Obesity: An independent protective factor for localized renal cell carcinoma in a systemic inflammation state

ABSTRACT Objectives To explore the prognostic value of obesity (measured by BMI) on RCC in a systemic inflammation state. Patients and Methods Clinicopathological and hematological data of 540 surgically treated Chinese localized RCC patients between 2005 and 2010 were retrospectively collected. Found by receiver operating characteristic (ROC) curve for cancer-specific survival (CSS), the optimal cutoff values of neutrophil-lymphocyte ratio (NLR, an indicator of systemic inflammation state) and BMI were 2.12 and 23.32, respectively. Survival curves were drawn using Kaplan-Meier method. Univariate and multivariate Cox regression analyses were used to evaluate the prognostic value of BMI in localized RCC patients with different NLR. Results Overall, 36 patients died with a median follow-up of 70 months. Median overall survival (OS) was 66 months and the 5-year OS rate was 92.7%. In the multivariate analysis of total patients, higher BMI was an independent protective factor for CSS in total patients (p=0.048). While in systemic inflammation subgroup (high NLR subgroup) patients, higher BMI (obesity) turned out to be an independent protective factor for both CSS (p=0.025) and RFS (p=0.048). Conclusion In localized RCC patients, obesity was an independent protective factor for CSS and RFS in a systemic inflammation state.

摘要
研究目的：探讨以体质量指数（Body Mass Index, BMI）衡量的肥胖状态在全身炎症状态下对肾细胞癌（Renal Cell Carcinoma, RCC）的预后价值。
患者与方法：回顾性收集2005至2010年间540例接受手术治疗的中国局限性肾细胞癌患者的临床病理及血液学数据。经针对癌症特异性生存期的受试者工作特征曲线（Receiver Operating Characteristic curve, ROC）分析后发现，中性粒细胞与淋巴细胞比值（Neutrophil-Lymphocyte Ratio, NLR，全身炎症状态的评估指标）与BMI的最佳截断值分别为2.12和23.32。采用Kaplan-Meier法绘制生存曲线，通过单因素及多因素Cox回归分析评估不同NLR分层的局限性肾细胞癌患者中BMI的预后价值。
结果：总体而言，共有36例患者死亡，中位随访时长为70个月。中位总生存期（Overall Survival, OS）为66个月，5年总生存率达92.7%。对全部患者的多因素分析显示，较高的BMI是癌症特异性生存期的独立保护因素（p=0.048）。而在全身炎症亚组（高NLR亚组）患者中，较高的BMI（即肥胖）被证实为癌症特异性生存期（p=0.025）与无病生存期（Recurrence-Free Survival, RFS）的独立保护因素（p=0.048）。
结论：在局限性肾细胞癌患者中，处于全身炎症状态时，肥胖是癌症特异性生存期与无病生存期的独立保护因素。