Adjuvant Radioactive Therapy after Reoperation for Locoregionally Recurrent Papillary Thyroid Cancer in Patients Who Initially Underwent Total Thyroidectomy and High-Dose Remnant Ablation

Context: Some patients have elevated stimulated thyroglobulin (sTg) concentrations after reoperation for locoregionally recurrent/persistent papillary thyroid cancer (PTC). Little is known, however, about the efficacy of adjuvant radioactive iodine (RAI) therapy in these patients. Objective: The objective of the study was to evaluate the efficacy of adjuvant RAI therapy in patients with elevated sTg after reoperation for locally recurrent/persistent PTC. Design and Settings: This was a retrospective observational cohort study in a tertiary referral hospital. Patients: We evaluated 45 consecutive patients with sTg greater than 2 ng/ml after reoperation for locoregionally recurrent PTC, all of whom had previously undergone initial total thyroidectomy followed by high-dose RAI remnant ablation. Of these 45 patients, 23 received adjuvant RAI therapy (adjuvant group) and 22 did not (control group). Main Outcome Measures: Main outcome measures included changes in sTg concentration after reoperation and disease-free survival. Results: Over time, there were no significant differences in means Tg concentration in the adjuvant (P = 0.35) and control (P = 0.74) groups. Only 15% of patients in the adjuvant group and 33% in the control group showed a greater than 50% decrease in sTg level from baseline. There were no between-group differences in changes (P = 0.83) or percent decrease (P = 0.97) in sTg concentration and no difference in clinical recurrence-free survival (P = 0.20). Conclusion: In patients who still have elevated sTg after reoperation for locally recurrent/persistent PTC, adjuvant RAI therapy compared with no additional RAI therapy resulted in no significant differences in the subsequent sTg changes or the recurrence-free survival. (J Clin Endocrinol Metab 96: 3695-3700, 2011)