Association Between Sarcopenia and Survival of Patients with Organ-Confined Renal Cell Carcinoma after Radical Nephrectomy.

BACKGROUND We aimed to describe the effect of preoperative sarcopenia on oncologic outcomes of organ-confined renal cell carcinoma (RCC) after radical nephrectomy. PATIENTS AND METHODS A total of 632 patients with pT1-2 RCC who underwent radical nephrectomy between 2004 and 2014 were retrospectively analyzed. From preoperative computerized tomography (CT) scans, skeletal muscle index (SMI) was measured and gender-specific cutoff values at third lumbar vertebra of 52.4 cm2/m2 for men and 38.5 cm2/m2 for women were used to define sarcopenia. Survivals were compared and associations with sarcopenia were analyzed using Kaplan-Meier log rank tests and Cox proportional hazard regression models. Median follow-up was 83 months. RESULTS Of 632 patients, 268 (42.4%) were classified as sarcopenic. The sarcopenic group was more advanced in age (57 versus 53 years) and more predominantly male (71.3% versus 59.9%). Sarcopenic patients had lower body mass index (BMI, 23.0 versus 25.9 kg/m2), but there was no difference in tumor size, stage, or nuclear grade. Sarcopenia was associated with poorer overall survival (OS) and cancer-specific survival (CSS; OS 94.0% versus 82.1%; p < 0.001 and CSS 97.5% versus 91.8%; p < 0.001). On multivariate analysis, sarcopenia was an independent risk factor for all-cause mortality [hazard ratio (HR) 2.58; 95% CI 1.02-6.54] and cancer-specific mortality (HR 3.07; 95% CI 1.38-6.83). CONCLUSIONS Sarcopenia at diagnosis was an independent risk factor for all-cause and cancer-specific mortality after radical nephrectomy for pT1-2 RCC. These findings underscore the importance of assessing presence of sarcopenia for risk stratification even among surgical candidates.