The role of sarcopenia in treatment-related outcomes in patients with renal cell carcinoma: A systematic review and meta-analysis

Background: in recent years, more attention has been paid to the fuzzy relationship between skeletal muscle components and renal cell carcinoma (RCC). This study attempts to conduct a meta-analysis using all relevant research evidence to explore the impact of sarcopenia on the final survival and recurrence outcome of RCC patients and the change process of this impact after treatment. Methods: This systematic review and Meta-analysis study took "sarcopenia", "kidney" and "tumor" and their synonyms as the main search terms, and comprehensively searched all relevant literatures published in PubMed, web of science, SpringerLink, EMBASE, Cochrane Library, Ovid (Lww oup), Wiley, ScienceDirect and Scopus databases since February 2, 2022. Multivariate hazard ratio (HR) and 95% confidence interval (CI) of overall survival (OS), cancer specific survival (CSS), and progression free survival (PFS), as well as rough data of Kaplan-Meier survival curve, were combined as the main analysis results. Subgroup analyses based on cohort characteristics (treatment, ethnicity, and BMI factors) for each study were used as secondary outcomes. The combined effect was estimated by random effect model or fixed effect model, and the heterogeneity was evaluated by I-2 value. Because this study belongs to secondary literature, the medical ethics committee of the First Affiliated Hospital of Xinjiang Medical University considers that ethical review is unnecessary. Results: Eighteen retrospective studies involving 3591 patients with RCC were analyzed, of which 71.5% were men and the median age of the cohort was 61.6. The prevalence of sarcopenia was 43% (38-48%). Sarcopenia is an independent predictor of OS (HR: 1.83, 95% CI = [1.41, 2.37]), and this prognostic value can also be reflected in Asian populations (HR: 2.59, 95% CI = [1.90, 3.54]) and drug treated patients (HR: 2.07, 95% CI = [1.07, 4.04]). Sarcopenia can also be used as an independent predictor of CSS (HR: 1.78, 95% CI = [1.34, 2.36]) and PFS (HR: 1.98, 95% CI = [1.34, 2.92]). The effect of low skeletal muscle mass on OS and CSS increased slowly from 1 to 5 years. Conclusion: Sarcopenia can be used as a comprehensive prognostic factor in RCC population, but the detailed effects from ethnic characteristics and treatment mechanism need to be further studied.