A lower psoas muscle volume was associated with a higher rate of recurrence in male clear cell renal cell carcinoma

BACKGROUND: Sarcopenia is defined as a low skeletal muscle volume. Recent studies have reported that sarcopenia is associated with a poor prognosis in various cancers. The purpose of this study is to evaluate the correlation between the psoas muscle volume and recurrence-free survival in patients with localized clear cell renal cell carcinoma (ccRCC). METHODS: A total of 316 male patients with localized ccRCC who underwent radical nephrectomy at Yokohama City University Hospital (Yokohama, JAPAN) and Kanagawa Cancer Center (Yokohama, JAPAN) between 2002 and 2018 were enrolled in this study. The psoas muscle index (PMI) was calculated by normalizing the psoas muscle area on the contralateral side of the tumor on axial CT, which was calculated at the level of L4 (mm(2)) divided by the square of the body height (m(2)). We divided patients into two groups based on the median PMI (409.64mm(2)/m(2)). RESULTS: The lower PMI group showed poorer recurrence-free survival (RFS) than the higher PMI group (p = 0.030). Regarding 5-year RFS, a lower PMI was a significant predictor of recurrence (p = 0.022, hazard ratio (HR): 2.306) and a multivariate analysis revealed that a lower PMI (<median, p = 0.035, HR: 2.167), tumor size >4 cm (p = 0.044, HR: 2.341), and pathological stage >2 (p<0.001, HR: 3.660) were independent risk factors for poor RFS. CONCLUSIONS: The presence of sarcopenia (lower PMI) was found to be associated with poor RFS in male ccRCC patients. The PMI might serve as a measure of patient frailty and might be useful for prognostic risk stratification in ccRCC.