The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.

The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.

The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.

Cellular senescence causes cell cycle arrest and promotes permanent cessation of proliferation. Since the senescence of mesenchymal stem cells (MSCs) reduces proliferation and multipotency and increases immunogenicity, aged MSCs are not suitable for cell therapy. Therefore, it is important to inhibit cellular senescence in MSCs. It has recently been reported that metabolites can control aging diseases. Therefore, we aimed to identify novel metabolites that regulate the replicative senescence in MSCs. Using a fecal metabolites library, we identified nervonic acid (NA) as a candidate metabolite for replicative senescence regulation. In replicative senescent MSCs, NA reduced senescence-associated β-galactosidase positive cells, the expression of senescence-related genes, as well as increased stemness and adipogenesis. Moreover, in non-senescent MSCs, NA treatment delayed senescence caused by sequential subculture and promoted proliferation. We confirmed, for the first time, that NA delayed and inhibited cellular senescence.Considering optimal concentration, duration, and timing of drug treatment, NA is a novel potential metabolite that can be used in the development of technologies that regulate cellular senescence.

Postoperative pathological diagnosis of differentiated thyroid cancer (DTC) is important to confirm the diagnosis and predict the risk of recurrence and death. Further treatment plans, such as completion thyroidectomy, radioiodine remnant ablation, or external beam radiation therapy, are then opted for to reduce the predicted risk of recurrence or death. The World Health Organization has classified thyroid cancers into seven distinct categories based on the molecular profile and tumor cell origin. Our recommendation is applicable to differentiated follicular cell-derived carcinoma, the most common form of thyroid cancer, and cribriform morular thyroid carcinoma. Postoperative clinical and pathological staging is recommended for all patients with DTC to determine their prognosis and subsequent treatment decisions. In particular, the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) staging system is recommended for staging DTCs for disease mortality prediction and national cancer registries. The information in the pathology report, including histologic features of the tumor that are necessary for AJCC/UICC staging and recurrence prediction, can help assess the patient’s risk.

The prevalence of thyroid cancer in pregnant women is unknown; however, given that thyroid cancer commonly develops in women, especially young women of childbearing age, new cases are often diagnosed during pregnancy. This recommendation summarizes the follow-up and treatment when thyroid cancer is diagnosed during pregnancy and when a woman with thyroid cancer becomes pregnant. If diagnosed in the first trimester, surgery should be postponed until after delivery, and the patient should be monitored with ultrasound. If follow-up before 24–26 weeks of gestation shows that thyroid cancer has progressed, surgery should be considered. If it has not progressed at 24–26 weeks of gestation or if papillary thyroid cancer is diagnosed after 20 weeks of pregnancy, surgery should be considered after delivery.

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.

The selected treatment for a nodule that is diagnosed as thyroid cancer is surgery. Imaging and blood tests are performed prior to surgery to determine the extent of the surgery. An Ultrasound (US) of the thyroid and neck should be performed to evaluate the size of the cancer, whether it is multifocal and has invaded surrounding tissues, and the status of the cervical lymph nodes (LNs). In addition to US, contrast-enhanced computed tomography may help detect cervical LN metastasis and evaluate patients suspected with invasive thyroid cancer.Generally, routine preoperative measurement of serum thyroglobulin and thyroglobulin antibody concentrations is not recommended. Integrated 18F-fluorodeoxyglucose positron-emission/computed tomography may be helpful either in patients with suspected lateral cervical LNs or distant metastasis or in patients with aggressive histology.

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).

Only a small percentage of patients (2-5%) with differentiated thyroid cancer (DTC) exhibit distant metastasis at the initial diagnosis or during the disease course. The most common metastatic sites of DTC are the lungs, followed by the bones. Radioactive iodine (RAI) therapy is considered the primary treatment for RAI-avid distant metastatic DTC. Depending on the characteristics of metastatic lesions, local treatment such as surgical resection, radiofrequency ablation, and external beam radiation therapy may be considered for some patients with metastatic DTC. Slowly growing and asymptomatic metastases can be monitored with follow-up while receiving thyroid-stimulating hormone (TSH) suppression therapy. In patients with a limited number of lung metastases and good performance status, surgical removal of the metastatic lesions may be considered. Systemic therapy should be considered for patients with progressive RAI refractory DTC. In this clinical guideline, we aim to outline the treatment principles for patients with lung, bone, and brain metastases of DTC.