The negative outlook: Long-term follow up of ThyroSeq negative and low-risk nodules.

ABSTRACT

BACKGROUND: Molecular testing of thyroid nodules is an essential tool to help risk stratify nodules with indeterminate cytology. Although ThyroSeq testing has been around for over a decade, there is a paucity of long-term follow-up data on cytologically indeterminate nodules that are determined to be molecularly negative or low-risk. The objective of this study is to assess the outcomes of nodules with indeterminate cytology (Bethesda III or IV) and negative or low-risk ThyroSeq results. METHODS: This is a single academic institution retrospective cohort study. Patients with at least one thyroid nodule sampled with fine-needle aspiration who underwent ThyroSeq testing from 2012 to 2018 and had negative or low-risk ThyroSeq results on a cytologically indeterminate sample (n = 159 patients, 167 nodules) were included in the study. Outcomes include the false-negative rate and negative predictive value of each test version, as well as follow-up length for each nodule. RESULTS: There were 159 patients with a mean age of 58 years (7-84 years) included in this study; the majority were female (81.8%). The mean follow-up was 4.0 years. Of 167 nodules, three were found to be malignant on resection (1.8%). The negative predictive value for the entire cohort was 98.2% and it was 89.3% for the surgical series. CONCLUSION: ThyroSeq testing has good negative predictive value and can help risk stratify cytologically indeterminate nodules. Routine follow-up allows for safe monitoring of nodules for features suggestive of malignancy.