Correlation between body mass index and clinicopathological features of papillary thyroid microcarcinoma.

OBJECTIVES To demonstrate the relationships between body mass index (BMI) and the clinicopathological features of papillary thyroid microcarcinoma (PTMC) and papillary thyroid carcinoma (PTC). METHODS A total of 810 consecutive patients with PTC (501 patients with PTMC) who underwent total thyroidectomy in 2009-2013 were retrospectively reviewed. Height and weight were used to calculate BMI. RESULTS Increased BMI was strongly associated with i) extrathyroidal invasion (P < 0.001) and advanced TNM stage (P = 0.005) in patients with PTMC (n = 501), and ii) extrathyroidal invasion (P = 0.001), advanced TNM stage (P = 0.001), and multifocality (P = 0.002) in patients with PTC (n = 810). As compared with normal-weight patients with PTMC, obese patients with PTMC had greater risks of extrathyroidal invasion (OR = 5.214, P = 0.0270), and overweight patients with PTMC had greater risks of extrathyroidal invasion (OR = 2.165, P = 0.0013) and advanced TNM stage (OR = 2.019, P = 0.0137). As compared with normal-weight patients with PTC, obese patients with PTC had greater risks of extrathyroidal invasion (OR = 3.101, P = 0.0172), and overweight patients with PTC had greater risks of extrathyroidal invasion (OR = 1.486, P = 0.0279), advanced TNM stage (OR = 1.650, P = 0.0347), and multifocality (OR = 1.651, P = 0.0054). CONCLUSIONS Increased BMI might elevate the risks of aggressive clinicopathological features, such as extrathyroidal invasion and advanced TNM stage. Obesity control may play an important role in preventing the development of aggressive PTMCs and all PTCs.