Long-Term Changes in the Mortality Rates of Thyroid Cancer in Korea: Analysis of Korean National Data from 1985 to 2020

Association Between Metabolic Dysfunction-Associated Steatotic Liver Disease and Thyroid Cancer

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a hepatic manifestation of metabolic syndrome. This study investigated the association between newly developed nomenclature MASLD and the risk of thyroid cancer in the Korean population. Methods: After excluding individuals with a history of liver disease or malignancy, we analyzed a cohort of 214,502 Korean adults aged 40 years and above who participated in the National Health Screening Program from 2009 to 2010. Participants were categorized into four groups: no steatotic liver disease (SLD) without a cardiometabolic risk factor (CMRF), no SLD with at least one CMRF, MASLD, and metabolic and alcohol-related/associated liver disease (MetALD). SLD was diagnosed using a fatty liver index threshold of ≥30. The primary outcome was the diagnosis of new thyroid cancer during the follow-up period. We examined the relationship between CMRF/SLD and thyroid cancer incidence using the multivariable-adjusted Cox proportional hazards model. Results: A total of 2761 participants (1.3%) were newly diagnosed with thyroid cancer over an average follow-up of 9.61 years. Compared with participants without CMRF and SLD, those with CMRF (hazard ratio [HR] 1.33, confidence interval [CI] 1.16-1.52), those with MASLD (HR 1.36, CI 1.17-1.58), and the MetALD group (HR 1.40, CI 1.04-1.88) exhibited a significantly higher risk of thyroid cancer. In addition, MetALD is significantly associated with thyroid cancer incidence solely in men. Conclusions: In addition to CMRF, MASLD and MetALD were associated with a higher incidence of thyroid cancer in the Korean population. This study is the first to demonstrate the association between thyroid cancer and the CMRF-MASLD-MetALD continuum.

Thyroid cancer-specific mortality during 2005-2018 in Korea, aftermath of the overdiagnosis issue: a nationwide population-based cohort study

BACKGROUND

Thyroid cancer (TC) has underwent notable changes in its diagnosis and treatments following the concerns regarding overdiagnosis and overtreatment. However, there is little research on evaluating the effects of these alterations on TC-specific mortality.

MATERIALS AND METHODS

This population-based cohort study included 434 228 patients with TC using Korean National Health Insurance Service-National Health Information Database. The age-standardized and sex-standardized mortality rates of TC per 1000 person-years were calculated considering the number of patients diagnosed with TC in 2013 per our database to evaluate the TC-specific mortality trends according to the year of TC diagnosis.

RESULTS

The authors enrolled 434 228 patients with TC, including 352 678 women and 81 550 men, with a mean age of 48.6±12.5 years and a median follow-up duration of 7.4 (interquartile range: 4.5-10.1) years. TC incidence increased from 2005 to 2012, with a standardized rate of 91.9 per 100 000 people in 2012, decreased rapidly to 50.6 in 2015, and remained stable until 2018. However, TC-specific age-standardized and sex-standardized mortality rates decreased from 1.94 per 1000 person-years in 2005 to 0.76 per 1000 person-years in 2013 and then increased to 2.70 per 1000 person-years in 2018. The TC-specific age-standardized and sex-standardized mortality rates of patients who had undergone hemithyroidectomy or subtotal thyroidectomy remained steady during 2005-2018, but increased in patients who had undergone total thyroidectomy or not undergone thyroidectomy between 2013 and 2018.

CONCLUSIONS

The TC-specific mortality rates among patients with TC diagnosed since 2015 have increased, in contrast to the significant decline in TC incidence during the same period. This underscores the importance of appropriate diagnosis and treatment in patients with TC at high-risk of progression, simultaneously emphasizing efforts to reduce overdiagnosis and overtreatment in those with low-risk TC.

A Clinical Audit of Thyroid Hormonal Replacement After Total Thyroidectomy

Background Thyroid hormone replacement (THR) in athyreotic patients post-thyroidectomy due to thyroid cancer might seem like a straightforward clinical issue to address. To investigate the impact of THR on enhancing thyroid-stimulating hormone (TSH) levels, we conducted a clinical audit, tailoring the dosage based on patient weight and aligning with the standards outlined by the National Institute for Health and Care Excellence and the American Thyroid Association guidelines. Methodology This retrospective and prospective audit analyzed outpatient clinic records for hormone replacement therapy (HRT) post-total thyroidectomy. Retrospective data from March to May 2022 were collected, followed by prospective data after interventions adjusting HRT based on patient weight to digitize clinic notes. The second phase involved changes for 20 scheduled thyroidectomy patients among the total 37 included in the study. Results The thyroid profiles of both groups in the initial and subsequent cycles, treated with adjusted doses of THR, exhibited normal levels of thyroid hormones and calcium. No substantial differences were observed between the groups. On multivariate logistic regression analysis, we found that older age, male sex, body mass index, and preoperative TSH level were the only significant predictors of the need for hormonal therapy. Conclusions Optimal dose of THR after total thyroidectomy had a positive effect on TSH levels in hypothyroidism patients. Hence, THR should be prescribed according to patient weight based on standards and guidelines.