A randomized controlled trial comparing non-selective versus selective TIRADS-based cytology in thyroid cancer diagnostics.

内容摘要

Several ultrasound risk stratification systems have been developed mainly with the aim of identifying benign lesions and thereby avoiding unnecessary fine needle aspiration (FNA) cytology. This randomized controlled trial assessed if the use of an ultrasound risk stratification system improved identification of lesions requiring surgical treatment. This was a multi-centre, unblinded and interventional randomized trial comparing selective and non-selective FNA in Western Sweden. Patients were randomized to either selective cytology according to EU-TIRADS criteria or non-selective cytology. A total of 195 patients were included, 93 in the non-selective group and 102 in the selective group, between February 2022 and December 2023. The frequency of nodules with Bethesda category IV-VI (primary outcome) was higher in the selective group (26% versus 13%, p=0.039). The rate of malignancy (secondary outcome) was similar in both groups; 8% in the selective group versus 5% in the non-selective group. The frequency of patients undergoing cytology was reduced from 83% in the non-selective group, to 71% in the selective group. Considering only patients with at least one nodule yielding EU-TIRADS 3 or higher, cytology was omitted in 7% of patients in the selective group, whereas no cytology was omitted in the non-selective group. This randomized controlled trial supports the use of EU-TIRADS to correctly select neoplastic nodules for FNA without missing thyroid cancer. The proportion of patients where FNA can be safely omitted using EU-TIRADS may however be exaggerated, indicating a need for further refinement of risk stratification systems for thyroid cancer diagnostics. Ultrasound is usually the first imaging test used to examine thyroid nodules (lumps in the thyroid gland). Over the past 15 years, several ultrasound-based systems have been developed to estimate the risk that a nodule is cancerous. These systems mainly aim to identify harmless (benign) nodules so that unnecessary needle tests—called fine needle aspiration (FNA)—can be avoided.This study presents results from the first randomized trial investigating whether using such an ultrasound risk system improves the identification of nodules that do not need FNA. The main goal of this study was to see how well the EU-TIRADS system can identify thyroid nodules that should be tested with FNA. The main outcome we looked at was how often these biopsies showed results that could indicate cancer (Bethesda categories IV–VI), since these findings usually lead to more tests or treatment. We expected that using EU-TIRADS to carefully select which nodules to biopsy would result in a higher proportion of these concerning findings compared to biopsying nodules without using this system.A second goal was to understand the risk of missing thyroid cancer when using EU-TIRADS. To measure this, we calculated the rate of malignancy (ROM), which is the number of patients diagnosed with thyroid cancer after surgery divided by the total number of patients examined in each group. We expected that this rate would be similar between the two groups, meaning that using EU-TIRADS would not increase the risk of missing cancer. This was a regional, multi-centre study carried out at four hospitals in Western Sweden. It was a forward-looking (prospective), randomized, and unblinded trial.Patients were randomly assigned to one of two groups: Selective testing: FNA was only performed based on recommendations from an ultrasound risk system called EU-TIRADS.Non-selective testing: FNA was performed more routinely, without strict use of the risk system. Between February 2022 and December 2023, 195 patients took part in the study: 93 in the non-selective group and 102 in the selective group. Nodules classified as higher risk (Bethesda categories IV–VI) were more common in the selective group (26%) than in the non-selective group (13%).The actual cancer rate was similar in both groups: 8% in the selective group and 5% in the non-selective group.The number of patients who underwent FNA was lower in the selective group (71%) compared to the non-selective group (83%).When looking only at patients with nodules considered at least mildly suspicious (i.e. EU-TIRADS 3 or higher): FNA was omitted in 7% of patients in the selective group.No patients omitted FNA in the non-selective group.This randomized study supports using the EU-TIRADS system to help decide which thyroid nodules should be tested with FNA, without missing cancers. However, the results suggest that the number of patients who can safely avoid FNA using this system may have been overestimated. This means that further improvements to these risk assessment systems are still needed.