Can Ultrasound Be as a Surrogate Marker for Diagnosing a Papillary Thyroid Cancer? Comparison with BRAF Mutation Analysis

Abstract

PurposeWe investigated the merit of ultrasound (US) features and BRAFV600E mutation as an additional study of cytology and compared the diagnostic performances of cytology alone, cytology with US correlation, cytology with BRAFV600E mutation, and a combination of cytology, US, and BRAFV600E mutation all together.Materials and MethodsThis study included 185 patients (mean age, 48.4 years; range 20-77 years) with 191 thyroid nodules who underwent US-guided fine-needle aspiration (FNA) with an additional BRAFV600E mutation test. Three radiologists highly experienced in thyroid imaging retrospectively reviewed US images and classified each nodule into two categories (positive for malignancy or negative for malignancy). Interobserver variability (IOV) of US assessment between the three readers was estimated using the generalized kappa statistic of Landis and Koch. We also calculated the diagnostic performances of these studies.ResultsThere were 131 cases of malignancy (131/191, 68.6%) and 60 cases of benign nodules (60/191, 31.4%). In terms of IOV of US assessment, the generalized kappa value was 0.242, indicating fair agreement was reached. The combination of cytology with BRAFV600E showed higher specificity (100%) and positive predictive value (PPV) (100%) compared to the combination of cytology, BRAFV600E, and US (specificity 28.3%, 66.7%, 68.3%; PPV 74.6%, 86.6%, 86.8%, respectively; p<0.001). However, cytology with BRAFV600E showed lower sensitivity (84.7%) than cytology with BRAFV600E and US (96.2%, 98.5%, 95.4%, respectively; p<0.001).ConclusionConsidering the diagnostic performance and low reproducibility of US, the combination of FNA with BRAFV600E is the most reliable and objective method for diagnosing thyroid malignancy.

Diagnostic value of BRAFV600E mutation analysis in fine needle aspiration for evaluation of thyroid nodules

“…in the investigation by Seo et al 25 In this study, the sensitivity of the combination of FNA, ultrasonographic findings, and the BRAF V600E mutation test was 92.9%. This result demonstrates the im-portance of ultrasonographic findings.…”

What to do with thyroid nodules showing benign cytology and BRAFV600E mutation? A study based on clinical and radiologic features using a highly sensitive analytic method

“…The analytical sensitivity was evaluated using the plasmid clone BRAF V600E mutation, and the 95% positive cut-offvalue (limit of detection; LOD) was calculated at 21.5 copy/mL by the Probit analysis. 10,15 RESULTS Figure 1 represents the clinical course of the 22 thyroid nodules. A total of 17 cases underwent thyroidectomy.…”

Thyroid Nodules: Nondiagnostic Cytologic Results according to Thyroid Imaging Reporting and Data System before and after Application of the Bethesda System

“…A recent study proposed that nondiagnostic cytologic results from an appropriately performed initial FNA may indicate benignity, which may reassure practitioners that imaging follow-up can be considered over follow-up US-guided FNA (21). Imaging features also may provide practitioners with the confidence to consider conservative follow-up for these nodules, because nodules with nondiagnostic cytologic results and no features suspicious for cancer at US also had significantly lower malignancy rates compared with nodules with features suspicious for cancer at US (2,(22)(23)(24)(25)(26)(27).…”