A RNA sequencing-based test significantly reduces the number of unnecessary surgeries in thyroid cancer diagnoses, according to a study recently published in JAMA Surgery. The test, marketed by Veracyte as their the next-generation Afirma Genomic Sequencing Classifier (GSC) identifies at least one third more benign thyroid nodules among those deemed indeterminate by cytopathology, as compared to the original Afirma test. The findings suggest that the test can further reduce the number of patients who undergo unnecessary surgery as part of thyroid cancer diagnosis.
“Thyroid nodules are often challenging to diagnose with traditional methods and, as a result, many patients undergo surgery only to find out their nodules were benign,” says Kepal Patel, MD, FACS, chief, Division of Endocrine Surgery, NYU Langone Health, and lead author of the new paper. “The original Afirma genomic test has changed care by identifying patients with benign nodules before they go to surgery. These new findings suggest that the next-generation Afirma GSC can enable even more patients to safely avoid unnecessary surgery, along with the risks, costs and potential lifelong implications of such surgery.”
The Afirma GSC combines RNA sequencing and advanced machine learning methods to leverage extensive genomic content – including gene expression, variants, fusions, copy number and loss of heterozygosity – from thyroid fine needle aspiration samples. This approach provides a more granular genomic picture of thyroid nodules, enabling the test to further distinguish between benign cases and those that are suspicious for cancer and to provide additional diagnostic information that can inform patient care.
In the newly published study, researchers evaluated the Afirma GSC’s clinical validity using a prospective, multicenter, blinded cohort of 191 indeterminate thyroid nodule fine needle aspiration samples – from the same sample set previously used to validate the first-generation Afirma Gene Expression Classifier (GEC). Using histopathology results as the reference standard, the researchers found that the Afirma GSC maintained the original Afirma test’s high sensitivity (91 percent vs. 90 percent) and increased its specificity by 30 percent (from 52 percent to 68 percent). The Afirma GSC also identified benign Hürthle cells – which are usually very difficult to discern from cancer – with an increased specificity of 59 percent, compared to 12 percent with the Afirma GEC. Among the primary categories of indeterminate thyroid nodules – known as Bethesda III and IV – the negative predictive value of the Afirma GSC was 96 percent.
The Afirma product offering also includes tests for medullary thyroid cancer and the presence of gene alterations such as the BRAF V600E mutation and RET/PTC gene fusions, which may inform surgery and treatment decisions for patients with suspected thyroid cancer. In the current study, when these relatively rare conditions were found among the 191 study samples, the results were concordant with reference methods.
“Our original Afirma test has already transformed thyroid cancer diagnosis, helping an estimated 40,000 patients to date avoid unnecessary surgery,” says Giulia C. Kennedy, PhD, Veracyte’s chief medical and scientific officer. “By leveraging the latest advances in genomic science and machine learning technology, we believe the next-generation Afirma GSC will help improve care for significantly more patients and further reduce costs in the healthcare system.”
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