Targeted Next Generation Sequencing with ThyroSeq v2.1 for Indeterminate Thyroid Nodules in Clinical Practice.

OBJECTIVE: To determine if patients elect molecular testing over diagnostic surgery or repeat fine needle aspiration for indeterminate thyroid nodules. Can ThyroSeq v2.1 molecular testing reduce diagnostic thyroid surgery and rule out cancer? STUDY DESIGN: Retrospective review Setting: Single institution, single-practice surgeon. SUBJECTS AND METHODS: Fifteen month retrospective review of indeterminate thyroid nodules that went on to ThyroSeq v2.1 testing. RESULTS: 286 patients met American Thyroid Association guideline criteria for surgeon- performed, ultrasound-guided fine needle aspiration for a thyroid nodule with on-site cytopathology. The indeterminate (Bethesda III or IV) fine needle aspiration cytology rate was 9.1 percent. Prevalence of malignancy in indeterminate nodules was 19 percent. 26/26 (100 percent) patients with indeterminate thyroid nodules elected molecular testing. 16 patients had no mutation, 9 had one or more mutations, and I had no result. 16 of 25 (64 percent) patients with no mutation elected not to undergo diagnostic surgery for indeterminate thyroid nodules. CONCLUSIONS: Patients demonstrated a strong preference for molecular testing instead of diagnostic thyroid surgery for indeterminate thyroid nodules. All patients in this series, 25/25 (100 percent) with indeterminate thyroid nodules elected molecular testing instead of repeat biopsy or diagnostic thyroid surgery. 16 of 25 (64 percent) patients tested had no mutation. All 16/16 (100 percent) patients with no mutation on ThyroSeq "rule out" testing elected active surveillance rather than surgery or biopsy, reducing diagnostic surgery. The risk of malignancy among mutation negative patients was not definitively established. There are a number of factors currently that may mute the power of "rule in" testing.