Visceral fat accumulation is associated with different pathological subtypes of renal cell carcinoma (RCC): a multicentre study in China.

Objective To investigate whether visceral obesity is associated with certain histological subtypes of renal cell carcinoma (RCC) in a multicentre Chinese cohort. Patients and Methods A kidney tumour database was created using three tertiary centres in China; 487 patients were enrolled presenting with localised RCC and complete computer tomography (CT)/magnetic resonance imaging (MRI) information. A single-slice CT image was used to measure the area of visceral and subcutaneous adipose tissues in each patient. Statistical methods were used to analyse clear-cell RCC (ccRCC) and non-clear-cell RCC (non-ccRCC) as they relate to visceral fat area (VFA) and other risk factors, such as age, gender, tumour size, diabetes, hypertension, total fat area (TFA) and body mass index (BMI). Results In all, 418 patients had a ccRCC subtype and 69 had a non-ccRCC subtype. For all the patients with RCC, the mean VFA was 102 cm2, while mean BMI was 24 kg/m2. The mean VFA was greater in ccRCC than non-ccRCC patients by 25 cm2. There were significant differences in the mean VFA and TFA between patients with ccRCC and those with non-ccRCC. Multivariate analysis showed that the presence of VFA was more important than the effects of BMI and Type 2 diabetes on pathology prediction. In patients with a normal BMI, those with a higher quartile of VFA were more likely to develop ccRCC than those with a low VFA. Conclusions Increased visceral fat was found to be associated with ccRCC and the significance of VFA outweighed the effects of BMI and Type 2 diabetes for the prediction of RCC pathology in multivariate analyses. As a result, VFA could constitute a primary explanation for the link between obesity and ccRCC.