Thyroid FNA cytology: Impact of the COVID-19 pandemic and vaccination in a Brazilian series.

Background: The coronavirus disease 2019 pandemic prompted changes in medical practice, with a reduction in cytopathology volumes and a relative increase in the malignancy rate during lockdown and the initial postlockdown period. To date, no study has evaluated the impact of these changes on the volume of rapid on-site evaluation (ROSE) or on the frequency of cases according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) categories after vaccination.
Methods: Ultrasound-guided thyroid fine-needle aspiration (FNA) and ROSE assessments performed from January 2019 to May 2022 were evaluated retrospectively according to TBSRTC categories for three periods: prepandemic (period 1), from transmission to expansion (period 2), and after vaccination (period 3).
Results: There were 7531 nodules from 5815 patients. FNA cases increased throughout the pandemic despite a drop during lockdown. The frequency of TBSRTC categories changed. Nondiagnostic cases had an increase of 18.1% in period 2 and 76.2% after vaccination compared with prepandemic levels. Malignant cases increased from 2.3% to 4.2% in period 2 and to 5.1% in period 3, representing increases of 83.1% and 121.2%, respectively, compared with period 1. Data corrected by time showed increases in categories IV, V, and VI and a decrease in benign nodules during the two pandemic periods. ROSE was performed in 787 cases during the prepandemic period, and there were decreases of 29.4% and 22.8% in periods 2 and 3, respectively. The ROSE-to-category I ratio was reduced significantly after vaccination.
Conclusions: Increased volume with sustained lower benign rates and higher malignant rates before and after vaccination indicate better selection of patients for FNA. A worse adequacy rate was correlated with a decrease in the number of ROSE assessments.
(© 2023 American Cancer Society.)