Prognostic impact of CT-derived sarcopenic obesity in solitary hepatocellular carcinoma after hepatectomy: Does the definition matter?

PURPOSE: To evaluate the prognostic impact of different CT-derived definitions of sarcopenic obesity (SO) in solitary hepatocellular carcinoma (HCC) after hepatectomy.

METHODS

Patients undergoing curative-intent hepatectomy for solitary HCC between February 2014 and December 2023 were retrospectively identified from three tertiary centers in China. Preoperative CT images at the third lumbar vertebral (L3) level were used to segment skeletal muscle and adipose tissue and derive the skeletal muscle index (SMI), visceral fat area (VFA), and visceral-to-subcutaneous fat ratio (VSR). CT-defined low muscle mass was assessed using two established SMI thresholds (Western: <52.4/<38.5 cm2/m2; Japanese: <42/<38 cm2/m2 for men/women), whereas visceral obesity was assessed by VFA or sex-specific VSR cutoffs. Four conventional (SO1-SO4) and one composite (SO5) SO definitions were evaluated. Associations with overall survival were assessed using multivariable Cox models.

RESULTS

Among 668 patients (median age, 58 years [interquartile range, 49-67]; 535 men), SO prevalence ranged from 3.7% to 17.4% across conventional definitions (SO1-SO4) and reached 21.6% with the composite definition (SO5). Median overall survival was consistently shorter in patients with SO than in those without SO across all definitions (25.4-42.0 vs. 74.3-80.1 months; all p < 0.001). In multivariable analyses, SO was independently associated with increased mortality risk under both conventional (SO1-SO4: hazard ratio [HR], 2.84-5.36; all p < 0.001) and composite (SO5: HR, 3.05; p < 0.001) definitions, after adjustment for cirrhosis, microvascular invasion, and tumor size.

CONCLUSION

Across the evaluated definitions, CT-derived SO was independently associated with poor survival in patients with solitary HCC after hepatectomy.