The Value of Repeated Fine-Needle Aspiration Biopsy in an Academic Community Hospital after the Bethesda System

Abstract

Background: Follow-up of thyroid nodules with repeated fine-needle aspiration biopsies (rFNA) is recommended in nondiagnostic (ND) samples and in cases of atypia of unknown significance (AUS)/follicular lesions of uncertain significance (FLUS), however, the impact of this approach is generally unexplored. We evaluated the risk of neoplasia (RN) and malignancy (RM) in rFNA. Design: All FNA from Jan/04 to Dec/10 were reclassified according to Bethesda System: ND, benign (B), AUS/FLUS, suspicious for follicular neoplasm (FN), suspicious for malignancy (SM) and malignant (M). Patients with one FNA (1FNA) and with rFNA were compared according to the worst diagnosis in the first FNA (fFNA) or in the rFNA. Surgical pathology (SP) and clinical follow-up were retrieved. Results: In 480 patients (F:M=7:1, average age 53), 70 (14.6%) had rFNA. Average number of rFNA was 1.3±0.8. A total of 125 (26%) had a thyroidectomy (21.4% in the rFNA and 26.8% in 1FNA - p=0.3). Diagnoses upon fFNA in rFNA group were ND in 10 (14.3%), B in 49 (70%), AUS/FLUS in 8 (11.4%) and FN/SM in 3 (4.3%). In B group rFNA changed in 3 patients (6.1%) (2 AUS/FLUS, 1 FN) and 11 patients (22.4%) had SP follow-up: 1 follicular adenoma (FA) and 10 benign non-neoplastic lesion (BN), including 1 patient with AUS/FLUS at rFNA. In ND group rFNA changed in all patients: 9 (90%) to B and 1 (10%) to M – SP confirmed papillary carcinoma (PC). In AUS/FLUS group rFNA changed to B in 3 (37.5%) and ND in 1 (12.5%), none with SP. AUS/FLUS rFNA was unchanged in 4 (50%) – SP available in 3: 1 PC, 1 papillary microcarcinoma (PMC) and 1 BN. rFNA changed to B in the 3 patients of FN/MS group, one with BN at SP. Diagnoses in 1FNA group with SP follow-up were ND in 1 (0.9%), B in 60 (54.5%), AUS/FLUS in 15 (13.6%) and FN/SM/M in 34 (30.9%). The 1 ND was BN at SP. In 1FNA B group SP confirmed 7 incidental PMC (11.7%) and 1 FA (1.7%). In 1FNA AUS/FLUS group SP showed 1 FA (6.7%), 1 PC (6.7%) and 1 PMC (6.7%). In 1FNA FN/SFN/M group SP showed 18 PC (52.9%), 6 PMC (17.6%), 1 follicular and 1 medullary carcinoma. RM was 9.1% for all ND FNA. General RN was 9.1% in rFNA B group, 15% in the 1FNA B, 66% in rFNA AUS/FLUS, 20% in 1FNA AUS/FLUS and 82.4% in 1FNA FN/SM/M. Conclusions: Our data support the recommendation of rFNA in ND category. A repeated diagnosis of AUS/FLUS increased the general RN from 20% to 66% (p=0.1). A B fFNA diagnosis had a 4% chance of changing upon rFNA, and a virtually null RM.