Preoperative BRAF(V600E) mutation screening is unlikely to alter initial surgical treatment of patients with indeterminate thyroid nodules: a prospective case series of 960 patients.

Overview

abstract

BACKGROUND: Preoperative B-type Raf kinase Val600Glu mutation, or BRAF(V600E), analysis has been proposed as a tool to guide initial surgery for indeterminate thyroid nodules. This study sought to determine if cytologic markers of malignancy are associated with the BRAF(V600E) mutation and if preoperative BRAF(V600E) testing would alter the initial management of patients with indeterminate nodules. METHODS: Patients who underwent surgery for a thyroid nodule between 2003 and 2012 at a tertiary care center were prospectively enrolled. Stored nodule samples were retrospectively genotyped for the BRAF(V600E) mutation. BRAF(V600E) status, demographics, cytologic and histopathologic findings, and choice of initial surgery were examined. RESULTS: A total of 960 patients were enrolled, of which 310 (32%) had an indeterminate nodule. The BRAF(V600E) mutation was identified in 13 patients (4%), 12 of whom had either cytologic atypia or were Bethesda category V. Three percent of Bethesda category III or IV nodules that were malignant harbored the mutation compared with 42% of Bethesda category V malignancies. Nuclear grooves (P = .030), pseudoinclusions (P < .001), and oval nuclei (P = .022) were all more common among BRAF(V600E) mutants. The sensitivities of using BRAF testing alone, cytologic atypia/Bethesda category V classification, or both, were 15%, 73%, and 76%, respectively. Twelve of the 13 BRAF(V600E) mutants had total thyroidectomies initially due to worrisome cytologic features, and therefore the initial management of only one patient would have been altered if BRAF(V600E) testing had been performed preoperatively. CONCLUSIONS: Preoperative mutation screening for BRAF(V600E) does not meaningfully improve risk stratification and is unlikely to alter the initial management of patients with indeterminate nodules.