ECE2015 Eposter Presentations Thyroid cancer (90 abstracts)
1Endocrinology Department, Universitary Basurto Hospital, Bilbao, Spain; 2Pathology Department, Universitary Basurto Hospital, Bilbao, Spain.
Introduction: BRAF(V600E) mutation has received great attention to improve risk stratification in patients with PTC. Its prognostic value in the different Cytological variants (CytV) of PTC is not well established. The aim of this study was to investigate differences in clinicopathological features according to CytV, among patients harbouring the mutation.
Methods: We evaluated 102 patients with pathological diagnosis of PTC. All of them underwent total thyroidectomy and radioiodine ablation, 87 central lymph node (LN) dissection (67 prophylactic, and 18 lateral neck dissection as well. DNA was extracted from neoplastic cells and BRAF mutation was detected by PCR and sequencing. Analysis included histological subtype, age, multifocality (MF), extrathyroidal extension (EET), LN metastases (LNMx), LNratio (LNR) (number of positive LN divided by the total amount of dissected nodes) and clinical remission(CR) after 1 year of initial treatment (stimulated thyroglobulin (Tg) undetectable, no presence of Tg antibodies and negative cervical ultrasound).
Results: patients harboured BRAF mutation (45,1%). According to CytV: 27/38 (71%) classic variant (CV), 3/33 (9%) follicular variant (FV) and 16/25 (64%) mixed forms (MV). In mutation carriers mean age was 47 years in CV, 58 in FV and 60 in MV. MF was present in 59% of CV, 66% FV, 50% MV. EET was found in 51% of CV, 33% FV, 33% MV. The rate of central LNMx was 85% in CV, 37%MV and no patients in FV. The LNR was 22.4% in CV, and 6.1% in MV. CR was achieved in 15 out of 20 evaluated patients with CV and all the 11 with MV.
Conclusions: In our series BRAF mutation is more prevalent in CV of PTC as it has been described previously, and at a younger age. We also emphasise the high prevalence of LNMx and the higher LNR found in patients with CV tumours. Given the prognostic value of BRAF mutation, these results confirm the more benign behaviour of FVPTC.