Increased workload without clinical benefit: Results following implementation of the ACR‐TIRADS system for thyroid nodules

Abstract

AbstractObjectiveThe ACR‐TIRADS system for stratifying thyroid nodule malignancy risk has been widely promoted and implemented. We audited its introduction at a large public hospital in Auckland, New Zealand.DesignAudit of outcomes following thyroid nodule fine needle aspiration (FNA) before/after ACR‐TIRADS.PatientsIndividuals undergoing thyroid FNA 2017−2019.MeasurementsFrom medical records, we obtained details from the pre‐FNA ultrasound (nodule size, TIRADS points/levels, radiologist recommendation for FNA), Bethesda (B) cytology classification, histology and post‐FNA follow‐up.ResultsFour hundred and twenty‐two individuals had 564 FNAs, 163 had surgery and 54 (13%) had cancer in the primary nodule. 37/54 (69%) cancers were papillary thyroid carcinoma (median size 25 mm, 87% ≥10 mm, 61% ≥20 mm). Following ACR‐TIRADS introduction, FNA recommendations increased greater than twofold, FNAs performed by 71%−83%, and the monthly rate of FNAs and operations by 60% and 40%, respectively. However, the proportion of cancers/FNA remained similar (9.9% post‐TIRADS vs. 8.7% pre‐TIRADS). The proportions of FNA results remained stable for B2−B4 categories, but doubled (11% vs. 5%) for B5−B6: 15 FNAs were needed to identify an additional B5/B6 lesion. TIRADS‐5 nodules had a higher proportion of B5/B6 (20%) and a lower proportion of B2 (30%) than TIRADS‐3 (2%, 57%, respectively) and TIRADS‐4 (9%, 56%) nodules. About 5 additional cancers/year were diagnosed, but they were more often small (49% vs. 8% <2 cm, 17% vs. 0% <1 cm).ConclusionACR‐TIRADS introduction increased workload (FNAs and operations), without increasing the proportion of cancers/FNA. It led to a few more cancers being diagnosed, but many were small and of uncertain clinical significance.