Long-Term Outcomes of Thyroid Nodule AFIRMA GEC Testing and Literature Review: An Institutional Experience

Objective: To assess outcomes of thyroid nodules analyzed with the AFIRMA gene expression classifier (GEC) and to perform a comprehensive literature review. Study Design: Retrospective analysis of patients with thyroid nodules who underwent AFIRMA GEC testing at our institution. Settings: A tertiary care academic institution. Subjects and Methods: We collected clinical outcomes for 416 thyroid nodules that were analyzed with AFIRMA GEC between 2011 and 2015, including long-term follow-up through 2019. We performed a comprehensive literature review. Results: The resection rate for nodules with “suspicious” GEC results was 85% with a positive predictive value of 37%. The resection rate for nodules with “benign” GEC results was 24% with a negative predictive value of 90%. The prevalence of thyroid malignancy in patients with thyroid nodules with indeterminate cytology at our institution during this timeframe was 41%, thus lowering our negative predictive value. Mean follow-up duration for unresected nodules was 27.8 months. Our resection rates for nodules with “benign” GEC were among the highest reported in the literature. Conclusions: Molecular marker testing of thyroid nodules with indeterminate cytology can aid in the surgical decision making by obviating the need for diagnostic surgery and/or guiding extent of resection. Patients with other indications for surgery may not benefit from such costly testing.