The association between muscle mass and the degree of myosteatosis of the psoas muscle and mortality in older patients with cancer.

OBJECTIVE

Comprehensive geriatric assessment (CGA) is used for oncological management in older patients. The evaluation of muscle characteristics is currently not included in the CGA. This study investigates whether muscle mass and the degree of myosteatosis is associated with mortality in older patients with cancer.

METHODS

CGA was performed in a cohort of older patients with cancer. Cross sectional area (CSA) and mean pixel density (Hounsfield units, HU), as measure for respectively muscle mass and myosteatosis, were obtained from CT images of the psoas muscle at the level of mid L3. Mortality was recorded. Correlation was determined between CSA and HU. Paired sample t-test was used to follow changes in muscle mass and density. Logistic regression was performed to define relevant prognostic factors for mortality.

RESULTS

In total, 183 patients were included (86 male and 97 female), 120 patients (66%) died. Mean age was 80 years (range 70-94 years). Mean days of survival was 606 (range 1-2023). There was a significant correlation between CSA and HU (PCC = 0.196) at time of diagnosis and at follow-up (PCC = 0.257). There was a significant decrease in CSA (p = .008) and HU (p = .004) in men at follow-up. No significant changes were observed in women. In multivariate analysis, a higher gender-corrected CSA was linked to a lower mortality rate with an odds ratio of 0.657 (CI = 0.457-0.944, p = .023). No association was found between HU and mortality.

CONCLUSIONS

Muscle mass correlated with the degree of myosteatosis. CSA and HU tended to decrease during follow-up. Having a greater CSA was prognostic for a lower mortality rate.