The biopsy-proven benign thyroid nodule: is long-term follow-up necessary?

Abstract

Thyroid nodules are common, and of those biopsied by fine-needle aspiration (FNA), the majority will be benign colloid nodules (BCN). Current guidelines suggest these BCN should be followed by ultrasonographic examination (US) every 3 years, with no endpoint specified. This study evaluated if long-term follow-up of benign thyroid nodules was associated with change in treatment or improvement in diagnosing a missed malignancy compared with short-term follow-up. All patients with FNA-based diagnosis of BCN at our institution from 1998 to 2009 were identified. Patients observed after the diagnosis were divided into short-term follow-up (<3 years) and long-term follow-up (≥3 years). Rates of repeat FNA, thyroidectomy, and malignancy detection were compared. Of 738 patients with BCN, 92 patients underwent thyroid resection after the initial US. Six hundred forty-six patients were observed, of which 366 returned for 1 or more follow-up US: 226 in the short-term group (median 13 months) and 140 in the long-term group (median 57 months). There were more follow-up US in long-term vs short-term (medians 4 vs 2, p < 0.01), more repeat FNAs in the long-term group (18 of 140 vs 8 of 226, p < 0.01); but no difference in interval thyroidectomies (13 of 140 vs 31 of 226, p = 0.25) or malignant final pathology (0 of 13 vs 2 of 31, p > 0.99). For all patients undergoing surgery, pathology was malignant in 2 of 136 (1.5%). Long-term follow-up of patients with BCN is associated with increased repeat FNA and US without improvement in the malignancy detection rate. After 3 years of follow-up, consideration should be given to ceasing long-term routine follow-up of biopsy-proven BCN.