The Korean Breast Cancer Society (KBCS) has collected nationwide registry data on clinicopathologic characteristics and treatment since 1996. This study aimed to analyze the clinical characteristics of breast cancer in Korea and assess changes in breast cancer statistics for 2021 using data from the KBCS registry and the Korean Central Cancer Registry. In 2021, 34,628 women were newly diagnosed with breast cancer. The median age of women diagnosed with breast cancer was 53.4 years, with the highest incidence occurring in the 40–49 age group. The most common molecular subtype was hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative, accounting for 69.1% of cases, while HER2-positive subtypes comprised 19.3%. During the coronavirus disease 2019 pandemic, the national breast cancer screening rate declined. However, the incidence of early-stage breast cancer (stages 0 and I) continued to increase, accounting for 65.6% of newly diagnosed cases in 2021. Our results showed that the overall survival rate for patients with breast cancer has improved, primarily due to a rise in early-stage diagnoses and advancements in treatment.

By investigating the characteristics and prognosis of breast cancer (BC) patients who have undergone hormone replacement therapy (HRT), this study addresses a gap in the existing literature. A total of 17,355 postmenopausal patients with BC were analyzed using data from the Korea Breast Cancer Society database (2000–2014). Among them, 3,585 (20.7%) had a history of HRT before BC diagnosis (HRT group), while 13,770 (79.3%) never received HRT (non-HRT group). The HRT group exhibited an earlier pathologic stage, lower histologic and nuclear grades, and a higher rate of breast conservation surgery compared to the non-HRT group. Furthermore, this group had a higher rate of screening participation and a greater proportion of patients with a normal or overweight body mass index (BMI). The prognosis of the HRT group was better than that of the non-HRT group, with a 5-year overall survival rate of 93.9% versus 91.7% (p < 0.001). The hazard ratio for the HRT group was 0.7 (95% confidence interval, 0.608–0.805; p < 0.001). Increased screening participation, longer HRT duration, and a normal or overweight BMI were associated with a better prognosis in the HRT group. Patients with BC who underwent HRT showed better clinicopathological characteristics and prognosis than those who did not receive HRT. The results highlighted significant differences in patients who underwent screening and those with a normal or overweight BMI. Furthermore, a longer HRT duration was associated with a better prognosis.

Background: Since the emergence of hypervirulent strains of Clostridioides difficile, the incidence of C. difficile infections (CDI) has increased significantly. Methods: To assess the incidence of CDI in Korea, we conducted a prospective multicentre observational study from October 2020 to October 2021. Additionally, we calculated the incidence of CDI from mass data obtained from the Health Insurance Review and Assessment Service (HIRA) from 2008 to 2020. Results: In the prospective study with active surveillance, 30,212 patients had diarrhoea and 907 patients were diagnosed with CDI over 1,288,571 patient-days and 193,264 admissions in 18 participating hospitals during 3 months of study period; the CDI per 10,000 patientdays was 7.04 and the CDI per 1,000 admission was 4.69. The incidence of CDI was higher in general hospitals than in tertiary hospitals: 6.38 per 10,000 patient-days (range: 3.25–12.05) and 4.18 per 1,000 admissions (range: 1.92–8.59) in 11 tertiary hospitals, vs. 9.45 per 10,000 patient-days (range: 5.68–13.90) and 6.73 per 1,000 admissions (range: 3.18–15.85) in seven general hospitals. With regard to HIRA data, the incidence of CDI in all hospitals has been increasing over the 13-year-period: from 0.3 to 1.8 per 10,000 patient-days, 0.3 to 1.6 per 1,000 admissions, and 6.9 to 56.9 per 100,000 population, respectively. Conclusion The incidence of CDI in Korea has been gradually increasing, and its recent value is as high as that in the United State and Europe. CDI is underestimated, particularly in general hospitals in Korea.

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.

In the 2023 series, we summarized the major clinical research advances in gynecologic oncology based on communications at the conference of Asian Society of Gynecologic Oncology Review Course. The review consisted of 1) Endometrial cancer: immune checkpoint inhibitor, antibody drug conjugates (ADCs), selective inhibitor of nuclear export, CDK4/6 inhibitors WEE1 inhibitor, poly (ADP-ribose) polymerase (PARP) inhibitors. 2) Cervical cancer: surgery in low-risk early-stage cervical cancer, therapy for locally advanced stage and advanced, metastatic, or recurrent setting; and 3) Ovarian cancer: immunotherapy, triplet therapies using immune checkpoint inhibitors along with antiangiogenic agents and PARP inhibitors, and ADCs. In 2023, the field of endometrial cancer treatment witnessed a landmark year, marked by several practice-changing outcomes with immune checkpoint inhibitors and the reliable efficacy of PARP inhibitors and ADCs.

Systemic sclerosis (SS) is an autoimmune disease and pathological mechanisms of SS are unclear. In this study, we investigated the role of T cells in the progression of SS using SKG mice and humanized mice. SKG mice have a spontaneous point mutation in ZAP70. We induced scleroderma in SKG mice and a humanized SS mouse model to assess whether T cell-mediated immune responses induce SS. As a result, we found increased dermal thickness, fibrosis, and lymphocyte infiltration in skin tissue in SKG SS mice compared to BALB/c mice (control). Also, blood cytokine level, including IL-4- and IFN-α which are produced by CD4+ T cells via STIM1/STING/STAT6/IRF3 signaling pathways, were increased in SKG mice. Interestingly, skin fibrosis was reduced by inhibiting STING pathway in skin fibroblast.Next, we demonstrated the pathophysiological role of IL-4 and IFN-α in skin fibrosis using a humanized SS mouse model and found increased IL-4- and IFN-α-producing CD4+ T cells and fibrosis. In this study, we found that STING-induced production of IL-4- and type I IFN by CD4+ T cells is a key factor in mouse model and humanized mouse model of SS. Our findings suggest that the STING/STAT6/IRF3 signaling pathways are potential therapeutic targets in SS.

The Korean Breast Cancer Society (KBCS) has collected nationwide registry data on clinicopathologic characteristics and treatment since 1996. This study aimed to analyze the clinical characteristics of breast cancer in Korea and assess changes in breast cancer statistics for 2021 using data from the KBCS registry and the Korean Central Cancer Registry. In 2021, 34,628 women were newly diagnosed with breast cancer. The median age of women diagnosed with breast cancer was 53.4 years, with the highest incidence occurring in the 40–49 age group. The most common molecular subtype was hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative, accounting for 69.1% of cases, while HER2-positive subtypes comprised 19.3%. During the coronavirus disease 2019 pandemic, the national breast cancer screening rate declined. However, the incidence of early-stage breast cancer (stages 0 and I) continued to increase, accounting for 65.6% of newly diagnosed cases in 2021. Our results showed that the overall survival rate for patients with breast cancer has improved, primarily due to a rise in early-stage diagnoses and advancements in treatment.

By investigating the characteristics and prognosis of breast cancer (BC) patients who have undergone hormone replacement therapy (HRT), this study addresses a gap in the existing literature. A total of 17,355 postmenopausal patients with BC were analyzed using data from the Korea Breast Cancer Society database (2000–2014). Among them, 3,585 (20.7%) had a history of HRT before BC diagnosis (HRT group), while 13,770 (79.3%) never received HRT (non-HRT group). The HRT group exhibited an earlier pathologic stage, lower histologic and nuclear grades, and a higher rate of breast conservation surgery compared to the non-HRT group. Furthermore, this group had a higher rate of screening participation and a greater proportion of patients with a normal or overweight body mass index (BMI). The prognosis of the HRT group was better than that of the non-HRT group, with a 5-year overall survival rate of 93.9% versus 91.7% (p < 0.001). The hazard ratio for the HRT group was 0.7 (95% confidence interval, 0.608–0.805; p < 0.001). Increased screening participation, longer HRT duration, and a normal or overweight BMI were associated with a better prognosis in the HRT group. Patients with BC who underwent HRT showed better clinicopathological characteristics and prognosis than those who did not receive HRT. The results highlighted significant differences in patients who underwent screening and those with a normal or overweight BMI. Furthermore, a longer HRT duration was associated with a better prognosis.

In the 2023 series, we summarized the major clinical research advances in gynecologic oncology based on communications at the conference of Asian Society of Gynecologic Oncology Review Course. The review consisted of 1) Endometrial cancer: immune checkpoint inhibitor, antibody drug conjugates (ADCs), selective inhibitor of nuclear export, CDK4/6 inhibitors WEE1 inhibitor, poly (ADP-ribose) polymerase (PARP) inhibitors. 2) Cervical cancer: surgery in low-risk early-stage cervical cancer, therapy for locally advanced stage and advanced, metastatic, or recurrent setting; and 3) Ovarian cancer: immunotherapy, triplet therapies using immune checkpoint inhibitors along with antiangiogenic agents and PARP inhibitors, and ADCs. In 2023, the field of endometrial cancer treatment witnessed a landmark year, marked by several practice-changing outcomes with immune checkpoint inhibitors and the reliable efficacy of PARP inhibitors and ADCs.

Background and Objectives: Angiographic assessment of coronary stenosis severity using quantitative coronary angiography (QCA) is often inconsistent with that based on fractional flow reserve (FFR) or intravascular ultrasound (IVUS). We investigated the incidence of discrepancies between QCA and FFR or IVUS, and the outcomes of FFR- and IVUS-guided strategies in discordant coronary lesions. Methods: This study was a post-hoc analysis of the FLAVOUR study. We used a QCA-derived diameter stenosis (DS) of 60% or greater, the highest tertile, to classify coronary lesions as concordant or discordant with FFR or IVUS criteria for percutaneous coronary intervention (PCI). The patient-oriented composite outcome (POCO) was defined as a composite of death, myocardial infarction, or revascularization at 24 months. Results: The discordance rate between QCA and FFR or IVUS was 30.2% (n=551). The QCAFFR discordance rate was numerically lower than the QCA-IVUS discordance rate (28.2% vs. 32.4%, p=0.050). In 200 patients with ≥60% DS, PCI was deferred according to negative FFR (n=141) and negative IVUS (n=59) (15.3% vs. 6.5%, p<0.001). The POCO incidence was comparable between the FFR- and IVUS-guided deferral strategies (5.9% vs. 3.4%, p=0.479).Conversely, 351 patients with DS <60% underwent PCI according to positive FFR (n=118) and positive IVUS (n=233) (12.8% vs. 25.9%, p<0.001). FFR- and IVUS-guided PCI did not differ in the incidence of POCO (9.5% vs. 6.5%, p=0.294). Conclusions The proportion of QCA-FFR or IVUS discordance was approximately one third for intermediate coronary lesions. FFR- or IVUS-guided strategies for these lesions were comparable with respect to POCO at 24 months.