Abstract
Introduction
Age-related loss of functional muscle mass is associated with reduced functional ability and life expectancy. In disseminated cancer, age-related muscle loss may be exacerbated by cachexia and poor nutritional intake, increasing functional decline, morbidity, and accelerate death. Patients with spinal metastases frequently present for decompressive surgery with decision to operate based upon functional assessment. A subjective assessment of physical performance has, however, been shown to be a poor indicator of life expectancy in these patients. We aimed to develop an objective measure based upon lean muscle mass to aid decision-making, in these individuals, by investigating the association between muscle mass and 1-year survival.
Materials and Methods
Muscle mass was calculated as total psoas area (TPA)/vertebral body area (VBA), by two independent blinded doctors from CT images, acquired within 7 days of spinal metastases diagnosis, at the L3 level. Outcome at 1 year following surgery was recorded from a prospectively updated metastatic spinal cord compression database.
Results
A total of 86 patients were followed for 1 year, with overall mortality at 39.5%. There was no gender difference although those alive at 1 year were of a significantly younger age. Alive at 1 year mean age was 62 years (IQR 53–71.75) versus dead at 1 year mean age was 68 years (IQR 61.75–76.25); (p = 0.04). Significantly more patients in the lowest quartile of muscle mass died within 1 year, compared with the highest quartile (57.1 vs. 23.8%, p = 0.02). Individuals who died within a year had significantly lower lean muscle mass on initial CT compared with those alive at the end of 1 year (p = 0.05). Patients with lung and gastrointestinal primary malignancies were more likely to die at 1 year, with both groups having 1-year survival rates less than 50%. Of the malignancies recorded, lung primary patients had a significantly lower muscle mass on CT than breast and lymphoma patients (p < 0.01).
Conclusion
Death within 1 year in individuals with spinal metastases is related to lean muscle mass at presentation. Assessment of lean muscle mass may influence decision to operate patients with spinal metastases.