Ablation has been an effective therapy in treating intrathoracic metastases. However, for hepatocellular carcinoma with pulmonary oligometastasis, ablation of metastases remains relatively unexplored and still needs clinical evidence.

Systemic therapy is the standard treatment for advanced hepatocellular carcinoma (HCC) with metastasis. However, metastases with limited number (oligometastasis) can represent a subtype and transition point between localized disease and widespread metastases. Thus, eliminating metastases could be advantageous and beneficial to the prognosis if feasible and permitted. Image-guided ablation therapy, such as microwave ablation (MWA), radiofrequency ablation (RFA), and cryoablation, has attracted great interest as a minimally invasive approach against intrathoracic metastases. Recently, ablation has been used on patients with pulmonary metastases from various cancers. This technique yields high proportions of sustained complete responses and is associated with relatively low morbidity. This multicenter study focuses on the management of ablation of oligometastasis therapy combined with systemic therapy.

Inclusion Criteria:

1. diagnosis of primary HCC, confirmed histologically or clinically according to the criteria of the American Association for the Study of Liver Diseases;
2. presence of pulmonary oligometastasis, the metastases found within three month of HCC diagnosis;
3. metastases with limited five sites and no more two organs involved, with a maximum diameter of ≤5cm;
4. receipt of first-line systemic therapy for minimum of 3 months before ablation, with controlled intrahepatic tumors and no progression of metastases. Controlled intrahepatic tumors were defined as those showing a partial or stable response according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST);
5. undergone locoregional treatments, including transarterial artery chemoembolization (TACE) or hepatic arterial infusion chemotherapy (HAIC) were included;
6. classified as Child-Pugh class A or B and having an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1;
7. no history of other malignancies.
8. life expectancy more than 3 months;
9. agreed to participated in this clinical trial;
10. Hemameba ≥3.0 x109/L, neutrophil ≥1.5x109/L, hemoglobin≥10.0 g/L, platelet≥100x 109/L, ALT; AST; bilirubin ≤1.5-fold normal, GFR≥60ml/min.

Exclusion Criteria:

1. intermediate HCC;
2. age < 18 years or > 75 years;
3. advanced HCC with more than five metastases;
4. no response to Lenvatinib;
5. metastases size > 5 cm;
6. life expectancy less than 3 months.

Thermal ablation, as a minimal therapy, has been recommended as a favorable therapy for metastases worldwide. However, for advanced hepatocellular carcinoma with pulmonary oligometastasis, the standard of care is system therapy. However, the evidence of ablating the oligometastasis is limited. In this multicenter study, we want to indicate that compared with systemic therapy, patients received thermal ablation of pulmonary oligometastasis plus system therapy showed significantly longer survival. This study will supplement the current situation where system therapy is the standard of care for hepatocellular carcinoma with oligometastasis.