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Background: Thyroidectomy is the typical treatment for pediatric thyroid carcinoma; total thyroidectomy is commonly performed. We aimed to report our experience at a single tertiary institution and to evaluate the risk factors for recurrence, especially based on surgical extent, in pediatric patients with differentiated thyroid carcinoma (DTC)., Methods: A data of 94 pediatric patients who underwent thyroid surgery for DTC from January 1982 to December 2012 at Yonsei University Hospital (Seoul, Korea) were reviewed. The clinicopathologic features and surgical outcomes were retrospectively analyzed through complete chart reviews., Results: The mean age was 16.6 ± 3.0 (range, 5-19) years. Fourteen patients had recurrence. Tumor size >2 cm (hazard ratio [HR], 14.241; p = 0.011) and positive lymph nodes (HR, 1.056; p = 0.039) were significant risk factors for disease-free survival (DFS) in multivariate analysis. In Kaplan-Meier analysis, a statistically significant difference was noted in the DFS according to tumor size 2 cm (p < 0.001). However, the DFS was not significantly different between the bilateral total thyroidectomy (BTT) and less than BTT groups (p = 0.215)., Conclusions: BTT remains the treatment of choice in pediatric patients with DTC. Lobectomy may be considered for patients with limited disease, including those with tumor size <2 cm, no suspicious lymph nodes, intrathyroidal lesion, and no multifocal disease.

Understanding how comorbidities contribute to death in cancer patients is becoming an important topic. The present study assessed the role of comorbidities in overall mortality and causes of death in patients with differentiated thyroid carcinoma (DTC). This retrospective cohort study included 2070 patients who underwent thyroidectomy for DTC at a single institution between 2002 and 2005. Probabilities of overall, DTC-specific and other-cause death were examined according to the number of comorbidities, with consideration for competing events. The estimated 15-year cumulative incidences of overall, DTC-specific, and other-cause death were 7.3%, 1.6%, and 5.7%, respectively. Taking the group without comorbidities as a reference, we found that the group with 1-2 comorbidities and the group with ≥3 comorbidities had higher probabilities of other-cause death (subhazard ratios = 2.48 and 9.41, respectively; p < 0.01) and consequently shorter overall survival (hazard ratio = 1.95 and 5.33, respectively; p < 0.01), with adjustment for age, sex, and tumor-node-metastasis classification. In contrast, the probability of DTC-specific death was reduced in patients with ≥3 comorbidities (subhazard ratio = 6.81e-10, p < 0.01). For overall death, the relative proportion of death from DTC reduced when the number of comorbidities increased, and DTC-specific death was not observed in patients with ≥3 comorbidities. Our results show that death from DTC itself accounted for only a fraction of the overall deaths among patients who underwent surgery for DTC. Comorbidities increased overall mortality by increasing the probability of other-cause death. Patients with multiple comorbidities had a low probability of dying from DTC because they died earlier from comorbidities.

Obesity is associated with increased operating times and higher complication rates in many types of surgery. Its impact on robotic thyroidectomy however, is not well documented. The aim of this study was to investigate the relationship between body mass index (BMI) and robotic transaxillary thyroidectomy (RTAT). A retrospective review of prospectively collected data of all patients who underwent RTAT at Yonsei University Health System from October 2007 to December 2014 was performed. Patients were divided into three groups based on BMI (Group 1: BMI < 25, Group 2: BMI 25-29.99, Group 3: BMI ≥ 30), and compared. A total of 3697 patients were analyzed. No differences between the three groups were observed in clinicopathological factors, extent of surgery or length of stay. After multivariate analysis, only seroma and transient voice hoarseness were related to increasing BMI. Total operative time was significantly longer for Group 3 patients with less-than-bilateral total thyroidectomy (BTT), but was not significantly different for patients with BTT. Although obese patients undergoing RTAT have a slightly higher risk of seroma, transient voice hoarseness, and longer operative times, BMI did not influence the other important surgical outcomes of thyroidectomy. Therefore, obesity should not be a contraindication for performing RTAT.

Background: Recent guidelines advocate unilateral thyroidectomy for low-risk 1-cm to 4-cm differentiated thyroid cancer (DTC). This study was designed to examine the association between the extent of thyroidectomy and oncologic outcomes in patients with 1-cm to 4-cm DTC., Materials and Methods: From April 1978 to December 2011, 16 057 patients with DTC underwent thyroidectomy at Yonsei University Hospital. Among them, 5266 (32.8%) patients were classified as having 1-cm to 4-cm DTC and were enrolled in this study. Clinicopathologic features and prognostic results (disease-free survival [DFS] and disease-specific survival [DSS] rates) were analyzed by retrospective medical record review. The mean follow-up duration was 57.3 ± 58.1 months., Results: Of tumor subtypes in the study group, papillary thyroid carcinoma was the most common (97.5%) and follicular thyroid carcinoma occurred at a rate of 2.5%. In this study, the mean tumor size was 1.84 ± 0.74 cm. Patients had extrathyroidal extension (69.3%), multiplicity (35.1%), bilaterality (26.4%), central lymph node metastasis (53.0%), and lateral neck node metastases (19.9%). Of the 5266 patients, 4292 (81.5%) underwent total thyroidectomy and 974 (18.5%) had lobectomies. Recurrence rates in the total thyroidectomy and lobectomy groups were 5.7% and 9.4%, respectively. The lobectomy group had lower DFS (P = .007) and higher DSS (P = .034) than the total thyroidectomy group. A multivariate analysis for DFS revealed that tumor size, N classification, and extent of thyroidectomy were independent risk factors. On multivariate analysis, independent risk factors for DSS were age, sex, tumor size, and M classifications., Conclusion: Although extent of thyroidectomy does not affect DSS, total thyroidectomy is beneficial for reducing recurrence in patients with 1-cm to 4-cm DTC. However, if such tumors have such low-risk features as being unifocal, intrathyroidal, and lymph node metastasis-negative, extent of thyroidectomy does not affect oncologic outcome and lobectomy may be sufficient., (© 2018 Wiley Periodicals, Inc.)

Background: Diffuse lymphocytic infiltration (DLI) is frequently found with papillary thyroid cancer (PTC), so there has been long interest in how it affects the characteristics of PTC. This purpose of this study was to define the association between DLI and PTC aggressiveness according to thyroperoxidase antibody (TPOAb) and B-type Raf (BRAF) V600E mutation positivity., Methods: There were 1879 patients with PTC who underwent surgery and were enrolled in this study. Clinicopathologic characteristics were compared between groups according to the presence of DLI and TPOAb. Multiple logistic regression analysis was conducted to assess odds ratio (OR) for each dependent variable (BRAF V600E mutation, tumor size >1.0 cm, multifocality, extrathyroidal extension, and lymph node metastasis) of each group according to the presence of DLI and TPOAb, with the group with neither DLI or TPOAb (DLI-negative TPOAb-negative PTC) as the reference., Results: The DLI-positive PTC showed more frequent multifocality and less frequent BRAF V600E mutation than DLI-negative PTC. Among patients with DLI-positive PTC, extrathyroidal extension and BRAF V600E mutation was less frequent when serum TPOAb was positive. In multiple logistic regressions, DLI-positive TPOAb-positive PTC showed a high OR for multifocality (1.410; P = .017), but low ORs for BRAF V600E mutation (0.521; P < .001) and extrathyroidal extension (0.691; P = .008). The patients with DLI-positive TPOAb-positive PTCs showed a high OR for multifocality (1.588; P = .002), and high ORs for tumor size >1.0 cm (2.205; P = .019) and lymph node metastasis (2.005; P = .032) in subgroup analyses of PTC with wild-type BRAF. The DLI-negative TPOAb-positive group was not associated with any tumor aggressiveness-related variables., Conclusion: Although DLI was associated with multifocality regardless of TPOAb positivity, it was associated with an indolent feature when TPOAb was positive but with aggressive features in PTC with wild-type BRAF when TPOAb was negative. The TPOAb and BRAF status may help to define the clinical implication of lymphocytic infiltration found with PTC., (© 2018 Wiley Periodicals, Inc.)

Background: Hereditary medullary thyroid carcinoma can present as a part of multiple endocrine neoplasia syndrome by rearranged during transfection gene mutation. We evaluated the prevalence of rearranged during transfection gene mutation in patients who have medullary thyroid carcinoma and the correlations of genotype with medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism according to the revised American Thyroid Association risk level., Methods: A total of 331 patients were diagnosed with medullary thyroid carcinoma, 172 of whom were tested for the rearranged during transfection germline mutation by sequencing of exon 8, 10, 11, and 13-16. These patients were diagnosed during the years 1982-2012 at 2 Korean tertiary hospitals. Patients were analyzed according to the route of diagnosis (screened versus index cases) or the mutational site of rearranged during transfection gene (the American Thyroid Association risk group)., Results: Rearranged during transfection mutation was found in 23.8% of patients tested, showing a decreasing trend with time. The most commonly mutated codon was codon 634 (37.1%), followed by codon 918 (14.3%). rearranged during transfection-positive patients were younger than rearranged during transfection-negative patients, although no other clinicopathologic characteristics differed. Screened cases were younger and had smaller tumors than index cases. Among rearranged during transfection-positive patients, pheochromocytoma manifested in 35.1% and hyperparathyroidism in 7.0%. Notably, pheochromocytoma and hyperparathyroidism emerged at any time after the diagnosis of medullary thyroid carcinoma. The American Thyroid Association risk-group analysis demonstrated that medullary thyroid carcinoma patients in the highest risk group were younger, had larger tumors, and higher disease-specific mortality. Similar results for pheochromocytoma were found, according to the American Thyroid Association risk group, although the results were not significant., Conclusions: Korean patients who have medullary thyroid carcinoma showed a similar distribution of rearranged during transfection gene mutation with those in Western countries. The American Thyroid Association risk classification was shown to be useful for pheochromocytoma, as well as for medullary thyroid carcinoma. Familial screening for rearranged during transfection mutation and lifelong monitoring for associated pheochromocytoma should be emphasized in hereditary medullary thyroid carcinoma., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: The 2015 American Thyroid Association (ATA) management guidelines for adult patients with differentiated thyroid cancer propose the use of the modified initial risk stratification and response to therapy re-stratification systems. This study was conducted to validate the practicality of the revised guidelines for predicting tumor recurrence in patients with differentiated thyroid cancer., Methods: Patients with papillary thyroid cancer (n = 2425) who underwent total thyroidectomy with central neck node dissection with or without modified radical neck node dissection at a single institution between October 1985 and July 2009 were retrospectively enrolled. The accuracy of three different risk-stratification strategies for predicting disease-free survival, set out in the 2009 and 2015 ATA management guidelines, was assessed: the initial risk stratification (ATA 2009-RSS), the modified initial risk stratification (ATA 2015-RSS), and the response to therapy re-stratification (ATA 2015-RTR)., Results: After applying the ATA 2015-RSS, 258/1913 (13.5%) of patients originally designated as intermediate risk by the ATA 2009-RSS were designated as low risk. This was mainly due to the small number of metastatic lymph nodes. Recurrence was detected in 136 (5.6%) patients during follow-up. Of the 2425 cases examined, 375 were designated as low risk by the ATA 2009-RSS, with a recurrence rate of 1.1%. However, the ATA 2015-RSS designated 633 (26.1%) cases as low risk, with a recurrence rate of 0.9%. Implementing the ATA 2015-RTR predicted an excellent response in 1597 (65.9%) cases, with a recurrence rate of 1.1%. According to the proportion of variance explained (PVE), the Akaike information criterion, Harrell's c index, and integrated area under the curve, comparing the predictive accuracy of the ATA 2009-RSS, ATA 2015-RSS, and ATA 2015-RTR revealed that the ATA 2015-RTR was a superior predictor of recurrence., Conclusions: A proportion of patients designated as intermediate risk by the ATA 2009-RSS were designated as low risk by the ATA 2015-RSS. The ATA 2015-RTR may be the most accurate predictor of risk of recurrence.

Regional lymph node (LN) metastasis has a significant impact for prediction of recurrence in patients with papillary thyroid cancers (PTC); however, the prognostic value of the lymph node ratio (LNR), which is defined as the ratio of the number of metastatic LNs to the total number of investigated LNs, is controversial. In this study, we determined the optimal cut-off values of LNRs for the prediction of recurrence in PTC patients.This large cohort study retrospectively evaluated 2294 patients who had undergone total thyroidectomy for PTC at a single institution from October 1985 to June 2009. The prediction probability of central LNR (cLNR, level VI) and total LNR (tLNR, levels II-VI) were estimated by binominal logistic regression analysis. Hazard ratios of the cut-off LNR values for cancer recurrence were calculated for relevant covariates using multivariate Cox regression analyses. Kaplan-Meier analyses were also utilized to assess the effects of estimated LNR cut-off values on recurrence-free survival (RFS).Of the 2294 patients, 138 (6.0%) presented cancer recurrence during the follow-up period (median duration = 107.1 months). The prediction probability indicated that LNRs of 0.4 and 0.5 for central LN and total LN, respectively, are optimal cut-off values for precise prediction with minimization of outliers. Multivariate Cox regression analyses revealed that cLNR ≥0.4 was independently predictive of recurrence in patients with N0 and N1a PTCs (hazard ratio [HR]: 7.016, 95% confidence interval [CI]: 3.72-12.986, P < 0.001) and that tLNR ≥0.5 indicated a significantly increased risk of recurrence in patients with N1b PTCs (HR: 2.372, 95% CI: 1.458-3.860, P < 0.001). In addition, Kaplan-Meier analyses clearly demonstrated that these LNR cut-off values are precisely operational in RFS estimation.The cut-off LNR values of 0.4 and 0.5 for cLNR and tLNR, respectively, were identified. Risk stratification combined with these LNR cut-off values may prove useful to determine treatment and follow-up strategies for PTC patients.

Purpose: The radioiodine ablation therapy is required for patients who underwent a total thyroidectomy. Through a comparative review of a low iodine diet (LID) and a restricted iodine diet (RID), the study aims to suggest guidelines that are suitable for the conditions of Korea., Materials and Methods: The study was conducted with 101 patients. With 24-hour urine samples from the patients after a 2-week restricted diet and after a 4-week restricted diet, the amount of iodine in the urine was estimated. The consumed radioiodine amounts for 2 hours and 24 hours were calculated., Results: This study was conducted with 47 LID patients and 54 RID patients. The amounts of iodine in urine, the 2-week case and 4-week case for each group showed no significant differences. The amounts of iodine in urine between the two groups were both included in the range of the criteria for radioiodine ablation therapy. Also, 2 hours and 24 hours radioiodine consumption measured after 4-week restrictive diet did not show statistical differences between two groups., Conclusion: A 2-week RID can be considered as a type of radioiodine ablation therapy after patients undergo a total thyroidectomy.

Metabolic reprogramming has been regarded as an essential component of malignant transformation. However, the clinical significance of metabolic heterogeneity remains poorly characterized. The aim of this study was to characterize metabolic heterogeneity in thyroid cancers via the analysis of the expression of mitochondrial ribosomal proteins (MRPs) and genes involved in oxidative phosphorylation (OxPhos), and investigate potential prognostic correlations. Gene set enrichment analysis (GSEA) verified by reverse transcription polymerase chain reaction and gene network analysis was performed using public repository data. Cross-sectional observational study was conducted to classify papillary thyroid cancer (PTC) by the expression of MRP L44 (MRPL44) messenger RNA (mRNA), and to investigate the clinicopathological features. GSEA clearly showed that the expression of OxPhos and MRP gene sets was significantly lower in primary thyroid cancer than in matched normal thyroid tissue. However, 8 of 49 primary thyroid tumors (16.3%) in the public repository did not show a reduction in OxPhos mRNA expression. Remarkably, strong positive correlations between MRPL44 expression and those of OxPhos and MRPs such as reduced nicotinamide adenine dinucleotide dehydrogenase (ubiquinone) 1 α subcomplex, 5; succinate dehydrogenase complex, subunit D; cytochrome c, somatic; adenosine triphosphate synthase, H+ transporting, mitochondrial Fo complex, subunit C1 (subunit 9); and MRP S5 (MRPS5) (P < 0.0001) were clearly denoted, suggesting that MRPL44 is a representative marker of OxPhos and MRP expressions. In laboratory experiments, metabolic heterogeneity in oxygen consumption, extracellular acidification rates (ECARs), and amounts of OxPhos complexes were consistently observed in BCPAP, TPC1, HTH-7, and XTC.UC1 cell lines. In PTCs, metabolic phenotype according to OxPhos amount defined by expression of MRPL44 mRNA was significantly related to lymph node metastasis (LNM) (P < 0.001). Furthermore, multivariate analysis clearly indicated that expression of MRPL44 is associated with an increased risk of lateral neck LNM (odds ratio 9.267, 95% confidence interval 1.852-46.371, P = 0.007). MRPL44 expression may be a representative marker of metabolic phenotype according to OxPhos amount and a useful predictor of LNM.

Purpose: Most patients with well-differentiated thyroid cancer (WDTC) have favorable prognosis and survive for many years. We investigated the effect of thyroid cancer surgery on subsequent psychological aspects., Methods: Demographic parameters, clinical characteristics, and other data were obtained from self-administered questionnaires administered to WDTC patients at various times after thyroid cancer surgery. The questionnaires assessed psychological aspects based on three scales: a performance of everyday activities questionnaire developed for this study, the Hospital Anxiety and Depression Scale (HADS), and the Fear of Progression Questionnaire (FoP-Q)., Results: The mean time since thyroid surgery and the survey was 3.5 years. More than half of the patients (60.7%) were able to perform all activities without limitations. The HADS scores indicated no anxiety or depression in most patients, and the FoP-Q scores indicated little fear of cancer progression. The time since surgery, type of surgery, use of postoperative radioiodine ablative therapy, and recurrence or metastasis had no significant effect on the psychological scores., Conclusions: Our study indicates that most WDTC patients are psychologically stable after the thyroid cancer surgery.