Do patients with a higher body mass index have a greater risk of advanced-stage renal cell carcinoma?

Objectives: To evaluate whether patients with a higher body mass index (BMI) are at elevated risk of an advanced tumor stage for renal cell carcinoma at diagnosis. A high BMI has recently been proved to be associated with advanced tumor stages for some malignant diseases. Methods: From January 1994 to December 2000, 693 operations for renal cell carcinoma were performed in 683 patients at our institution. Ten patients underwent surgery twice for bilateral tumors. Of the 683 patients, 417 were men and 266 women. The mean age at surgery was 62.2 years, and the mean tumor diameter was 5.2 cm. Seventy-eight percent of the patients were asymptomatic at tumor diagnosis. The following parameters were evaluated with regard to a possible correlation to tumor stage and/or tumor diameter: BMI, presence of symptoms, age, sex, hemoglobin, lactate dehydrogenase, erythrocyte sedimentation rate, serum cholesterol, and triglycerides. For statistical analysis, the Spearman rank correlation test was used. Results: The mean BMI was 26.8 +/- 4.4 (range 16.9 to 44.3). Statistical analysis showed a significant positive correlation between advanced T stage and the presence of symptoms (P <0.0001), erythrocyte sedimentation rate (P <0.0001), lactate dehydrogenase (P = 0.0015), and age (P = 0.046), and an inverse correlation with hemoglobin (P <0.0001) and serum cholesterol (P <0.0001). For all other investigated parameters, including BMI, no significant correlation could be proved. Conclusions: Our data indicate that obese patients are not at greater risk of advanced tumor stages of renal cell carcinoma at the time of diagnosis compared with a population of normal weight.