title: Sentinel Lymph Node Biopsy Status Correlates with Postoperative Stimulated Thyroglobulin Levels in Low-risk Papillary Thyroid Cancer Patients.
abstract: OBJECTIVE
  Radioactive iodine (RAI) remnant ablation in low-risk papillary thyroid cancer (PTC) is controversial. Current patient selection guidelines recommend the use of postoperative stimulated thyroglobulin (stim-Tg), neck dissections, and sonography but fail to include sentinel lymph node biopsy (SLNB). The objective of this study was to evaluate the correlation between SLNB status and postoperative stimulated thyroglobulin as a surrogate marker of clinical outcome.
  
  
  METHODS
  Retrospective chart review of low-risk PTC patients who underwent a total thyroidectomy with SLNB at the McGill Thyroid Cancer Center. SLNBs were obtained using methylene blue dye. Biochemical measurements were acquired between 4 and 12 weeks postoperatively. Statistical analyses were performed using logistic regression models and receiver operating characterisitc (ROC) curves. A P-value <.05 was considered significant.
  
  
  RESULTS
  Ninety-six patients were included in this study. The positive SLNB rate was 14.6%. The mean postoperative Tg level was 1.41 μg/L. There were no significant correlations between the SLNB and the covariates analyzed (age, gender, histology, tumor size, and thyrotropin levels). Patients with negative SLNB were significantly more likely to have a lower stim-Tg (P<.0001). When postoperative Tg was analyzed as a categorical variable, a threshold of <1 μg/L was significantly associated with a negative SLNB, with a sensitivity and specificity (determined by ROC curves) of 0.86 and 0.88, respectively.
  
  
  CONCLUSIONS
  There exists a correlation between SLNB and postoperative Tg. This creates the possibility of a new approach to RAI administration among low-risk PTC patients incorporating SLNB to the current guidelines.
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Joe
authors: J
authors: Saliba
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Richard J
authors: RJ
authors: Payne
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Rickul
authors: R
authors: Varshney
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Eyal
authors: E
authors: Sela
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Anastasios
authors: A
authors: Maniakas
authors: Department of Medicine, Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre.
authors: Elham
authors: E
authors: Rahme
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Alexander
authors: A
authors: Mlynarek
authors: Department of Pathology, McGill Thyroid Cancer Center, Montreal, Canada.
authors: Derin
authors: D
authors: Caglar
authors: Department of Otolaryngology-Head & Neck Surgery, McGill Thyroid Cancer Center.
authors: Michael P
authors: MP
authors: Hier
authors: Department of Medicine, Division of Endocrinology and Metabolism, Jewish General Hospital.
authors: Michael
authors: M
authors: Tamilia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000097:blood / Q000473:pathology* / Q000601:surgery; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood / Q000473:pathology* / Q000601:surgery
chemical_list: D007457:Iodine Radioisotopes; D013954:Thyroglobulin