MON-LB84 Validation of TI-RADS (Thyroid Imaging, Reporting and Data System) Follow-Up Recommendations

Background:Thyroid nodules are exceedingly common, leading to costly interventions for many lesions that ultimately prove benign. Therefore, a reliable, noninvasive method to identify which nodules warrant fine needle aspiration and/or follow-up on the basis of a reasonable likelihood of malignancy is highly desirable. American College of Radiology (ACR) created a standard terminology (lexicon) to describe all thyroid nodules on sonography and standardized TI-RADS risk-stratification system to identify nodules that warrant biopsy and/or follow-up. Many healthcare institutions including UPMC adapted the TI-RADS scoring system in order to identify most clinically significant malignancies while reducing the number of biopsies and follow-up ultrasounds performed on benign nodules. According to ACR, TI-RADS category 3 nodules <1.5 cm and TI-RADS category 4 nodules <1 cm do not warrant follow-up imaging. There are no validation studies on TI-RADS follow-up recommendations. Methods:We completed a retrospective chart review from UPMC endocrine surgery thyroid nodule database from 2002 to 2012. We identified 57 nodules that showed a change in size during follow-up and had surgical data. Patient demographics, nodule baseline TI-RADS category, size, follow-up volume change and histopathological data were recorded. We reviewed ultrasound images and calculated TI-RADS category at baseline and during follow-up. Results:TI-RADS category 1-2 (TR1 and TR2) nodules(n=4) did not show any change in size over an average of 6.5 years confirming the recommendations that TR1 and TR2 nodules do not need follow-up.TI-RADS category (TR3) nodules (n=22) showed an average 225% change in volume over 4 years of follow-up. TR3 nodules <1.5 cm showed 397% volume change; 3 out of 15 (20%) nodules that showed a change in size proved to have thyroid cancer >1cm. TI-RADS category (TR4) nodules(n=31) showed a 786% volume change over 2.6 years of follow-up. TR4 nodules <1 cm, 5/14(35%) proved to have thyroid cancer >1 cm in follow up. Conclusions:TR1 and TR2 nodules did not show thyroid cancer during follow-up validating ACR recommendations not to follow these nodules. 3/15(26.5%) TR3 nodules <1.5 cm that showed a change in volume proved to have thyroid cancer. 5/14(35%) TR4 nodules <1cm that changed in volume were found to have thyroid cancer. Further studies are needed to identify nodules that require follow-up in order to decrease the misdiagnosis of thyroid cancer.