title: Preoperative subclinical hyperthyroidism in patients with papillary thyroid carcinoma.
abstract: OBJECTIVE
  Numerous studies have reported the effects of subclinical hyperthyroidism on the cardiovascular system, osteoporosis, and metabolic syndrome. However, there are few studies examining the relationships between subclinical hyperthyroidism and thyroid cancer. The aim of this study was to investigate the relationships between preoperative subclinical hyperthyroidism and clinicopathological characteristics in patients with papillary thyroid carcinoma (PTC) in terms of thyroid-stimulating hormone (TSH) levels and TSH receptor antibody (TRAb) values.
  
  
  METHODS
  Between January 2001 and December 2007, 462 patients were eligible for analysis in our study; we compared the clinicopathological characteristics of 39 preoperative subclinical hyperthyroidism patients with those of 423 euthyroid patients.
  
  
  RESULTS
  There were no statistical differences between the 2 groups with respect to age, male to female ratio, primary tumor size, extrathyroidal extension (ETE), multifocality, lymph node metastasis, TNM and AMES stages, recurrence, and survival, despite significant difference in TSH concentrations between the 2 groups. In the evaluation for TRAb, primary tumor size was significantly larger in patients with normal TRAb than in patients with elevated TRAb. When the patients were subdivided into 4 categories according to TRAb values (<5.0%; 5.0%-10.0%; 10.1%-15.0%; >15.0%), tumor size and ETE were significantly different. However, we could not find linear relationships in the increase or decrease of TRAb values.
  
  
  CONCLUSIONS
  The results of our study suggest that subclinical hyperthyroidism is not independently associated with tumor aggressiveness and prognosis in PTC in spite of reduced TSH levels and increased TRAb values as compared with euthyroid patients.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Dongbin
authors.initials: D
authors.lastname: Ahn
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Sohn
authors.affiliation: Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Jae Han
authors.initials: JH
authors.lastname: Jeon
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Junesik
authors.initials: J
authors.lastname: Park
keywords: Hyperthyroidism; Papillary carcinoma; Thyroid; Thyrotropin