Perirenal fat as a new independent prognostic factor in patients with surgically treated clear cell renal cell carcinoma

Abstract Introduction : Recently increasing evidence has suggested that obesity is associated with the development and prognosis of renal cell carcinoma. The aim of the study was to investigate the association between different obesity measurements and overall survival in patients with surgically treated clear cell renal cell carcinoma. Patients and Methods : The data of 342 consecutive patients who underwent radical or partial nephrectomy at Peking University People's Hospital from January 2009 to November 2014 were retrospectively reviewed. Median follow-up was 82 months. The association between different obesity measurements and overall survival was evaluated using the Kaplan-Meier method and Cox regression models. Results : In univariate Cox regression analyses, perirenal fat accumulation was significantly associated with overall survival (HR: 2.271; 95%CI: 1.311-3.935; p=0.003), as well as age, sex, clinical manifestation, surgical option, tumor size and grade. The other obesity measurements, including body mass index, waist circumference, total adipose tissue, visceral adipose tissue and percentage of visceral adipose tissue, were not assessed as prognostic indicators of overall survival in this study (p>0.05). After adjusting for age, sex, clinical manifestation, surgical option, tumor size, T stage and tumor grade, perirenal fat accumulation was still identified as an independent predictor of overall survival (HR: 2.264; 95%CI: 1.305-3.926; p=0.004). The results of Kaplan-Meier model also revealing that patients with higher percentage of perirenal fat showed poorer overall survival (p=0.003). Conclusion : Higher percentage of perirenal adipose tissue is independently associated with increased mortality risk in surgically treated clear cell renal cell carcinoma. MicroAbstract : The association between obesity and the prognosis of ccRCC patients is conflicting. Herein we conducted this study to examine the association between different obesity measurements and overall survival in patients with surgically treated ccRCC. In total, 342 patients with ccRCC were enrolled. The results indicate that the percentage of perirenal adipose tissue is superior to both BMI and percentage of visceral fat surface area for predicting overall survival.