A low psoas muscle volume predicts longer hospitalization and cancer recurrence in upper urinary tract urothelial carcinoma.

The aging population is becoming a primary global problem. The most important alteration that occurs in the body with age, is the loss of skeletal muscle. Previously, sarcopenia, which is associated with the loss of skeletal muscle, has been reported to be associated with the prognosis of cancer and complications. The present study investigated the importance of sarcopenia with regard to the prognosis or postoperative complications of upper urothelial cancer patients who underwent nephro-ureterectomy. A total of sixty patients (male, n=44; female, n=16) underwent nephro-ureterectomy for upper urothelial carcinoma. The psoas muscle volume was calculated at the level of the umbilicus using axial computed tomography images obtained prior to nephro-ureterectomy. The psoas muscle index (PMI) was calculated by the following formula: (right side psoas muscle area at the level of the umbilicus mm2 )/(body height m)2 . The median and mean (± standard deviation) ages of the 44 patients were 71 and 68.0 years (± 12.2 years). The lower PMI group demonstrated a significantly poorer recurrence-free survival compared with the higher PMI group (634 vs. 2,317 days, P=0.005). In terms of the duration of postoperative admission, the long-admission group (≥13 days) demonstrated a significantly lower PMI compared with the short-admission group (≤12 days) (383.0 vs. 433.1, P=0.039). Although the overall survival of the two groups did not differ significantly, the lower PMI group tended to have a shorter survival period compared with the higher PMI group (P=0.080). Of the patients with upper urothelial carcinoma, the lower PMI group exhibited a longer postoperative admission period and poorer recurrence-free survival compared with the higher PMI group. The present findings suggest that sarcopenia is a meaningful factor that should be considered when selecting therapy for upper urothelial carcinoma.