Sex-Specific Prognostic Significance of Obesity in Nonmetastatic Clear-Cell Renal-Cell Carcinoma in Korea: A Large Multicenter Cohort Analysis

The prognostic value of body mass index (BMI) in relation to sex was assessed in 2097 patients with nonmetastatic clear-cell renal-cell carcinoma in Korea. BMI was a favorable prognosticator in male but not female patients. The association between BMI and renal-cell carcinoma prognosis may differ by sex. Introduction: We assessed the prognostic significance of obesity in relation to sex in patients with nonmetastatic clear-cell renal-cell carcinoma (nm-cRCC) in a large multicenter setting in Korea. Patients and Methods: A total of 2097 patients with nm-cRCC who underwent surgery with curative intent were enrolled from 6 institutions in Korea between April 2000 and February 2014. Obesity was determined by body mass index (BMI) before surgery. BMI was used as a continuous variable and was categorized as normal (≥ 18.5 to < 25.0 kg/m², normal BMI) and overweight or obese (≥ 25 kg/m², high BMI). The relationships between BMI, sex, recurrence-free survival (RFS), and cancer-specific survival (CSS) were evaluated. Results: Male patients had a greater high BMI ratio than female patients (P =.030). In men, the 5-year RFS and CSS rates in the high BMI group were greater than those in the normal BMI group (P =.003 and.006, respectively). Multivariate analyses revealed that in men, a high BMI was associated with greater RFS or CSS rates (hazard ratio: RFS, 0.901, P =.001; CSS, 0.822, P <.001). In women, there were no significant differences in the 5-year RFS and CSS rates according to BMI (P =.531 and.323, respectively), and high BMI was not associated with RFS or CSS (P =.250 and.180, respectively). Conclusion: In patients with nm-cRCC, obesity was a favorable prognosticator in male but not female patients. Therefore, the association between obesity and nm-cRCC prognosis might differ by sex.