The deterioration of muscle mass and radiodensity is prognostic of poor survival in stage I–III colorectal cancer: a population‐based cohort study (C‐SCANS)

BACKGROUND: Muscle abnormalities such as low muscle mass and low muscle radiodensity are well known risk factors for unfavourable cancer prognosis. However, little is known in regard to the degree and impact of longitudinal changes in muscle mass and radiodensity within the context of cancer. Here, we explore the relationship between muscle wasting and mortality in a large population‐based study of patients with non‐metastatic colorectal cancer (CRC). METHODS: A total of 1924 patients with stage I–III CRC who underwent surgical resection in the Kaiser Permanente Northern California Health System were included. Muscle mass and radiodensity were quantified using computed tomography images obtained at diagnosis and after approximately 14 months. Cox proportional‐hazards models were used to estimate hazard ratios for all‐cause mortality. RESULTS: The hazard ratio for all‐cause mortality among patients with the largest deterioration in muscle mass (≥2 SD; ≥11.4% loss from baseline), as compared with those who remained stable (±1 SD; 0.0 ± 5.7%) was 2.15 [95% confidence interval (CI): 1.59–2.92; P < 0.001]. The hazard ratio for all‐cause mortality among patients who experienced the largest deterioration in muscle radiodensity (≥2 SD; ≥20.2% loss from baseline), as compared with those who remained stable (±1 SD; 0.0 ± 10.1%) was 1.61 (95% CI: 1.20–2.15; P = 0.002). CONCLUSIONS: In patients with stage I–III CRC, muscle wasting is a risk factor for mortality, independent of change in body mass and other body composition parameters.