Use of Pre-Ablation Radioiodine-131 Scan to Assess the Impact of Surgical Volume and Specialisation following Thyroidectomy for Differentiated Thyroid Carcinoma

Abstract

Background: We evaluated the relationship between thyroid remnant size following thyroidectomy for differentiated thyroid carcinoma and surgical volume and specialisation by assessing pre-ablation radioiodine-131 (¹³¹I) thyroid bed uptake (TBU) scanning as a surrogate for residual thyroid tissue. Methods: We analysed data of 651 patients in our thyroid cancer database. Patients' data were included if the following criteria were met: (1) diagnosis of differentiated thyroid carcinoma, (2) total or near-total thyroidectomy, (3) pre-ablation ¹³¹I scan prior to radioiodine ablation (RAI), (4) no distant metastasis, and (5) >3,000 MBq ablative dose of ¹³¹I. ¹³¹I diagnostic whole-body scans and measurement of thyroglobulin levels were carried out 3-9 months after RAI. 305 patients were included in the final analysis. Results: Four endocrine, 19 otolaryngology and 25 general surgeons performed thyroidectomies with median pre-ablation ¹³¹I TBU values of 1.0, 1.8 and 2.9%, respectively (p = 0.0031). There was a statistically significant relationship between number of thyroidectomies performed and median pre-ablation ¹³¹I TBU values up to the optimal number of 11 operations beyond which there was no further significant difference between surgeons. There were differences in remnant size between endocrine and general surgeons (p = 0.001), otolaryngology and general surgeons (p = 0.023) but not between endocrine and otolaryngology surgeons (p = 0.167). Conclusion: Using the pre-ablation ¹³¹I uptake scan as a surrogate for thyroid remnant quantification following thyroidectomy demonstrates the relationship between the surgical volume and size of thyroid remnant. The study also demonstrated beneficial effects of specialisation with specialist surgeons achieving the smallest thyroid remnant.