5 YEARS FOLLOW UP OF THYROGLOBULIN (TG), THYROGLOBULIN ANTIBODIES (TGAB) AND NECK ULTRASOUND (US) IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA (MPTC) TREATED WITH TOTAL THYROIDECTOMY BUT NOT ABLATED WITH 131I

Serum Thyroglobulin (Tg) and Thyroglobulin Antibodies (TgAb) as- says are considered as the cornerstone for the post-operative manage- ment of patients with differentiated thyroid cancer (DTC) after the initial treatment. Less is known about the significance of this parameters in pts who do not perform radioiodine ablation (RRA) as in case of mPTC We retrospectively evaluated epidemiological, clinical and path- ological data of 170 consecutive patients with mPTC, surgically treated at our Department from 2006 to 2012. The inclusion criteria were the unifocality of the tumor and at least three or more deter- minations of serum Tg, TgAb and US in our department. The ex- clusion criteria were pts who performed RRA or during the follow up and a lower number of serum Tg, TgAb and US determination. The aim of our study was to clarify the significance of the Tg and TgAb trends during the follow up. We divided our pts in group A (120 pts) (TgAb < 20 mU/L) and in group B (50 pts) (TgAb > 20 mU/L) and we analyzed the Tg and TgAb course during the follow up (mean 5.1 yrs, median 5 yrs). In Group A, 78/120 (65%) had an undetectable Tg ( < 0.5 ng/ml) at the first control, 22/120 (18%) had a Tg between 0,5-1 ng/ml and 20/120 (17%) had Tg > 1 ng/ml; at the end of follow up only in 16/120 (13%) Tg values were >1ng/ml, but in all pts (120/120) neck US was negative for lymphnode metastases, at the beginning and at the end of follow up. In group B, only in 3/50 (6%) there was an increase in TgAb more than 20%, in 42/50 (84%) pts, there was a decrease more than 20%, and 5 (10%) pts have stable titers of TgAb; in this sub- group of pts neck US was negative (50/50). The 5 years follow up of mPTC not treated with RRA shows a very good outcome and the absence of recurrence until now. The course of Tg and TgAb in this subgroup of pts seems to give limited informations with respect to neck US, maybe related to the good prognosis of this tumor.