A Prospective, Open-Label, Randomized Controlled Clinical Study Comparing Hepatic Arterial Infusion Chemotherapy (HAIC) With Capecitabine as Adjuvant Therapy After Radical Surgery for Malignant Biliary Tract Tumors

3\. Study Design 3.1.1 Study Site and Overall Population Overview This study is a prospective, open-label, randomized controlled clinical trial designed to observe and evaluate the efficacy and safety of hepatic arterial infusion chemotherapy compared with capecitabine in the adjuvant treatment of malignant biliary tract tumors after radical surgery. The study population consists of postoperative patients from the Hepatobiliary Surgery Department of our hospital, who are pathologically confirmed to have malignant biliary tract cancer (BTC), including intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, gallbladder cancer, and other subtypes, and who have completed radical resection (R0 or R1 resection), with postoperative pathology confirming no distant metastasis. Using a computer-generated random sequence, participants will be assigned in a 1:1 ratio to either the hepatic arterial infusion chemotherapy group or the capecitabine group. The study will use recurrence-free survival (RFS) as the primary efficacy endpoint, and plans to enroll approximately 90 patients with malignant biliary tract tumors after radical surgery. After giving informed consent and being screened as eligible, participants will receive the following regimens: Hepatic arterial infusion chemotherapy group: Oxaliplatin 40 mg/m2 will be infused on days 1-3 of each cycle over 2 hours, followed by continuous infusion of 5-fluorouracil 800 mg/m2 over a total of 22 hours. One cycle lasts 4 weeks. Treatment will continue for 3-4 consecutive cycles or until disease progression, intolerable toxicity, or withdrawal for other reasons. Capecitabine group: Capecitabine, 1250 mg/m2, orally, twice daily (once in the morning and once in the evening, equivalent to a total daily dose of 2500 mg/m2), administered from day 1 to day 14 of each 3-week cycle (d1-14, q3w; that is, 2 weeks of continuous treatment followed by 1 week off). One treatment cycle lasts 3 weeks, and a total of 8 cycles will be administered.

Inclusion Criteria: \- Age ≥18 years, male or female; Pathologically confirmed biliary malignancy (intrahepatic cholangiocarcinoma, hilar cholangiocarcinoma, gallbladder cancer, and distal cholangiocarcinoma), and had undergone curative surgery with negative surgical margins; No history of other tumors, and no antitumor therapy received before or after surgery (including but not limited to chemotherapy, immunotherapy, radiotherapy, targeted therapy, etc.); ECOG: 0-1; Baseline blood count tests and blood biochemistry must meet the following criteria: hemoglobin ≥80 g/L; absolute neutrophil count ≥1.5×10\^9/L; platelet count ≥60×10\^9/L; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3 times the upper limit of normal (ULN); total bilirubin ≤2 times ULN; serum creatinine ≤1.5 times ULN; albumin ≥30 g/L; INR \160 μmol/L). Renal disease: chronic renal failure, MDRD ≥ stage III: GFR1.8 mg/dL (or \>160 μmol/L) Uncontrolled active infection (e.g., severe suppurative cholangitis, sepsis), requiring intravenous antibiotics and hemodynamic instability. ⑤ ASA score \>3; ⑥ BMI ≥35.; Active gastrointestinal bleeding, ulcer, or refractory ascites; Drug-uncontrolled hypertension, coagulation dysfunction, or severe portal hypertension; Tumor recurrence within 1 month after surgery; History of other malignant tumors; Receipt of other clinical trial drugs within 28 days; Those deemed unsuitable for inclusion by the investigator. Allergy and contraindications: severe allergy to iodinated contrast media that cannot be relieved by premedication, or presence of contraindications to angiography. Postoperative pathology confirms non-biliary tract carcinoma.