The futility of intraoperative frozen section in the evaluation of follicular thyroid lesions.

OBJECTIVE Investigate the utility of intraoperative frozen section (iFS) in patients with follicular thyroid lesions following publication of the 2015 American Thyroid Association (ATA) guidelines. STUDY DESIGN Retrospective chart review. METHODS Patient demographics, preoperative cytology, frozen pathology, and final pathology were reviewed on patients undergoing thyroid surgery at a tertiary care hospital in which iFS was utilized over a 5-year period. The test performance of iFS and the frequency of indicated completion/total thyroidectomies pre- and postpublication of the 2015 ATA guidelines were calculated. RESULTS One hundred and one patients met inclusion criteria: 54 patients with follicular lesions of undetermined significance (FLUS) and 47 patients with a cytologic diagnosis of suspicious for follicular neoplasm/follicular neoplasm. The malignancy rate was 36%, but only 14% of malignancies were identified on iFS. A definitive benign or malignant diagnosis was given on iFS in only 21% of cases, and operative management was altered in two cases as a result of iFS. There was a statistically significant reduction in the frequency of indicated total/completion thyroidectomies based on high-risk features as a result of the 2015 ATA guidelines compared to prior recommendations (20.8% vs. 5.0%, P = < 0.001). None of these patients had findings on iFS that would have altered management intraoperatively. CONCLUSION Intraoperative frozen section offers minimal diagnostic utility in the evaluation of follicular thyroid lesions. Updates in the 2015 ATA guidelines further diminish its potential to impact management intraoperatively. Significant improvements in its ability to identify malignancies would be needed to justify its use. LEVEL OF EVIDENCE 4. Laryngoscope, 2017.