title: Factors affecting disease-free status of differentiated thyroid carcinoma patients.
abstract: OBJECTIVE
  The study aim was to assess factors that impact on the outcome of radioiodine therapy in patients diagnosed with differentiated thyroid carcinoma (DTC).
  
  
  METHODS
  We performed a retrospective cohort study on 256 patients with DTC who underwent thyroidectomy and received radioiodine therapy during December 2003 to January 2012. All patients were followed up for at least 1 year. They were considered disease- free by the criteria of the revised American Thyroid Association Management Guideline for Patients with Thyroid nodules and DTC (ATA guideline 2009).
  
  
  RESULTS
  On Cox univariate analysis, factors associated with disease-free status were age<45, stage I tumor, low risk group by histopathology, unifocal tumor involvement, stimulated serum Tg level at 1st dose of radioiodine therapy and no distant metastasis from 1st post-treatment WBS (post RxWBS). On multivariate analysis, stage I tumor and stimulated serum Tg level at 1st dose of radioiodine therapy<30 ng/mL were the significant prognostic factors that increased disease-free rate by 1.73 times and 2.60 times, respectively (P-value<0.05).
  
  
  CONCLUSIONS
  Factors affecting the outcome of radioiodine therapy in our study were age, stage, risk of recurrence by histopathology, unifocal tumor involvement and 1st postRxWBS findings. From these factors, stage I tumor and stimulated serum Tg level at 1st dose of radioiodine therapy were independent prognostic factors that substantial increase the disease-free rate.
authors: Nuclear Medicine Division, Department of Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand E-mail : ning_ray@hotmail.com.
authors: Kanungnij
authors: K
authors: Thamnirat
authors: Chirawat
authors: C
authors: Utamakul
authors: Wichana
authors: W
authors: Chamroonrat
authors: Arpakorn
authors: A
authors: Kositwattanarerk
authors: Yoch
authors: Y
authors: Anongpornjossakul
authors: Chanika
authors: C
authors: Sritara
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D002454:Cell Differentiation; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes