Concurrent low skeletal muscle mass and fat area may predict poor survival in patients with unresectable hepatocellular carcinoma treated with atezolizumab plus bevacizumab therapy.

BACKGROUND & AIMS: Combination immunotherapy is the standard first-line treatment for hepatocellular carcinoma. Body composition may affect treatment outcomes; however, the prognostic relevance of skeletal muscle and adipose tissue during immunotherapy remains unclear. We aimed to determine whether integrating skeletal muscle and adipose tissue measurements stratifies survival outcomes in patients with hepatocellular carcinoma receiving atezolizumab plus bevacizumab therapy. METHODS: In this retrospective cohort study, conducted at nine institutions, body composition was assessed using the body mass index, skeletal muscle index at the L3 level, and total fat area at the umbilical level. L3 skeletal muscle index was dichotomized using sex-specific cutoffs, and body mass index and total fat area were dichotomized at the cohort median values. RESULTS: Japanese patients (n=445, 74 years median age; 80.4% men) were included. In this cohort, median body mass index, L3 skeletal muscle index (men/women), and total fat area were 23.3, 44.0/37.6 cm2/m2, and 262.8 cm2, respectively. The response rate was 33.0%; the median progression-free and overall survival were 8.4 and 25.1 months, respectively. Low body mass index, L3 skeletal muscle index, and total fat area were associated with poorer overall survival. In the L3 skeletal muscle index × total fat area analysis, the low muscle/low fat group had the poorest overall survival. Per multivariable analysis, this body composition was an independent predictor of poor prognosis. CONCLUSIONS: Concurrent low skeletal muscle mass and fat area may predict poor prognosis in patients with hepatocellular carcinoma receiving atezolizumab plus bevacizumab therapy. Baseline body composition profiling may aid in risk stratification of these patients.