BRAF mutation in papillary thyroid carcinoma in a Japanese population: Its lack of correlation with high-risk clinicopathological features and disease-free survival of patients

Abstract

Recent studies have demonstrated that BRAFV600E mutation is a common event in papillary thyroid carcinoma and a majority of these lesions have shown a direct relationship between BRAFV600E mutation and aggressive characteristics, including a worse patient prognosis. However, there are no studies from Japan regarding this issue in a large series with adequate postoperative follow-up periods. We investigated BRAFV600E mutation in 631 patients with papillary carcinoma having median follow-up periods of 83 months. The prevalence of BRAFV600E mutation was 38.4%, and the rate was higher in carcinoma larger than 1.0 cm but did not successively increase with tumor size. Furthermore, the prevalence did not significantly increase in cases demonstrating high-risk biological features such as clinically apparent lymph node metastasis, massive extrathyroid extension, advanced age, distant metastasis at surgery, and advanced Stage. The disease-free survival of patients with BRAFV600E mutation did not differ from that of those without BRAFV600E mutation. These findings indicate that, although BRAF V600E mutation may play some roles in local carcinoma development, there is no evidence that BRAFV600E mutation significantly reflects the aggressive characteristics and poor prognosis of patients with papillary carcinoma in Japan.