Potential Effects of Molecular Testing of Indeterminate Thyroid Nodule Fine Needle Aspiration Biopsy on Thyroidectomy Volume

Abstract

Increasing utilization of genetic expression profiling (GEP) for thyroid nodules with indeterminate fine needle aspiration (FNA) results will potentially decrease the number of patients requiring diagnostic thyroidectomy. This study sought to determine the potential effects of GEP for indeterminate thyroid FNA results on thyroidectomy volume. A retrospective review of thyroidectomy procedures performed over 1year at the University of Michigan in the endocrine surgery division evaluated the indications for thyroidectomy, FNA Bethesda classification, and final surgical pathology to determine how application of GEP on indeterminate FNA results would affect decision for surgery and subsequent thyroidectomy volume. During the study period, 358 thyroidectomies were performed. The indication for procedure included: FNA findings, n=122; symptomatic multinodular goiter, n=85; nodule >4cm, n=30; Graves', n=26; other, n=95. FNA was performed in 231 patients. Bethesda classification included: benign, n=69; malignant, n=55; follicular lesion of undetermined significance, n=59; follicular neoplasm, n=20; suspicious for malignancy, n=16; nondiagnostic, n=12. If standard GEP was performed for all indeterminate FNA results, it would have influenced the decision for surgery in 68 (19%) patients. Assuming 38% of indeterminate FNA specimens will have benign results on genetic profiling, 27 patients would not have undergone thyroidectomy, translating into a 7.2% decrease in overall thyroidectomy volume over a year. In an academic endocrine surgery program, the most common indication for thyroidectomy is an FNA result; however, standard application of GEP for all indeterminate thyroid FNAs would result in a minimal reduction in overall thyroidectomy volume.