Lab test may guide smarter chemo for bile duct cancer patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Signing of written informed consent prior to participation; 2. Age ≥18 years, regardless of sex; 3. Histologically confirmed stage II/III biliary tract malignancies (including intrahepatic cholangiocarcinoma, extrahepatic/hilar cholangiocarcinoma, gallbladder cancer, distal bile duct cancer, or ampullary cancer); 4. Must have undergone radical resection (R0/R1), including liver/pancreatic resection or, less commonly, both; 5. ECOG performance status (PS) score: 0-1; 6. Expected survival \>6 months and ability to tolerate combined therapy; 7. Adequate organ function (without blood component or growth factor support within 14 days): 8. Hematology: Neutrophils ≥1,500/mm³, platelets ≥100,000/mm³, hemoglobin ≥9 g/dL; 9. Liver/kidney function: Serum creatinine (SCr) ≤1.5×ULN or creatinine clearance ≥50 mL/min (Cockcroft-Gault formula); total bilirubin (TBIL) ≤2×ULN; AST/ALT ≤3×ULN; urine protein \<2+ (if ≥2+, 24-hour urine protein ≤1 g); Biliary drainage: Adequate surgical drainage, no signs of infection; 10. Normal coagulation function, no active bleeding or thrombotic disease:INR ≤1.5×ULN, APTT ≤1.5×ULN, PT ≤1.5×ULN; 11. Contraception: 1. Non-surgically sterilized or reproductive-age patients must use medically approved contraception (e.g., IUD, oral contraceptives, condoms) during and for 3 months after treatment; 2. Reproductive-age females must have negative serum/urine pregnancy test (HCG) within 7 days before enrollment and must not be breastfeeding; 3. Reproductive-age males must agree to use contraception with partners during and for 3 months after treatment; 12. Voluntary participation, good compliance, and willingness to follow up for safety and survival assessments. Exclusion Criteria: 1. Early-stage BTC patients; 2. Pancreatic cancer patients; 3. Patients who have undergone other postoperative radiotherapy/chemotherapy; preoperative chemoradiotherapy followed by radical resection, but postoperative pathology still indicates Stage II/III disease is allowed; 4. Incomplete surgical recovery or unresolved biliary obstruction; 5. Patients with radiologically confirmed distant metastasis; 6. Patients with a history of or concurrent other malignancies (except for cured basal cell carcinoma of the skin and in-situ carcinoma of other sites); 7. Known allergies to any component of the investigational drug; 8. Factors significantly affecting oral drug absorption, such as inability to swallow, chronic diarrhea, or intestinal obstruction; 9. Patients with any active autoimmune disease or a history of autoimmune disease (e.g., but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism, or hypothyroidism; patients with vitiligo or childhood asthma that has been completely resolved and requires no intervention in adulthood may be included; patients requiring bronchodilators for medical intervention due to asthma cannot be included); 10. Patients using immunosuppressants or systemic/absorbable local corticosteroids for immunosuppressive purposes (dose \>10 mg/day prednisone or equivalent) and continuing use within 2 weeks prior to enrollment; 11. Symptomatic ascites or pleural effusion requiring therapeutic paracentesis or drainage; 12. Poorly controlled cardiac symptoms or diseases, such as: 1. NYHA Class II or higher heart failure, 2. unstable angina, 3. myocardial infarction within 1 year, 4. clinically significant supraventricular or ventricular arrhythmias requiring treatment or intervention; 13. Coagulation abnormalities (PT \>16s, APTT \>43s, TT \>21s, Fbg \>2g/L), bleeding tendency, or receiving thrombolytic/anticoagulant therapy; 14. Active infection or unexplained fever \>38.5°C during screening or before the first dose; 15. History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 4 weeks before the first dose; 16. History of pulmonary fibrosis, interstitial pneumonia, pneumoconiosis, radiation pneumonia, drug-related pneumonia, or severe lung dysfunction; 17. Congenital or acquired immunodeficiency, such as HIV infection, or active hepatitis (liver enzymes not meeting inclusion criteria; for hepatitis B: HBV DNA ≥103/ml; for hepatitis C: HCV RNA ≥103/ml); chronic HBV carriers with HBV DNA \<2000 IU/ml (\<104 copies/ml) may be included if receiving antiviral therapy during the trial; 18. Participation in other drug-related clinical trials within 1 month before enrollment or potential receipt of other systemic anti-cancer therapies during the study; 19. Live vaccination within 4 weeks before the first dose or planned during the study; 20. History of substance abuse, alcoholism, or drug addiction; 21. Inability or unwillingness to bear the cost of self-funded examinations and treatments; 22. Other factors deemed by the investigator to exclude the patient, such as severe diseases (including mental illness) requiring treatment, significant laboratory abnormalities, or family/social factors that may compromise patient safety or data/sample collection.