Combination immunotherapy is currently the standard first-line systemic treatment for unresectable hepatocellular carcinoma (HCC). Approximately 30 % of patients treated with atezolizumab plus bevacizumab (Atezo-Bev) achieve complete or partial tumor response. Some patients who reach a partial response experience enough tumor regression to undergo curative therapies and subsequently attain a disease-free state. However, whether the prognosis of patients who become disease-free after curative therapy equals that of patients who achieve complete response with Atezo-Bev alone is unclear. Likewise, it remains uncertain whether patients who achieve partial response with Atezo-Bev and later undergo curative therapy fare better than those who remain in partial response without further curative treatment. Therefore, we designed this multinational, multicenter, retrospective chart-review study to address these questions.

Planned Cohorts

• Curative-therapy cohort: Patients with unresectable HCC who achieve partial response to Atezo-Bev and subsequently receive curative therapy-surgical resection, radiofrequency ablation, or definitive radiotherapy-to achieve a disease-free state.
• Control cohort: Patients with unresectable HCC who achieve complete or partial response to Atezo-Bev but do not undergo subsequent curative therapy.

Methods and End-points Data will be collected from no more than 30 hospitals worldwide, targeting roughly 400 patients in the curative-therapy cohort and 1,200 patients in the control cohort. Medical-record review will gather baseline characteristics, disease status, liver function, Atezo-Bev treatment details, curative-therapy specifics, treatment responses, and survival outcomes. The primary objective is to compare recurrence-free survival between the two cohorts. This retrospective study will close data collection on 31 March 2025.

Inclusion Criteria:

1. Histologically or clinically (the presence of liver cirrhosis and typical HCC imaging findings by multi-phase CT or MRI) diagnosed HCC.
2. Received Atezo-Bev containing treatment as first-line systemic therapy for HCC
3. Patients with or without macrovascular invasion and main portal vein invasion before Atezo-Bev containing treatment can be enrolled
4. Patients with or without extrahepatic spread before Atezo-Bev containing treatment can be enrolled
5. Obtained CR or PR, according to RECIST version 1.1, to Atezo-Bev treatment

Exclusion Criteria:

1. Fibrolamellar carcinoma or mixed hepatocellular cholangiocarcinoma.
2. Received anti-CTLA4 antibodies simultaneously with Atezo-Bev Patients who received Atezo-Bev in combination with investigational drugs such as tiragolumab, relatlimab, and tocilizumab were allowed to enter the study.
3. Received locoregional therapy simultaneously with Atezo-Bev treatment, such as transarterial chemoembolization (TACE), hepatic arterial infusion of chemotherapy (HAIC), transarterial radioembolization, radiofrequency ablation, and microwave ablation before obtaining PR or not for curative intent

Patients who obtained CR or PR, according to RECIST version 1.1, after receiving Atezo-Bev as first-line systemic therapy for clinically or histologically diagnosed HCC