Preliminary Study on the Relationship of BRAF Mutations with the Outcome of the First (131)I Radiotherapy and Malignant Biological Characteristics in Papillary Thyroid Carcinoma

OBJECTIVE: To investigate the relationship of BRAF mutation with the outcome of the first postoperative (131)I treatment and malignant biological characteristics in papillary thyroid carcinoma (PTC). METHODS: Thirty-three patients with PTC who underwent their first (131)I treatment after total thyroidectomy were enrolled in this study. BRAF mutation in postoperative tumor tissue and circulating tumor DNA (ctDNA) in peripheral blood at the time of (131)I treatment were detected. According to the status of BRAF mutation, all patients were divided into 2 groups in each category of tumor tissues and ctDNA, respectively: 1) BRAF mutation, 2) BRAF wild-type. The Fisher’s exact test was performed to analyze the relationship of BRAF mutation in either tumor tissue or ctDNA with the outcome of the first (131)I treatment and malignant characteristics of PTC. RESULTS: BRAF mutation was detected in tumor tissues in 25 patients (25/33,75.8%), and all the patients had single mutation site. In ctDNA, BRAF mutation was detected in 5 patients (5/33, 15.2%), and all the patients had single mutation site. In both tumor tissues and ctDNA, BRAF mutation showed no relationship with the outcome of first (131)I treatment and the malignant biological characteristics (P>0.05). CONCLUSION: The value of BRAF mutation alone might be limited in predicting therapeutic outcome of the first (131)I treatment in PTC. No definitive relevance was found between BRAF mutation and malignant biological features in PTC.