Supplementary Material for: Efficacy of Local Treatment in Lymph Node Metastasis from Hepatocellular Carcinoma

Introduction: We aimed to investigate the significance of lymph node metastasis from hepatocellular carcinoma and the efficacy of local treatment. Methods : We included patients diagnosed with hepatocellular carcinoma with lymph node metastasis. The pattern of lymph node metastasis was evaluated based on imaging examinations and stratified by three locations: regional (group A), beyond regional intra-abdomen (group B), and extra-abdomen (group C) lymph node metastasis. Results: Among 14474 patients, 852 (5.8%) were identified as having lymph node metastasis. Regarding the location of presentation, group A showed the highest incidence, followed by groups B and C. The 1-year overall survival of patients was 31.7%. The survival significantly differed according to the location of lymph node metastasis. The 1-year overall survival rates were 39.8%, 25.5%, and 22.2% in groups A, B, and C, respectively. All patients underwent systemic treatment, with others receiving additional local treatment. Local treatment yielded superior overall survival compared with no local treatment. After propensity score matching, local treatment was associated with improved survival. Additionally, patients were stratified based on disease status at the time of diagnosis of lymph node metastasis: lymph node alone and combined extra-nodal metastasis. The survival benefits of local treatment were observed in both groups. Conclusions: Our findings demonstrated the clinical significance of lymph node metastasis from hepatocellular carcinoma, which was well discriminated according to location, favoring regional metastasis. In patients with hepatocellular carcinoma presenting lymph node metastasis, active application of local treatment for lymph node metastasis can improve oncologic outcomes.