Objective: To investigate whether visceral obesity is associated with certain histological subtypes of renal cell carcinoma (RCC) ina 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 ofVFA 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.