1.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
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.
2.Tocilizumab for Patients with Severe Fever with Thrombocytopenia Syndrome: Tocilizumab Observational SFTS Study-1
Jeong Rae YOO ; Misun KIM ; Myeong Jin KANG ; Sora KIM ; Keun Hwa LEE ; Sang Taek HEO
Yonsei Medical Journal 2025;66(5):321-327
There is no established treatment for severe fever with thrombocytopenia syndrome (SFTS). However, the potential role of tocilizumab (TCZ) in cytokine storm modulation warrants further investigation. In this study, we aimed to investigate the therapeutic potential of TCZ in adult patients with SFTS and provide valuable insights into the development of effective treatment strategies for this challenging infectious disease by assessing the impact of TCZ on cytokine dynamics and patient outcomes. This prospective longitudinal observational study included adult patients with SFTS at a teaching hospital in Korea between April 2013 and December 2023. Patients with SFTS and interleukin (IL)-6 levels ≥30 ng/mL received TCZ. The 14- and 28-day mortality rates were compared between the TCZ and therapeutic plasma exchange (TPE) groups during the study period. Among the total of 97 patients, the clinical characteristics showed no significant differences between the TCZ (n=10) and TPE groups (n=30). Compared with TPE, TCZ treatment showed a trend towards lower mortality rate (14-day mortality rate: 10.0% vs. 16.7%, p=0.608; 28-day mortality rate:10.0% vs. 20.0%, p=0.480). Both treatments showed the potential to reduce the viral load and IL-6 levels, indicating their efficacy in managing the disease course. TCZ is a potential therapeutic option for SFTS as it modulates IL-6 levels and improves clinical outcomes.
3.Tocilizumab for Patients with Severe Fever with Thrombocytopenia Syndrome: Tocilizumab Observational SFTS Study-1
Jeong Rae YOO ; Misun KIM ; Myeong Jin KANG ; Sora KIM ; Keun Hwa LEE ; Sang Taek HEO
Yonsei Medical Journal 2025;66(5):321-327
There is no established treatment for severe fever with thrombocytopenia syndrome (SFTS). However, the potential role of tocilizumab (TCZ) in cytokine storm modulation warrants further investigation. In this study, we aimed to investigate the therapeutic potential of TCZ in adult patients with SFTS and provide valuable insights into the development of effective treatment strategies for this challenging infectious disease by assessing the impact of TCZ on cytokine dynamics and patient outcomes. This prospective longitudinal observational study included adult patients with SFTS at a teaching hospital in Korea between April 2013 and December 2023. Patients with SFTS and interleukin (IL)-6 levels ≥30 ng/mL received TCZ. The 14- and 28-day mortality rates were compared between the TCZ and therapeutic plasma exchange (TPE) groups during the study period. Among the total of 97 patients, the clinical characteristics showed no significant differences between the TCZ (n=10) and TPE groups (n=30). Compared with TPE, TCZ treatment showed a trend towards lower mortality rate (14-day mortality rate: 10.0% vs. 16.7%, p=0.608; 28-day mortality rate:10.0% vs. 20.0%, p=0.480). Both treatments showed the potential to reduce the viral load and IL-6 levels, indicating their efficacy in managing the disease course. TCZ is a potential therapeutic option for SFTS as it modulates IL-6 levels and improves clinical outcomes.
4.Risk of Osteoporotic Fractures among Patients with Thyroid Cancer: A Nationwide Population-Based Cohort Study
Eu Jeong KU ; Won Sang YOO ; Yu Been HWANG ; Subin JANG ; Jooyoung LEE ; Shinje MOON ; Eun Kyung LEE ; Hwa Young AHN
Endocrinology and Metabolism 2025;40(2):225-235
Background:
The associations between thyroid cancer and skeletal outcomes have not been thoroughly investigated. We aimed to investigate the risk of osteoporotic fractures in patients with thyroid cancer compared to that in a matched control group.
Methods:
This retrospective cohort study included 2,514 patients with thyroid cancer and 75,420 matched controls from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC, 2006–2019). The rates of osteoporotic fractures were analyzed, and associations with the levothyroxine dose were evaluated.
Results:
Patients with thyroid cancer had a significantly lower risk of fracture than did the control group (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69 to 0.94; P=0.006). Patients diagnosed with thyroid cancer after the age of 50 years (older cancer group) had a significantly lower risk of fracture than did those in the control group (HR, 0.72; 95% CI, 0.6 to 0.85; P<0.001), especially those diagnosed with spinal fractures (HR, 0.66; 95% CI, 0.51 to 0.85; P=0.001). Patients in the older cancer group started osteoporosis treatment earlier than did those in the control group (65.5±7.5 years vs. 67.3±7.6 years, P<0.001). Additionally, a lower dose of levothyroxine was associated with a reduced risk of fractures.
Conclusion
In the clinical setting, the risk of fracture in women diagnosed with thyroid cancer after the age of 50 years was lower than that in the control group, which was caused by more proactive osteoporosis treatment in postmenopausal women with thyroid cancer.
5.Tocilizumab for Patients with Severe Fever with Thrombocytopenia Syndrome: Tocilizumab Observational SFTS Study-1
Jeong Rae YOO ; Misun KIM ; Myeong Jin KANG ; Sora KIM ; Keun Hwa LEE ; Sang Taek HEO
Yonsei Medical Journal 2025;66(5):321-327
There is no established treatment for severe fever with thrombocytopenia syndrome (SFTS). However, the potential role of tocilizumab (TCZ) in cytokine storm modulation warrants further investigation. In this study, we aimed to investigate the therapeutic potential of TCZ in adult patients with SFTS and provide valuable insights into the development of effective treatment strategies for this challenging infectious disease by assessing the impact of TCZ on cytokine dynamics and patient outcomes. This prospective longitudinal observational study included adult patients with SFTS at a teaching hospital in Korea between April 2013 and December 2023. Patients with SFTS and interleukin (IL)-6 levels ≥30 ng/mL received TCZ. The 14- and 28-day mortality rates were compared between the TCZ and therapeutic plasma exchange (TPE) groups during the study period. Among the total of 97 patients, the clinical characteristics showed no significant differences between the TCZ (n=10) and TPE groups (n=30). Compared with TPE, TCZ treatment showed a trend towards lower mortality rate (14-day mortality rate: 10.0% vs. 16.7%, p=0.608; 28-day mortality rate:10.0% vs. 20.0%, p=0.480). Both treatments showed the potential to reduce the viral load and IL-6 levels, indicating their efficacy in managing the disease course. TCZ is a potential therapeutic option for SFTS as it modulates IL-6 levels and improves clinical outcomes.
6.Risk of Osteoporotic Fractures among Patients with Thyroid Cancer: A Nationwide Population-Based Cohort Study
Eu Jeong KU ; Won Sang YOO ; Yu Been HWANG ; Subin JANG ; Jooyoung LEE ; Shinje MOON ; Eun Kyung LEE ; Hwa Young AHN
Endocrinology and Metabolism 2025;40(2):225-235
Background:
The associations between thyroid cancer and skeletal outcomes have not been thoroughly investigated. We aimed to investigate the risk of osteoporotic fractures in patients with thyroid cancer compared to that in a matched control group.
Methods:
This retrospective cohort study included 2,514 patients with thyroid cancer and 75,420 matched controls from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC, 2006–2019). The rates of osteoporotic fractures were analyzed, and associations with the levothyroxine dose were evaluated.
Results:
Patients with thyroid cancer had a significantly lower risk of fracture than did the control group (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69 to 0.94; P=0.006). Patients diagnosed with thyroid cancer after the age of 50 years (older cancer group) had a significantly lower risk of fracture than did those in the control group (HR, 0.72; 95% CI, 0.6 to 0.85; P<0.001), especially those diagnosed with spinal fractures (HR, 0.66; 95% CI, 0.51 to 0.85; P=0.001). Patients in the older cancer group started osteoporosis treatment earlier than did those in the control group (65.5±7.5 years vs. 67.3±7.6 years, P<0.001). Additionally, a lower dose of levothyroxine was associated with a reduced risk of fractures.
Conclusion
In the clinical setting, the risk of fracture in women diagnosed with thyroid cancer after the age of 50 years was lower than that in the control group, which was caused by more proactive osteoporosis treatment in postmenopausal women with thyroid cancer.
7.Tocilizumab for Patients with Severe Fever with Thrombocytopenia Syndrome: Tocilizumab Observational SFTS Study-1
Jeong Rae YOO ; Misun KIM ; Myeong Jin KANG ; Sora KIM ; Keun Hwa LEE ; Sang Taek HEO
Yonsei Medical Journal 2025;66(5):321-327
There is no established treatment for severe fever with thrombocytopenia syndrome (SFTS). However, the potential role of tocilizumab (TCZ) in cytokine storm modulation warrants further investigation. In this study, we aimed to investigate the therapeutic potential of TCZ in adult patients with SFTS and provide valuable insights into the development of effective treatment strategies for this challenging infectious disease by assessing the impact of TCZ on cytokine dynamics and patient outcomes. This prospective longitudinal observational study included adult patients with SFTS at a teaching hospital in Korea between April 2013 and December 2023. Patients with SFTS and interleukin (IL)-6 levels ≥30 ng/mL received TCZ. The 14- and 28-day mortality rates were compared between the TCZ and therapeutic plasma exchange (TPE) groups during the study period. Among the total of 97 patients, the clinical characteristics showed no significant differences between the TCZ (n=10) and TPE groups (n=30). Compared with TPE, TCZ treatment showed a trend towards lower mortality rate (14-day mortality rate: 10.0% vs. 16.7%, p=0.608; 28-day mortality rate:10.0% vs. 20.0%, p=0.480). Both treatments showed the potential to reduce the viral load and IL-6 levels, indicating their efficacy in managing the disease course. TCZ is a potential therapeutic option for SFTS as it modulates IL-6 levels and improves clinical outcomes.
8.Tocilizumab for Patients with Severe Fever with Thrombocytopenia Syndrome: Tocilizumab Observational SFTS Study-1
Jeong Rae YOO ; Misun KIM ; Myeong Jin KANG ; Sora KIM ; Keun Hwa LEE ; Sang Taek HEO
Yonsei Medical Journal 2025;66(5):321-327
There is no established treatment for severe fever with thrombocytopenia syndrome (SFTS). However, the potential role of tocilizumab (TCZ) in cytokine storm modulation warrants further investigation. In this study, we aimed to investigate the therapeutic potential of TCZ in adult patients with SFTS and provide valuable insights into the development of effective treatment strategies for this challenging infectious disease by assessing the impact of TCZ on cytokine dynamics and patient outcomes. This prospective longitudinal observational study included adult patients with SFTS at a teaching hospital in Korea between April 2013 and December 2023. Patients with SFTS and interleukin (IL)-6 levels ≥30 ng/mL received TCZ. The 14- and 28-day mortality rates were compared between the TCZ and therapeutic plasma exchange (TPE) groups during the study period. Among the total of 97 patients, the clinical characteristics showed no significant differences between the TCZ (n=10) and TPE groups (n=30). Compared with TPE, TCZ treatment showed a trend towards lower mortality rate (14-day mortality rate: 10.0% vs. 16.7%, p=0.608; 28-day mortality rate:10.0% vs. 20.0%, p=0.480). Both treatments showed the potential to reduce the viral load and IL-6 levels, indicating their efficacy in managing the disease course. TCZ is a potential therapeutic option for SFTS as it modulates IL-6 levels and improves clinical outcomes.
9.Risk of Osteoporotic Fractures among Patients with Thyroid Cancer: A Nationwide Population-Based Cohort Study
Eu Jeong KU ; Won Sang YOO ; Yu Been HWANG ; Subin JANG ; Jooyoung LEE ; Shinje MOON ; Eun Kyung LEE ; Hwa Young AHN
Endocrinology and Metabolism 2025;40(2):225-235
Background:
The associations between thyroid cancer and skeletal outcomes have not been thoroughly investigated. We aimed to investigate the risk of osteoporotic fractures in patients with thyroid cancer compared to that in a matched control group.
Methods:
This retrospective cohort study included 2,514 patients with thyroid cancer and 75,420 matched controls from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC, 2006–2019). The rates of osteoporotic fractures were analyzed, and associations with the levothyroxine dose were evaluated.
Results:
Patients with thyroid cancer had a significantly lower risk of fracture than did the control group (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69 to 0.94; P=0.006). Patients diagnosed with thyroid cancer after the age of 50 years (older cancer group) had a significantly lower risk of fracture than did those in the control group (HR, 0.72; 95% CI, 0.6 to 0.85; P<0.001), especially those diagnosed with spinal fractures (HR, 0.66; 95% CI, 0.51 to 0.85; P=0.001). Patients in the older cancer group started osteoporosis treatment earlier than did those in the control group (65.5±7.5 years vs. 67.3±7.6 years, P<0.001). Additionally, a lower dose of levothyroxine was associated with a reduced risk of fractures.
Conclusion
In the clinical setting, the risk of fracture in women diagnosed with thyroid cancer after the age of 50 years was lower than that in the control group, which was caused by more proactive osteoporosis treatment in postmenopausal women with thyroid cancer.
10.Risk of Osteoporotic Fractures among Patients with Thyroid Cancer: A Nationwide Population-Based Cohort Study
Eu Jeong KU ; Won Sang YOO ; Yu Been HWANG ; Subin JANG ; Jooyoung LEE ; Shinje MOON ; Eun Kyung LEE ; Hwa Young AHN
Endocrinology and Metabolism 2025;40(2):225-235
Background:
The associations between thyroid cancer and skeletal outcomes have not been thoroughly investigated. We aimed to investigate the risk of osteoporotic fractures in patients with thyroid cancer compared to that in a matched control group.
Methods:
This retrospective cohort study included 2,514 patients with thyroid cancer and 75,420 matched controls from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC, 2006–2019). The rates of osteoporotic fractures were analyzed, and associations with the levothyroxine dose were evaluated.
Results:
Patients with thyroid cancer had a significantly lower risk of fracture than did the control group (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69 to 0.94; P=0.006). Patients diagnosed with thyroid cancer after the age of 50 years (older cancer group) had a significantly lower risk of fracture than did those in the control group (HR, 0.72; 95% CI, 0.6 to 0.85; P<0.001), especially those diagnosed with spinal fractures (HR, 0.66; 95% CI, 0.51 to 0.85; P=0.001). Patients in the older cancer group started osteoporosis treatment earlier than did those in the control group (65.5±7.5 years vs. 67.3±7.6 years, P<0.001). Additionally, a lower dose of levothyroxine was associated with a reduced risk of fractures.
Conclusion
In the clinical setting, the risk of fracture in women diagnosed with thyroid cancer after the age of 50 years was lower than that in the control group, which was caused by more proactive osteoporosis treatment in postmenopausal women with thyroid cancer.

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