Is skeletal muscle radiodensity able to indicate physical function impairment in older adults with gastrointestinal cancer?

Background: Worsening nutritional status in older adult cancer patients can lead to sarcopenia, a condition that occurs with low quantity or quality of muscle mass associated with low physical function. However, most of the studies with cancer patients have only analyzed the quantity of muscle mass for diagnostic of sarcopenia, without exploring muscle characteristics and physical function. The purpose of the present study is to explore the associations between muscle mass characteristics and physical function in older adult patients with cancer. Methods: Gastric older cancer patients were enrolled in a cross-sectional study. Computed tomography images of the abdominal region evaluated skeletal muscle mass using the Slice-O-Matic version 5.0 Software program (Tomovision, Montreal, Canada) to determine the parameters of skeletal muscle index (SMI, muscle quantity) and skeletal muscle radiodensity (SMD). The physical function was evaluated through handgrip strength and gait speed test. Four musculature phenotypes were identified: normal SMI and SMD, only low SMI, only low SMD, and low SMI and SMD. Linear regression analyses adjusted by age and tumor stage verified the associations between SMI, SMD and physical function. A One-Way Covariance Analysis with Bonferroni post hoc test was used to compare the physical function variables among the four different phenotypes. Results: In total, 167 patients were evaluated (58.1% males; mean age 69.17 +/- 7.97 years). The results showed that muscle mass characteristics explains, at least partially, the variability in handgrip strength and gait speed in a direct relationship. The phenotypes with low muscular SMI and/or SMD presented worse performances in handgrip strength and gait speed tests. When stratified for sexes, the significant difference occurs only in males. Conclusions: Low SMD has negatively impacted physical function in older adults with gastrointestinal cancer, especially in males.