Impact of the covid-19 pandemic on surgery for indeterminate thyroid nodules: results from a large multicentric international (the thycovid) study

Abstract Background During the COVID-19 pandemic, planned surgery was ubiquitously suspended or slowed down. We focused our attention on surgery for indeterminate thyroid nodules (ITNs). Methods This was a retrospective multicentric study. Patients with ITNs were included in the study and were divided into three groups based on when they were submitted to thyroidectomy: The main aims of the THYCOVID study were: Results We included 22974 patients with ITNs from 157 centers, mainly located in Europe (76.5%) and Asia (11.8%). The median monthly operations per center were 2 (IQR: 0.9-3.7) in P1, 1.4 (IQR: 0.6-3.4) in P2, and 2.3 (IQR: 1-5) in P3; the differences among the phases were all significant (p<0.001). At pathological examination, the incidence of lymph node metastases was significantly higher in P2 (11.7%) and in P3 (12.2%) than in P1 (9.3%; p<0.0001). Considering the ATA classification for risk of disease recurrence, the incidence of high-risk tumours increased over time from 203 (5.7%) patients in P1, to 198 (6.2%) in P2, and to 155 (7.7%) in P3; the difference between P1 and P3 was significant (p=0.0072). Conclusion Surgical activity for ITNs decreased significantly during the pandemic. In the last phase, an increased incidence of aggressive tumours was found.