Endocrine Abstracts

Objective: Treatment decision-making for Bethesda IV nodules remains challenging. Active surveillance(AS) is now a well-established strategy for low-risk, differentiated thyroid carcinoma. Since most of the Bethesda IV nodules are operated on unnecessary basis, and molecular testing is costly and is not available in a lot of centers. We started AS for the clinically low-risk Bethesda IV nodules, which would be a practical option, and hereby we are sharing our preliminary results.

Methods: Thirty-four patients with a nodule with a long axis of less than 30 mm, having no sonographically detectable high-risk features (HRF) or only with one HRF and <1 cm (EU-TIRADS), no extrathyroidal extension and no detected lymph nodes suggestive of metastasis, with Bethesda IV (2017) has been found eligible for AS. Patients were monitored with ultrasound(US) at 6-12 months intervals. A 30% volume increase with regard to the baseline measurement was considered as significant nodule growth, whereas a 100% volume increase, the long axis exceeding 30 mm, or identification of pathological lymph node(s) were defined as surgical indications.

Results: Of the patients, 24/34 (70.6%) were female, and the median (min-max) age at diagnosis was 47 (range 18-79) years. The median (min-max) follow-up period was 24(6-108) months, and 29/34(85 %) patients had a follow-up of 1 year or more. The long diameter of the nodules on baseline ultrasound(US) was mean±sd 13.23±5.43 mm, median(min-max) 14(3-24)mm, and baseline median nodule volume (min-max) was 0.72(0.01-4.84) ml. According to the EU-TIRADS, 8/34 (24%) were classified as EU-TIRADS-3, 22/34(65%) as EU-TIRADS-4, and 4/34(12%) as EU-TIRADS-5 (i.e. all <1 cm, 3 markedly hypoechogenic, one with microechogenities). At the last US, the long diameter was mean±s.d 14.26±6.12 mm with a median(min-max) of 14(4-30)mm, and median nodule volume (min-max) was 0.6(0.03-14.13)ml. When the volume change of the nodules during follow-up was analyzed, it was observed that the volume change was less than 30% in 14/34 (42%) patients, while the number of patients with volume increases and decreases was equal in 10/34 (29.41%) for both. None of the patients developed pathologic lymphadenopathy in the neck.

Conclusions: The first results of our AS group revealed that Bethesda IV patients, who were found to be eligible for AS, showed no signs of significant tumor progression or metastasis after a median follow-up of almost two years.