Background and Aims: Skeletal muscle loss has been identified as a prognostic factor in patients with unresectable hepatocellular carcinoma (uHCC) undergoing treatment with lenvatinib (LEN). While atezolizumab plus bevacizumab (ATZ-BEV) is recommended as first-line therapy for uHCC, the impact of skeletal muscle loss in these patients remains unclear. Methods: We enrolled 97 patients treated with either LEN or ATZ-BEV as their first-line therapy and divided them into two groups based on the presence or absence of a low psoas muscle index (low PMI) before treatment. We compared patient characteristics and overall survival (OS) between the groups. Additionally, we investigated the transition of the PMI during drug therapy, specifically before treatment, at the initial evaluation, and after the end of treatment. Results: Seventy percent of patients in the LEN group and seventy-one percent in the ATZ-BEV group had a low PMI. Multivariate analysis across all patients revealed a low PMI (hazard ratio [HR] 3.25, p = 0.0004) as a prognostic factor for OS. The PMI decreased more in the LEN group compared to the ATZ-BEV group. In the Barcelona Clinic Liver Cancer-C group, the OS of ATZ-BEV therapy was significantly better than that of LEN therapy when a low PMI was present (p = 0.046). Conclusions: A low PMI emerges as a significant prognostic factor in uHCC patients undergoing drug therapy, not only in LEN therapy but also in ATZ-BEV therapy. Additionally, ATZ-BEV therapy may be more favorable for sarcopenic patients with advanced HCC stages.
Keywords: atezolizumab plus bevacizumab; hepatocellular carcinoma; lenvatinib; psoas muscle; sarcopenia; survival.