THU678 Real-world Performance Of Afirma Genomic Sequencing Classifier (GSC) In A Community Healthcare Setting
Authors: Master Vidisha , Nasir Syeda Javeria , Charatz Seth , Reidy Dawn , Clary Karen 
Published: October 2023

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. References: Nasr CE, Andrioli M, Endo M, Harrell RM, Livhits MJ, Osakwe I, Polavarapu P, Siperstein A, Wei S, Zheng X, Jiang R, Hao Y, Huang J, Klopper JP, Kloos RT, Kennedy G, Angell TE. Real World Performance of The Afirma Genomic Sequencing Classifier (GSC) - A Meta-analysis. J Clin Endocrinol Metab. 2022 Dec 6:dgac688. doi: 10.1210/clinem/dgac688. Epub ahead of print. PMID: 36470585. Patel KN, Angell TE, Babiarz J, Barth NM, Blevins T, Duh QY, Ghossein RA, Harrell RM, Huang J, Kennedy GC, Kim SY, Kloos RT, LiVolsi VA, Randolph GW, Sadow PM, Shanik MH, Sosa JA, Traweek ST, Walsh PS, Whitney D, Yeh MW, Ladenson PW. Performance of a Genomic Sequencing Classifier for the Preoperative Diagnosis of Cytologically Indeterminate Thyroid Nodules. JAMA Surg. 2018 Sep 1;153(9):817-824. doi: 10.1001/jamasurg.2018.1153. PMID: 29799911; PMCID: PMC6583881.
Presentation: Thursday, June 15, 2023