THU678 Real-world Performance Of Afirma Genomic Sequencing Classifier (GSC) In A Community Healthcare Setting

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Abstract Disclosure: V. Master: None. J. Syeda: None. S. Charatz: None. D. Reidy: None. K. Clary: None. Introduction: Indeterminate thyroid nodules pose a significant clinical challenge due to their potential risk of malignancy. The Afirma GSC has emerged as a valuable tool for the non-invasive management of these nodules. However, its real-world performance in community healthcare settings remains poorly understood. Aim: Comparison of GSC performance in a community healthcare setting to the validation study (VS) metrics. Method: A retrospective study was conducted in a community endocrine practice, where 91 Afirma GSC samples were obtained from patients who had either suspicious cytology or atypia of undermined significance (AUS) between 1/1/2021 and 12/31/2022. Ten samples were excluded due to insufficient material. Surgical pathology was used as the gold standard for diagnosis. Molecular benign results without surgical pathology were considered true negatives, and 2 unoperated patients with suspicious results were excluded from analysis. We calculated observed positive predictive value (oPPV) and observed specificity (oSP) to account for these exclusions. Non-invasive follicular neoplasm with papillary-like features is considered malignant. The prevalence of thyroid cancer in the study population was 19%. Results are compared to previously published VS of 191 samples. Result: Our study showed a higher accuracy of 89% of the Afirma GSC in our community healthcare setting, with a sensitivity (SN) of 93%, oSP of 88%, oPPV of 63%, and negative predictive value (NPV) of 98%. In comparison, the VS had a SN of 91%, SP of 68%, PPV of 47%, NPV of 96%, and accuracy of 74%. Additionally, our study showed a higher benign call rate (BCR) of 70% compared to 54% in the VS. Conclusion: Our study provides evidence of the real-world performance of the Afirma GSC and supports its use as a non-invasive tool for the management of indeterminate thyroid nodules. Better oSP and oPPV are suggestive of higher yield of cancers for resected nodules based on suspicious GSC.