Predictive value of the preablation serum thyroglobulin level after thyroidectomy is combined with postablation 131I whole body scintigraphy for successful ablation in patients with differentiated thyroid carcinoma

Objectives: To investigate the clinical importance of the combined use of serum thyroglobulin (Tg) levels measured just before ablation (ablation-Tg) and postablation I-131 whole body scintigraphy (WBS) patterns for predicting ablation success in patients with differentiated thyroid carcinoma who received total thyroidectomy and I-131 ablation therapy. Methods: We retrospectively studied the early clinical outcomes for 81 differentiated thyroid carcinoma patients treated with total thyroidectomy and high-dose I-131 ablation therapy between June 2001 and July 2004. Results: Ablation success was achieved in 42 (97.7%) of the 43 patients with uptake in the thyroid bed only and ablation-Tg levels less than 10 ng/mL, whereas successful ablation was achieved in 9 (75.0%) of the 12 patients with uptake in the thyroid bed only and ablation-Tg levels equal to or greater than 10 ng/mL (P = 0.029). Among 15 patients with uptake including a lymph node and ablation-Tg levels less than 10 ng/mL, 14 patients (93.3%) showed ablation success, whereas successful ablation was achieved in only 2 (18.2%) of the 11 patients with uptake including a lymph node and ablation-Tg levels equal to or greater than 10 ng/mL (P < 0.001). Conclusions: These data indicate that the combined use of serum Tg levels measured just before ablation and the I-131 WBS patterns after ablation may be an early predictor of ablation success in patients with differentiated thyroid carcinoma who received total thyroidectomy and high-dose I-131 ablation therapy.