Utility of Afirma Gene Expression Classifier for Evaluation of Indeterminate Thyroid Nodules and Correlation With Ultrasound Risk Assessment: Single Institutional Experience
Sultan R, Levy S, Sulanc E, Honasoge M, and Rao SD. Utility Of Afirma Gene Expression Classifier For Evaluation Of Indeterminate Thyroid Nodules And Correlation With Ultrasound Risk Assessment: Single Institutional Experience. Endocr Pract 2020.
Objective: We assessed our experience with Afirma gene expression classifier (GEC) combined with sonographic risk assessment, using both the ATA and TI-RADS in evaluating indeterminate thyroid nodules. Methods: We identified 98 patients with 101 nodules who had a second fine needle aspiration biopsy (FNA) between 01/01/2014 and 09/30/2017 and sent to Veracyte for cytopathology and subsequent Afirma GEC testing. A second FNA biopsy was performed if the initial cytopathology was either Bethesda III or IV (n= 94) or non-diagnostic (n= 7). We correlated cytopathology, histopathology, and Afirma GEC results with sonographic risk assessment using both the ATA system and TI-RADS. Results: The mean age of the cohort was 57.4 +/- 12.3 years; 84% women and 60% white. Repeat FNA was benign in 51 of 101 nodules, and of the remaining 50 nodules, 18 (36%) were GEC-benign and 32 (64%) GEC-suspicious. Eighteen of the 32 GEC-suspicious nodules underwent surgery with the following results: 7 benign (39%), 1 follicular thyroid carcinoma (6%), 6 follicular variant of papillary thyroid cancer (33%), and 4 non-invasive follicular tumor with papillary-like nuclear features (22%). The malignancy rate among the surgical cohort was 39% (without NIFTP) and 61% (with NIFTP) and about 50% and 20% of this group scored in the high suspicion category by ATA and TR5 by TI-RADS respectively. Conclusion: Afirma GEC was useful in avoiding surgery in one-third of indeterminate nodules and performed similarly to ATA and TI-RADS. However, use of echogenicity in scoring may underestimate the risk of malignancy in patients with indeterminate nodules.
ePub ahead of print