The risk of thyroid cancer and obesity: A nationwide population-based study using the Korea National Health Insurance Corporation cohort database.

INTRODUCTION: In recent years, the incidence of thyroid cancer and obesity has increased rapidly worldwide. Many studies have been conducted on the relationship between thyroid cancer and obesity; however, the potential mechanisms are not well understood, and few studies have been performed in Asia. This study aimed to identify the relationship between the risk of thyroid cancer and obesity in the Korean population based on a large cohort of data. METHOD: We analyzed clinical data from a total of 351,402 individuals (males: 181,709, females: 169,693) aged over 20 years who received medical examinations arranged by the national insurance program from 2003 to 2008. Newly diagnosed thyroid cancer was identified using insurance claims data. The median follow-up duration was 7.01 years. RESULTS: The mean body mass index (BMI) of the subjects was 23.6 ±â€¯3.2 kg/m2 (males, 24 ±â€¯3; females, 23.1 ±â€¯3.3). A total of 3308 individuals (0.94%) developed thyroid cancer during the study period. The risk of thyroid cancer was higher with increasing BMI in both men and women. Hazard ratios (95% confidence interval) for obese (25-29.9 kg/m2) and extremely obese (≥30 kg/m2) groups were 1.23 (1.13-1.34) and 1.26 (1.02-1.50), respectively, compared to the normal group (18.5-22.9 kg/m2). In particular, the association between the risk of thyroid cancer and BMI was more remarkable in the male group than female group. CONCLUSION: Our findings show that higher BMI is positively associated with the risk of thyroid cancer. Furthermore, this study supports the positive association between obesity and the increased incidence of thyroid cancer.

Effect of selenium supplementation for protection of salivary glands from iodine-131 radiation damage in patients with differentiated thyroid cancer.

OBJECTIVE: In the current study, we examined whether selenium supplementation during iodine-131 (131I) treatment had a radio-protective effect on salivary glands. SUBJECTS AND METHODS: Sixteen patients with differentiated thyroid cancer were prospectively enrolled in the study. Patients after total thyroidectomy, before 131I treatment, were divided into two groups; 8 patients in the selenium group and 8 patients in the control group. Patients in the selenium group received 300νg of selenium orally for 10 days, from 3 days before to 6 days after 131I treatment. The control group received a placebo over the same period. To assess salivary gland function, salivary gland scintigraphy was performed before and 6 months after 131I treatment. Serum amylase and whole blood selenium levels were measured before and 2 days and 6 months after 131I treatment. Using salivary gland scintigraphy, maximum uptake ratio (MUR), maximum secretion percentage (MSP), and ejection fraction (EF) of each salivary gland were calculated. RESULTS: Baseline clinical characteristics, baseline amylase and selenium levels, and parameters of baseline salivary gland scintigraphy were not significantly different between selenium and control groups (P>0.05). On a blood test performed 2 days after 131I treatment, the selenium group showed a significantly higher whole blood selenium level (P=0.008) and significantly lower serum amylase level (P=0.009) than the control group. On follow-up salivary gland scintigraphy, the control group showed significantly decreased, MUR of the bilateral parotid and left submandibular glands, MSP of the bilateral parotid and submandibular glands, and EF of the left submandibular glands (P<0.05), while the selenium group only had a significant decrease in MSP of the right submandibular gland and EF of the left submandibular gland (P<0.05). CONCLUSION: Selenium supplementation during 131I treatment was effective to reduce salivary glands damage by 131I radiation in patients with differentiated thyroid cancer.

Medullary thyroid carcinoma: a 30-year experience at one institution in Korea.

PURPOSE: The objective of this study was to review the clinical outcome and prognosis of patients with sporadic and hereditary medullary thyroid cancer (MTC) who were treated at a single tertiary hospital in Korea. METHODS: We retrospectively reviewed the case files of 85 patients treated from August 1982 to February 2012. RESULTS: In all, 65 patients (76.5%) had sporadic MTC and 20 patients (23.5%) had hereditary MTC. Patients in the sporadic group were older than in the hereditary group (P < 0.001). However, the hereditary group had more tumor multiplicity (P < 0.001) and bilaterality (P < 0.001). Neither survival rate was significantly different between the sporadic and hereditary groups (P = 0.775 and P = 0.866). By multivariate analysis, distant metastasis was a significant prognostic factor for overall and progression-free survival. CONCLUSION: In general, patients with MTC have favorable outcomes. Distant metastasis appears to be the strongest predictor of overall and progression-free survival.

A prospective comparison of patient body image after robotic thyroidectomy and conventional open thyroidectomy in patients with papillary thyroid carcinoma.

BACKGROUND: Body image is associated with self-esteem and identity and has a close relationship with quality of life (QoL). We compared the impact of surgical scars on the patient's perception of body image between conventional open thyroidectomy (OT) and robotic thyroidectomy (RT) in female papillary thyroid carcinoma patients. METHODS: From October 2009 to December 2010, we enrolled prospectively 116 papillary thyroid carcinoma patients who underwent total thyroidectomy at the Yonsei University Health System (Seoul, Korea). Of these 116 patients, 56 had OT and 60 RT. Their scars were assessed using the Vancouver Scar Scale (VSS), and psychometric properties were evaluated using the Body Image Scale (BIS) questionnaire postoperatively. Both groups were compared using cross-sectional and time-series methods. RESULTS: Mean age was significantly younger in the RT group. Regarding scar quality, the OT group showed superiority in scar pigmentation and the total VSS score during the early postoperative period, but the VSS score improved over time and was similar between both groups at 9 months. The RT group had better scores regarding most of the BIS items, a trend that remained relatively constant over time. In patients with noticeable scars (VSS ≥ 2) at 9 months, the RT group had better BIS scores regarding almost all items, including "self-conscious," "physical attractiveness," "feeling of less feminine," "sexual attractiveness," "dissatisfaction with body, scar and appearance when dressed," and "avoidance of people due to appearance." CONCLUSION: RT provides a better self-body image and improves QoL compared with conventional OT by avoiding a noticeable cervical scar.

Factors contributing to surgical outcomes of transaxillary robotic thyroidectomy for papillary thyroid carcinoma.

INTRODUCTION: Transaxillary robotic thyroidectomy is considered a technically feasible and safe treatment option for patients with low-risk papillary thyroid carcinoma (PTC). The aim of the present study was to determine the factors that contribute to the perioperative surgical outcomes of robotic thyroidectomy and to suggest guidelines for patient selection to be used by surgeons inexperienced in the technique. METHOD: We reviewed the records of 275 patients with PTC who underwent robotic total thyroidectomy using a gasless, transaxillary single-incision approach at Yonsei University Health System, South Korea, between January 2011 and May 2012. The association between surgical outcomes and clinicopathologic factors was assessed using linear and logistic regression analysis. RESULTS: The contributing factors for surgical outcomes of robotic thyroidectomy were categorized as patient factors, including gender and body mass index (BMI), and thyroid-specific factors, including thyroid gland size, coexistent thyroiditis, tumor size, and serum anti-thyroglobulin antibody and anti-microsomal antibody titers. Of these, male gender, a large thyroid gland, and thyroiditis significantly increased the total operation time. Male gender, thyroiditis, and overweight BMI increased the working space time, and a large thyroid gland and overweight BMI affected the console time. A large thyroid gland and histological thyroiditis were associated with increased intraoperative blood loss. There was no association between postoperative complications and clinicopathologic parameters. CONCLUSION: Male gender, overweight BMI, a large thyroid gland, and coexistent thyroiditis adversely affected the surgical outcome of robotic thyroidectomy. Surgeons inexperienced in the technique should avoid or carefully approach individuals with these factors.

Surgical completeness of robotic thyroidectomy: a prospective comparison with conventional open thyroidectomy in papillary thyroid carcinoma patients.

BACKGROUND: Using the da Vinci(®) robotic system, surgeons can complete secure thyroidectomy without noticeable neck scarring. This study compared the surgical completeness of transaxillary robotic thyroidectomy (RT) with conventional open procedures (OT) in treating papillary thyroid carcinoma (PTC) patients. MATERIALS AND METHODS: From April 2009 through February 2011, 94 PTC patients underwent total thyroidectomy with central compartment neck dissection (CCND) at Yonsei University College of Medicine. All patients received 1.1 GBq radioactive iodine (RAI) ablation, post-therapy whole-body scans (TxWBS), and diagnostic WBS (DxWBS) 1 year later. We prospectively compared patient clinicopathologic characteristics and surgical completeness between the two groups. RESULTS: Fifty-one patients underwent OT and 43 underwent RT. Mean age was significantly younger in the RT group. Tumor size, capsular-invasion frequency, multifocality, bilaterality, and central nodal metastasis were not different between the two groups. The number of retrieved nodes during CCND did not significantly differ between the groups. There was no significant difference between the OT and RT groups in stimulated thyroglobulin levels acquired during TxWBS and DxWBS. The RAI uptake ratios at TxWBS were significantly higher in the RT group compared with the OT group; however, follow-up DxWBS showed no difference in RAI uptake ratios. Also, the ablation success rate was similar between the two groups. There were no abnormal findings in follow-up neck ultrasonography in either group. CONCLUSION: Remnant thyroid tissue ablation after transaxillary RT was successfully managed by 1.1 GBq RAI. RT showed similar surgical completeness versus conventional OT, and provides a safe and feasible surgical option for PTC patients.

Lobectomy and prophylactic central neck dissection for papillary thyroid microcarcinoma: do involved lymph nodes mandate completion thyroidectomy?

BACKGROUND: The present study was designed to investigate the necessity of completion thyroidectomy for patients who underwent thyroid lobectomy for low-risk papillary thyroid microcarcinoma (PTMC) that was later pathologically diagnosed as central lymph node (CLN) metastasis. METHODS: Between 1986 and 2001, we assessed 551 patients who underwent thyroidectomy with prophylactic ipsilateral central compartment neck dissection, and 409 patients were followed-up completely. Thyroid lobectomy were performed in 281 and 128 patients, respectively. The patients were divided into two groups according to CLN metastasis. Clinicopathological profiles and follow-up details were investigated by retrospective chart review. RESULTS: The CLN-positive and -negative groups were comprised of 43 (15.2 %) and 238 patients (84.8 %), respectively. The mean ages of the two groups were not significantly different (p > 0.05). The mean tumor size of the CLN-positive group (6.8 mm) was significantly larger than that of the CLN-negative group (5.6 mm; p < 0.05). Microscopic capsular invasion was significantly higher in the CLN-positive group (51.2 vs. 23.9 %; p < 0.05). Overall, 21 patients (7.4 %, 21/281) experienced recurrence. Among these, 2 (4.7 %, 2/43) and 19 (8.0 %, 19/238) were in the CLN-positive and -negative groups, respectively. There was no significant correlation between CLN metastasis and tumor recurrence. CONCLUSIONS: Postoperative recurrence was lower in the CLN-positive group, and there was no significant correlation between CLN metastasis and tumor recurrence. Our results suggest that it is not necessary to perform completion thyroidectomy for PTMC patients who have undergone thyroid lobectomy and who have been pathologically diagnosed with CLN metastasis.

The impact of body habitus on the surgical outcomes of transaxillary single-incision robotic thyroidectomy in papillary thyroid carcinoma patients.

BACKGROUND: Robotic applications have achieved safe and precise thyroidectomy with notable cosmetic and functional benefits. This study was designed to document the influence of body habitus on robotic thyroidectomy in papillary thyroid carcinoma (PTC) patients. METHODS: From July 2009 to February 2010, 352 patients underwent robotic thyroidectomy using a gasless, transaxillary single-incision approach at Yonsei University Health System. Body habitus was described using body mass index category (normal weight, overweight, obese), neck length, shoulder width, and shoulder width to neck length ratios. The impact of body habitus on surgical outcomes was analyzed with respect to operation time, number of retrieved central nodes, bleeding amount, and postoperative complications. RESULTS: Of the 352 patients, 217 underwent less than total thyroidectomy and 135 underwent total thyroidectomy. Operative variables (i.e. operation times, bleeding amounts, and numbers of retrieved central nodes) showed no significant differences between three BMI groups for less than total thyroidectomy. However, total operation and working space times were longer for obese patients during total thyroidectomy. In particular, shoulder width was positively correlated with total operation time, working space time, console time, and number of retrieved central nodes. On the other hand, postoperative complications were not significantly different in the three BMI groups and showed no significant correlation with the other indices of body habitus. CONCLUSIONS: Standardized robotic thyroidectomy can be performed safely and feasibly in patients with a large body habitus despite longer operation times.