Association between Visceral Obesity and Tumor Grade in Middle-aged and Elderly Patients with Renal Cell Carcinoma

  Objective   In this retrospective study, we investigated whether visceral obesity is associated with Fuhrman grade in middle-aged and elderly patients with renal cell carcinoma.

  Methods   Medical records of 278 middle-aged and elderly patients who underwent radical or partial nephrectomy at Peking University People's Hospital from January 2009 to September 2014 were retrospectively reviewed. The quantities of visceral, subcutaneous and total adipose tissue were measured with pre-operative computed tomography scans at the level of umbilicus. Visceral obesity was indicated by the percentage of visceral adipose tissue. The logistic regression analysis was used to determine the risk factor of high grade disease(Fuhrman grade Ⅲ or Ⅳ).

  Results   A total of 29(10.43%) tumors were classified as high-grade disease. Patients in high-grade group were found to have a higher percentage of visceral adipose tissue(P=0.022) and a larger tumor size(P=0.021). However, body mass index, total adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue were comparable between low-grade and high-grade groups. The result of logistic analysis showed that visceral obesity was associated with high-grade tumors(OR=1.045, 95% CI:1.002-1.090, P=0.042). In the subgroup analysis, the percentage of visceral adipose tissue was associated with Fuhrman grade in advanced patients(OR=1.131, 95% CI:1.017-1.256, P=0.023) or patients with a larger tumor(OR=1.061, 95% CI:1.005-1.121, P=0.032), but not in patients with an organ-confined disease or a smaller tumor.

  Conclusions   Visceral obesity was associated with higher Furhman grade in middle-aged and elderly patients with renal cell carcinoma, especially in patients with an advanced disease or a larger tumor. Vesceral obesity may be the risk factor of high-grade renal cell carcinoma.