In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

Purpose: Breast cancer gene (BRCA) mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years.We investigated patients who were BRCA mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM. Methods: Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed. Patients who underwent RRM with BRCA mutation who underwent RRM between January 2010 and November 2023 were included in this study.Among patients who underwent contralateral RRM, those with a primary cancer diagnosis were included, and those with occult malignancy on the contralateral RRM side were reviewed additionally. The demographics and pathologies of both primary breast cancer and occult malignancies were evaluated. Results: In our institution, 925 patients were identified as BRCA mutation carriers, and 320 patients underwent contralateral RRM along with primary breast cancer surgery. BRCA2 mutation occurred more frequently (54.8%) in the overall BRCA mutation cohort. Furthermore, we reviewed 320 patients diagnosed with breast cancer and detected as BRCA mutation carriers who underwent contralateral RRM; high proportion of them were BRCA1 mutation carriers.Interestingly, we found a low incidence of only seven patients (2.2%) with occult malignancy on contralateral RRM side, which is different from that reported in other nations. Conclusion The incidence of occult malignancy in the contralateral breast of breast cancer patients with breast cancer with BRCA mutation is significantly low, and may be influenced by several factors. Increased utilization of screening and advancements in diagnostic technologies in South Korea have reduced the chance of occult malignancy in RRM, and a variety of pathologic examination methods may affect the rate of incidence.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Purpose: Breast cancer gene (BRCA) mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years.We investigated patients who were BRCA mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM. Methods: Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed. Patients who underwent RRM with BRCA mutation who underwent RRM between January 2010 and November 2023 were included in this study.Among patients who underwent contralateral RRM, those with a primary cancer diagnosis were included, and those with occult malignancy on the contralateral RRM side were reviewed additionally. The demographics and pathologies of both primary breast cancer and occult malignancies were evaluated. Results: In our institution, 925 patients were identified as BRCA mutation carriers, and 320 patients underwent contralateral RRM along with primary breast cancer surgery. BRCA2 mutation occurred more frequently (54.8%) in the overall BRCA mutation cohort. Furthermore, we reviewed 320 patients diagnosed with breast cancer and detected as BRCA mutation carriers who underwent contralateral RRM; high proportion of them were BRCA1 mutation carriers.Interestingly, we found a low incidence of only seven patients (2.2%) with occult malignancy on contralateral RRM side, which is different from that reported in other nations. Conclusion The incidence of occult malignancy in the contralateral breast of breast cancer patients with breast cancer with BRCA mutation is significantly low, and may be influenced by several factors. Increased utilization of screening and advancements in diagnostic technologies in South Korea have reduced the chance of occult malignancy in RRM, and a variety of pathologic examination methods may affect the rate of incidence.

Purpose: Breast cancer gene (BRCA) mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years.We investigated patients who were BRCA mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM. Methods: Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed. Patients who underwent RRM with BRCA mutation who underwent RRM between January 2010 and November 2023 were included in this study.Among patients who underwent contralateral RRM, those with a primary cancer diagnosis were included, and those with occult malignancy on the contralateral RRM side were reviewed additionally. The demographics and pathologies of both primary breast cancer and occult malignancies were evaluated. Results: In our institution, 925 patients were identified as BRCA mutation carriers, and 320 patients underwent contralateral RRM along with primary breast cancer surgery. BRCA2 mutation occurred more frequently (54.8%) in the overall BRCA mutation cohort. Furthermore, we reviewed 320 patients diagnosed with breast cancer and detected as BRCA mutation carriers who underwent contralateral RRM; high proportion of them were BRCA1 mutation carriers.Interestingly, we found a low incidence of only seven patients (2.2%) with occult malignancy on contralateral RRM side, which is different from that reported in other nations. Conclusion The incidence of occult malignancy in the contralateral breast of breast cancer patients with breast cancer with BRCA mutation is significantly low, and may be influenced by several factors. Increased utilization of screening and advancements in diagnostic technologies in South Korea have reduced the chance of occult malignancy in RRM, and a variety of pathologic examination methods may affect the rate of incidence.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Purpose: Axillary surgery is increasingly omitted in patients with early-stage breast cancer undergoing upfront surgery, as supported by trials such as SOUND and INSEMA. However, in the neoadjuvant setting, the omission of axillary surgery has only been explored in small single-arm studies involving highly selected patients with confirmed breast pathologic complete response (pCR). The NeoNAUTILUS trial aimed to evaluate the oncologic safety of omitting sentinel lymph node biopsy (SLNB) in patients with a high probability of achieving an axillary pCR (ypN0) following neoadjuvant systemic therapy (NST), regardless of breast pCR status. Methods NeoNAUTILUS is a prospective, multicenter, randomized, controlled, noninferiority trial conducted at 12 tertiary centers in Korea. Eligible participants were women with clinical T1–T3, N0, or selected N1 invasive breast cancer, who completed NST and were candidates for breast-conserving surgery (BCS). Prior to enrollment, all patients underwent axillary ultrasound after NST completion to exclude suspicious lymph nodes. Patients with clinical N0 disease of any subtype were eligible for inclusion. Patients with clinical N1 disease with human epidermal growth factor receptor 2-positive or triple-negative tumors may be included if their primary tumor demonstrates a > 30% reduction on magnetic resonance imaging after NST. Participants were randomized 1:1 to undergo BCS with or without SLNB, stratified by clinical nodal status and tumor subtype. Patients were randomized and remained blinded until surgery. The primary endpoint is the 5-year invasive disease-free survival. A total of 464 patients are expected to be enrolled over 3 years, with a 5-year follow-up period.Discussion: NeoNAUTILUS is the first randomized trial to assess the omission of axillary surgery after NST based on the predicted nodal response, independent of breast pCR. This study may redefine axillary management in the neoadjuvant setting by identifying patients who can safely avoid SLNB, thereby reducing surgical morbidity without compromising oncologic outcomes.