Is body mass index relevant to prognosis of papillary thyroid carcinoma? A clinicopathological cohort study

Purpose Obesity appears to be related to papillary thyroid carcinoma (PTC) in the observational studies, although its relationship concerning the PTC prognosis has not been established. We investigated the association between body mass index (BMI) and the prognosis of PTC. Methods The WHO BMI classification was used to stratify the degree of obesity. The final outcome was disease status, including recurrence and persistence, of 783 PTC patients. We reviewed patients' BMI, disease status, and other prognostic factors retrospectively. Results The mean BMI was 24.2 kg/m(2). When stratified according to the WHO BMI classification, 21 were Underweight, 482 were Normal, 232 were Overweight, and 48 were Obese. We divided patients into two groups: < 25.0 kg/m(2) (n = 503) vs. >= 25.0 kg/m(2) (n = 280). The BMI >= 25.0 group was older and more likely to be male in a multivariate analysis (p < 0.001). For those with BMI < 25.0 and >= 25.0, recurrence occurred in 3.0 and 2.1 % (p = 0.486), persistence in 7.2 and 5.1 % (p = 0.265), and either recurrence or persistence in 9.9 and 7.1 %, respectively (p = 0.189). A multivariate analysis revealed that older age and male gender in Overweight vs. Normal, older age in Obese vs. Normal, and advanced T stage in Normal vs. Underweight were statistically significant prognostic factors. Conclusion There was no significant difference in the prognosis according to BMI in PTC patients. However, old age, male gender, and advanced T-stage patients were found more frequently in the higher BMI group than in the lower BMI group.