Sarcopenia predicts survival outcomes among patients with urothelial carcinoma of the upper urinary tract undergoing radical nephroureterectomy: a retrospective multi-institution study

Background We aimed to evaluate the effect of sarcopenia, a condition of low muscle mass, on the survival among patients who were undergoing radical nephroureterectomy (RNU) for urothelial carcinoma of the upper urinary tract (UCUT). Methods We retrospectively reviewed consecutive patients with UCUT (cT[any] N0M0) who underwent RNU between 2003 and 2013 at our department and its affiliated institutions. Preoperative computed tomography images were used to calculate each patient's skeletal muscle index, an indicator of whole-body muscle mass. Sarcopenia was defined according to the sex-specific consensus definitions, based on the patient's skeletal muscle and body mass indexes. We analyzed the relapse-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) after RNU to identify factors that predicted patient survival. Results A total of 137 patients were included, and 90 patients (65.7 %) were diagnosed with sarcopenia. Compared to the non-sarcopenic patients, the sarcopenic patients had a significant inferior 5-year RFS (48.8 vs. 79.6 %, p = 0.0002), CSS (57.1 vs. 92.6 %, p < 0.0001), and OS (48.2 vs. 90.6 %, p < 0.0001). Multivariate analyses revealed that sarcopenia was an independent predictor of shorter RFS, CSS, and OS (all, p < 0.0001). Conclusions Sarcopenia was an independent predictor of survival among patients with UCUT who were undergoing RNU.