Background: This study aimed to investigate the usefulness of the psoas muscle index (PMI) as an independent predictor of survival after systemic targeted therapy initiation in patients with hepatocellular carcinoma (HCC). Method: In total, 214 patients with HCC who underwent systemic targeted therapy at the Gifu University Hospital were enrolled. The correlation between the PMI and the skeletal muscle index (SMI) was assessed using Pearson’s correlation coefficient (PCC). The Cox proportional hazards model was employed to determine whether the PMI, along with the α-fetoprotein (AFP) level and the ALBI score, influenced survival; these variables were considered time-dependent covariates. The optimal PMI cut-off value that yielded the most significant differences in survival was determined using maximally selected statistics. Results: The PMI was significantly correlated with the SMI (PCC = 0.38 andp< 0.001 for women; PCC = 0.62 andp< 0.001 for men). The PMI independently influenced survival (hazard ratio: 0.852; 95% confidence interval: 0.755–0.962; andp< 0.001), along with established prognostic factors such as the AFP and the ALBI score. The optimal PMI cut-off values that yielded the most significant differences in survival were 2.86 cm2/m2for women and 3.55 cm2/m2for men, and these values significantly stratified patient outcomes for both sexes (p< 0.001). Conclusions: The PMI serves as a reliable surrogate for the SMI in assessing skeletal muscle mass and predicting survival.
背景：本研究旨在探讨腰大肌指数（PMI）作为肝细胞癌（HCC）患者开始系统性靶向治疗后生存期的独立预测指标的有效性。方法：共纳入214名在岐阜大学医院接受系统性靶向治疗的HCC患者。采用皮尔逊相关系数（PCC）评估PMI与骨骼肌指数（SMI）之间的相关性。使用Cox比例风险模型确定PMI、甲胎蛋白（AFP）水平和ALBI评分是否影响生存期；这些变量被视为时依协变量。通过最大选择统计法确定能产生最显著生存差异的最佳PMI截断值。结果：PMI与SMI显著相关（女性PCC=0.38，p<0.001；男性PCC=0.62，p<0.001）。PMI与AFP、ALBI评分等既定预后因素共同独立影响生存期（风险比：0.852；95%置信区间：0.755–0.962；p<0.001）。产生最显著生存差异的最佳PMI截断值为女性2.86 cm²/m²、男性3.55 cm²/m²，该数值对两性患者的预后均具有显著分层作用（p<0.001）。结论：在评估骨骼肌质量和预测生存期方面，PMI可作为SMI的可靠替代指标。
肿瘤(癌症)患者之家