Background: Molecular tests for suspicious thyroid nodules decrease rates of unnecessary surgeries but are not widely used due to reimbursement issues. The aim of this study was to assess the rate of unnecessary surgery performed in real life setting for Bethesda III, IV and V nodules in the absence of molecular testing.

Method: This is a single-center retrospective study of consecutive patients undergoing fine needle aspiration cytology (FNAC) with rapid on-site evaluation between January 2017 and December 2021. Unnecessary surgery was defined as surgery performed because of Bethesda III, IV or V results in the absence of local compressive symptoms with final benign pathology and as second surgery for completion thyroidectomy.

Results: Among 862 patients (640 female, mean age 54.2 years), 1010 nodules (median size 24.4 mm) underwent 1189 FNAC. Nodules were EU-TIRADS 2, 3, 4 and 5 in 3%, 34%, 42% and 22% of cases, respectively. FNAC was Bethesda I, II, III, IV, V and VI in 8%, 48%, 17%, 17%, 3% and 6%, respectively. Surgery was performed in 36% of Bethesda III nodules (benign on pathology: 81%), in 74% of Bethesda IV nodules (benign on pathology: 76%) and in 97% of Bethesda V nodules (benign on pathology: 21%). Surgery was considered unnecessary in 56%, 68% and 21% of patients with Bethesda III, IV and V nodules, respectively.

Conclusion: In this real data cohort surgery was unnecessary in more than half of patients with Bethesda III and IV nodules and in 21% of patients with Bethesda V nodules.