title: Factors influencing radioiodine uptake after thyroid cancer surgery.
abstract: BACKGROUND
  Total thyroidectomy followed by radioactive iodine (RAI) ablation is indicated for most patients with differentiated thyroid cancer. There have been no quantitative studies testing factors that affect uptake on post-ablation whole body scan. We hypothesized greater RAI uptake in patients who underwent two-stage total thyroidectomy (diagnostic hemithyroidectomy followed by completion thyroidectomy) compared to patients who underwent one-stage total thyroidectomy.
  
  
  METHODS
  Medical records and whole body scan images of thyroid cancer patients were reviewed. Thyroid uptake as a percentage of Iodine-131 dose was calculated for each scan. RAI uptake was compared to procedure type, central lymph node dissection (CLND), extrathyroidal invasion, presence of thyroiditis and pre-operative diagnosis.
  
  
  RESULTS
  One hundred six patients who underwent total thyroidectomy and RAI ablation for differentiated thyroid cancer were included. There was a trend to higher RAI uptake in patients who had undergone two-stage thyroidectomy compared to one-stage thyroidectomy (P = 0.06). CLND was associated significantly lower RAI uptake (P = 0.003). On multivariate analyses, CLND was the only variable that retained statistical significance (P = 0.023). CLND was performed more often in patients undergoing one-stage thyroidectomy (P = 0.001), as these patients' cancer diagnosis was known prior to surgery.
  
  
  CONCLUSIONS
  RAI uptake appeared higher in two-stage thyroidectomy than one-stage thyroidectomy. This difference may be attributed to CLND being performed more often in one-stage thyroidectomy. These results add to the discussion about the role of CLND in surgery for differentiated thyroid cancer.
authors: Department of Surgery, University of Melbourne, Parkville, Victoria, Australia.
authors: Jia Bin
authors: JB
authors: Bai
authors: Department of Surgery, Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors: Rezvaneh
authors: R
authors: Shakerian
authors: Department of Nuclear Medicine, Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors: James David
authors: JD
authors: Westcott
authors: Department of Nuclear Medicine, Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors: Meir
authors: M
authors: Lichtenstein
authors: Department of Surgery, University of Melbourne, Parkville, Victoria, Australia.|Department of Surgery, Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors: Julie A
authors: JA
authors: Miller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics*; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods*; D013966:Thyroiditis / Q000150:complications
chemical_list: D007457:Iodine Radioisotopes
keywords: central lymph node dissection; central lymph nodes; differentiated thyroid cancer; radioactive iodine ablation; thyroid cancer; thyroid carcinoma; thyroidectomy; whole body scan