Thyroid nodules are very common, occurring in up to 50% of individuals. Thyroid cancer is found in ~5% of thyroid nodules, so the vast majority are benign (noncancerous). A thyroid nodule biopsy can be benign (normal), malignant (cancer) or indeterminate. Indeterminate means the pathologist cannot tell if the nodule is benign or malignant with certainty. Historically, most patients with indeterminate thyroid nodule biopsies were referred for surgery though most would ultimately not have thyroid cancer (around 75% or more would have an “unnecessary surgery”). Currently, gene tests can provide more information as to whether an indeterminate nodule is a cancer or not. One such test is the Afirma gene test.
The original Afirma gene test was a gene expression classifier (GEC) that used a technology called a microarray that results in a pattern of gene expression. These gene patterns are better at ruling out thyroid cancer in an indeterminate nodule than confirming cancer. Therefore, a new version of the Afirma test was created called a gene sequencing classifier (GSC) to better predict thyroid cancers in indeterminate nodule while still being able to rule out cancer in benign nodules. The GSC incorporates nuclear and mitochondrial RNA transcriptome gene expression, RNA sequencing, and genomic copy number analysis.
The aim of this study was to determine the clinical performance of the GSC as compared with the GEC at one academic medical center.
THE FULL ARTICLE TITLE
Endo M et al 2019 Afirma Gene Sequencing Classifier compared with Gene Expression Classifier in indeterminate thyroid nodules. Thyroid 29:1115–1124.
SUMMARY OF THE STUDY
Patients with thyroid nodule biopsies with indeterminate cytology results were chosen for additional genetic testing; the Afirma GEC (during the period February 2, 2011–July 11, 2017) or the Afirma GSC (during the period July 11, 2017–December 19, 2018).