27 Can Sarcopenia be Used to Estimate Outcomes in Elderly Patients Treated with Chemoradiotherapy for Bladder Cancer?

Abstract

Introduction Ageing is a risk factor for bladder cancer, with a median age at diagnosis of 71 years. In addition, sarcopenia shows promise as a prognostic biomarker for bladder cancer. This study evaluates sarcopenia as a predictor of overall survival (OS) for older patients treated with chemoradiotherapy for bladder cancer. Methods 185 bladder cancer patients treated (from 2010–2017) with chemoradiotherapy were available for analysis. Pre-therapeutic computed tomography scans were identified and single slices at the L3 level were identified. Machine learning software was used to segment skeletal muscle and obtain its cross-sectional area. This was normalised against height squared to calculate a skeletal muscle index for each patient. Sarcopenia was defined using international consensus definitions (<39 cm2/m2 in females and < 55 cm2/m2 in males). Differences in survival function between patients ≤75 and > 75 years were visualised using Kaplan–Meier curves. Age distribution between sarcopenic and non-sarcopenic patients was also explored. Finally, a multivariable Cox proportional hazards model was conducted to investigate interactions between sarcopenia and increased age with respect to OS. Results Of 185 patients, 114 (61.6%) were sarcopenic and 71 (38.4%) were non-sarcopenic; 101 (54.6%) and 84 (45.4%) patients were ≤ 75 and > 75 years old respectively. No differences in OS were observed between the two age groups (p = 0.50). There was no interaction between sarcopenia and age as a continuous variable was observed with respect to OS (p = 0.682); however, when age was categorised an interaction was seen (p = 0.058). Nevertheless, after adjusting for performance status, T-stage, hydronephrosis, albumin, haemoglobin, neutrophil and lymphocyte counts, the interactions between age and sarcopenia were no longer observed (age continuous, p = 0.474; age categorized, p = 0.765). Conclusions Patients with bladder cancer over 75 years of age have a modest increase in probability of developing sarcopenia but this does not impact on OS.