Preoperative cholesterol level as a new independent predictive factor of survival in patients with metastatic renal cell carcinoma treated with cyto-reductive nephrectomy

Background: The obesity and lipid metabolism were previously proposed to be related with the clinical outcomes of metastatic renal cell carcinoma (mRCC). We tried to investigate the relationship between preoperative cholesterol level (PCL) and survival outcomes in patients with mRCC. Methods: We analysed the data of 244 patients initially treated with cyto-reductive nephrectomy after being diagnosed with mRCC. Patients were stratified into two groups according to the PCL cut-off level of 170 mg/dL. The postoperative survival rates were compared using Kaplan-Meier analysis and the possible predictors of patients' cancer-specific survival (CSS) and overall survival (OS) were tested using multivariate Cox-proportional hazard models. Results: The low cholesterol group showed significantly worse postoperative CSS (p = 0.013) and OS (p = 0.009) than the high cholesterol group. On multivariate analysis, low PCL was revealed as an independent predictor of worse CSS (hazard ratio [HR], 2.162; 95% CI, 1.221-3.829; p = 0.008) and OS (HR, 2.013; 95% CI, 1.206-3.361; p = 0.007). Subsequent subgroup analysis showed that these results were maintained in the clear cell subgroup but not in the non-clear cell subgroup. Conclusion: Decreased PCL was significantly correlated with worse survival outcomes in patients with mRCC treated with cytoreductive nephrectomy. The underlined mechanism is still uncharted and requires further investigation.