Surgical resection is the primary curative treatment for patients with hepatocellular carcinoma (HCC), with a 5-year overall survival rate of 60-80% post-surgery. Therefore, guidelines recommend surgical resection as the first-line choice for early to mid-stage HCC (CNLC stages IA-IIA or BCLC stages A/B) patients with well liver reserve function. However, the high postoperative recurrence rate is the main factor limiting long-term survival in HCC patients, with literature reporting recurrence rates exceeding 70%. Among these, half of the patients experience recurrence within two years post-surgery, imposing a heavy burden on patients' physical and mental health as well as on societal medical resources. Adopting effective treatment to improve surgical curability and reduce postoperative recurrence rates is one of the current research hotspots.

Recent studies from the investigators' center indicate that hepatic arterial infusion chemotherapy (HAIC) and immunotherapy can provide definite efficacy for patients with advanced HCC, extending their survival time. Mechanistically, chemotherapy and immunotherapy have synergistic effects: tumor cell necrosis induced by chemotherapy can promote immune activation, while cytokines and neutralizing antibodies secreted by immune cells can enhance the toxicity of chemotherapeutic drugs.

Therefore, this study aims to conduct a prospective, single-arm, phase II clinical study, targeting HCC patients with high-risk recurrence factors, to evaluate whether neoadjuvant HAIC combined with a PD-1 monoclonal antibody (Tislelizumab) followed by adjuvant Tislelizumab post-surgery can reduce postoperative recurrence rates in HCC patients. The primary endpoint is the 1-year recurrence-free survival (RFS) rate post-surgery, while secondary endpoints include the objective response rate (ORR) of neoadjuvant therapy, the incidence of perioperative complications, the incidence of treatment-related adverse events, overall survival (OS) time, pathological complete response (pCR) rate of neoadjuvant therapy, and major pathological response (MPR) of neoadjuvant therapy. The investigators aim to comprehensively assess the efficacy and safety of neoadjuvant HAIC plus PD-1 and adjuvant PD-1 in the perioperative treatment of HCC.

Inclusion Criteria:

1. Newly diagnosed and untreated hepatocellular carcinoma (clinical diagnostic criteria based on the " Chinese Guidelines for the Diagnosis and Treatment of Hepatocellular Carcinoma (2024 Edition) " formulated by the National Health Commission of China and the Barcelona Clinic Liver Cancer (BCLC) strategy for prognosis prediction and treatment recommendation of the European Association for the Study of the Liver (EASL));
2. Tumor staging: beyond Milan criteria (single tumor >5 cm, or 2-3 tumors with the largest diameter >3 cm), resectable CNLC stage Ib/IIa hepatocellular carcinoma;
3. No tumor thrombus, distant metastasis, or lymph node metastasis;
4. Normal liver volume ≥ 700 cc, estimated residual liver volume >40% after resection;
5. Patient KPS ≥ 90;
6. Liver function Child-Pugh class A;
7. Estimated survival of more than 6 months;
8. Function of important organs meets the following requirements: white blood cells ≥ 4.0×10^9/l, neutrophils ≥ 1.5×10^9/l, platelets ≥ 80.0×10^9/l, hemoglobin ≥ 90 g/l; serum albumin ≥ 2.8 g/dl; total bilirubin ≤ 1.5 × ULN, ALT/AST/ALP ≤ 2.5 × ULN; serum creatinine ≤ 1.5 × ULN or creatinine clearance rate > 60 mL/min; no severe organic diseases;
9. The subject must be able to understand and voluntarily sign a written informed consent form, and must sign the informed consent form prior to any specific procedure of the study, agreeing to comply with the medication and postoperative follow-up requirements as designed in this study.

Exclusion Criteria:

1. Combined with severe impairment of functions of other important organs such as heart, lungs, and kidneys; active infections other than viral hepatitis or other serious comorbid conditions, making the patient unable to tolerate treatment;
2. Contraindications to surgical resection and immunotherapy;
3. History of other malignant tumors;
4. Combined with immunological diseases or other conditions requiring long-term steroid treatment;
5. Known or suspected allergy to the study drug or any drugs administered in connection with this trial;
6. History of organ transplantation;
7. Pregnant or breastfeeding women;
8. Other factors that may affect patient enrollment and assessment outcomes;
9. Refusal to follow-up according to the requirements set by the study protocol, and refusal to sign the informed consent form.