FOLFOX Plus Lenvatinib Adjuvant Therapy for Hepatocellular Carcinoma Post-Liver Transplantation

Inclusion Criteria: 1. Age between 18 and 75 years inclusive. 2. Histologically confirmed hepatocellular carcinoma without other non-hepatocellular carcinoma components. 3. ECOG performance status 0-1. 4. Child-Pugh class A liver function. 5. Eligible for chemotherapy and targeted therapy within 1-2 months after liver transplantation. 6. Immunosuppressive regimen including calcineurin inhibitors, mycophenolate mofetil, and sirolimus. 7. Adequate liver, kidney, and bone marrow function: serum albumin \>28g/L, total bilirubin ≤3mg/dL (51.3 umol/l), ALT and AST ≤5 times the upper limit of normal; serum creatinine ≤1.5 times the upper limit of normal; hemoglobin \>90g/L, absolute neutrophil count (ANC) \>1.5×10\^9/L, platelet count \>60×10\^9/L; PT-INR \<1.5 or PT within normal limits +6 seconds. 8. Negative serum/urine pregnancy test within 7 days prior to treatment initiation for fertile women. 9. Reliable contraception must be used by all male and female participants during the trial and for six months after its completion. 10. Ability to take oral medications. 11. Participants must provide written informed consent. Exclusion Criteria: 1. Life expectancy less than 6 months. 2. High suspicion of hepatocellular carcinoma recurrence and metastasis. 3. Concurrent malignancies. 4. Allergy to lenvatinib or chemotherapy drugs. 5. Pregnant or lactating women (female participants must undergo pregnancy testing within 7 days prior to treatment). 6. History of severe cardiovascular diseases: congestive heart failure \>NYHA class 2; active coronary artery disease (myocardial infarction within 6 months prior to enrollment); severe arrhythmias requiring antiarrhythmic therapy (β-blockers or digoxin permitted); uncontrolled hypertension. 7. History of HIV infection. 8. Severe active clinical infections. 9. Patients requiring medication for epilepsy (e.g., steroids or antiepileptic drugs). 10. Patients with kidney diseases requiring dialysis. 11. Drug abuse, medical conditions, psychiatric illnesses, or social status that may interfere with the participant's participation in the study or evaluation of study results. 12. Patients unable to swallow oral medications, such as those with severe upper gastrointestinal obstruction requiring gastric tube feeding. 13. Previous treatment with other anti-angiogenic therapies, surgery, TACE, local therapy, systemic chemotherapy, immunotherapy, etc., before liver transplantation. 14. Clear evidence of main portal vein/hepatic vein tumor thrombus or inferior vena cava tumor thrombus. 15. Clear evidence of lymph node metastasis.