title: Papillary thyroid cancer: factors involved in restaging N1 disease after total thyroidectomy and radioactive iodine treatment.
abstract: BACKGROUND
  The presence of cervical lymph node metastases is a strong predictor of persistent disease in papillary thyroid cancer (PTC).
  
  
  OBJECTIVE
  The objective of the study was to investigate factors associated with improved outcome in patients with PTC and lymph node metastases.
  
  
  METHODS
  Retrospective Cohort Setting: The study was conducted at a tertiary university-affiliated medical center.
  
  
  METHODS
  PATIENTS treated for PTC and N1 disease since 1995 participated in the study. Partial thyroidectomy, distant metastases, and poor differentiation were the exclusion criteria.
  
  
  METHODS
  The intervention was a data search of the Thyroid Registry.
  
  
  METHODS
  Significant association of clinical and disease-related factors with persistent disease was measured.
  
  
  RESULTS
  Of 800 patients treated for PTC during the study period, 182 (69% female; mean age at diagnosis 46.5 ± 15 y) had N1 disease (47% N1a, 53% N1b). Most (93.4%) had a classical/follicular variant; 65% had T1-2 disease; and 42.6% had extrathyroid extension. All patients were treated with total thyroidectomy and radioactive iodine (mean first dose 147 ± 26 mCi). Lateral neck dissection was performed in 53% patients. Mean follow-up was 9.2 ± 4.5 years. On regression analysis, factors significantly and independently associated with persistent disease at 1 year (94 of 182, 52%; 40% of N1a group, 59% of N1b group) were primary tumor size, focality, and extrathyroid extension and at the last follow-up (62 of 182, 34%; 27% of N1a group, 33% of N1b group), primary tumor size, 1-year stimulated thyroglobulin level, and cumulative I(131) dose. Stimulated thyroglobin less than 2.1 ng/mL at 1 year predicts the absence of disease at the last follow-up with an 86% negative predictive value.
  
  
  CONCLUSIONS
  PATIENTS with PTC and N1 disease treated with total thyroidectomy and radioactive iodine have a significant risk of persistent disease at early and late follow-up. The extension of the primary tumor at diagnosis appears to be the only significant predictor of persistency in these patients.
authors.affiliation: Endocrine Institute (A.G., D.H., A.T., E.R., I.S., C.A.B.), Department of Otolaryngology Head and Neck Surgery (G.B.), and Statistics Unit (T.S.), Rabin Medical Center, Beilinson Campus, Petah Tiqwa, Israel 49100; and Sackler Faculty of Medicine (A.G., D.H., G.B., A.T., E.R., I.S., C.A.B.), Tel Aviv University, Tel Aviv, 69978, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Guy
authors.forename: Dania
authors.initials: D
authors.lastname: Hirsch
authors.forename: Tzippy
authors.initials: T
authors.lastname: Shohat
authors.forename: Gideon
authors.initials: G
authors.lastname: Bachar
authors.forename: Amit
authors.initials: A
authors.lastname: Tirosh
authors.forename: Eyal
authors.initials: E
authors.lastname: Robenshtok
authors.forename: Ilan
authors.initials: I
authors.lastname: Shimon
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Benbassat
mesh_terms: D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D019275:Radiopharmaceuticals / Q000627:therapeutic use*; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals