OBJECTIVES: Preclinical studies showed that BRAF mutation significantly reduced 
radioiodine uptake and decreased the sensitivity to radioactive iodine (RAI) 
therapy. However, clinical data regarding its role in therapeutic decision 
making with respect to RAI therapy are currently insufficient. Thus, this study 
aimed to evaluate the effect of BRAF mutation on the clinical response to RAI 
therapy for papillary thyroid microcarcinoma (PTMC) with intermediate-risk to 
high-risk features.
PATIENTS AND METHODS: From January 2012 and October 2015, consecutive patients 
with PTMC with intermediate-risk to high-risk features who underwent RAI therapy 
were retrospectively included. The data about BRAF mutation status were also 
obtained. The association between clinicopathological characteristics and 
mutation was investigated. After a median follow-up of 40 months, the clinical 
response to RAI therapy was also compared between positive and negative mutation 
groups.
RESULTS: A total of 236 patients were included, of whom 147 (62.3%) had positive 
mutation. The clinicopathological features did not show significant correlation 
with BRAF mutation status except the sex, extrathytoidal extension and T stage. 
Patients with PTMC with BRAF mutation showed an increased likelihood of having 
advanced T stage and extrathyroidal extension. In addition, this mutation did 
not affect the clinical outcome of RAI therapy.
CONCLUSION: The status of BRAF mutation may not affect the clinical response to 
RAI therapy for patients with PTMC with intermediate-risk to high-risk features. 
More trials examining the role of BRAF mutation in guiding postoperative RAI 
therapy are needed.