Prognostic significance of sarcopenia in upper tract urothelial carcinoma patients treated with radical nephroureterectomy

We investigated the prognostic significance of sarcopenia in upper tract urothelial carcinoma (UTUC) patients treated with radical nephroureterectomy (RNU). The skeletal muscle index (SMI) was calculated from computed tomography images. Sarcopenia was defined as SMI <43 cm(2)/m(2) for males with body mass index <25 kg/m(2), <53 cm(2)/m(2) for males with BMI ≥25 kg/m(2), and <41 cm(2)/m(2) for females. Associations of sarcopenia with cancer‐specific survival (CSS) and overall survival (OS) were evaluated in 81 consecutive UTUC patients who underwent RNU. Forty‐seven (58%) out of 81 patients had sarcopenia. Multivariate analyses identified sarcopenia as a significant and independent poor prognostic factor for both CSS (hazard ratio [HR] 8.58, 95% confidence interval [CI]: 1.63–158.1, P = 0.008) and OS (HR 6.05, 95%CI 2.00–26.21, P < 0.001). In patients with locally advanced disease (pT3/4 or pN+), those with sarcopenia showed significantly worse CSS and OS than those without (5‐year CSS rate 55% vs. 100%, P = 0.014; 5‐year OS rate 40% vs. 86%, P = 0.007). In contrast, no prognostic difference was observed between patients with and without sarcopenia in those with organ‐confined disease (pTa‐2pN0/x). Sarcopenia is an independent poor prognostic factor for UTUC patients treated with RNU, particularly for those with locally advanced disease.