Endocrine Abstracts

Introduction: The prevalence of B-type Raf kinase (BRAFV600E) mutation in PTC has been observed in 30% to over 80%, and it seems that the mutation occurred in the early stage of thyroid carcinoma progression which precedes histological change. Based on previous reports, high body mass index (BMI) is considered a thyroid cancer risk. However, it is unclear whether high BMI has a certain association with the BRAFV600E mutational status. We assess whether high BMI is associated with higher BRAFV600E mutational risk.

Materials and Methods: We screened 6,558 papillary thyroid carcinoma (PTC) patients who had BRAFV600E test result between January 2009 and December 2017. After exclusion, 6,442 PTC patients were enrolled. We used logistic regression to assess the association between BMI and BRAFV600E mutational risk. Also, we categorized patients into two groups according to the primary tumor size.

Results: Of the 6,442 patients, 5,105 patients (76.2%) had BRAFV600E mutation, and 4,957 patients (76.9%) were female. Median BMI was 23.8 (21.6 – 26.2) kg/m2. Primary tumor size was ≤1 cm in 4,226 patients, and >1 cm in 2,212 patients. BRAFV600E mutational status was significantly associated with high BMI only in primary tumor size >1 cm (OR 1.035; 95% CI 1.004 – 1.006; P = 0.025). No clear association was found in the primary tumor size ≤1 cm (OR 1.004; 95% CI 0.98 – 1.028; P = 0.740). The pattern of odds ratio (OR) plots were similar in each group (primary tumor size ≤1 cm, and >1 cm) after adjusting with age, alcohol, and smoking status.

Conclusion: Higher BMI seems positively associated with BRAFV600E mutational status in primary tumor size >1 cm. However, the association between BMI and BRAFV600E mutation status may differ by primary tumor size.