BRAF V600E mutation is associated with aggressive features in papillary thyroid carcinomas ≤ 1.5 cm.

BACKGROUND

While some studies suggest that the BRAF V600E mutation correlates with a high-risk phenotype in papillary thyroid microcarcinoma (PTMC), more evidence is necessary before this mutation can be used to help guide decision making in the management of small thyroid nodules. This study investigated whether BRAF V600E mutation is associated with aggressive features in PTMC (≤ 1 cm) and small PTC (1-1.5 cm).

METHODS

Retrospective chart review was performed on 121 patient cases. Patients who underwent thyroid surgery for PTMC (≤ 1 cm) or small PTC (1-1.5 cm) were included if molecular testing was done for BRAF V600E mutation. Two study groups were created based on tumour size: PTMC (n = 55) and small PTC (n = 66). The groups were analysed for the presence of a BRAF V600E mutation and aggressive features, including macroscopic extrathyroidal extension (ETE), lymph node metastasis (LNM), and high-risk histological features (tall cell, columnar cell, hobnail, solid/trabecular, and diffuse sclerosing). The Fischer exact test was used to calculate statistical significance.

RESULTS

BRAF V600E mutations were detected in 43.6% of PTMC and 42.4% of small PTC. Of the mutated PTMC nodules, 54.1% demonstrated aggressive characteristics as compared to 19.4% of the non-mutated PTMCs (p = 0.010). Of the mutated small PTC tumours, 82.1% had aggressive features. In contrast, 28.9% of the non-mutated small PTCs showed aggressive features (p < 0.001).

CONCLUSIONS

Our findings demonstrate an association between a BRAF V600E mutation and aggressive features in PTMC (≤ 1 cm) and small PTC (1-1.5 cm). Therefore, determining the molecular status of these thyroid nodules for the presence of BRAF V600E can help guide patient management.