Effects of Implementing a Higher Threshold for Recommending Thyroid Biopsies on Malignancy Rates.

Abstract

We implemented a new thyroid nodule classification system in which a biopsy was recommended for thyroid lesions ≥ 1 cm with at least 2 or more suspicious features. Three consecutive years of thyroid biopsies using the new classification system were reviewed for patient demographics, biopsy recommendation based on nodule size and imaging characteristics, and pathology results. The primary outcome was malignancy rates for thyroid biopsies. These results were compared to a 3-year historical data set. Review of thyroid biopsies from 2010 to 2012, prior to the implementation of current recommendations, revealed 996 thyroid biopsies with a malignancy rate of 12.8%. Subsequent to the new classification system in 2017, 483 thyroid biopsies were performed over the next 3 years with a malignancy rate of 21.9%. Implementation of the new classification system with a higher threshold for biopsy reduced our yearly biopsy volume by approximately 50% while also increasing our malignancy rate from 12.8% to 21.9%, which is more in line with published rates of malignancy. In a community setting performing less than 200 biopsies per year, the use of more stringent requirements for thyroid biopsy are necessary to achieve malignancy rates comparable to the published literature.