Endocrine Abstracts

Most thyroid nodules are benign after fine needle aspiration biopsy (FNAB). Nevertheless approximately 10–25% of nodules are classified in indeterminate classes. Literature reports different risks of malignancy in Thy 3 – Thy 4 nodules. In our center malignancy was observed in 26% of Thy 3a nodules and 14% of the Thy 3f nodules (Giusti et al. 2017) while it was >75% in Thy 4 nodules. Strategies for nodules stratification according to risk are now needed to reduce thyroidal surgery. The aim of the study was to report results of active surveillance in Thy 3 nodules in which thyroidectomy was refused or delayed. Sixty-five nodules (patients) with indeterminate thyroid cytology at the 1st FNAB (n=33 Thy 3a, n=12 Thy 3f, n=10 Thy 3) underwent active surveillance. Active surveillance includes: calcitonin and thyroid blood tests, neck ultrasonography (US), elastosonography (USE), contrast enhanced US (CEUS), BRAF mutation analysis and a 2nd FNAB. BRAF analysis was negative in all nodules and all patients showed normal hormonal levels. At present the active surveillance period is of 48 months. Eight of the 65 nodules receded from surveillance for thyroid surgery (n=1: 1 NIFPT; 1 follicular adenoma), severe cardiac failure (n=1), change of geographical area (n=1) or retire of consensus (n=4). Twelve patients (18%) did not perform/refused 2nd FNAB. The 2nd FNAB showed down classification to Thy 2, stable Thy 3 category and subcategories, and non-diagnostic information in 64%, 29% and 7%, respectively. US score doesn’t show significant changes from the baseline (n=65; 1.95±1.08) compared to the last examination (n=38; 1.87±1.07). In average, nodules were not significant in maximal diameter from the baseline (25±12 mm) compared to the last examination (23±13 mm) even if in 16% of nodules there was a change (>20%) in size [increase (10%), decrease (6%)]. All the nodules with an increase in size were Thy 2 at the 2nd FNAB evaluation. USE and CEUS did not add further information after inclusion of patients under active surveillance. In conclusion our prospective study suggest that active surveillance can be proposed to patients with indeterminate cytology when no BRAF mutation is found from FNAB. The down classification to Thy 2 class is a frequent phenomenon when further information and material are collected for the pathologist. Simple changes in diameter of the nodule do not suggest surgical decision. However more data need to be collected.