Preoperative serum total cholesterol is a predictor of prognosis in patients with renal cell carcinoma: a meta-analysis of observational studies

PURPOSE: Several studies have demonstrated the strong correlation between the levels of preoperative serum total cholesterol (TC) and the survival of patients with surgically treated renal cell carcinoma (RCC). However, this association remains controversial. We performed a meta-analysis of published reports to evaluate the prognostic significance of the preoperative serum TC levels for patients with surgically treated RCC. MATERIAL AND METHODS: The databases from MEDLINE (via PubMed), Embase, Web of Science and Cochrane Library were systematically searched to identify the eligible studies published before August 2019. Multivariate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated through inverse variance by using random-effects models. RESULTS: Nine cohort studies comprising 15.609 patients were identified. Low preoperative serum TC levels were associated with poor cancer-specific survival (CSS; HR=0.98, 95% CI: 0.97-0.99; P=0.005; I(2)=74.2%) and progression-free survival (PFS; HR=0.69, 95% CI: 0.49-0.98; P=0.036; I(2)=80%) in patients with surgically treated RCC. However, no significant association was observed between low preoperative serum TC levels and shorter overall survival (HR=0.93, 95% CI: 0.87-1.00; P=0.057; I(2)=86.2%). Sensitivity analyses validated the reliability and rationality of the results. CONCLUSIONS: Preoperative serum TC level is an independent poor prognostic factor for patients with surgically treated RCC, with lower levels associated with worse CSS and PFS. Hence, this parameter may provide additional guidance in the selection of therapeutic strategies to improve prognosis, considering that cholesterol is a broadly applied routine marker in clinical practice.