Evaluation of the Role of BRAFV600E Somatic Mutation on Papillary Thyroid Cancer Disease Persistence: A Prospective Study

Background: BRAFV600E (c.1799T>A) somatic mutation evaluation in fine needle aspiration biopsies (FNAB) is a powerful diagnostic tool in the settings of papillary thyroid cancer (PTC). However, its prognostic value is still a matter of great debate and has been addressed mostly in retrospective studies. Objectives: evaluate whether the somatic BRAFV600E mutation, assessed by direct sequencing in FNAB material of thyroid nodules, may correlate with disease persistence in PTC patients. Study design: We conducted a prospective cohort study investigating 160 PTC patients previously assessed for the somatic BRAFV600E mutation, and submitted to total thyroidectomy, with a follow-up of 2-10 years. Patients were matched according to somatic BRAFV600E mutation (80 BRAF+ and 80 BRAF- patients) and to the presence (LN+, 40 patients each group) or absence (LN, 40 patients each group) of neck lymphnode metastases. Disease persistence was considered according to basal or TSH-stimulated Thyroglobulin (TG) levels, anti-TG antibodies, neck ultrasound, CT scan where applicable and whole body scan after radioiodine ablation treatment (RAI). Results: The presence of the somatic BRAFV600E mutation did not influence the indication for RAI. None of the enrolled patients showed disease recurrence nor died due to disease-related causes. During follow-up disease persistence did not correlate with the presence of somatic BRAFV600E mutation both in patients submitted to RAI nor in those treated more conservatively. Conclusions: The somatic BRAFV600E mutation does not associate with a worse prognosis in low risk PTC and, in our settings, may not be considered an independent risk factor for disease persistence.