Ultrasound follow-up of small suspicious thyroid nodules: a service evaluation
Steve Klarich, Walsall Healthcare NHS Trust
Objective
The British Thyroid Association (BTA) guidelines state that suspicious thyroid nodules <10 mm in diameter should not have fine needle aspiration (FNA) cytology unless high-risk features are present. No guidance is provided on management of these patients. Local practice for these nodules is to monitor with serial ultrasound scans every six months, with FNA to be performed if nodules grow beyond the 10 mm threshold. This service evaluation aims to assess how well this is adhered to, and how effective this is at identifying nodules that require FNA.
Methods
Search performed for neck ultrasound exam reports containing keywords ‘threshold’, ‘too small’, ‘FNA’ and ‘U3’, ‘U4‘ or ‘U5’. Inclusion criteria: patients with nodule(s) <10 mm scoring U3 or higher with at least two scans. Exclusion criteria: patients with U2 nodule or normal thyroid, patients with only a single scan. Data extracted from reports: nodule size, U score, interval between scans, whether FNA performed and if so the cytology results. Results also assessed in terms of number of malignancies identified and number of nodules that crossed the 10 mm threshold.
Results
61 patients with 65 nodules matched inclusion criteria. On average 3.2 scans performed per nodule. Mean interval between scans = 6.6 months. Of 145 scan intervals, only 14 adhered to six months. Mean nodule size at initial scan = 6.2 mm, mean nodule size at final scan = 6.3 mm. Only two nodules increased in size >10 mm. 15 FNAs performed, 10/15 were non-diagnostic. Diagnostic FNAs were all thy3a or thy3f. Two patients underwent hemithyroidectomy, histology reporting a Hürthle cell adenoma and a follicular adenoma. No malignant nodules identified.
Conclusion
Local practice of 6-monthly ultrasound scans for suspicious thyroid nodules <10 mm is poorly adhered to. These nodules do not significantly increase in size and are rarely malignant.