Selection of Atypia/Follicular Lesion of Unknown Significance Patients for Surgery Versus Active Surveillance, Without Using Genetic Testing: A Single Institute Experience, Prospective Analysis, and Recommendations

Abstract

Background: Atypia/follicular lesion of unknown significance (AUS/FLUS) has variable rates of malignancy. The recommended management includes active surveillance (AS), repeated fine-needle aspiration (RFNA), diagnostic surgery, or genetic testing for malignancy. The objective of this study was to assess the management of AUS/FLUS patients in a dedicated thyroid clinic without implementing genetic testing. Methods: This was a single institute cohort study of all patients aged ≥18 years who underwent ultrasound-guided FNA thyroid biopsies between January 2009 and January 2013 and were followed until January 2016. The median follow-up time was 4.6 years (range 3.2–6.8 years). Forty-eight (57%) patients were referred to AS, and 36 (43%) patients were referred for diagnostic surgery. Thirty-six (75%) patients from the AS group underwent RFNA. An additional eight patients from the AS group subsequently underwent diagnostic surgery. Results: Malignancies were found in 15/44 (34%) diagnostic surgical samples, and benign cytologies were found in 61.1% of the RFNAs. Analysis of adherence to follow-up in the 36 AS patients showed an adherence rate of only 53%, with males tending to comply better than females did (31.6% vs. 5.8%, respectively; p = 0.052), especially males in their sixth decade of life. Conclusions: Genetic tests for AUS/FLUS patients are accepted today as complementary evaluations in many well-developed health systems. Yet, when these tests are not feasible due to financial or availability issues, careful management of AUS/FLUS patients may still offer good results in the selection of patients for surgery or AS. The present results also indicate that compliance to follow-up schedules is a major consideration when selecting patients for AS.