Use of the thyroid imaging, reporting, and data system (TI-RADS) scoring system for the evaluation of subcentimeter thyroid nodules.

BACKGROUND: The American Thyroid Association (ATA) recommends fine-needle aspiration (FNA) biopsy of nodules measuring >1.5 cm with low-suspicion sonographic patterns or >1.0 cm with high/intermediate-suspicion features. Routine biopsy of nodules <1 cm is not recommended. However, despite these recommendations, subcentimeter nodules are often referred for FNA biopsy. METHODS: This was a retrospective chart review of consecutive thyroid FNAs during an 18-month period (1157 patients, 1491 nodules, 2016-2017) to evaluate age, sex, medical history, diagnoses, and follow-up. Radiographic information was used to identify 61 subcentimeter nodules (4%) from 57 patients. Ultrasound studies were re-evaluated using criteria according to the American College of Radiology Thyroid Imaging, Reporting, and Data System (TI-RADS). RESULTS: Reported reasons for biopsy included a larger companion nodule (44%), a personal or family history of cancer (26%), or a suspicious sonogram, including calcification and/or irregular contours (16%). FNA diagnoses included: 69% benign (42 of 61 nodules), 10% papillary thyroid carcinoma (PTC) (6 of 61 nodules), and 15% atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) (9 of 61 nodules). Seven percent of nodules were unsatisfactory/nondiagnostic (4 of 61 nodules) compared with a 3% nondiagnostic rate for all sized nodules. Fifty-one nodules had an ultrasound available for re-review using the TI-RADS scoring system. A high TI-RADS score (4-5) was indicative of PTC in 29.4% of nodules. A low TI-RADS score (1-2) was indicative of PTC in 0% of nodules (P < .01). High and intermediate TI-RADS scores (3 and 4-5, respectively) were indicative of PTC/AUS/FLUS in 32% of nodules compared with 0% in those with low TI-RADS scores (P < .01). CONCLUSIONS: The current results demonstrate successful use of the TI-RADS scoring system in evaluation of the risk of malignancy in subcentimeter nodules. Larger studies will be necessary to determine whether biopsy is warranted for TI-RADS high-subcentimeter nodules. Cancer Cytopathol 2018. © 2018 American Cancer Society.