BACKGROUND&AIMS: Low muscle mass is associated with poor immune checkpoint inhibitor (ICI) efficacy in patients with melanoma
however, whether this is true in all populations remains to be explored. The current study aimed to investigate the effect of low muscle mass on overall survival (OS) and progression-free survival (PFS) of patients with advanced melanoma treated with ICI. METHODS: We retrospectively collected the clinical data of consecutive patients with advanced melanoma who received ICI as first-line treatment between 2013 and 2024 at our institution. To diagnose low muscle mass, the skeletal muscle index (SMI) at the third lumbar spine was calculated from computed tomography (CT) images, and SMI values <
42 cm2/m2 for men and <
38 cm2/m2 for women diagnosed low muscle mass. The association of low muscle mass, OS, and PFS with ICI treatment in patients was investigated. RESULTS: Seventy-six patients with advanced melanoma were assessed retrospectively at our institution
32 were in the low muscle mass group, while 44 were in the normal muscle mass group. The median OS in patients with and without low muscle mass was 7.1 and 26.6 months (hazard ratio [HR] 3.12, 95% confidence interval [Cl], 1.65-5.89
p <
0.001) and median PFS was 2.1 and 14.8 months, respectively (HR, 3.10
95% Cl 1.74-5.54, p <
0.001). Multivariate analysis showed significantly poor differences in OS (HR, 2.46
95% CI, 1.20-5.03
p = 0.01) and significant differences in PFS independently in the low muscle mass group (HR, 3.10
95% CI, 1.74-5.54
p <
0.001). CONCLUSIONS: Low muscle mass may be a poor prognostic factor for patients with advanced melanoma treated with ICI.