RESUMO
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. CONCLUSION: 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.
