The role of BRAF(V600E) mutation as poor prognostic factor for the outcome of patients with intrathyroid papillary thyroid carcinoma

Background: BRAF(V600E) mutation, which represents the most frequent genetic mutation in papillary thyroid carcinoma (PTC), is widely considered to have an adverse outcome on PTC outcome, however its real predictive value is not still well stated. The aim of the present study was to evaluate if BRAF(V600E) mutation could be useful to identify within patients with intrathyroid ultrasound-N0 PTC those who require more aggressive treatment, by central neck node dissection (CLND) or subsequent postoperative (131)I treatment.

Methods: Among the whole series of 931 consecutive PTC patients operated on at 2nd Clinical Surgery of University of Padova and at General Surgery Department of University of Trieste during a period from January 2007 to December 2012, we selected 226 patients with an intrathyroid tumor and no metastases (preoperative staging T1-T2, N0, M0). BRAF(V600E) mutation was evaluated by PCR-single-strand conformation polymorphism analysis and direct genomic sequencing. We analyzed the correlation between the presence/absence of the BRAF(V600E) mutation in the fine-needle aspiration (FNA) and the clinical-pathological features: age, gender, extension of surgery, node dissection, rate of cervical lymph node involvement, tumor size, TNM stage, variant of histotype, mono/plurifocality, association with lymphocitary chronic thyroiditis, radioactive iodine ablation doses, and outcome.

Results: The BRAF(V600E) mutation was present in 104 of 226 PTC patients (47.8%). BRAF(V600E) mutation correlated with multifocality, more aggressive variants, infiltration of the tumoral capsule, and greater tumor's diameter. BRAF(V600E) mutation was the only poor prognostic factor in these patients.

Discussion: In our series, BRAF(V600E) mutation demonstrated to be an adverse prognostic factor indicating aggressiveness of disease and it could be useful in the management of low-risk PTC patients, as supplementary prognostic factor to assess the preoperative risk stratification with the aim to avoid unnecessary central neck node dissection (BRAF pos.) or to perform complementary (131)I-therapy (BFAF neg.).