Sarcopenia as a useful predictor of postoperative complications following radical cystectomy: An assessment of preoperative CT scans

351 Background: Muscle-invasive urothelial carcinoma is usually treated with radical cystectomy (RC). However, patients face a relevant risk of postoperative complications on variable factors. Recent reports described that sarcopenia, which is defined by a loss of sceletal muscle body composition, may enhance risk stratification. Methods: Our retrospective study includes 200 patients (154 men, 46 women, mean age: 67.9 years) which were treated with RC between 2005 and 2014. Median follow-up time was 26 months. Computed tomography (CT) scans were performed within 60 days prior to surgery. Lumbar skeletal muscle index (SMI) were measured with MeVisLab 2.7 by manually segmentation of preoperative CTs. The fat mass index (FMI) was calculated based on the same CT slides. Cut off points were developed for men and women separately. Additionally, short-, mid- and long-term complications were assessed using the Clavien-Dindo classification. Results: SMI (cm2/m2), FMI (kg/m2) and BMI (kg/m2) for men were calculated with mean scores of 52.8, 9.6 and 26.7, respectively. The corresponding calculated means for women were 38.9, 10.0 and 26.1. The SMI for short- and mid-term complications was statistically significant (p < 0.01) when applied on patients with a BMI over 25 kg/m2. Using Kaplan-Meier plots none of the other markers (BMI and FMI) correlated with complications or overall survival (OS). Conclusions: The presence of sarcopenia assessed by CT may improve risk stratification in patients undergoing radical cystectomy. BMI and FMI may not be used in risk stratification models, even though further validation for subgroups is needed. Future research is needed to validate the current findings. Noninvasive and semiautomatic calculation of SMI in preoperative CT scans may improve risk stratification in patients undergoing radical cystectomy and thus could reduce morbidity and mortality.