Sarcopenia as a marker for prediction of long-term survival following radical cystectomy.

Abstract

435 Background: Patients undergoing radical cystectomy (RC) face a relevant risk of tumor relapse and mortality based on variable factors. Risk stratification may be enhanced by objective measures such as sarcopenia (loss of skeletal muscle mass) which has been described as a potential biomarker associated with survival after radical cystectomy. However, data on this highly interesting biomarker in conjunction with urothelial carcinoma of the bladder are sparse. Methods: A retrospective study including patients that were treated with RC at Hannover Medical School between 2005 and 2011 were included. The lumbar skeletal muscle index (SMI) was measured on preoperative computed tomography (CT) which was performed within 60 days prior to surgery. MeVisLab 2.7 was used to perform calculations. The fat mass index (FMI) was calculated based on the same CT slides. The body mass index (BMI) was used as a comparative value. Cut off points were developed for men and women separately. Results: Indices were measured on 103 patients (79 men, 24 women, mean age: 67.5 yrs). 72 (70%) pts. had muscle-invasive disease, 21 (20%) pts. were lymph node positive and 6 (6%) pts. had synchronous metastasis. Median follow-up time was 39 months. SMI (cm2/m2), FMI (kg/m2) and BMI (kg/m2) for men were calculated with mean scores of 51.2, 9.6 and 27.0, respectively. The corresponding calculated means for women were 38.7, 10.0 and 25.3. None of the stratification markers correlated with overall survival (OS) using Kaplan-Meier plots. However when applied on patients that survived at least 12 months, the sarcopenia index (SMI) became statistically significant (p < 0.05). Conclusions: The presence of sarcopenia may be predictor of poor overall survival later than 12 months after radical cystectomy. BMI and FMI may not be used in risk stratification models. Further research is needed to validate the current findings.