[Overweight is an advantageous prognostic marker in patients with clear cell kidney cancer].

Objectives: Obesity increases the risk of developing renal cell carcinoma (RCC). We assessed whether different body mass index (BMI) levels and the body surface area (BSA) at the time of surgery had an effect on aggressiveness and long-term prognosis of RCC.

Methods: The study included 1,595 RCC patients with complete information about their BMI who had undergone surgery for renal cell cancer at the University Hospitals in Hannover (MHH) and Marburg between 1990 and 2005. The mean follow-up was 5.0 years.

Results: A higher BMI and a higher than average BSA were significantly associated with younger age. A high BMI value was additionally related to a lower tumor grade, the clear cell histological subtype, and metastasis at the time of diagnosis. Overweight patients had a significantly lower risk of cancer-related death; their median 5-year tumor-specific survival rate was 76.9% (BMI>30) and 72.6% (BMI 25-30) as opposed to 63.5% for patients with a BMI below 25 (p<0.001). However, the positive correlation between a high BMI and tumor-specific survival could be confirmed in multivariable analyses for localized clear cell RCC only.

Conclusion: We identified BMI as an independent prognostic marker of improved cancer-specific survival in patients with RCC, particularly with organ-confined clear cell cancer.