The goal of this observational study is to learn about the long-term treatment outcomes for patients with initially unresectable hepatocellular carcinoma (HCC) who achieve successful downstaging with the combination therapy of TACE, lenvatinib, and a PD-1 inhibitor. The main questions it aims to answer are:

Can distinct disease subtypes be identified in successfully downstaged patients using radiomics and clinical data?

Do these different subtypes show significant differences in long-term outcomes, such as recurrence-free survival and overall survival, after undergoing either curative-intent surgical resection or continuing maintenance therapy?

Based on the identified subtypes, can the investigators objectively determine which patients are more suitable for surgical resection and which patients may benefit more from continued maintenance therapy after successful downstaging?

The study will include patients who have already undergone the combination therapy as part of their regular medical care, successfully achieved tumor downstaging (making the tumor technically resectable), and subsequently received either surgical resection or continued maintenance treatment. Researchers will retrospectively analyze their existing clinical and imaging data to compare long-term outcomes between these two treatment paths based on their identified disease subtype.

Inclusion Criteria:

1. Patients diagnosed with hepatocellular carcinoma (HCC) based on clinical or pathological criteria;
2. Barcelona Clinic Liver Cancer (BCLC) stage B or C, assessed as unresectable by surgical evaluation; Underwent treatment with TACE combined with lenvatinib and a PD-1 inhibitor, after which the tumor was re-evaluated and deemed resectable by surgical assessment;
3. Following the achievement of surgical resectability criteria, patients subsequently underwent either R0 surgical resection or continued treatment with TACE combined with lenvatinib and a PD-1 inhibitor;
4. Liver function classified as Child-Pugh Class A or B, or achieved this standard after medical treatment;
5. Performance status (PS) score of 0 or 1.

Exclusion Criteria:

1. Patients with unclear diagnoses or those with concurrent other malignancies.
2. For patients in the downstaging surgery group: Those who underwent non-R0 resection or received additional anti-tumor therapies postoperatively.
3. For patients in the maintenance treatment group: Those who received anti-tumor therapies other than TACE/lenvatinib/PD-1 inhibitors.
4. Liver function classified as Child-Pugh Class C or above, unresponsive to hepatoprotective therapy.
5. Patients with severe infections, such as respiratory, biliary tract, or abdominal infections.
6. Patients with severe underlying diseases, particularly immune-related disorders.

Patients with initially unresectable hepatocellular carcinoma who were treated with a combination therapy of TACE, lenvatinib, and a PD-1 inhibitor and subsequently achieved successful tumor downstaging.

The dataset contains detailed and potentially re-identifiable patient information, including medical images, clinical records, and treatment outcomes. Due to institutional data privacy policies, ethical restrictions related to patient confidentiality, and the lack of broad consent from participants for data sharing beyond the scope of this specific research, the investigators are unable to publicly share individual participant data (IPD). All data will be stored securely within the hospital's internal research database, and access will be restricted to the study investigators for analysis purposes only. Requests for aggregated or de-identified results may be considered upon reasonable inquiry to the corresponding author, subject to institutional review and compliance with applicable regulations.