Diagnosis of Indeterminate Thyroid Nodules: Comparison of Current Molecular Testing Techniques
Posted: Wednesday, December 23, 2020
Diagnostic assessment of thyroid nodules can be successfully predicted with high specificity utilizing both the Afirma genomic sequencing classifier (RNA test) and ThyroSeq v3 multigene genomic classifier (DNA-RNA test), according to a study published in JAMA Oncology. These findings suggest that “the choice of molecular test may hinge on factors other than diagnostic performance, such as cost, processing time, sample inadequacy rate, and information regarding specific mutations that may guide future treatment,” explained Michael W. Yeh, MD, of the David Geffen School of Medicine at UCLA, Los Angeles, and colleagues.
From 2017 to 2020, a total of 346 patients who underwent thyroid fine-needle aspiration and had a single cytologically indeterminate nodule were included in the study. All patients were recruited from the UCLA Health System. Collected specimens were randomly assigned to be diagnostically assessed with either the RNA or DNA-RNA test.
Analysis of indeterminate nodules revealed an overall prevalence of malignancy of 20%. Furthermore, the benign call rates for the RNA and DNA-RNA test were 53% and 61%, respectively. Differences in specificity (80% with RNA test vs. 85% with DNA-RNA test) and positive predictive value (53% vs. 63%) were also identified. Moreover, a comparison of the current RNA test (54%) with its previous version (38%) revealed an increased positive predictive value. However, this trend was not identified for the DNA-RNA test.
Based on the findings of the diagnostic assessments, thyroidectomy was avoided in 51% of patients who underwent the RNA test and 49% of those who underwent the DNA-RNA test. In addition, follow-up protocol of 90 nodules using surveillance ultrasonography did not reveal advanced disease progression in 94% of nodules.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.