Total Thyroidectomy Followed by Postsurgical Remnant Ablation May Improve Cancer Specific Survival in Differentiated Thyroid Carcinoma

Abstract

Purpose: To determine the effect of the extent of thyroidectomy and additional postsurgical radioiodine remnant ablation (RRA) on the survival of patients with differentiated thyroid carcinoma (DTC) after adjustment for risk stage. Methods: We electronically identified 614 cases of DTC at our institution between 1987 and 2006. Two treatment variables were created, surgical extent dichotomized to total versus other and a composite of surgery and radioactive iodine ablation. The odds of cancer specific survival and disease-free survival (DFS) were determined using Cox proportional hazards model with adjustment for quantitative tumor-node-metastasis risk score. Results: Of 614 patients with DTC during our period, 504 (83%) underwent total thyroidectomy and 104 (17%) underwent lesser surgery. Radioiodine administration was reported for 394 patients who underwent total thyroidectomy with a dose range of 24 to 297 mCi (mean of 116 mCi). Ten-year survival was higher for patients with total thyroidectomy compared with lobectomy: 96% versus 84% (P < 0.001, Gehan's Wilcoxon test). Ten-year survival for complete versus incomplete surgery for tumor stages 1 and 2 was 99% versus 96%, and for stages 3 and 4 was 88% versus 52%. Cancer specific death tended to occur earlier in those without RRA postsurgery. There was no overall relationship between DFS and RRA or surgery, but in the higher risk categories surgery retained significance. Conclusion: Our data support the routine use of both total or near-total thyroidectomy followed by RRA over all risk categories in DTC. Although the effect of surgery is clear, there is also a trend toward improvement in outcome with RRA for cancer specific survival.