Molecular Profiling of Thyroid Nodules: Current Role for the Afirma Gene Expression Classifier on Clinical Decision Making

Thyroid fine-needle aspiration biopsy results are cytologically indeterminate in 15-30% of cases. When these nodules undergo diagnostic surgery, approximately three-quarters are histologically benign. These unnecessary surgeries diminish quality of life, generate complications, and increase healthcare costs. The Afirma gene expression classifier (GEC) is validated to pre-operatively identify cytologically indeterminate nodules likely to be truly benign so that surgery can be avoided. Its performance is supported by robust multicenter prospective and blinded clinical validation studies, and supported by extensive independent clinical utility publications which show a marked reduction in surgery among patients with benign Afirma GEC results. To rule-out cancer and avoid unnecessary diagnostic surgery, Afirma’s quality and depth of validation stand alone. The accuracy of a benign result is the negative predictive value (NPV). Afirma achieves an NPV ≥94% among cytologically indeterminate nodules (Bethesda III or IV). Thirteen clinical utility studies describing 1468 GEC benign patients demonstrate that few Afirma GEC benign nodules undergo surgery, including after 3 years of follow-up. With a specificity of 52%, over half of the truly benign nodules with indeterminate cytology receive a benign GEC result. High test sensitivity is critical to safely rule out cancer. The Afirma GEC’s 90% sensitivity means that regardless of the pre-test risk of malignancy, 90% of all malignant nodules are GEC suspicious. The Afirma GEC has transformed patient care. Where the majority of cytologically indeterminate patients were once operated to determine if the nodule was benign or malignant, now nearly half of these surgeries can be avoided.