San Diego, CA USA (UroToday.com) Both the incidence of obesity and renal masses have been on the rise; although obesity is an established risk factor for the development of renal cancer, its connection to histologic subtype of the tumor, prognosis, and grade remains unclear. There has been data suggesting an “obesity paradox”, which is a correlation between increasing BMI and survival in patients diagnosed with renal cell carcinoma.
In order to better understand this relationship, the authors retrospectively analyzed 1,750 patients who underwent surgery for clinically localized renal masses between 2000 and 2010 at two separate institutions (one in the United States and one in Italy). Patients were grouped into four categories of Body Mass Index (BMI): A (<25), B (25-27.9), C (28-31.9), and D (≥32).
The distribution of tumor subtypes (of which clear cell was the most common) did not vary significantly by BMI group. This also held true for clinical stage distribution. However, in terms of Fuhrman grade, the proportion of low-grade (1 and 2) renal cell carcinoma was significantly higher with increasing BMI; this significant relationship also held true in subgroups stratified by gender, stage, and age.
This data is very interesting, especially when taken in the context of other recent data showing better cancer-specific and overall survival in obese patients. This study seems to support the “obesity paradox” of renal cell carcinoma with large numbers and a correlation between increasing BMI and low-grade cancer. Further study into the pathogenesis of renal cell carcinoma and its relationship to obesity and fat distribution is warranted.
Presented By: Matvey Tsivian, MD
Written By: Rahul Dutta, BS; Urology Fellow, Department of Urology, University of California, Irvine at the 2016 AUA Annual Meeting - May 6 - 10, 2016 – San Diego, California, USA