“Real World” Performance of Afirma GSC and Xpression Atlas in Thyroid Cancer Diagnosis

Researchers from leading institutions presented posters showing that use of the Afirma GSC at their respective centers significantly increased the identification of benign thyroid nodules among those deemed indeterminate – not clearly benign or malignant – following cytopathology review, compared to the original Afirma test.The Ohio State University – Researchers compared results of 113 indeterminate samples that were tested with the Afirma GSC to those of 403 samples using the earlier version of the test (the Afirma Gene Expression Classifier, or GEC). The Afirma GSC identified 74.1 percent of the nodules as benign, compared to 48.4 percent with the GEC, an increase of 53 percent. The overall surgery rate among all patients who underwent genomic testing decreased by more than half – from 42.2 percent with the GEC to 20.2 percent with the GSC.
Brigham and Women’s Hospital – Researchers evaluated results for 583 thyroid nodules tested with either the Afirma GSC (n=97) or GEC (n=486) between 2011 and 2018. They found that the Afirma GSC identified 64.9 percent of nodules as benign, compared to 47.9 percent with the GEC, an increase of 35 percent.Additionally, in two oral presentations, researchers shared the first “real world” Afirma Xpression Atlas data, providing insights into the distribution of a wide range of gene variants and fusions across key categories of indeterminate thyroid nodules and Afirma GSC results. For example, among 13,549 indeterminate thyroid nodules evaluated using the Afirma GSC and Xpression Atlas, more than a quarter (25.9 percent) of GSC-suspicious nodules (in primary risk categories known as Bethesda III/IV) contained RAS variants. Additionally, RET, NTRK, BRAF and ALK fusions were only found in GSC-suspicious, versus GSC-benign, cases (in all Bethesda categories).The field of precision medicine is progressing rapidly, and multiple targeted therapies are in clinical trials or have been approved for treatment of advanced cancers that harbor specific genomic alterations. In the new data presented at the ATA conference, genomic changes (or alterations) targeted by these new therapies were identified in Afirma GSC-suspicious cases by the Xpression Atlas.