Background and Objectives: The relationship between iodine intake and effects of antithyroid drugs (ATD) for Graves' disease, especially in iodine-deficient areas, has been demonstrated in many studies. However, it was not clear how chronic high iodine intake influenced the effectiveness of ATD in an iodine-replete area. This study aimed to clarify the effect of iodine intake on clinical outcomes of Graves' disease after discontinuation of ATD in Korea, an iodine-replete area. Methods: A total of 142 patients with Graves' disease who visited the outpatient clinic regularly and stopped their ATD between October 2011 and April 2013 were enrolled in our study. Urinary iodine concentration (UIC) was measured just before and after the discontinuation of ATD. Results: Median UIC was not significantly different between the remission and relapse groups, as well as among the four treatment groups (group 1, remission after initial treatment; group 2, remission after repeated treatment; group 3, early relapse within a year; group 4, late relapse after a year). Remission rates did not show a significant difference between the excessive iodine intake (UIC ≥300 μg/l) and average iodine intake groups (UIC <300 μg/l). Conclusions: The present study suggests that excessive iodine intake does not have an effect on the clinical outcomes of Graves' disease in an iodine-replete area, and therefore diet control with iodine restriction might not be necessary in the management of Graves' disease.

Background: The incidence of childhood thyroid cancer is increasing in several populations; however, contributing factors have not been adequately discussed. Objectives: Our aim was to identify trends of childhood thyroid cancer based on the Korea Central Cancer Registry (KCCR) database and to elucidate changes in detection methods of cancers using a single-center database. Methods: Data from the KCCR and Statistics Korea between 1999 and 2012 were used to calculate the crude incidence of thyroid cancer in children. To analyze detection methods for cancers, pediatric patients (aged 0-19 years, n = 126) who underwent thyroid surgery for thyroid cancers at our institution were identified. Subjects were divided into two groups by detection method: (1) palpation group and (2) screening group. Results: The crude incidence of childhood thyroid cancer increased from 0.5 per 100,000 in 1999 to 1.7 in 2012. The proportion of thyroid cancer among total cancers also increased from 4.4% in 1999 to 10.6% in 2012. Among 126 children from our institution, 91 cases (72%) were identified as palpable neck masses, and the remainder were discovered during imaging studies. The numbers in both groups gradually increased during the study period. Conclusions: The incidence of childhood thyroid cancer has steadily increased in Korea. Regarding the detection methods of cancers, most tumors are detected by palpation rather than screening, although the rate of masses identified during screening has increased.

Objective: Previous reports suggest that a high body mass index (BMI) increases the risk of thyroid carcinoma. However, it remains unclear whether a high BMI is associated with the risk of BRAFV600E mutation. We aimed to assess whether a high BMI is associated with an increased risk of BRAFV600E mutation.

Design and Methods: We screened 6,558 PTC patients who had undergone BRAFV600E mutation testing between January 2009 and December 2017. After exclusion, 6,438 PTC patients were enrolled. We used logistic regression, and restricted cubic spline plots of the adjusted odd ratios (ORs) were illustrated to model the relationship between BMI and BRAFV600E mutation.

Results: Among the 6,438 patients, 5,102 (79.2%) had the BRAFV600E mutation, and 4,954 (76.9%) were female. The median BMI was 23.8 (21.6 – 26.2) kg/m2. The primary tumor size was ≤ 1cm in 4,226 patients (65.6 %) and > 1cm in 2,212 patients (34.4 %). The BRAFV600E mutation was significantly associated with high BMI only in patients with primary tumor size > 1cm (OR 1.034; 95% CI 1.003 – 1.065; P = 0.029), whereas no clear association was found in patients with primary tumor size ≤ 1cm (OR 1.007; 95% CI 0.984 – 1.030; P = 0.570). Gender was not a significant factor in either group.

Conclusions: Our study found that a higher BMI was positively associated with BRAFV600E mutation in patients with primary tumor size > 1cm. These results suggest that the association between BMI and BRAFV600E mutation status differs depending on primary tumor size.

Background: Acute short-term hypothyroidism induced by thyroid hormone withdrawal (THW) for follow-up surveillance or therapeutic radioiodine causes patients with differentiated thyroid cancer to suffer from a myriad of deleterious symptoms. Objectives: To know how patient recognition of hypothyroid symptoms compares to physician perception of patient symptoms. Methods: The survey was performed in 10 referral hospitals throughout Korea from December 2010 to May 2011 and targeted patients with total thyroidectomy and remnant ablation. The survey consisted of questions regarding the effect of THW on patient symptoms, the duration of symptoms, impact on social life, and patient complaints. The physicians treating thyroid cancer patients also responded to the survey and provided their perceptions of patient symptoms and treatment decisions. Results: About 70% of the patients responded that they experienced a negative physical or psychological impact on their life and work due to hypothyroid symptoms. However, 76% of doctors thought hypothyroidism could negatively impact a patient's daily life but would be endurable. Two thirds of physicians do not routinely recommend recombinant human TSH (rhTSH) to their patients. Multivariate analysis showed patients with female sex, stronger educational background, emotionally negative experiences of hypothyroidism, and younger age were more willing to pay for therapy that could prevent hypothyroidism symptoms. Conclusions: There was a substantial gap in the perception of hypothyroid symptoms during THW between physicians and patients. Physicians who are aware of the seriousness of hypothyroidism in their patients were more likely to recommend the use of rhTSH for their patients.