Modified cancer cachexia index and prognosis after radical cystectomy for bladder cancer: a multicenter retrospective study

Abstract We examined whether the modified cancer cachexia index (mCXI), which uses the psoas muscle index instead of the skeletal muscle index, is associated with oncological outcomes after radical cystectomy for bladder cancer. This multicenter retrospective study included 438 patients who underwent radical cystectomy at four institutions between March 2009 and December 2024 and for whom preoperative mCXI could be calculated. mCXI was defined as psoas muscle index × serum albumin / neutrophil-to-lymphocyte ratio. The median mCXI in the overall cohort was 8.2. Median age was 74 years, and 351 patients (80%) were male. Median recurrence-free survival (RFS) and overall survival (OS) were 107 and 81 months, respectively, and the 5-year RFS and OS rates were 62% and 53%. Patients with low mCXI had significantly shorter RFS and OS than those with high mCXI (median RFS, 26 vs. 162 months; median OS, 54 vs. 162 months; both P < 0.01). In multivariable analyses, low mCXI remained independently associated with poorer RFS (HR 1.54, 95% CI 1.14–2.06, P < 0.01) and OS (HR 1.49, 95% CI 1.07–2.07, P = 0.01). Similar associations were observed in sex-specific subgroup analyses.