Cachexia index, allostatic load, and body composition phenotypes in racially and ethnically diverse patients with metastatic colorectal cancer.

Abstract

e15601 Background: Cachexia Index (CXI), which integrates muscle mass, nutritional status, and systemic inflammation, and Allostatic Load (AL), a measure of cumulative physiologic stress, appear to be prognostic biomarkers in patients with newly diagnosed cancers. Similarly, maladaptive body composition phenotypes, including sarcopenia, sarcopenic obesity, and myosteatosis determined at cancer diagnosis, are also predictors of reduced quality of life and decreased overall survival. Few studies have examined the associations between these biomarkers at diagnosis in men with metastatic colorectal cancer (MCRC). This study examines the associations between CXI, AL and adverse body composition phenotypes in patients with newly diagnosed MCRC. Methods: We conducted a retrospective cross-sectional study of adults with newly diagnosed MCRC using clinical data from the electronic medical record, CT at third lumbar (L3) and labs nearest to date of diagnostic imaging. AL was calculated as a composite score from nine biomarkers (0–9). CXI = skeletal muscle index × albumin ÷ neutrophil-to-lymphocyte ratio. Sarcopenia, sarcopenic obesity, and myosteatosis were defined using published CT cutoffs. Descriptive statistics, nonparametric tests, and multivariable logistic regression assessed associations among AL, CXI, BC, age, and race/ethnicity. Results reported as median (IQR). Results: Of 151 patients (51% male), 72.2% self-reported as B/AA and 27.8% Latinx. Mean age and BMI were 61.8 years and 27.2, respectively. 23% were obese (BMI≥30.0) and 53.0% had sarcopenia, 45.7% had myosteatosis, and 4.6% had sarcopenic obesity. CXI and AL were negatively correlated (Spearman’s ρ = -0.439, p = < 0.001). In adjusted models, CXI was independently associated with sarcopenia (OR = 0.98, 95% CI 0.97-0.99, p < 0.004), while AL was not (OR = 0.94, 95% CI 0.71–1.23, p = 0.639). Conversely, AL was independently associated with myosteatosis (OR = 1.41, 95% CI 1.05–1.90, p = 0.023), whereas cachexia index (CXI) was not (OR = 0.99, 95% CI 0.98–1.00, p = 0.124). Neither CXI nor AL showed independent associations with sarcopenic obesity. Conclusions: Lower CXI and higher AL were associated with maladaptive body composition phenotypes in patients with MCRC. Specifically, CXI was independently associated with sarcopenia, reflecting reduced skeletal muscle mass, whereas AL was independently associated with myosteatosis, suggesting a role of systemic physiologic stress and fatty infiltration of muscle.