IMRT Plus PD-1 Blockade and Lenvatinib for HCC With PVTT (Vp3) Before Liver Transplantation

Inclusion Criteria: * Patients must have pathologically or cytologically or by radiological criteria proven hepatocellular carcinoma（exceeding Milan criteria）; known mixed histology (e.g. hepatocellular carcinoma plus cholangiocarcinoma) or fibrolamellar variant is not allowed. * The maximum diameter of a single tumor ≤9cm. Or the number of tumors ≤3 and the maximum diameter of the largest tumors ≤5cm, and the sum of the maximum diameters of all tumors ≤9cm. * Vp3 PVTT according to Japanese Vp classification. * Without lymph node metastasis or extrahepatic metastasis. * Baseline AFP≥20ng/ mL * Has an eligibility scan (CT of the chest, triphasic CT scan and MRI of the abdomen) \<1 week before the treatment. * Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 within 7 days prior to Cycle 1, Day 1. * Has a Child-Pugh A-B7 liver score (5 to 7 points) within 7 days prior to Cycle 1, Day 1. * Laboratory tests within 7 days prior to Cycle 1, Day 1: * Neutrophils ≥1.5×109/L * Hemoglobin ≥8.5g/dL * Platelets ≥100×109/L, * Creatinine ≤1.5× upper limit of normal (ULN) and endogenous creatinine clearance ≥50ml/min (standard Cockcroft Gaul formula) * Total bilirubin ≤3×ULN, ALT≤5×ULN, AST≤5×ULN, INR≤1.7 * Has controlled hepatitis B (HBV-DNA\<105IU/ml) * The estimate time length between enrollment and liver transplantation should be at least 3 months. * No prior systematic therapy such as immunotherapy, targeted therapy and chemotherapy for HCC. * No prior local treatment such as TACE, HAIC, radiofrequency ablation or radiotherapy was received within 2 months before enrollment. * If female, is not pregnant or breastfeeding, and at least one of the following conditions applies: 1) Is not a woman of childbearing potential (WOCBP); or 2) Is a WOCBP and using a contraceptive method that is highly effective or be abstinent from heterosexual intercourse as their preferred and usual lifestyle (a WOCBP must have a negative pregnancy test within 72 hours before the first dose of study treatment). * No obvious insufficiency of other organs. * Patients with a history of hypertension should be well controlled (\< 140/90 mmHg) on a regimen of anti-hypertensive therapy. * Patients voluntarily joined the study and signed informed consent with good compliance and follow-up. Exclusion Criteria: * • Known mixed histology (e.g. hepatocellular carcinoma plus cholangiocarcinoma) or fibrolamellar variant. * Surgery within the past 6 months. * Has had esophageal or gastric variceal bleeding within the last 6 months. * Has clinically apparent ascites on physical examination. * Has received systematic therapy such as immunotherapy, targeted therapy and chemotherapy for HCC. * Has received TACE, HAIC, radiofrequency ablation and other local treatments in recent 2 months. * Has received liver radiotherapy. * Has received radiotherapy with grade 4 toxicity. * Significant history of cardiac disease is not allowed: Congestive heart failure \> class II New York Heart Association (NYHA) Myocardial infarction within 6 months prior to registration Serious myocardial dysfunction, defined as scintigraphically (multigated acquisition scan \[MUGA\], myocardial scintigram) determined absolute left ventricular ejection fraction (LVEF) below 45% or an LVEF on echocardiogram (ECHO) below the normal limit at the individual institution. * Has severe hypersensitivity (≥Grade 3) to monoclonal antibody. * Has an active autoimmune disease that has required systemic treatment (skin diseases that do not require systemic treatment such as vitiligo, psoriasis; type I diabetes, and autoimmune hypothyroidism due to hormone replacement therapy are allowed). * Patients with other active malignant tumors within 5 years before the first use of the study drug (cured localized tumors such as basal cell carcinoma of skin, squamous cell carcinoma of skin, superficial bladder cancer, carcinoma in situ of prostate, carcinoma in situ of cervix and carcinoma in situ of breast are allowed). * Has an active infection requiring systemic therapy. * Has a known history of human immunodeficiency virus (HIV) infection. * Has known active tuberculosis within 5 years. * Has received a live vaccine within 30 days prior to the first dose of study treatment. * Has received bone-marrow allotransplantation or solid organ transplantation. * Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to Cycle 1, Day 1. * Dysphagia or known drug absorption disorder. * Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the study, starting with the screening visit through 120 days after the last dose of study treatment. * Conditions considered unsuitable for inclusion by other researchers.