Hepatic Arterial Infusion Chemotherapy Versus Capecitabine as Adjuvant Therapy for Resected Biliary Tract Cancer

Inclusion Criteria: * Age ≥ 18 years, male or female. Histopathologically confirmed biliary tract malignancy (intrahepatic cholangiocarcinoma, perihilar cholangiocarcinoma, gallbladder cancer, and distal cholangiocarcinoma) and underwent radical surgery with negative surgical margins. No history of other tumors, and no prior anti-tumor therapy (including but not limited to chemotherapy, immunotherapy, radiotherapy, targeted therapy, etc.) before or after surgery. ECOG performance status: 0\~1. Baseline blood counts and biochemistry must meet: hemoglobin ≥ 80 g/L; absolute neutrophil count ≥ 1.5 × 10\^9/L; platelet count ≥ 60 × 10\^9/L; ALT/AST ≤ 3 times ULN; total bilirubin ≤ 2 times ULN; serum creatinine ≤ 1.5 times ULN; albumin ≥ 30 g/L; INR \< 1.7 or PT prolonged ≤ 4 seconds. Women of childbearing potential must agree to use contraception during the study and for 6 months after; negative pregnancy test within 7 days prior to enrollment; non-lactating. Men must agree to use contraception. Patients with active HBV infection must receive anti-HBV therapy starting from screening and willing to continue; HCV RNA positive patients must receive standard antiviral therapy and liver function within CTCAE grade 1 elevation. Voluntary participation, signed informed consent, good compliance, willing to cooperate with follow-up. Exclusion Criteria: * Pregnant or lactating. Received anti-tumor drug therapy for cholangiocarcinoma before or after surgery. Cardiac, pulmonary, or renal insufficiency, severe hepatic insufficiency (Child-Pugh C): (1) severe cardiovascular diseases; (2) severe respiratory diseases; (3) renal disease: chronic renal failure, MDRD ≥ stage III; (4) uncontrolled active infection; (5) ASA \> 3; (6) BMI ≥ 35. Active gastrointestinal bleeding, ulcer, refractory ascites. Uncorrectable hypertension, coagulopathy, or severe portal hypertension. Tumor recurrence within 1 month after surgery. History of other malignancies. Received other investigational drugs within 28 days. Deemed unsuitable by the investigator. Allergy \& Contraindications: severe allergy to iodine contrast media unmanageable by premedication, or contraindications to angiography. Postoperative pathology confirmed non-cholangiocarcinoma.