Endocrine Abstracts

Background: The BRAF^V600E mutation is the most common mutation in papillary thyroid carcinoma (PTC). Its presence has been associated with extrathyroid invasion, lymph node metastasis, and tumor recurrence. Recently, assessment of the BRAF^V600E mutation status in patients with PTC has been used as a method to predict tumor aggressiveness.

Objective: Our aim has been to analyze the prevalence of BRAF^V600E mutation in a cohort of patients with PTC in our geographical and its relationship with poor prognostic factors or aggressiveness of the disease. We also investigated whether this mutation is related to the persistence of the disease 12 months after initial therapy.

Patients and methods: We retrospectively studied patients older than 18 years who underwent surgery for PTC at our centre from 2011 to 2017. Clinical, analytical, histological and molecular data were obtained from all patients with assessed BRAF^V600E mutation (n=159). In patients with more than 12 months of follow up after initial therapy data on the dynamic risk stratification results were recorded.

Results: The prevalence of BRAF^V600E mutation was 58.3% (95% confidence interval, 49.6–66.5). No differences in patients classified by gender or age groups were found. We could not find any significant association between BRAF^V600E mutation status and the evaluated clinical and analytical parameters (including radioiodine remnant ablation and postsurgical serum thyroglobulin levels). Tumor size, multifocal disease, extrathyroidal extension, or the presence of lymph node metastases were not related to the presence or absence of BRAF^V600E mutation. A significant association between this mutation and the histological variants of PTC was found. BRAF^V600E mutation was found in 71.4% of patients with the classical variant of PTC and only in 44.2% of those with the follicular variant of PTC (P=0.002). Twelve months after initial therapy 66% of our patients showed no evidence of disease according to the criteria of dynamic risk stratification (excellent response). We did not find any relationship between BRAF^V600E mutation and the persistence or remission of disease at this time.

Conclusion: BRAF^V600E mutation is very common (58.3%) in our population of patients with PTC. In this cohort of patients the presence of BRAF^V600E mutation is related with the histological variant of PTC, but we could not find any significant relationship with other histopathological features or with the response to treatment one year after initial therapy.