Screening Model for Estimating Undiagnosed Diabetes among People with a Family History of Diabetes Mellitus: A KNHANES-Based Study

A screening model for estimating undiagnosed diabetes mellitus (UDM) is important for early medical care. There is minimal research and a serious lack of screening models for people with a family history of diabetes (FHD), especially one which incorporates gender characteristics. Therefore, the primary objective of our study was to develop a screening model for estimating UDM among people with FHD and enable its validation. We used data from the Korean National Health and Nutrition Examination Survey (KNHANES). KNAHNES (2010-2016) was used as a developmental cohort (n = 5939) and was then evaluated in a validation cohort (n = 1047) KNHANES (2017). We developed the screening model for UDM in male (SMM), female (SMF), and male and female combined (SMP) with FHD using backward stepwise logistic regression analysis. The SMM and SMF showed an appropriate performance (area under curve (AUC) = 76.2% and 77.9%) compared with SMP (AUC = 72.9%) in the validation cohort. Consequently, simple screening models were developed and validated, for the estimation of UDM among patients in the FHD group, which is expected to reduce the burden on the national health care system.

Long Work Hours Are Associated with Hypothyroidism: A Cross-Sectional Study with Population-Representative Data

Background: Studies have highlighted the adverse effects of long work hours on workers' health; however, the association of long work hours with thyroid function has not been studied. This study aimed at assessing long work hours as a risk factor for thyroid dysfunction. Methods: This cross-sectional study was based on data obtained from the Korea National Health and Nutrition Examination Survey conducted from 2013 to 2015. A total of 2160 adults who worked 36-83 hours per week were included. Thyroid function was defined based on the population thyroid-stimulating hormone reference ranges, after excluding individuals with positive results for thyroid peroxidase antibody. The association between work hours and thyroid function was confirmed via multinomial logistic regression. Results: Hypothyroidism was more prevalent among those with longer work hours (3.5% vs. 1.4% for 53-83 and 36-42 work hours per week, respectively). Individuals who worked longer hours had an increased odds for hypothyroidism (odds ratio 1.46, confidence interval 1.12 - 1.90, per 10-hour increase in work hours per week), after adjustment for age, sex, body mass index, urine iodine concentration, smoking status, work schedule, and socioeconomic status. The association between work hours and hypothyroidism was consistent in various subgroups stratified by sex or socioeconomic status. Conclusions: To our knowledge, this study is the first to show that long work hours are associated with hypothyroidism. Further large longitudinal studies are needed to clarify causality.

A Phase II Multi-Center, Non-Randomized, Parallel Group, Non-Inferiority Study to Compare the Efficacy of No Radioactive Iodine Remnant Ablation to Remnant Ablation Treatment in Low- to Intermediate-Risk of Papillary Thyroid Cancer: The MOREthyroid Trial Protocol

BACKGROUND

Radioactive iodine (RAI) remnant ablation is recommended in patients with papillary thyroid cancer (PTC) and extrathyroidal extension or central lymph node metastasis. However, there exists little evidence about the necessity of remnant ablation in PTC patients with low- to intermediate-risk, those have been increasing in recent decades.

METHODS

This multicenter, prospective, non-randomized, parallel group clinical trial will enroll 310 eligible patients with low- to intermediate-risk of thyroid cancer. Inclusion criteria are patients who recently underwent total thyroidectomy for PTC with 3 or less tumors of size 1≤ to ≤2 cm with no microscopic extension and N0/x, or size ≤2 cm with microscopic extension and/or N1a (number of lymph node ≤3, size of tumor foci ≤0.2 cm, and lymph node ratio <0.4). Patients choose to undergo RAI ablation (131I, dose 1.1 GBq) or diagnostic whole-body scan (DxWBS) (131I or 123I, dose 0.074 to 0.222 GBq), followed by subsequent measurement of stimulated thyroglobulin (sTg) within 1 year. Survey for quality of life (QOL) will be performed at baseline and at 1 year after follow-up. The total enrollment period is 5 years, and patients will be followed up for 1 year. The primary endpoint is the non-inferiority of surgery alone to surgery with ablation in terms of biochemical remission (BCR) rate (sTg ≤2 ng/mL) without evidence of structural recurrence. The secondary endpoint was the difference of QOL.

CONCLUSION

This study will evaluate whether surgery alone achieves similar BCR and improved QOL compared to RAI ablation in patients with low- to intermediate-risk PTC within 1 year.

Diagnosis and Treatment of Growth Hormone Deficiency: A Position Statement from Korean Endocrine Society and Korean Society of Pediatric Endocrinology

Growth hormone (GH) deficiency is caused by congenital or acquired causes and occurs in childhood or adulthood. GH replacement therapy brings benefits to body composition, exercise capacity, skeletal health, cardiovascular outcomes, and quality of life. Before initiating GH replacement, GH deficiency should be confirmed through proper stimulation tests, and in cases with proven genetic causes or structural lesions, repeated GH stimulation testing is not necessary. The dosing regimen of GH replacement therapy should be individualized, with the goal of minimizing side effects and maximizing clinical improvements. The Korean Endocrine Society and the Korean Society of Pediatric Endocrinology have developed a position statement on the diagnosis and treatment of GH deficiency. This position statement is based on a systematic review of evidence and expert opinions.

Aspirin Use Is Not Associated with Lower Thyroid Cancer Risk: A Nationwide Nested Case-Control Study

Background: While aspirin use is known to be associated with reduced incidence of various cancer types, it is unclear whether this benefit extends to thyroid cancer. We aimed to evaluate the association between aspirin use and thyroid cancer development. Methods: This nested case-control study used nationwide data from the Korean National Health Insurance Service-National Sample Cohort 2002-2015. In total, 4547 individuals with newly developed thyroid cancer were matched with 13,641 controls based on age, sex, and follow-up period. Odds ratios (ORs) and 95% confidence intervals (CIs) for thyroid cancer development according to aspirin use were analyzed using a multivariable conditional logistic regression model. Results: The number of days for which patients with thyroid cancer used aspirin (the proportions of no use, <30 days/year, 30-90 days/year, and ≥90 days/year were 93.03%, 6.51%, 0.31%, and 0.15%, respectively) was comparable with that of the controls (p = 0.371, chi-squared test). The risk of thyroid cancer development was not associated with the duration of aspirin use (ORs [CI] for aspirin use <30 days/year, 30-90 days/year, and ≥90 days/year were 1.11 [0.96-1.28], 1.01 [0.54-1.88], and 1.23 [0.50-3.06], respectively, compared with no use) after adjusting for body mass index, smoking status, hypertension, Charlson comorbidity index, and number of outpatient visits per year. In addition, subgroup analyses stratified by age, sex, and follow-up duration did not reveal any significant association between aspirin use and thyroid cancer. Conclusions: Our findings suggest that even extended aspirin use may not impact the prevention or onset of thyroid cancer.

0935 Association Between Chronotype, Sleep Duration, Weekend Catch-Up Sleep, and Depression Among Korean High School Students

Introduction

The present study aimed to examine the association between chronotype, sleep duration, weekend catch-up sleep (CUS) duration, and depression among Korean high school students.

Methods

A total of 8,565 high school students who were analyzed from 15 nationwide districts in South Korea completed an online self-report questionnaire. Depressive mood was assessed using the Korean version of the Beck Depression Inventory. The following sleep characteristics were assessed: weekday and weekend sleep durations, weekend CUS duration, chronotype, perceived sufficiency of sleep, self-reported snoring and sleep apnea, daytime sleepiness, and sleep environment. Age, sex, body mass index, number of private classes, and proneness to internet addiction were also measured. Logistic regression analysis was conducted to compute odds ratios for the association between depression and sleep characteristics, after controlling for relevant covariates.

Results

The prevalence of depression (BDI ≥ 16) was 1,794 (20.9%). In the analyses of multivariate logistic regression, the late chronotype (odds ratio [OR], 1.71; 95% CI, 1.47-1.99), female (OR, 2.24; 95% CI, 1.99-2.53), underweight (OR, 1.27; 95% CI, 1.02-1.57) and obesity (OR, 1.41; 95% CI, 1.13-1.75), weekday sleep duration (OR, 0.86; 95% CI, 0.81-0.91), weekend CUS duration ≥ 2 hours (OR, 0.68; 95% CI, 0.55-0.85), ESS (OR, 1.08; 95% CI, 1.07-1.10), much (OR, 2.15; 95% CI, 1.63-2.84) and insufficient (OR, 1.71; 95% CI, 1.46-2.01) perceived sleep, snoring (OR, 1.27; 95% CI, 1.11-1.46) and witnessed apnea (OR, 2.10; 95% CI, 1.75-2.52), increased internet addiction (OR, 1.06; 95% CI, 1.05-1.06), high number of private education (OR, 0.76; 95% CI, 0.60-0.95), and poor sleep environment (OR, 1.86; 95% CI, 1.56-2.21) were associated with depression.

Conclusion

Eveningness preference, insufficient weekday sleep duration, short weekend CUS duration, and self-reported snoring and sleep apnea were associated with an increased risk for depression.

Support

 

OR28-06 Assessment of Long Term Quality of Life According to Treatment Options in Low Risk Papillary Thyroid Microcarcinoma Patients - Active Surveillance or Immediate Surgery, (A Follow up Interim Analysis of Maestro)

Background: The Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) started in June 2016. As a follow-up study of comparing the quality of life (QoL) of the active surveillance (AS) and immediate surgery (OP) groups at 8 months (9.3±4.8 and 7.1±4.2 months, respectively), here we aimed to compare the QoL between the AS and OP groups after 18 months (22.8±4.0 and 22.3±4.3 months, respectively) of follow-up.

Methods: QoL of 108 participants who chose AS, 101 who underwent OP, twelve who changed from AS to OP was evaluated using a thyroid‐specific QoL questionnaire at diagnosis and during follow‐up (median 23 months).

Results: The mean ages of the participants in the AS and OP groups were 47.7±11.0 and 45.1±10.0 years (p=0.075), respectively. At baseline, better physical (8.2±1.4 vs. 7.6±1.8, p=0.032), psychological (7.4±1.2 vs. 6.7±1.6, p=0.010), and total health (7.4±1.0 vs. 6.7±1.3, p=0.005) were observed in the AS group than in the OP group. After a mean follow up of 22.7±4.2 months, better physical (8.1±1.5 vs. 7.4±1.7, p=0.008), psychological (7.7±1.3 vs. 7.0±1.5, p=0.002), and total health (7.5±1.2 vs. 6.8±1.3, p=0.001) were observed in the AS group than in the OP group, whereas spiritual health was comparable between the two groups: compared with the AS group, the OP group experienced more alterations in appetite, sleep, menstrual cycle, voice, motor skill, weight, appearance, cold or heat tolerance, and body swelling. Furthermore, better QOL scores were observed in the AS group in self-concept, personal relationships, sexual life, work motivation, productivity and quality of work, feeling of isolation, driving, doing household chores, preparing meals and doing leisure activities after long term follow up.

Conclusion: Patients who underwent AS had better QOL even after long term follow up. Low risk papillary thyroid microcarcinomas do not influence survival, however surgery related deterioration of QOL lasted long and did not improve even in late post-operative stages when patients were fully recovered from surgery.

Keywords: Quality of life; papillary thyroid microcarcinoma; active surveillance; immediate surgery

SUN-417 Long Working Hours Are Associated with Hypothyroidism: A Cross-Sectional Study with Population-Representative Data

Background: Studies have highlighted the adverse effects of long working hours on workers’ health; however, the association of long working hours with thyroid function has not been studied. This study aimed to assess long working hours as a risk factor for thyroid dysfunction.

Methods: This cross-sectional study was based on data obtained from the Korea National Health and Nutrition Examination Survey conducted from 2013 to 2015. A total of 2,160 adults who worked 36–83 hours per week were included. Thyroid function was defined based on the population thyroid-stimulating hormone reference ranges, after excluding individuals with positive results for thyroid peroxidase antibody. The association between working hours and thyroid function was confirmed via multinomial logistic regression.

Results: Hypothyroidism was more prevalent among those with longer working hours (3·5% vs. 1·4% for 53–83 and 36–42 working hours per week, respectively). Individuals who worked longer hours had an increased odds for hypothyroidism (odds ratio 1·46, 95% confidence interval 1·12−1·90, per 10 hour increase in working hours per week), after adjustment for age, sex, body mass index, urine iodine concentration, smoking status, shift work, and socioeconomic characteristics such as occupation, income level, and educational attainment. The association between working hours and hypothyroidism was consistent in various subgroups stratified by sex or socioeconomic characteristics.

Conclusions: To our knowledge, this study is the first to show that long working hours are associated with hypothyroidism. Our findings suggest that appropriate monitoring and treatment of hypothyroidism are necessary among individuals who work long hours.

Incidence of Diabetes After Cancer Development: A Korean National Cohort Study

Importance

Diabetes is an established risk factor for developing cancer. A limited body of evidence also suggests that cancer can increase the risk of developing new cases of diabetes, but the evidence is inconclusive.

Objective

To evaluate whether the development of cancer is associated with increasing risk of subsequent diabetes.

Design, Setting, and Participants

This cohort study included a nationally representative sample of the Korean general population observed for up to 10 years (January 1, 2003, to December 31, 2013). A total of 524 089 men and women 20 to 70 years of age without diabetes and with no history of cancer at baseline were included.

Exposures

Incident cancer (time-varying exposure).

Main Outcomes and Measures

Incident type 2 diabetes using insurance claim codes.

Results

During 3 492 935.6 person-years of follow-up (median follow-up, 7.0 years) in 494 189 individuals (50.0% female; mean [SD] age, 41.8 [12.5] years), 15 130 participants developed cancer and 26 610 participants developed diabetes. After adjustment for age, sex, precancer diabetes risk factors, metabolic factors, and comorbidities, the hazard ratio (HR) for diabetes associated with cancer development was 1.35 (95% CI, 1.26-1.45; P < .001). The excess risk for diabetes was highest in the first 2 years after cancer diagnosis, but it remained elevated throughout follow-up. By cancer type, development of pancreatic (HR, 5.15; 95% CI, 3.32-7.99), kidney (HR, 2.06; 95% CI, 1.34-3.16), liver (HR, 1.95; 95% CI, 1.50-2.54), gallbladder (HR, 1.79; 95% CI, 1.08-2.98), lung (HR, 1.74; 95% CI, 1.34-2.24), blood (HR, 1.61; 95% CI, 1.07-2.43), breast (HR, 1.60; 95% CI, 1.27-2.01), stomach (HR, 1.35; 95% CI, 1.16-1.58), and thyroid cancer (HR, 1.33; 95% CI, 1.12-1.59) was associated with a significantly increased risk of diabetes.

Conclusions and Relevance

In this large Korean cohort, cancer development increased the risk of subsequent diabetes. These data provide evidence that cancer is associated with an increased risk of diabetes in cancer survivors independent of traditional diabetes risk factors. Physicians should remember that patients with cancer develop other clinical problems, such as diabetes, with higher frequency than individuals without cancer, and should consider routine diabetes screening in these patients.

Longitudinal Assessment of Quality of Life According to Treatment Options in Low-Risk Papillary Thyroid Microcarcinoma Patients: Active Surveillance or Immediate Surgery (Interim Analysis of MAeSTro)

Background: In this ongoing multicenter prospective cohort study on active surveillance (AS) in low-risk papillary thyroid microcarcinoma (PTMC), we aimed to compare the quality of life (QoL) of participants based on their choice of treatment, that is, AS or immediate surgery (OP). Methods: QoL of 203 participants who chose AS and 192 participants who underwent OP was evaluated using a thyroid-specific QoL questionnaire at diagnosis and during follow-up (median 8 months). Results: The mean ages of the participants in the AS and OP groups were 47.3 ± 11.7 and 45.6 ± 10.5 years (p = 0.138), respectively, and the mean tumor sizes were 5.7 ± 1.6 and 6.5 ± 2.1 mm (p = 0.065), respectively. At baseline, significantly better psychological health (7.1 ± 1.3 vs. 6.8 ± 1.6, p = 0.023) and overall health (6.8 ± 1.2 vs. 6.5 ± 1.3, p = 0.018) were observed in the AS group than in the OP group. During follow-up, significantly better physical (7.9 ± 1.1 vs. 7.4 ± 1.2, p < 0.001), psychological (7.4 ± 1.3 vs. 6.9 ± 1.6, p = 0.004), and overall health (6.9 ± 1.0 vs. 6.5 ± 1.1, p = 0.002) were observed in the AS group than in the OP group, whereas spiritual health was comparable between the two groups. Compared with the AS group, the OP group experienced more fatigue, changes in voice and appearance, less satisfaction, and low fear of recurrence. The self-assessed financial burden was similar at baseline and follow-up in both groups. Conclusion: The QoL of PTMC patients is different according to the type of treatment. Better psychological health at baseline and physical and psychological health at follow-up were observed in the AS group than in the OP group. However, studies with longer follow-up periods are needed.

Tumor doubling time predicts response to sorafenib in radioactive iodine-refractory differentiated thyroid cancer

Sorafenib has emerged as an effective therapeutic option for radioactive iodine (RAI)-refractory, locally advanced or metastatic differentiated thyroid cancer (DTC). We investigated the efficacy and safety of sorafenib treatment in a real-world setting and unveil predictive markers of responsiveness to sorafenib. The treatment response, progression-free survival (PFS), overall survival, and adverse events (AEs) of sorafenib-treated RAI-refractory, locally advanced or metastatic DTC patients at three institutes were retrospectively reviewed, and their tumor doubling time was calculated by three investigators. Total eighty-five patients were treated with sorafenib, and seven patients discontinued sorafenib due to AEs before the first tumor assessment. The median PFS was 14.4 months, and the objective response rate was 10.3% in 78 patients who were able to evaluate the tumor response. Age, sex, histologic type, tumor location, RAI avidity, or the presence of FDG-PET uptake did not affect PFS. However, smaller tumor size (≤1.5 cm) of the target lesions in lung showed better PFS (hazard ratio [HR] 0.39, p = 0.01), and tumors with the shortest doubling time (≤6 months) had worse outcome (HR 2.70, p < 0.01). Because of AEs, dose reductions or drug interruptions were required in 64% of patients, and eventually, 23% of patients discontinued sorafenib permanently. The most common AE was hand-foot skin reaction (HFSR). Patients with severe HFSR showed better PFS, but there were no statistical significance (HR 0.65, p = 0.05). In conclusion, small tumor size and long doubling time of each target lesion can be a prognostic marker to predict the responsiveness to sorafenib in RAI-refractory DTC patients.

Genome-Wide Association Study Reveals Distinct Genetic Susceptibility of Thyroid Nodules From Thyroid Cancer

CONTEXT

Thyroid nodules are very common, and 7% to 15% of them are diagnosed as thyroid cancer. However, the inherited genetic risk factors for thyroid nodules and their associations with thyroid cancer remain unknown.

OBJECTIVE

To identify the genetic variants associated with susceptibility to thyroid nodules in comparison with thyroid cancer.

DESIGN AND SETTING

We performed a three-stage genome-wide association study for thyroid nodules. The discovery stage involved a genome-wide scan of 811 subjects with thyroid nodules and 691 subjects with a normal thyroid from a population-based cohort. Replication studies were conducted in an additional 1981 cases and 3100 controls from the participants of a health checkup. We also performed expression quantitative trait loci analysis of public data.

RESULTS

The most robust association was observed in TRPM3 (rs4745021) in the joint analysis (OR, 1.26; P = 6.12 × 10-8) and meta-analysis (OR, 1.28; P = 2.11 × 10-8). Signals at MBIP/NKX2-1 were replicated but did not reach genome-wide significance in the joint analysis (rs2415317, P = 4.62 × 10-5; rs944289, P = 8.68 × 10-5). The expression quantitative trait loci analysis showed that TRPM3 expression was associated with the rs4745021 genotype in thyroid tissues.

CONCLUSIONS

To the best of our knowledge, we have performed the first genome-wide association study of thyroid nodules and identified a susceptibility locus associated with thyroid nodules, suggesting that thyroid nodules have a genetic predisposition distinct from that of thyroid cancer.

Genetic variations in TAS2R3 and TAS2R4 bitterness receptors modify papillary carcinoma risk and thyroid function in Korean females

Type 2 taste receptors (T2Rs, TAS2Rs) mediate bitterness perception and are involved in diverse defence mechanisms in extraoral tissues. The thyrocyte-expressed T2Rs control thyroid hormone production, and this regulatory role may be associated with susceptibility to thyroid diseases. This study examined whether the variations in TAS2Rs modify the risk of papillary thyroid carcinoma (PTC) and whether such T2R-related PTC risk is associated with genetically modified thyroid function. We conducted a case-control study with 763 Korean females, including 250 PTC cases. Seventy-three single-nucleotide polymorphisms in 13 TAS2R genes and the pre-diagnosis levels of 4 thyroid-related functional markers [total triiodothyronine (TT3), free thyroxine, thyroid-stimulating hormone and thyroglobulin] were analysed. Individuals with TAS2R3/4 CC haplotype (rs2270009 and rs2234001) were at a lower risk for PTC than those with the remaining haplotypes (odds ratio = 0.59, 95% confidence interval: 0.36-0.97). Furthermore, TT3 levels were significantly reduced for TAS2R3/4 CC haplotype carriers compared with other haplotype carriers (p = 0.005). No other genetic variants exhibited critical associations with the PTC phenotype and biomarkers. In summary, genetic variations in T2R3/4 bitterness receptors may modify the PTC risk, and the genetically modified thyroid hormone level by those variations may be linked with the PTC-T2Rs association.

Corrigendum: Author's Name Correction. Study Protocol of Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro)

This corrects the article on p. 278 in vol. 33, PMID: 29947183.

Relation of Subclinical Hypothyroidism is Associated With Cardiovascular Events and All-Cause Mortality in Adults With High Cardiovascular Risk

The aim of this study was to determine the association between subclinical hypothyroidism and cardiovascular (CVD) events, and mortality using the atherosclerotic CVD risk score. We carried out an observational study in a prospective cohort that was followed up for 12 years. The study included 3,021 participants aged ≥ 40 years at baseline from the Ansung cohort, part of the Korean Genome and Epidemiology Study. Cox regression models were constructed to evaluate the hazards ratio (HR) and 95% confidence interval (CI) for all-cause mortality and CVD events in groups classified according to thyroid status. Subgroup analysis was performed with a cut-off age of 65 years or 7.5% of the 10-year atherosclerotic CVD risk score. The subclinical hypothyroidism group in the highest quartile of thyroid-stimulating hormone (>6.57 mIU/L) had a significantly increased risk of all-cause mortality (HR 2.12, 95% CI 1.27 to 3.56) and CVD events (HR 1.92, 95% CI 1.21 to 3.04) compared with euthyroid participants. Subgroup analysis by CVD risk revealed that participants with high CVD risk only had a high risk of all-cause mortality (HR 2.18, 95% CI 1.22 to 3.87) and CVD events (HR 2.42, 95% CI 1.35 to 4.33). Further analysis showed that participants aged <65 years with high CVD risk had the highest risk of all-cause mortality (HR 3.50, 95% CI 1.50 to 8.16) and CVD events (HR 3.37, 95% CI 1.46 to 9.57). Our results demonstrated that high thyroid-stimulating hormone levels were associated with a greater risk of mortality and new CVD risks, particularly among subjects with high CVD risk.

Abstract 5269: Body mass index may not have causal association with thyroid cancer risk: A Mendelian randomization study

Background: Thyroid cancer (TC) is one of the endocrine tumors of which incidence rates have shown an upward trend worldwide. Obesity, another endemic health issue, has been recently reported in the association with increased TC risk. We attempted to examine if there is a causal association between body mass index (BMI) and TC using a Mendelian randomization approach.

Methods: Total 17,935 healthy individuals from the Korean Genome Epidemiology Study and 1,214 TC cases from National Cancer Center, Korea, and Seoul National University Hospital were selected with age, sex, BMI, and genetic information. Based on the thirteen previously reported single nucleotide polymorphisms associated with BMI, we constructed a genetic risk score (GRS) as a genetic instrumental variable (IV) representing BMI independent of possible confounding. IV analysis was performed using the ratio (or, Wald) method to test causal association.

Results: The odds of TC were 2.6 times higher in females than males. The cases were younger than the controls. The F-statistic from the regression of BMI on BMI GRS (IV) was 157.2 (usually, F larger than 10 indicates a strong and valid IV), and the IV explained 1.10% of the phenotypic variance for BMI. From IV analysis, genetically instrumented BMI was not associated with TC risk (causal odds ratio per 1kg/m2 increase in BMI 0.98 [0.79 - 1.20 95% confidence interval]).

Conclusion: Our analysis suggests that positive association between obesity and TC risk repeatedly reported from several meta-analyses may be null. Further investigation is needed as the incidence rates differ in different ethnicity.

Citation Format: Jeongseon Kim, Soo Ji Lee, Quy N. Nguyen, Jeonghee Lee, Eun Kyung Lee, Yul Hwangbo, Joohon Sung. Body mass index may not have causal association with thyroid cancer risk: A Mendelian randomization study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5269.

Study Protocol of Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro)

BACKGROUND

The ongoing Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) aims to observe the natural course of papillary thyroid microcarcinoma (PTMC), develop a protocol for active surveillance (AS), and compare the long-term prognosis, quality of life, and medical costs between the AS and immediate surgery groups.

METHODS

This multicenter prospective cohort study of PTMC started in June 2016. The inclusion criteria were suspicious of malignancy or malignancy based on fine needle aspiration or core needle biopsy, age of ≥18 years, and a maximum diameter of ≤1 cm. If there was no major organ involvement, no lymph node/distant metastasis, and no variants with poor prognosis, the patients were explained of the pros and cons of immediate surgery and AS before selecting AS or immediate surgery. Follow-up visits (physical examination, ultrasonography, thyroid function, and questionnaires) are scheduled every 6 months during the first 2 years, and then every 1 year thereafter. Progression was defined as a maximum diameter increase of ≥3, ≥2 mm in two dimensions, suspected organ involvement, or lymph node/distant metastasis.

RESULTS

Among 439 enrolled patients, 290 patients (66.1%) chose AS and 149 patients (33.9%) chose immediate surgery. The median follow-up was 6.7 months (range, 0.2 to 11.9). The immediate surgery group had a larger maximum tumor diameter, compared to the AS group (7.1±1.9 mm vs. 6.6±2.0 mm, respectively; P=0.014).

CONCLUSION

The results will be useful for developing an appropriate PTMC treatment policy based on its natural course and risk factors for progression.

Genome-Wide Association Studies of Autoimmune Thyroid Diseases, Thyroid Function, and Thyroid Cancer

Thyroid diseases, including autoimmune thyroid diseases and thyroid cancer, are known to have high heritability. Family and twin studies have indicated that genetics plays a major role in the development of thyroid diseases. Thyroid function, represented by thyroid stimulating hormone (TSH) and free thyroxine (T4), is also known to be partly genetically determined. Before the era of genome-wide association studies (GWAS), the ability to identify genes responsible for susceptibility to thyroid disease was limited. Over the past decade, GWAS have been used to identify genes involved in many complex diseases, including various phenotypes of the thyroid gland. In GWAS of autoimmune thyroid diseases, many susceptibility loci associated with autoimmunity (human leukocyte antigen [HLA], protein tyrosine phosphatase, non-receptor type 22 [PTPN22], cytotoxic T-lymphocyte associated protein 4 [CTLA4], and interleukin 2 receptor subunit alpha [IL2RA]) or thyroid-specific genes (thyroid stimulating hormone receptor [TSHR] and forkhead box E1 [FOXE1]) have been identified. Regarding thyroid function, many susceptibility loci for levels of TSH and free T4 have been identified through genome-wide analyses. In GWAS of differentiated thyroid cancer, associations at FOXE1, MAP3K12 binding inhibitory protein 1 (MBIP)-NK2 homeobox 1 (NKX2-1), disrupted in renal carcinoma 3 (DIRC3), neuregulin 1 (NRG1), and pecanex-like 2 (PCNXL2) have been commonly identified in people of European and Korean ancestry, and many other susceptibility loci have been found in specific populations. Through GWAS of various thyroid-related phenotypes, many susceptibility loci have been found, providing insights into the pathogenesis of thyroid diseases and disease co-clustering within families and individuals.

Favorable glycemic response after pancreatoduodenectomy in both patients with pancreatic cancer and patients with non-pancreatic cancer

Diabetes mellitus (DM) is prevalent in patients with pancreatic cancer and tends to improve after tumor resection. However, the glycemic response of non-pancreatic cancer patients after surgery has not been examined in detail. We aimed to investigate the changes in glucose metabolism in patients with pancreatic cancer or non-pancreatic cancer after pancreatoduodenectomy (PD).We prospectively enrolled 48 patients with pancreatic cancer and 56 patients with non-pancreatic cancer, who underwent PD. Glucose metabolism was assessed with fasting glucose, glycated hemoglobin (HbA1c), plasma C-peptide and insulin, quantitative insulin check index (QUICKI), and a homeostatic model assessment of insulin resistance (HOMA-IR) and β cell (HOMA-β) before surgery and 6 months after surgery. Patients were divided into 2 groups: "improved" and "worsened" postoperative glycemic response, according to the changes in HbA1c and anti-diabetic medication. New-onset DM was defined as diagnosis of DM ≤ 2 years before PD, and cases with DM diagnosis >2 years preceding PD were described as long-standing DM.After PD, insulin resistance (IR), as measured by insulin, HOMA-IR and QUICKI, improved significantly, although C-peptide and HOMA-β decreased. At 6 months after PD, new-onset DM patients showed improved glycemic control in both pancreatic cancer patients (75%) and non-pancreatic cancer patients (63%). Multivariate analysis showed that long-standing DM was a significant predictor for worsening glucose control (odds ratio = 4.01, P = .017).Favorable glycemic control was frequently observed in both pancreatic cancer and non-pancreatic cancer after PD. PD seems to contribute improved glucose control through the decreased IR. New-onset DM showed better glycemic control than long-standing DM.

Interaction between alcohol consumption and methylenetetrahydrofolate reductase polymorphisms in thyroid cancer risk: National Cancer Center cohort in Korea

The effect of alcohol intake on thyroid cancer is unestablished, and its interaction effects with genetic susceptibility are unclear. In this case-control study, the relationship among alcohol intake, the methylenetetrahydrofolate reductase (MTHFR) gene, and thyroid cancer risk has been evaluated. In total, 642 cases and 642 controls of Korean origin were included, and the genetic variants C677T and A1298C of the MTHFR gene were analysed. The interactions between alcohol-consumption behaviour and genetic variants were analysed with a likelihood ratio test, wherein a multiplicative interaction term was added to a logistic regression model. There was an independent association between the C677T polymorphism and thyroid cancer risk but not for drinking history. For C677T C/C homozygotes, individuals with a history of alcohol consumption showed a protective OR (95% CI) of 0.42 (0.15–1.13) when never drinkers were used as the reference. However, this protective association was not observed among individuals with a T+ allele with an OR (95% CI) of 1.27 (0.89–1.82), showing different directions for the association between genotypes with a significant interaction (P_interaction = 0.009). Based on the genetic characteristics of individuals included, an interaction between alcohol intake and MTHFR C677T may modify the risk of thyroid cancer.

Genome-wide association and expression quantitative trait loci studies identify multiple susceptibility loci for thyroid cancer

Thyroid cancer is the most common cancer in Korea. Several susceptibility loci of differentiated thyroid cancer (DTC) were identified by previous genome-wide association studies (GWASs) in Europeans only. Here we conducted a GWAS and a replication study in Koreans using a total of 1,085 DTC cases and 8,884 controls, and validated these results using expression quantitative trait loci (eQTL) analysis and clinical phenotypes. The most robust associations were observed in the NRG1 gene (rs6996585, P=1.08 × 10-10) and this SNP was also associated with NRG1 expression in thyroid tissues. In addition, we confirmed three previously reported loci (FOXE1, NKX2-1 and DIRC3) and identified seven novel susceptibility loci (VAV3, PCNXL2, INSR, MRSB3, FHIT, SEPT11 and SLC24A6) associated with DTC. Furthermore, we identified specific variants of DTC that have different effects according to cancer type or ethnicity. Our findings provide deeper insight into the genetic contribution to thyroid cancer in different populations.

Abstract 1325: Genome-wide association study of thyroid nodule in Korean population

Thyroid nodule is very common. Several autopsy surveys reported that 30% or more of patients had thyroid nodule. However, inherited genetic risk factors for thyroid nodule remain unknown. Genome-wide association studies (GWAS) are widely used in human genetics to identify genes associated with various diseases. We aimed to find genetic factors for thyroid nodule and conducted case-control GWAS.

Objective: To identify genetic variants associated with susceptibility to thyroid nodules

Methods: We performed a two-stage GWAS for thyroid nodule. The discovery stage involved a genome-wide scan of 713 subjects with thyroid nodule and 591 subjects with normal thyroid from a population-based cohort. replication testing was conducted in an additional 600 cases and 600 controls from the participants of a health check-up.

Results In discovery stage, 21 candidate single nucleotide polymorphisms (SNP) in 20 loci including NKX2-1, ITGB1 and ZBTB25 were selected for replication. The strongest signal located in NKX2-1 (P = 9x10-7), which is known susceptibility locus for differentiated thyroid cancer. However, no SNP showed significant association in replication test. In joint analysis, no association signals reaching genome-wide significance (P &lt;5x10-8) were detected.

Conclusion GWAS for thyroid nodule have failed to identify susceptibility locus. Therefore, genetic effect for development of thyroid nodule could be negligible.

Citation Format: Eun Kyung Lee, Yul Hwangbo, Young Joo Park, Jong-Il Kim, Yuh-Seog Jung, Jun Sun Ryu. Genome-wide association study of thyroid nodule in Korean population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1325. doi:10.1158/1538-7445.AM2017-1325