Null Association between BRAF V600E Mutation and Tumor Recurrence in Patients with Papillary Thyroid Microcarcinoma in South Korea

Abstract

Background and Objectives: The clinical implications of the BRAF V600E mutation in papillary thyroid microcarcinoma (PTMC), defined as ≤1.0 cm of tumor size, remain controversial. We investigated the association between the BRAF V600E mutation and PTMC recurrence in a retrospective cohort of patients with thyroid cancer.

Materials and Methods: This study included 2319 patients with PTMC (median age, 50 years [interquartile range (IQR), 41-57 years]) who underwent thyroid surgery from 2010 to 2019 at a single tertiary medical center. The median follow-up time was 75 months (IQR, 30-98 months). Tumor recurrence was confirmed by histological, cytological, radiographic, and biochemical criteria, combined with persistent and recurrent disease. Results: A total of 60.2% (1395/2319) patients with PTMC had the BRAF V600E mutation. The tumor recurrence rate was 2.1% (19/924) in BRAF mutation-negative patients and 2.9% (41/1395) in BRAF mutation-positive patients, with a hazard ratio (HR) of 1.05 (95% confidence interval [CI], 0.61-1.84) after adjusting for clinicopathological risk factors. Similar results were found in patients with high-risk PTMC (adjusted HR, 1.09; 95% CI, 0.56-2.11) who had lymph node metastasis (LNM), extrathyroidal extension (ETE), or distant metastasis (DM) at diagnosis and in patients with low-risk PTMC (adjusted HR, 1.00; 95% CI, 0.35-2.83) who had no LNM, ETE, or DM.

Conclusion: The finding that the BRAF V600E mutation was not associated with tumor recurrence in our cohort of Korean patients with PTMC, especially in patients with low-risk PTMC, suggests that its value in the prediction of disease progression is limited.