title: Predictive factors and pattern of locoregional recurrence after prophylactic central neck dissection in papillary thyroid carcinoma.
abstract: BACKGROUND
  Prophylactic central neck dissection (pCND) at the time of the total thyroidectomy (TT) remains controversial in clinically nodal-negative (cN0) papillary thyroid carcinoma. Our study was designed to examine the predictive factors and pattern of locoregional recurrence (LRR) after pCND in the context of the postoperative stimulated Tg (sTg) level.
  
  
  METHODS
  A total of 341 patients who underwent TT and unilateral pCND were analyzed. Patients with an identifiable lesion on ultrasonography or whole-body scan within 6 months of surgery were excluded. LRR was defined as an identifiable lesion on USG, which was later confirmed by cytology/histology. Preablation sTg level was taken 2 months after surgery, whereas postablation sTg level was taken 8 months after surgery. Cox regression was used in the univariate and multivariate analyses to identify significant independent factors for LRR.
  
  
  RESULTS
  After a follow-up of 66.6 ± 38.6 months, 14 (4.1 %) suffered from LRR. The duration to first LRR was 36.4 ± 21.7 months. The estimated 5- and 10-year LRR rates were 5.1 and 6.1 %, respectively. Of these 14 LRR, 3 (21.4 %) involved the central compartment alone, 9 (64.3 %) involved the lateral compartment alone, and 2 (14.3 %) involved both central and lateral compartments. After adjusting for other clinicopathological factors, postablation sTg level ≥ 1 µg/L (hazard ratio 265.109, 95 % confidence interval 1.132-62075.644, p = 0.045) was the only independent predictor of LRR.
  
  
  CONCLUSIONS
  Annualized risk of LRR after pCND was approximately 1 % in the first 5 years and 0.2 % in the subsequent 5 years. Most (78.6 %) LRRs involved the lateral compartment. Postablation sTg ≥ 1 µg/L significantly predicted risk of LRR.
authors.affiliation: Department of Surgery, The University of Hong Kong, Hong Kong SAR, China, blang@hku.hk.
authors.forename: Brian Hung-Hin
authors.initials: BH
authors.lastname: Lang
authors.forename: Diane T Y
authors.initials: DT
authors.lastname: Chan
authors.forename: Kai Pun
authors.initials: KP
authors.lastname: Wong
authors.forename: Kandy K C
authors.initials: KK
authors.lastname: Wong
authors.forename: Koon Yat
authors.initials: KY
authors.lastname: Wan
mesh_terms: D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000517:prevention & control / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000517:prevention & control / Q000601:surgery*; D013965:Thyroidectomy; D013997:Time Factors; D016896:Treatment Outcome