Skeletal muscle measures and physical function in older adults with cancer: sarcopenia or myopenia?

Abstract

BackgroundSkeletal muscle loss, commonly known as sarcopenia, is highly prevalent in older adults and linked with adverse outcomes in cancer, yet the definition and role of sarcopenia remains uncertain. The aim of this study was to examine the association of Computerized Tomography (CT) assessed skeletal muscle measures with physical function in older adults with cancer.ResultsCTs for 185 patients were available. Median age 73 (IQR 68–76) and 56.5% female. After controlling for sex and BMI, we found no evidence that SMI was associated with physical function impairments. Both SMD and SMG were associated physical function impairments and higher values were associated with decreased limitations in instrumental activities of daily living (RR 0.84 [CI 0.73–0.96] and 0.94 [CI 0.89–0.99], respectively), climbing stairs (RR 0.84 [CI 0.76–0.94] and 0.91 [CI 0.87–0.96]), walking 1 block (RR 0.77 [CI 0.67–0.90] and 0.91 [CI 0.85–0.97]), and prolonged Timed Up and Go (RR 0.83 [CI 0.75–0.92] and 0.92 [CI 0.88–0.96]).Materials and MethodsUsing the Carolina Senior Registry, we identified patients with CT imaging performed within 60 days +/− of baseline geriatric assessment (GA). Skeletal muscle area and density (SMD) were analyzed from L3 lumbar segments. Muscle area and height (m2) were used to calculate skeletal muscle index (SMI). Skeletal Muscle Gauge (SMG) was created by multiplying SMI x SMD.ConclusionsSkeletal muscle mass as assessed from CT imaging was not associated with physical function impairments. Skeletal muscle radiodensity was more associated with physical function and may aid in identifying older adults at risk for functional impairments.

Beyond sarcopenia: Characterization and integration of skeletal muscle quantity and radiodensity in a curable breast cancer population

“…Finally, low SMG values have also correlated with impaired physical functioning in older adults with cancer, including prolonged Timed Up and Go and impairments in Instrumental Activities of Daily Living, ability to walk a block, climb steps, and bend over. SMG values more closely mirrored SMD than SMI values when correlated with impaired physical function . Thus in various oncological body composition studies, SMG has demonstrated frank superiority or similar correlation with outcomes as its constituent measures, marking it as a promising unified body composition metric.…”

Cachexia and Sarcopenia in Older Adults with Cancer: A Comprehensive Review

“…Relying solely on weight and quantitative muscle mass to clinically characterize older adults, however, could be problematic. In this population, muscle mass and muscle function may not change in conjunction with one another nor will deficits in mass and function necessarily occur in a linear fashion [22][23][24]. This was illustrated in a study of 734 patients with lung cancer where patient function and quality of life did not significantly change until muscle mass dropped below a certain threshold value [25].…”

Predicting Outcomes of Abdominal Surgical Emergencies in the Elderly Population Using a CT Muscle Gauge

“…As muscle mass differs with body size, the cross-sectional muscle area measured by CT imaging is often standardized with the subject's height (16). However, muscle quality is also a key component affecting functional reserve (31,32). Fat cells replace skeletal muscle cells in the aging process, and a lower muscle intensity is detected on CT scans (11,(32)(33)(34).…”