Long-Term Evolution of Skeletal Muscle Quantity and Quality After Curative-Intent Colon Cancer Surgery: A Retrospective Cohort Study

<b>Background</b>: Computed tomography (CT)-based sarcopenia is a promising predictor of postoperative complications and recovery. However, studies on the longitudinal evolution of skeletal muscle markers are lacking and findings regarding its correlation with survival are still not clear. <b>Methods</b>: We conducted a retrospective single-center cohort study of consecutive patients undergoing curative-intent colon cancer surgery. Skeletal muscle area (SMA), skeletal muscle index (SMI), skeletal muscle radiation attenuation (SMRA), and intermuscular adipose tissue (IMAT) area and index (IMATI) were measured on a single axial CT slice at the third lumbar vertebral level before surgery and at 6, 12, and 24 months after. Descriptive statistics were used to report the evolution over time of CT-based sarcopenia markers. Their correlation with overall survival was analyzed using Cox's proportional hazards regression analysis. <b>Results</b>: The final cohort included 102 patients (65.7% males) with a mean age of 66 ± 13 years. Eighty-five (86.7%) patients were alive at 24 months, and forty-five (45.9%) underwent a CT scan at all time points. CT-based sarcopenia markers remained statistically stable over 2 years. Age (HR 1.07, 95% CI 1.00-1.14) and ASA score (HR 2.4, 95% CI 1.00-5.7) were negative independent predictive factors. Patients with larger differences (Δ) of IMAT area and IMATI at 12 months, HR 0.79 (95% CI 0.67-0.93) and 0.49 (95% CI 0.30-0.80), respectively, had a lower mortality. <b>Conclusions</b>: CT-based markers of skeletal muscle quantity (SMA, SMI) and quality (IMAT area, IMATI) remained statistically stable after curative-intent colon cancer surgery. No preoperative CT-based sarcopenia markers were predictive of overall survival. Larger cohorts are needed to generalize these initial findings.