The Ultracyt Study - is EU-TIRADS Useful in Selecting Nodules for Fine Needle Aspiration Cytology?

Overview

This is a randomized study evaluating selective fine-needle aspiration cytology based on structured ultrasound using EU-TIRADS versus non-selective ultrasound guided cytology. Primary outcome is frequency of suspicious cytology (Bethesda III-VI) which is expected to be higher in the selective group compared to the non-selective group. Secondary outcome is the frequency of malignancy which is expected to be equal in both groups. However, the investigators do not expect to reach statistical significance for the secondary outcome according to power calculations.

Thyroid nodules are common in the population, and the reported incidence of thyroid cancer is increasing in most parts of the world. Palpable thyroid nodules are reported in 4-5 per cent of the population, of which 5-10 per cent are malignant. The reported incidence of thyroid nodules on ultrasound is higher. EU-TIRADS has been shown in retrospective cohort studies to accurately stratify thyroid nodules with respect to risk of thyroid cancer. EU-TIRADS has been used in Western Sweden since 2017 and in 2021 it was implemented in the Swedish National Guidelines for thyroid cancer. To the knowledge of the investigators, no randomized controlled study has been carried out validating EU-TIRADS. This multicenter regional study aims to investigate the safety of using selective cytology using EU-TIRADS. Primary outcome is the result of cytology suspicious of thyroid cancer. In the selective group, low risk nodules will not undergo cytology and therefore the frequency of cytologically suspicious nodules (Bethesda III-VI) is expected to be higher in this group.