Follow-up of Benign Thyroid Nodules-Can We Do Less?

OBJECTIVE: To determine the incidence of malignancy, follow-up ultrasound (US), and repeat fine needle aspiration (FNA) in thyroid nodules that have been previously biopsied as benign. METHODS: This is a retrospective, descriptive study of benign thyroid nodules evaluated by US between 2010-2011. We determined the frequency of follow-up ultrasounds and FNAs, mean years of follow-up, interval between follow-up US, change in nodule size, reasons for repeat FNA (rFNA), frequency of thyroidectomy, and thyroid malignancy during 5 years of follow-up. RESULTS: A total of 733 benign thyroid nodules were reviewed in 615 patients. Mean years of US follow-up was 3.47 ± 1.65 years; 275 (37.5%) had no follow-up US; 109 (14.9%) had 1 follow-up US; 93 (12.7%) had 2 follow-up US; and 256 (34.9%) had 3 or more follow-up US. Assessment of thyroid nodule size showed that 215 (28.8%) nodules decreased in size, 145 (19.4%) increased in size by less than 50%, and 91 (12.1%) increased in size by more than 50%. Of the 733 nodules, 17 nodules (2.3%) underwent thyroidectomy for which the pathology result of 9 (1.2%) showed malignancy, and 65 (8.9%) thyroid nodules underwent rFNA. When applying the 2015 recommendations for repeat FNA, 35% were done unnecessarily. CONCLUSION: In our sample of initially benign thyroid nodules, only 9 patients (1.2%) had pathology-proven malignancy after a mean follow-up of 3.5 years. Over 30% of patients had more than 3 rUSs. Decreased interval and frequency of rUS should be considered in future guidelines for thyroid management.

Retrospective Application of the 2015 American Thyroid Association Guidelines for Ultrasound Classification, Biopsy Indications, and Follow-up Imaging of Thyroid Nodules: Can Improved Reporting Decrease Testing?

INTRODUCTION: Thyroid ultrasound has been widely used to determine which nodules need further investigation. The goal of this study is to determine if using an ultrasonographic features checklist based on 2015 American Thyroid Association (ATA) guidelines can improve reporting and decrease unnecessary further testing. METHODS: In this retrospective study, ultrasonographic images of all nodules biopsied at our institution in 2014 and 2015 were reviewed by radiologists blinded to fine needle aspiration (FNA) biopsy result using a checklist. The checklist was prepared based on 2015 ATA guidelines. The ultrasonographic characteristics of thyroid nodules were compared with the result of biopsy to determine positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity for predicting malignancy. Radiologists also made an overall recommendation on need for FNA. RESULTS: A total of 425 thyroid nodule ultrasound scans were reviewed by radiologists. Biopsy results of 31 nodules were malignant and 394 were non-malignant. Malignant nodules showed higher frequency of solid composition, hypoechoechogenicity, and cervical lymph node involvement compared to benign nodules. Solid nodule composition had the highest PPV (13%) and NPV (94.7%). Extra-thyroid extension had the highest specificity (90.1%). Lesion vascularity had the highest sensitivity (83.8%), followed by hypoechogenicity (65.6%). Overall, the checklist had a positive predictive value of 9%, negative predictive value of 97.5%, sensitivity of 96.8%, and specificity of 11.14%. Radiologists determined that 10% of the nodules were very low-risk and did not require FNA. CONCLUSION: Using a checklist based on 2015 ATA guideline thyroid nodule ultrasonographic features is a sensitive tool with high NPV to predict benign thyroid nodule, thereby preventing unnecessary FNAs.