Can sarcopenia predict outcomes in bladder cancer patients treated with chemoradiotherapy?

Abstract

Purpose or Objective Bladder cancer is the tenth commonest malignancy in the UK, with approximately 10,200 new diagnoses and 5,400 deaths annually. Sarcopenia shows promise as a prognostic factor for bladder cancer and has been shown to predict overall survival (OS) in patients treated with radical cystectomy. The present study aims to assess sarcopenia as a predictor of OS and progression-free survival (PFS) in patients with urothelial carcinoma (UC) of the bladder treated with organ-sparing concurrent gemcitabine and radiotherapy (GemX). Material and Methods 244 patients with non-metastatic UC, treated from 2010- 2017 with 52.5Gy in 20 fractions of curative intent radiotherapy with weekly gemcitabine, were identified for analysis. Pre-treatment computed tomography (CT) scans were obtained for 185 patients. The L3 vertebra was identified manually and machine learning software was used to assist skeletal muscle segmentation. Crosssectional area of skeletal muscle was obtained and normalised to patients’ height. This provided skeletal muscle index (SMI). Sarcopenia was defined using sexspecific international consensus SMI definitions of <39 cm²/m² in women and <55 cm²/m² in men. Associations between pre-treatment sarcopenia and OS and PFS were analysed using univariate and multivariate Cox proportional hazards models and Kaplan-Meier (KM) curves. Results Of 244 patients, 114 (46.7%) were sarcopenic, 71 (29.1%) were non-sarcopenic and 59 (24.2%) had unknown SMI as CT scans were not available. Sarcopenic patients tended to be male (85.1% vs 61.1% in non-sarcopenic patients). No significant differences were observed with respect to age, T stage, smoker status, presence of carcinoma in situ, albumin, haemoglobin, adult comorbidity evaluation-27, World Health Organisation Performance Status (WHO PS), hydronephrosis, neutrophil count, lymphocyte count, tumour stage and provision of neoadjuvant chemotherapy. Median OS and PFS were 40 (interquartile range [IQR] 23.8 – 62) and 32 (IQR 14 - 54.3) months respectively (see figure 1). Univariate analysis showed no association between sarcopenia and OS or PFS. On multivariate analysis, WHO PS, hydronephrosis and neutrophil count were associated with worse OS and PFS. Conclusion Sarcopenia is not associated with worse OS or PFS in bladder cancer patients treated with concurrent chemoradiotherapy.