These guidelines aim to establish the standard practice for diagnosing and treating patients with differentiated thyroid cancer (DTC). Based on the Korean Thyroid Association (KTA) Guidelines on DTC management, the “Treatment of Advanced DTC” section was revised in 2024 and has been provided through this chapter. Especially, this chapter covers surgical and nonsurgical treatments for the local (previous surgery site) or regional (cervical lymph node metastasis) recurrences. After drafting the guidelines, it was finalized by collecting opinions from KTA members and related societies. Surgical resection is the preferred treatment for local or regional recurrence of advanced DTC. If surgical resection is not possible, nonsurgical resection treatment under ultrasonography guidance may be considered as an alternative treatment for local or regional recurrence of DTC. Furthermore, if residual lesions are suspected even after surgical resection or respiratory-digestive organ invasion, additional radioactive iodine and external radiation treatments are considered.

Pediatric differentiated thyroid cancers (DTCs), mostly papillary thyroid cancer (PTC, 80-90%), are diagnosed at more advanced stages with larger tumor sizes and higher rates of locoregional and/or lung metastasis. Despite the higher recurrence rates of pediatric cancers than of adult thyroid cancers, pediatric patients demonstrate a lower mortality rate and more favorable prognosis. Considering the more advanced stage at diagnosis in pediatric patients, preoperative evaluation is crucial to determine the extent of surgery required. Furthermore, if hereditary tumor syndrome is suspected, genetic testing is required. Recommendations for pediatric DTCs focus on the surgical principles, radioiodine therapy according to the postoperative risk level, treatment and follow-up of recurrent or persistent diseases, and treatment of patients with radioiodine-refractory PTCs on the basis of genetic drivers that are unique to pediatric patients.

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.

The primary objective of initial treatment for thyroid cancer is minimizing treatment-related side effects and unnecessary interventions while improving patients’ overall and disease-specific survival rates, reducing the risk of disease persistence or recurrence, and conducting accurate staging and recurrence risk analysis. Appropriate surgical treatment is the most important requirement for this purpose, and additional treatments including radioactive iodine therapy and thyroid-stimulating hormone suppression therapy are performed depending on the patients’ staging and recurrence risk. Diagnostic surgery may be considered when repeated pathologic tests yield nondiagnostic results (Bethesda category 1) or atypia of unknown significance (Bethesda category 3), depending on clinical risk factors, nodule size, ultrasound findings, and patient preference. If a follicular neoplasm (Bethesda category 4) is diagnosed pathologically, surgery is the preferred option. For suspicious papillary carcinoma (suspicious for malignancy, Bethesda category 5), surgery is considered similar to a diagnosis of malignancy (Bethesda category 6). As for the extent of surgery, if the cancer is ≤1 cm in size and clinically free of extrathyroidal extension (ETE) (cT1a), without evidence of cervical lymph node (LN) metastasis (cN0), and without obvious reason to resect the contralateral lobe, a lobectomy can be performed. If the cancer is 1-2 cm in size, clinically free of ETE (cT1b), and without evidence of cervical LN metastasis (cN0), lobectomy is the preferred option. For patients with clinically evident ETE to major organs (cT4) or with cervical LN metastasis (cN1) or distant metastasis (M1), regardless of the cancer size, total thyroidectomy and complete cancer removal should be performed at the time of initial surgery. Active surveillance may be considered for adult patients diagnosed with low-risk thyroid papillary microcarcinoma. Endoscopic and robotic thyroidectomy may be performed for low-risk differentiated thyroid cancer when indicated, based on patient preference.

Purpose: Splenectomy for patients with remnant gastric cancer has been controversial. The purpose of this study is to identify the impact of splenectomy in the treatment of remnant gastric cancer. Methods: We retrospectively analyzed 285 patients with remnant gastric cancer who underwent completion total gastrectomy with or without splenectomy in Samsung Medical Center, between September 1996 and December 2017. We used a 1:1 propensity score matching method for the analysis. The matching factors were age, sex, and pathologic stage. After the matching process, we compared the 5-year overall survival (OS) and the disease-free survival (DFS) between patients with and without splenectomy during completion total gastrectomy. Results: The median duration of follow-up was 58.0 months (range, 0–132 months). After propensity score matching, there were no statistically significant differences between the splenectomy group (n = 77) and no splenectomy group (n = 77) in terms of clinicopathological features. The 5-year OS rate between the no splenectomy and splenectomy group were not significantly different. There was no significant difference between 5-year DFS of the matched groups. Multivariate analysis revealed that splenectomy is not a significant prognostic factor in terms of 5-year OS (no splenectomy vs. splenectomy; 61.5% vs. 60.2%, P = 0.884) or DFS (74.9% vs. 69.8%, P = 0.880). Conclusion Splenectomy has no impact on the OS and DFS in patients with remnant gastric cancer. Splenectomy during completion total gastrectomy may not be necessary.

Abattoirs ; Agriculture ; Animals ; Drug Resistance, Multiple ; Farmers ; Korea ; Livestock ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus ; Multilocus Sequence Typing ; Phenotype ; Prevalence ; Red Meat ; Staphylococcus aureus ; Swine ; Tetracycline ; Zinc

Objective: It is difficult to predict medical outcomes for acute pyelonephritis (APN) in women. A delay in diagnosis and treatment results in rapid progression to circulatory collapse, multiple organ failure, and death. We investigated the value of procalcitonin (PCT) and neutrophil-to-lymphocyte ratio (NLR) in APN patients hospitalized through the emergency room. Methods: We retrospectively evaluated women with APN presenting in the emergency room from January 2014 to May 2018. Inflammatory biomarkers, including PCT and NLR, were measured, and the severity of pyelonephritis was assessed using the Surviving Sepsis Campaign definitions (Sepsis-3). Multivariable logistic regression analysis was used to evaluate the risk factors associated with septic shock and the prediction for septic shock was compared using a receiver operating characteristic (ROC) curve. Results: A total of 357 female patients with APN were included. The median level of PCT and NLR was higher in the septic shock group compared with other groups. Multivariate logistic regression analysis showed that age and PCT were risk factors for septic shock. When the ROC curve of septic shock was compared, PCT showed a higher area under the curve than NLR (NLR 0.65 vs. PCT 0.80). Conclusion The initial NLR in the emergency room showed significant differences depending on the severity as classified by Sepsis-3 definitions. However, NLR was not found to be associated with septic shock in female patients with APN.

The emergence of livestock-associated (LA)-methicillin-resistant Staphylococcus aureus (MRSA) in livestock animal has become a significant zoonotic concern. In the present study, we investigated nationwide prevalence of LA-MRSA across pork production chain including pig farms, slaughterhouses, and retail markets. A total of 40 MRSA strains were isolated during the investigation and the overall prevalence of MRSA was 3.4% (n = 37), 0.6% (n = 2), and 0.4% (n = 1) in pig farms, slaughterhouses, and retail markets, respectively. Multilocus sequence typing analyses revealed that the 2 most significant clonal lineages in pork production chain in Korea were ST398 (n = 25) and ST541 (n = 6). All of the 40 MRSA isolates were further characterized to investigate key genotypic and phenotypic correlates associated with the emergence and spread of clonal complex 398 (CC398; ST398, and ST541) LA-MRSA. Although the prevalence of swine-associated MRSA was still relatively low and mostly restricted to pig farms, multidrug-resistant CC398 LA-MRSA isolates with new spa types (t18102 and t18103) were identified as a major clonal lineage. The CC398 LA-MRSA strains tended to exhibit increased levels of multiple drug resistance (MDR) phenotype compared with non-CC398 MRSA strains. Of note, in comparison with non-CC398 MRSA isolates, CC398 LA-MRSA isolates exhibited significantly enhanced tetracycline (TET) and zinc resistance. These findings suggested that co-selection pressure associated with MDR phenotype, especially TET resistance, and zinc resistance may have played a significant role in the emergence and persistence of CC398 LA-MRSA in pig farms in Korea.

Objective: It is difficult to predict medical outcomes for acute pyelonephritis (APN) in women. A delay in diagnosis and treatment results in rapid progression to circulatory collapse, multiple organ failure, and death. We investigated the value of procalcitonin (PCT) and neutrophil-to-lymphocyte ratio (NLR) in APN patients hospitalized through the emergency room. Methods: We retrospectively evaluated women with APN presenting in the emergency room from January 2014 to May 2018. Inflammatory biomarkers, including PCT and NLR, were measured, and the severity of pyelonephritis was assessed using the Surviving Sepsis Campaign definitions (Sepsis-3). Multivariable logistic regression analysis was used to evaluate the risk factors associated with septic shock and the prediction for septic shock was compared using a receiver operating characteristic (ROC) curve. Results: A total of 357 female patients with APN were included. The median level of PCT and NLR was higher in the septic shock group compared with other groups. Multivariate logistic regression analysis showed that age and PCT were risk factors for septic shock. When the ROC curve of septic shock was compared, PCT showed a higher area under the curve than NLR (NLR 0.65 vs. PCT 0.80). Conclusion The initial NLR in the emergency room showed significant differences depending on the severity as classified by Sepsis-3 definitions. However, NLR was not found to be associated with septic shock in female patients with APN.

The emergence of livestock-associated (LA)-methicillin-resistant Staphylococcus aureus (MRSA) in livestock animal has become a significant zoonotic concern. In the present study, we investigated nationwide prevalence of LA-MRSA across pork production chain including pig farms, slaughterhouses, and retail markets. A total of 40 MRSA strains were isolated during the investigation and the overall prevalence of MRSA was 3.4% (n = 37), 0.6% (n = 2), and 0.4% (n = 1) in pig farms, slaughterhouses, and retail markets, respectively. Multilocus sequence typing analyses revealed that the 2 most significant clonal lineages in pork production chain in Korea were ST398 (n = 25) and ST541 (n = 6). All of the 40 MRSA isolates were further characterized to investigate key genotypic and phenotypic correlates associated with the emergence and spread of clonal complex 398 (CC398; ST398, and ST541) LA-MRSA. Although the prevalence of swine-associated MRSA was still relatively low and mostly restricted to pig farms, multidrug-resistant CC398 LA-MRSA isolates with new spa types (t18102 and t18103) were identified as a major clonal lineage. The CC398 LA-MRSA strains tended to exhibit increased levels of multiple drug resistance (MDR) phenotype compared with non-CC398 MRSA strains. Of note, in comparison with non-CC398 MRSA isolates, CC398 LA-MRSA isolates exhibited significantly enhanced tetracycline (TET) and zinc resistance. These findings suggested that co-selection pressure associated with MDR phenotype, especially TET resistance, and zinc resistance may have played a significant role in the emergence and persistence of CC398 LA-MRSA in pig farms in Korea.