The Effect of Implementing Gene Expression Classifier on Outcomes of Thyroid Nodules with Indeterminate Cytology

Thyroid nodules are classified into six cytological categories under the Bethesda classification system. Two of these categories, atypical of undetermined significance (AUS) and suspicious for a follicular neoplasm (SFN), are further labeled as "indeterminate" diagnosis. Starting in June, 2012, Kansas University-Wichita Endocrine clinic implemented Afirma® Gene Expression Classifier (AGEC) to evaluate the need for surgical resection of thyroid nodules in patients with an indeterminate diagnosis. Electronic medical records of patients who underwent thyroid nodule fine-needle aspiration from 2004-2014 were reviewed. The aim of this study was to find whether implementing AGEC was associated with decreased surgical recommendation rate, decreased cost, and increased incidence of thyroid malignancy diagnosed by surgery in patients with indeterminate diagnosis. A total of 299 consecutive patients' charts were screened. Sixty-one (20 %) patients had an indeterminate diagnosis. Out of these, 27 (44 %) patients underwent evaluation before and 34 (56 %) patients underwent evaluation after AGEC implementation, respectively. Surgical recommendation for patients with indeterminate finding decreased from 81.5 to 50 % (p = 0.01) after AGEC implementation. Surgical pathology was read as malignant in 20 and 85.7 % (p < 0.01) of patients before and after AGEC implementation, respectively. Primary cost-benefit estimate showed implementing AGEC has saved $1048/patient in medical evaluation and initial management of patients with indeterminate diagnosis. AGEC implementation has decreased the number of surgical recommendations, has lowered financial burden, and has increased incidence of thyroid malignancy diagnosed by surgical pathology in patients with indeterminate diagnosis of thyroid nodules.