Neoadjuvant IMRT Combined With Camrelizumab and Apatinib for Resectable HCC With PVTT

Inclusion Criteria: 1. Signed written informed consent and able to comply with scheduled visits and related procedures; 2. Age ≥18 and ≤75 years, regardless of gender; 3. Patients with HCC who meet the clinical diagnostic criteria of China's "Guidelines for the Diagnosis and Treatment of Hepatocellular Carcinoma" (2022 Edition) or are diagnosed by biopsy, and have at least one measurable lesion according to the mRECIST criteria; 4. Presence of portal vein tumor thrombus (PVTT) of Cheng's type I/II/III, with the primary tumor being resectable; 5. Child-Pugh score of Class A; 6. Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) of 0-1; 7. No prior antitumor treatment (such as surgery, radiotherapy, TACE, ablation, chemotherapy, targeted therapy, immunotherapy, or systemic therapy). 8. For patients with hepatitis B virus (HBV) infection, testing for HBV-DNA is required; direct treatment initiation is allowed if HBV-DNA ≤2000 IU/mL; if HBV-DNA \>2000 IU/mL, antiviral therapy should be administered for one week before starting the treatment; all HBV positive patients will receive continuous antiviral treatment throughout the study; patients with hepatitis C virus (HCV) RNA positive must undergo antiviral treatment as per the guidelines; 9. Participants must provide a fresh tumor biopsy sample during the screening period (can be waived after discussion with the medical monitor) and blood samples for monitoring immune cells, cytokine levels, and other relevant immune status in the tumor microenvironment; 10. Expected survival of ≥12 weeks; 11. Adequate organ and marrow function, as defined by the following laboratory values: 1. Hematology: Absolute Neutrophil Count ≥1.5×109/L; Platelets ≥80×109/L; Hemoglobin ≥90g/L; 2. Liver function: Total bilirubin ≤3× upper limit of normal (ULN); Alanine Aminotransferase and Aspartate Aminotransferase ≤5×ULN; Serum albumin ≥30g/L; 3. Renal function: Serum creatinine (Cr) ≤1.5×ULN, or for patients with Cr \>1.5×ULN, creatinine clearance (CCr) ≥45 mL/min (Cockcroft-Gault formula); Urinalysis showing proteinuria \<2+; For participants with baseline proteinuria ≥2+, a 24-hour urine collection and quantitative protein \<1g is required; 4. Coagulation: International Normalized Ratio or APTT ≤1.5×ULN; 12. Females of childbearing potential must agree to abstain from heterosexual intercourse or use effective contraception from signing the informed consent until at least 120 days after the last dose of study medication. They must have a negative serum HCG test within 1 week before treatment and must not be breastfeeding. Females who have not reached menopause (≥12 months of amenorrhea without an alternative medical cause) and have not undergone sterilization (e.g., hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) are considered to be of childbearing potential; 13. Male participants with partners of childbearing potential must agree to abstain from heterosexual intercourse or use reliable and effective contraceptive methods from the time of signing the informed consent until at least 120 days after the last dose of study medication. During the same period, male participants must also agree not to donate sperm. Male subjects whose partners are pregnant must use condoms and do not need to use other contraceptive methods. Exclusion Criteria: 1. PVTT located in the portal vein branch opposite the tumor, or with inferior vena cava tumor thrombus, extrahepatic metastasis, or tumor invasion of adjacent organs; 2. Known intrahepatic cholangiocarcinoma, sarcomatoid HCC, mixed-cell carcinoma, and fibrolamellar carcinoma; active malignant tumors other than HCC within the past 5 years or concurrently, except for cured localized tumors such as basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, prostate carcinoma in situ, cervical carcinoma in situ, and breast carcinoma in situ, which are allowed; 3. Currently with interstitial pneumonia or interstitial lung disease, or history of interstitial lung disease requiring hormone treatment, or other conditions that may interfere with the judgement and management of immunotherapy-related pulmonary toxicity, such as pulmonary fibrosis, organizing pneumonia (e.g., obliterative bronchiolitis), pneumoconiosis, drug-related pneumonia, idiopathic pneumonia, or participants with active pneumonia or severe impairment of lung function shown on a chest CT during screening; active tuberculosis; 4. Active autoimmune disease or history of autoimmune disease that may recur, including but not limited to autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hypophysitis, vasculitis, nephritis, hyperthyroidism, hypothyroidism (patients controllable with hormone replacement therapy are allowed); Patients with skin conditions that do not require systemic treatment, such as vitiligo, psoriasis, and alopecia, those with controlled Type I diabetes mellitus undergoing insulin therapy, or individuals whose childhood asthma has fully resolved with no need for intervention in adulthood, are allowed; patients requiring bronchodilators for medical intervention of asthma are not allowed; 5. Use of immunosuppressive drugs or systemic corticosteroids for the purpose of immunosuppression (dose \>10mg/day of prednisone or equivalent) within 2 weeks before the start of the study; 6. Active infection, fever of unknown origin ≥38.5°C within 1 week before the study start, or baseline white blood cell count \>15×10\^9/L; therapeutic antibiotics orally or intravenously within 2 weeks before the study start (excluding prophylactic antibiotics given IV for no more than 48 hours); 7. Congenital or acquired immunodeficiency (e.g., HIV infection); 8. Receipt of live attenuated vaccines within 4 weeks before the study start or expectation of needing such vaccines during the camrelizumab treatment period or within 60 days after the last dose of camrelizuma; 9. Significant b