratified into pre-insurance period (PIP;October 2013–September 2016) and insurance period (IP; October 2016–March 2019) groups based on the date of birth with respect to initial insurance palivizumab implementation.Severe ALRI outcomes (hospitalization, respiratory support, and intensive care unit admission) were evaluated up to 1 year of age using multivariable logistic regression models. Results: Of the 11,722 MLPT infants included in the study, 6,716 and 5,006 infants were included in the IP and PIP groups, respectively. The incidences of ALRI-hospitalization and ALRI-respiratory support were significantly lower in the IP group than that in PIP group (24.0% vs. 26.0% and 3.1% vs. 4.0%, respectively). Additionally, ALRI-respiratory support risk was significantly lower in the IP group (adjusted odds ratio 0.771, 95% confidence interval 0.626–0.949, P = 0.014) than that in the PIP group. Among infants born during the RSV season, the risk of ALRI-hospitalization and ALRI-respiratory support were significantly lower in the IP group than that in the PIP group. However, no significant differences were observed between the IP and PIP groups for infants born during the non-RSV season. Conclusion The risks of severe ALRI outcomes decreased in Korea following the 2016 insurance implementation of palivizumab prophylaxis for MLPT infants born during the RSV season with older siblings.

The Korean Society of Infectious Diseases has been regularly publishing guidelines for adult immunization since 2007. Following the release of coronavirus disease 2019 (COVID-19) vaccination recommendations in 2023, significant changes have occurred due to the emergence of new variant strains and the waning immunity from previous vaccinations. This article provides a comprehensive update as of November 2024, incorporating the latest evidence and guidelines. Focusing on the 2024–2025 season, this article reviews vaccines currently authorized in Korea and assesses their effectiveness against the predominant JN.1 lineage variants. The updated recommendations prioritize high-risk groups, including adults aged 65 and older, individuals with underlying medical conditions, residents of facilities vulnerable to infection, pregnant women, and healthcare workers, for vaccination with updated vaccines targeting the JN.1 strain. Additionally, COVID-19 vaccination is available for all individuals aged 6 months and older. For most adults, a single-dose strategy is emphasized, while tailored schedules may be recommended for immunocompromised individuals. This update aims to optimize vaccination strategies in Korea to ensure comprehensive protection for high-risk populations.

Background and Objectives: Telomerase reverse transcriptase (TERT) promoter mutations are a poor prognostic factor in differentiated thyroid carcinoma (DTC). However, their prognostic value in anaplastic thyroid carcinoma (ATC) is unclear. Therefore, we investigated whether TERT promoter mutations also act as an independent poor prognostic factor in ATC. Materials and Methods: We reviewed the medical records of 41 patients with ATC who underwent the TERT promoter mutations test at Samsung Medical Center between November 1995 and December 2022. The aggressive treatment group was defined as patients who underwent surgery, external radiotherapy, and systemic therapy. Results: Among 41 patients, 15 (36.6%) showed TERT promoter mutations. There only differences in the clinicopathological characteristics between the TERT-mutant and wild-type groups were tumor size and coexistence of DTC. Median tumor size in the TERT-mutant group was 5.1 cm (3.0-11.0), which was significantly larger than that in the wild-type group (4.1 cm, 0.8-8.0, p=0.010). Nevertheless, the TERT-mutant group received relatively more aggressive treatment (53.3% vs. 19.2%, p=0.056), and the overall survival of the TERT-mutant group was longer than that of the wild-type group (9.4 months [0.4-51.5] vs. 7.1 months [0.4-49.5]), but its difference was not significant (p=0.458). In multiple regression analysis, distant metastasis was a significant prognostic factor, but TERT promoter mutation was not. Conclusion Unlike in DTC, TERT promoter mutations were not an independent poor prognostic factor in ATC.

Background: Respiratory syncytial virus (RSV) prophylaxis using palivizumab effectively reduces RSV-associated morbidity in preterm infants. In Korea, national insurance coverage for palivizumab was implemented in October 2016 for moderate-to-late preterm (MLPT) infants born during the RSV season (October-March) who have older siblings. However, no large-scale studies have investigated the changes in the incidence and risk of severe acute lower respiratory infections (ALRIs) after insurance coverage implementation for MLPT infants. Methods: This large-scale retrospective cohort study used data from the Korean National Health Insurance Service between October 2013 and December 2019. MLPT infants (32 0/7– 35 6/7 weeks of gestation) with older siblings were stratified into pre-insurance period (PIP;October 2013–September 2016) and insurance period (IP; October 2016–March 2019) groups based on the date of birth with respect to initial insurance palivizumab implementation.Severe ALRI outcomes (hospitalization, respiratory support, and intensive care unit admission) were evaluated up to 1 year of age using multivariable logistic regression models. Results: Of the 11,722 MLPT infants included in the study, 6,716 and 5,006 infants were included in the IP and PIP groups, respectively. The incidences of ALRI-hospitalization and ALRI-respiratory support were significantly lower in the IP group than that in PIP group (24.0% vs. 26.0% and 3.1% vs. 4.0%, respectively). Additionally, ALRI-respiratory support risk was significantly lower in the IP group (adjusted odds ratio 0.771, 95% confidence interval 0.626–0.949, P = 0.014) than that in the PIP group. Among infants born during the RSV season, the risk of ALRI-hospitalization and ALRI-respiratory support were significantly lower in the IP group than that in the PIP group. However, no significant differences were observed between the IP and PIP groups for infants born during the non-RSV season. Conclusion The risks of severe ALRI outcomes decreased in Korea following the 2016 insurance implementation of palivizumab prophylaxis for MLPT infants born during the RSV season with older siblings.

Background: The benefits of transradial access (TRA) over transfemoral access (TFA) for bifurcation percutaneous coronary intervention (PCI) are uncertain because of the limited availability of device selection. This study aimed to compare the procedural differences and the in-hospital and long-term outcomes of TRA and TFA for bifurcation PCI using secondgeneration drug-eluting stents (DESs). Methods: Based on data from the Coronary Bifurcation Stenting Registry III, a retrospective registry of 2,648 patients undergoing bifurcation PCI with second-generation DES from 21 centers in South Korea, patients were categorized into the TRA group (n = 1,507) or the TFA group (n = 1,141). After propensity score matching (PSM), procedural differences, in-hospital outcomes, and device-oriented composite outcomes (DOCOs; a composite of cardiac death, target vessel-related myocardial infarction, and target lesion revascularization) were compared between the two groups (772 matched patients each group). Results: Despite well-balanced baseline clinical and lesion characteristics after PSM, the use of the two-stent strategy (14.2% vs. 23.7%, P = 0.001) and the incidence of in-hospital adverse outcomes, primarily driven by access site complications (2.2% vs. 4.4%, P = 0.015), were significantly lower in the TRA group than in the TFA group. At the 5-year follow-up, the incidence of DOCOs was similar between the groups (6.3% vs. 7.1%, P = 0.639). Conclusion The findings suggested that TRA may be safer than TFA for bifurcation PCI using second-generation DESs. Despite differences in treatment strategy, TRA was associated with similar long-term clinical outcomes as those of TFA. Therefore, TRA might be the preferred access for bifurcation PCI using second-generation DES.

The Korean Society of Infectious Diseases has been regularly publishing guidelines for adult immunization since 2007. Following the release of coronavirus disease 2019 (COVID-19) vaccination recommendations in 2023, significant changes have occurred due to the emergence of new variant strains and the waning immunity from previous vaccinations. This article provides a comprehensive update as of November 2024, incorporating the latest evidence and guidelines. Focusing on the 2024–2025 season, this article reviews vaccines currently authorized in Korea and assesses their effectiveness against the predominant JN.1 lineage variants. The updated recommendations prioritize high-risk groups, including adults aged 65 and older, individuals with underlying medical conditions, residents of facilities vulnerable to infection, pregnant women, and healthcare workers, for vaccination with updated vaccines targeting the JN.1 strain. Additionally, COVID-19 vaccination is available for all individuals aged 6 months and older. For most adults, a single-dose strategy is emphasized, while tailored schedules may be recommended for immunocompromised individuals. This update aims to optimize vaccination strategies in Korea to ensure comprehensive protection for high-risk populations.