Endocrine Abstracts

Aim: Investigate, in patients with differentiated thyroid cancer (DTC) if thyroglobulin (Tg) values, immediately before and six months post radioiodine ablation are good predictors of disease progression.

Materials and methods: Basal Tg values (Tg-B) and rhTSH stimulated Tg (Tg-S) before ablation (0) and 6 months later (6) from 142 DTC patients, with post-surgical ablation therapy between 2003 and 2009 with a follow up of 5 years, were analysed.

Results: After a 5-year follow up, 121 patients (85.2%) were free of disease (FD), 15 patients (10.6%) had evidence of disease (ED) and six had died (4.2%). A Tg-B-0 <0.2 ng/ml. was present in 39 patients (27.5%), only one (2.5%) has ED because of positive antibodies and only one (2.5%) needed retreatment. In contrast: a Tg-B-0 >0.2 ng/ml, was present in the 103 patients (72.5%), 21 patients (20.4%) had ED and 27 (26.2%) needed retreatment A Tg-S-0 <1 ng/ml was found in 34.8% only one (2.6%) was ED and only one (2.6%) required retreatment. However, 65.2% of patients had these value >1 ng/ml, of which 22.5% was considered ED and 26.7% have required retreat. At 6-month when Tg-B-6 ablation >0.2 ng/ml, 40% was ED and 46.7% required retreatment and when Tg-S-6-ablation >1 ng/ml, 56% was ED, and 67% required retreatment in 5 years follow up.

Conclusion: Tg basal value at the time of ablation has a high specificity and sensitivity for predicting disease progression. Stimulated Tg at that time does not add predictive value At 6-month high levels of Tg value predicts evidence of disease in 5 years follow up.