(PTFS08-04-24) Associations of Radiologically Assessed Body Composition Measures With Overall Survival Among Colorectal Cancer Patients

Objectives: Colorectal cancer (CRC) is the second overall leading cause of cancer death in the United States. Body composition may influence CRC prognosis by regulating inflammation, insulin sensitivity, and microbial-modulated metabolism. We used a novel computer tomography (CT)-based approach to investigate associations of body composition with overall survival among 121 CRC patients.

Methods: We included patients with colon (40%) or rectum (60%) cancer stages I-IV (III-IV 65%), 58% male, median age 56, who had surgery at Moffitt Cancer Center from 1995-2020. We estimated visceral (VF), subcutaneous (SF) fat, and skeletal muscle mass (SKM) using the Data Analysis Facilitation Suite (DAFS) 3.5 platform to segment   standard of care CT  images. Respective body composition metric volumes were generated from axial CT images between the top of the 10th thoracic vertebral body to the bottom of the 5th lumbar vertebral body. Standard single-slice body composition metric areas were also obtained using the axial CT image through the mid-3rd lumbar vertebra(cm²). We normalized the SKM area by dividing it by height (m²). We used multivariate Cox proportional hazard regressions to estimate associations of body composition metrics with overall survival. Models were adjusted for sex, age at diagnosis, stage, and tumor site.

Results: Overall, all three single-slice CT body composition metrics were strongly positively correlated with overall survival. Single-slice mid-L3 Visceral and subcutaneous fat areas were associated with worse survival. For the cross-sectional area of VF and SF (cm²), the hazard ratios (HRs) and 95% confidence intervals (CIs) comparing the highest relative to lowest tertiles were HR=2.37 (95% CI= 1.04-5.36; P-Trend=0.04) and HR= 3.36 (95%CI=1.44-7.86; P-Trend= 0.01), respectively. Associations of the SKM index and volumetric metrics with survival were weaker and closer to null.

Conclusions: Our study suggests that pretreatment CT metrics of body composition reflecting visceral and subcutaneous fat may be associated with poorer CRC survival, potentially informing clinical decision-making and interventional strategies. These associations should be further studied in large, diverse populations with measured prognostic biomarkers.

Funding Sources: Doratha Byrd, PhD was supported by an Institutional Research Grant from the American Cancer Society.