Muscle radiodensity and mortality in patients with colorectal cancer: Muscle Radiodensity and Prognosis in CRC

BACKGROUND: Low skeletal muscle radiodensity (SMD) is related to higher mortality in several cancers, but the association with colorectal cancer (CRC) prognosis is unclear. METHODS: This observational study included 3262 men and women from the Kaiser Permanente Northern California population diagnosed between 2006 and 2011 with AJCC stages I to III CRC. The authors evaluated hazard ratios (HRs) of low SMD for all-cause and CRC-specific mortality, assessed by computed tomography using optimal stratification, compared with patients with normal SMD. They also evaluated the cross-classification of categories of low versus normal SMD and muscle mass (MM) with outcomes. RESULTS: The median follow-up was 6.9 years. Optimal stratification cutpoints for SMD were 32.5 in women and 35.5 in men. In multivariate-adjusted analyses, among patients with CRC, those with low SMD demonstrated higher overall (HR, 1.61; 95% confidence interval [95% CI], 1.36-1.90) and CRC-specific (HR, 1.74; 95% CI, 1.38-2.21) mortality when compared with those with normal SMD levels. Patients with low SMD and low MM (ie, sarcopenia) were found to have the highest overall (HR, 2.02; 95% CI, 1.65-2.47) and CRC-specific (HR, 2.54; 95% CI, 1.91-3.37) mortality rates. CONCLUSIONS: In patients with CRC, those with low SMD were found to have elevated risks of disease-specific and overall mortality, independent of MM or adiposity. Clinical practice should incorporate body composition measures into the evaluation of the health status of patients with CRC. Cancer 2018;124:3008-15. © 2018 American Cancer Society.