Prognostic significance of muscle quantity and quality for overall survival in non-metastatic castration-resistant prostate cancer.

Abstract

e17047 Background: This study evaluated whether computed tomography–derived skeletal muscle quantity and quality are associated with therapeutic response, safety, and overall survival (OS) in patients with non-metastatic castration-resistant prostate cancer (nmCRPC) treated with androgen receptor signaling inhibitors (ARSIs). Methods: In this multicenter retrospective study, 344 patients with nmCRPC were analyzed. Muscle quantity and quality were assessed using the psoas–lumbar vertebral index (PLVI) and intramuscular adipose tissue content (IMAC), respectively. Lower PLVI and higher IMAC indicated reduced muscle quantity and quality, respectively. The primary endpoint was OS. Secondary endpoints included PSA declines ≥50% and ≥90%, PSA progression-free survival (PSA-PFS), metastasis-free survival (MFS), and ARSI-related adverse events (AEs). Results: The median age was 76 years, and median follow-up was 48 months. A total of 137 patients (40%) died during follow-up. In univariable analyses, lower PLVI and higher IMAC were associated with shorter OS. In multivariable analysis, higher IMAC remained independently associated with shorter OS (HR 1.792; 95% CI 1.137–2.825; P = 0.012), whereas PLVI did not (HR 1.265; 95% CI 0.838–1.909; P = 0.263). Neither muscle quantity nor quality was associated with PSA response, PSA-PFS, MFS, or ARSI-related AEs. Conclusions: CT-derived muscle quality, but not muscle quantity, independently predicts OS in nmCRPC. However, muscle status does not appear to influence ARSI treatment response or safety. Multivariable analysis for overall survival. Factor P value Hazard ratio 95% CI Age Continuous 0.092 1.027 0.996–1.060 Performance status ≥ 1 0.121 1.408 0.913–2.169 Hypertension Present 0.177 0.766 0.521–1.128 Diabetes mellitus Present 0.296 0.766 0.464–1.264 Cardiovascular disease Present 0.319 0.780 0.478–1.272 Biopsy Gleason score ≥ 8 0.093 1.502 0.935–2.413 Diagnosis of nmCRPC before 2014 Positive 0.890 1.036 0.629–1.706 ARSI therapy during nmCRPC Received 0.020 0.609 0.401–0.926 PSA doubling time < 3.0 months < 0.001 2.206 1.449–3.359 Psoas‒lumbar vertebral index < 0.49 0.263 1.265 0.838–1.909 Intramuscular adipose tissue content ≥ -0.27 0.012 1.792 1.137–2.825 ARSI, androgen receptor signaling inhibitor; CI, confidence interval; nmCRPC, non-metastatic castration-resistant prostate cancer; PSA, prostate-specific antigen.