Supplementary Material for: Liver Stiffness Measured by Vibration-controlled Transient Elastography Predicts Hepatic Decompensation in Patients with Hepatocellular Carcinoma Receiving Systemic Treatments

Background/Aims: Hepatic decompensation (HD) following systemic treatment, including atezolizumab+bevacizumab (Atezo/Bev) and tyrosine kinase inhibitors (TKIs), is a critical prognostic event in advanced hepatocellular carcinoma (HCC). This study aims evaluate the predictive utility of liver stiffness measurement (LSM) by vibration-controlled transient elastography (VCTE) for HD incidence post-treatment. Methods: This multicenter study included 396 HCC patients treated who received systemic therapy (Atezo/Bev or TKIs) and underwent VCTE prior to treatment at seven university affiliated hospitals. Clinical outcomes including HD independent of tumor progression, variceal bleeding (VB), overall survival (OS), and progression-free survival (PFS) were assessed. A 25 kPa LSM threshold, based on Baveno VII criteria stratified patients into high and low LSM groups. Results: Of the 396 patients, 176 received Atezo/Bev, while 45 and 175 received lenvatinib and sorafenib, respectively. Treatment distribution was similar between high and low LSM groups (P=0.546). High LSM was associated with increased HD risk (HR=3.00, P < 0.001), VB risk (HR=2.34, P = 0.048), and a trend toward worse OS (HR=1.27, P=0.065). In the low LSM group, Atezo/Bev outperformed TKIs in OS and PFS (P<0.05) without increasing HD risk. In contrast, in the high LSM group, Atezo/Bev and TKIs showed no OS or PFS differences, but Atezo/Bev significantly increased HD and VB risk (P<0.05). A risk score based on four variables (Child-Pugh Score 5, LSM ≥25 kPa, multiple tumors, and high-grade portal vein tumor thrombosis) showed good predictive accuracy for HD at 12 months (AUC=0.832), and effectively identified patients at high risk for HD, VB, and poor survival (P<0.005). Conclusions: LSM by VCTE predicts HD following systemic treatment in advanced HCC. In patients with high LSM, Ate/Bev increases HD risk, warranting careful treatment selection.