Combined clinical and ultrasound follow-up assists in malignancy detection in Galectin-3 negative Thy-3 thyroid nodules.

Abstract

The use of galectin-3 ThyroTest in the preoperative evaluation of cytologically indeterminate (Thy-3) thyroid nodules has been largely validated by retrospective and prospective multicentre studies. Here we report the results of galectin-3 ThyroTest routinely applied in the management of Thy-3 nodules in combination with clinical and ultrasonography (US) examination, in which galectin-3 positive nodules were directly referred to surgery whereas galectin-3 negative lesions were considered for clinical and US long-term follow-up. A cohort of 331 patients, bearing 340 thyroid Thy-3 nodules, was enrolled and subjected to galectin-3 expression analysis. A total of 256 galectin-3 negative nodules were directed to periodical clinical and US examination, while 84 galectin-3 positive cases were referred to surgery. Excluding 63 dropout patients plus 15 patients that were operated because of clinical reasons the remaining 176 galectin-3 negative nodules were followed with clinical and US examination for an average period of 31months. During the follow-up, the volume of galectin-3 negative nodules was unchanged in 85 cases (48%), reduced in 47 (27%), and increased in 44 (25%). Based on combined clinical features and US follow-up results, a total of 36 out of 191 galectin-3 negative nodules (19%) were referred to surgery, with a final histological finding of 28 benign lesions, three follicular tumor of uncertain malignant potential (FT-UMP), and five malignant lesions, corresponding to a 7% false negative rate. In the group of 84 galectin-3 positive nodules, we detected 65 thyroid cancers with a prevalence of 77%, 12 FT-UMPs, and 7 false positive lesions, corresponding to a 4% false positive rate. A total of 150 patients were not operated and are still under clinical and US monitoring while surgery was performed in 118 patients with a final 70 thyroid cancers diagnosed, corresponding to a 59% prevalence of malignancy detected at surgery and to a 26% prevalence of malignancy among the entire Thy-3 nodule population. Galectin-3 ThyroTest is an easy and cheap diagnostic procedure that integrates conventional fine-needle-aspiration cytology, reduces the number of unnecessary thyroidectomies and increases the rate of malignancy at surgery. Clinical and US follow-up of galectin-3 negative lesions allows to further reduce false negative cases.