Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL) predominantly manifests in East Asia and Latin America. Despite shared intrinsic factors, such as ethnic and genetic backgrounds, the progression of ENKTL can be influenced by extrinsic factors related to changing lifestyle patterns. Materials and Methods: This study collected stool samples from newly diagnosed (ND)–ENKTL patients (n=40) and conducted whole genome shotgun sequencing. Results: ND-ENKTL revealed reduced alpha diversity in ND-ENKTL compared to healthy controls (HCs) (p=0.008), with Enterobacteriaceae abundance significantly contributing to the beta diversity difference between ENKTL and HCs (p < 0.001). Functional analysis indicated upregulated aerobic metabolism and degradation of aromatic compounds in ND-ENKTL. Enterobacteriaceae were associated not only with clinical data explaining disease status (serum C-reactive protein, stage, prognosis index of natural killer cell lymphoma [PINK], and PINK-E) but also with clinical outcomes (early relapse and short progression-free survival). The relative abundance of Enterobacteriaceae at the family level was similar between ENKTL and diffuse large B-cell lymphoma (DLBCL) (p=0.140). However, the ENKTL exhibited a higher abundance of Escherichia, in contrast to the prevalence of Enterobacter and Citrobacter in DLBCL. Linear regression analysis demonstrated a significant association between Escherichia abundance and programmed cell death-ligand-1 (PD-L1) levels in tissue samples (p=0.025), whereas no correlation with PD-L1 was observed for Enterobacteriaceae at the family level (p=0.571). Conclusion ND-ENKTL exhibited an abundance of Enterobacteriaceae and a dominant presence of Escherichia. These microbial characteristics correlated with disease status, treatment outcomes, and PD-L1 expression, suggesting the potential of the ENKTL microbiome as a biomarker and cause of lymphomagenesis, which warrants further exploration.

Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL) predominantly manifests in East Asia and Latin America. Despite shared intrinsic factors, such as ethnic and genetic backgrounds, the progression of ENKTL can be influenced by extrinsic factors related to changing lifestyle patterns. Materials and Methods: This study collected stool samples from newly diagnosed (ND)–ENKTL patients (n=40) and conducted whole genome shotgun sequencing. Results: ND-ENKTL revealed reduced alpha diversity in ND-ENKTL compared to healthy controls (HCs) (p=0.008), with Enterobacteriaceae abundance significantly contributing to the beta diversity difference between ENKTL and HCs (p < 0.001). Functional analysis indicated upregulated aerobic metabolism and degradation of aromatic compounds in ND-ENKTL. Enterobacteriaceae were associated not only with clinical data explaining disease status (serum C-reactive protein, stage, prognosis index of natural killer cell lymphoma [PINK], and PINK-E) but also with clinical outcomes (early relapse and short progression-free survival). The relative abundance of Enterobacteriaceae at the family level was similar between ENKTL and diffuse large B-cell lymphoma (DLBCL) (p=0.140). However, the ENKTL exhibited a higher abundance of Escherichia, in contrast to the prevalence of Enterobacter and Citrobacter in DLBCL. Linear regression analysis demonstrated a significant association between Escherichia abundance and programmed cell death-ligand-1 (PD-L1) levels in tissue samples (p=0.025), whereas no correlation with PD-L1 was observed for Enterobacteriaceae at the family level (p=0.571). Conclusion ND-ENKTL exhibited an abundance of Enterobacteriaceae and a dominant presence of Escherichia. These microbial characteristics correlated with disease status, treatment outcomes, and PD-L1 expression, suggesting the potential of the ENKTL microbiome as a biomarker and cause of lymphomagenesis, which warrants further exploration.

Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL) predominantly manifests in East Asia and Latin America. Despite shared intrinsic factors, such as ethnic and genetic backgrounds, the progression of ENKTL can be influenced by extrinsic factors related to changing lifestyle patterns. Materials and Methods: This study collected stool samples from newly diagnosed (ND)–ENKTL patients (n=40) and conducted whole genome shotgun sequencing. Results: ND-ENKTL revealed reduced alpha diversity in ND-ENKTL compared to healthy controls (HCs) (p=0.008), with Enterobacteriaceae abundance significantly contributing to the beta diversity difference between ENKTL and HCs (p < 0.001). Functional analysis indicated upregulated aerobic metabolism and degradation of aromatic compounds in ND-ENKTL. Enterobacteriaceae were associated not only with clinical data explaining disease status (serum C-reactive protein, stage, prognosis index of natural killer cell lymphoma [PINK], and PINK-E) but also with clinical outcomes (early relapse and short progression-free survival). The relative abundance of Enterobacteriaceae at the family level was similar between ENKTL and diffuse large B-cell lymphoma (DLBCL) (p=0.140). However, the ENKTL exhibited a higher abundance of Escherichia, in contrast to the prevalence of Enterobacter and Citrobacter in DLBCL. Linear regression analysis demonstrated a significant association between Escherichia abundance and programmed cell death-ligand-1 (PD-L1) levels in tissue samples (p=0.025), whereas no correlation with PD-L1 was observed for Enterobacteriaceae at the family level (p=0.571). Conclusion ND-ENKTL exhibited an abundance of Enterobacteriaceae and a dominant presence of Escherichia. These microbial characteristics correlated with disease status, treatment outcomes, and PD-L1 expression, suggesting the potential of the ENKTL microbiome as a biomarker and cause of lymphomagenesis, which warrants further exploration.

The American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging classification of thyroid cancer can predict death but cannot determine the type and frequency of follow-up testing. Risk stratification is a concept proposed by the American Thyroid Association that uses additional prognostic factors that are not included in the AJCC/UICC classification, such as number or size of metastatic lymph nodes, genetic mutations, and vascular invasion in follicular cancer, to further refine the prognosis of thyroid cancer. The risk of recurrence was categorized as low, intermediate, and high risk, and the need for total thyroidectomy, radioiodine therapy, or thyroid-stimulating hormone suppression was determined depending on each risk level. This approach has been accepted worldwide, and the previous recommendations of the Korean Thyroid Association followed a similar line of thinking but these have been modified in the revised 2024 guidelines.For the revised initial risk stratification, after careful review of the results of the recent meta-analyses and large observational studies and after a multidisciplinary meeting, four major changes were made: 1) thyroid cancer was reclassified according to the World Health Organization (WHO) 2022 tumor classification system; 2) recurrence risk was stratified by combining encapsulated follicular variant papillary thyroid cancer, follicular thyroid cancer, and oncocytic thyroid cancer, which have similar recurrence risk and associated factors, into follicular-patterned tumor; 3) low-risk groups were defined as those with a known recurrence rate of ≤5%, high-risk groups were upgraded to those with a known recurrence rate of ≥30%, and intermediate-risk groups were those with a recurrence risk of 5–30%; and 4) the intermediate risk group had the recurrence rate presented according to various clinicopathological factors, mainly based on reports from Korea. Thus, it is recommended to evaluate the initial risk group by predicting the recurrence rate by combining each clinical factor in individual patients, rather than applying the recurrence rate caused by single risk factor.

Surgical resection is typically the primary treatment for differentiated thyroid cancer (DTC), followed by radioactive iodine (RAI) and thyroid-stimulating hormone suppression therapies based on the cancer stage and risk of recurrence. Nevertheless, further treatment may be necessary for patients exhibiting persistent disease following RAI therapy, residual disease refractory to RAI, or unresectable locoregional lesions. This guideline discusses the role of external beam radiotherapy and chemotherapy following surgical resection in patients with DTC. External beam radiotherapy is ineffective if DTC has been entirely excised (Grade 2). Adjuvant external beam radiotherapy may be optionally performed in patients with incomplete surgical resection or frequently recurrent disease (Grade 2). In patients at high risk of recurrence following surgery and RAI therapy, adjuvant external beam radiotherapy may be optionally considered (Grade 3). However, external beam radiotherapy may increase the risk of serious adverse events after tyrosine kinase inhibitor therapy. Therefore, careful consideration is needed when prescribing external beam radiotherapy for patients planning to undergo tyrosine kinase inhibitor therapy. There is no evidence supporting the benefits of the routine use of adjuvant chemotherapy for DTC treatment (Grade 2).

Differentiated thyroid cancer demonstrates a wide range of clinical presentations, from very indolent cases to those with an aggressive prognosis. Therefore, diagnosing and treating each cancer appropriately based on its risk status is important. The Korean Thyroid Association (KTA) has provided and amended the clinical guidelines for thyroid cancer management since 2007. The main changes in this revised 2024 guideline include 1) individualization of surgical extent according to pathological tests and clinical findings, 2) application of active surveillance in low-risk papillary thyroid microcarcinoma, 3) indications for minimally invasive surgery, 4) adoption of World Health Organization pathological diagnostic criteria and definition of terminology in Korean, 5) update on literature evidence of recurrence risk for initial risk stratification, 6) addition of the role of molecular testing, 7) addition of definition of initial risk stratification and targeting thyroid stimulating hormone (TSH) concentrations according to ongoing risk stratification (ORS), 8) addition of treatment of perioperative hypoparathyroidism, 9) update on systemic chemotherapy, and 10) addition of treatment for pediatric patients with thyroid cancer.

Purpose: Firefighting duties range from field roles such as suppression, rescue, and emergency medical services (EMS) to various administrative tasks. Despite these differences, they face uniform fitness standards in Korea. This study seeks to define distinct fitness needs for each duty and provide data for customized standards. Methods: One hundred seventy-six Korean male firefighters participated, categorized into suppression (n=76), rescue (n=22), administrative (n=27), and EMS (n=51) roles. All underwent maximal oxygen consumption (VO2 max) tests for aerobic capacity, with body composition measured using bioelectrical impedance and height recorded with a stadiometer. Results: The VO2 max (mL/kg/min) among Korean male firefighters varied across different job duties: suppression (39.96±5.84), rescue (44.84±4.85), administration (40.27±7.01), and EMS (40.51±6.75). Rescue had the highest VO2 max, which was significantly higher (p=0.013). The body mass index (BMI, kg/m2 ) values were as follows: suppression (25.07±2.55), rescue (24.95±1.71), EMS (24.33±3.21), and administration (25.10±2.48). There was no statistically significant difference in BMI values (p=0.464). Conclusion This study evaluated the VO2 max and BMI of South Korean male firefighters according to their job duties. It found that 54.5% did not meet the recommended VO2 max standard of 42 mL/kg/min for their activities, and 77.5% had a BMI indicating overweight or higher. However, it is important to note that not every firefighting duty requires high fitness levels. The key is ensuring firefighters possess the fitness necessary for their specific roles to maintain safety and efficiency. The study aims to provide data for creating fitness management guidelines tailored to the diverse duties of firefighters.

Objective: Peritonitis is a life-threatening, emergent surgical disease with very high mortality and morbidity. Currently, there are insufficient Korean studies using the P-POSSUM (Portsmouth-Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) and the Mannheim Peritonitis Index (MPI) as risk prediction models for nontraumatic peritonitis patients who visit the emergency room. Methods: This retrospective study was carried out on 196 cases of non-traumatic peritonitis in a single emergency center from January 2015 to December 2019. Receiver operating characteristic (ROC) curves were obtained and the area under the ROC curve (AUC) was compared using both P-POSSUM and MPI. The observed mortality and expected mortality for P-POSSUM were compared using the goodness of fit assessed using the Hosmer-Lemeshow equation. Results: Diastolic blood pressure, blood urea nitrogen, potassium, length of stay, and intensive care unit admissions were significantly different between survivors and non-survivors. The AUC was 0.812 for P-POSSUM and 0.646 for MPI. The observed-to-expected mortality ratio for P-POSSUM indicated fewer than expected deaths in all quintiles of risk and this was more pronounced, especially when the expected mortality was over 60%. Conclusion In non-traumatic peritonitis patients, P-POSSUM was more useful in predicting risk than the MPI score. However, P-POSSUM overestimated the risk in high-risk patients. Although the MPI score is only somewhat useful for predicting mortality in patients with non-traumatic peritonitis, it is useful as an adjuvant.

Objective: After the coronavirus disease 2019 (COVID-19) outbreak, there have been some changes in the way the medical system deals with suspected infectious diseases. These changes may also affect non-COVID-19 patients. Acute appendicitis is a common disease that requires emergent surgical intervention in pediatric patients, and delayed diagnosis and treatment may cause some complications. This study analyzed the impact of the COVID-19 pandemic on the incidence of complicated appendicitis in pediatric patients presenting to emergency departments in South Korea. Methods: The target group (post-COVID group) included patients aged under 15 years and diagnosed with acute appendicitis between February 23 and November 30, 2020. Patients diagnosed during the same period in 2019 were selected as the control group (pre-COVID group). The difference in the incidence of complicated appendicitis before and after the COVID-19 outbreak was investigated, and the association with various variables was analyzed using the odds ratios and 95% confidence intervals. Results: The study enrolled a total of 94 patients: 54 in the pre-COVID group and 40 in the post-COVID group. There was no statistically significant variation in the incidence of complicated appendicitis (31.5% vs 35.0%, P=0.723) between the groups. In-hospital time was longer in the post-COVID group (7 hours vs. 10.5 hours, P=0.014), but pre-hospital time showed no significant difference (16 hours vs. 22 hours, P=0.768). In the multivariable logistic regression analysis, pre-hospital time (odds ratio [OR], 1.08; P=0.004), erythrocyte sedimentation rate (OR, 33.24; P<0.001), and the presence of fever (OR, 21.11, P=0.002) showed a significant correlation. Conclusion Post the COVID-19 pandemic outbreak, there was no difference in the incidence of pediatric complicated appendicitis in South Korea.

Background: Allogeneic hematopoietic stem cell transplantation (alloSCT) is a potentially curative treatment option for acute leukemia. We aimed to identify the comorbidity factors affecting survival outcomes after alloSCT and develop a new comorbidity index tool for predicting overall survival (OS). Methods: A Korean nationwide cohort of 3,809 adults with acute leukemia treated with alloSCT between January 2002 and December 2018 was analyzed as the development cohort.A retrospective cohort comprising 313 consecutive adults with acute leukemia who underwent alloSCT between January 2019 and April 2020 was analyzed as the validation cohort. Results: In the development cohort, advanced age, male sex, and comorbidities such as previous non-hematologic malignancy, hypertension, and coronary or cerebral vascular disease were significantly related to poor OS. Subsequently, a new comorbidity scoring system was developed, and risk groups were created, which included the low-risk (score ≤0.17), intermediate-risk (0.17＜ score ≤0.4), high-risk (0.4＜ score ≤0.55), and very high-risk (score ＞0.55) groups. The 1-year OS rates were discriminatively estimated at 73.5%, 66.2%, 61.9%, and 50.9% in the low-risk, intermediate-risk, high-risk, and very high-risk groups in the development cohort, respectively (P ＜0.001). The developed scoring system yielded discriminatively different 1-year OS rates and 1-year incidence of non-relapse mortality according to the risk group (P =0.085 and P =0.018, respectively).Furthermore, the developed model showed an acceptable performance for predicting 1-year non-relapse mortality with an area under the curve of 0.715. Conclusion The newly developed predictive scoring system could be a simple and reliable tool helping clinicians to assess risk of alloSCT in adults with acute leukemia.