Phase II Study of Gemcitabine Versus S-1 Adjuvant Therapy After Hemihepatectomy for Biliary Tract Cancer

Inclusion Criteria:

1. Biliary tract cancer (BTC) (>= Unio Internationalis Contra Cancrum (UICC) Stage IB), adenocarcinoma
2. R0 or R1 resection
3. no obvious recurrent lesion
4. 20 years old or more
5. Eastern Cooperative Oncology Group (ECOG) performance status must be 0 or 1
6. The patient underwent no other treatment than surgery for BTC
7. Neutrophil must be over 1500/μl, Hemoglobin must be over 9.0g/dL, platelet must be over 100,000/μl, Aspartate transaminase (AST) and Alanine aminotransferase (ALT) must be less than 150 IU/L, total bilirubin must be less than 1.5 mg/dL, Creatinine must be less than 1.2 mg/dl, and Creatinine clearance must be over 60 mL/min
8. The patient can intake drugs per os.
9. From 4 to 12 weeks after the surgery
10. Written informed consent

Exclusion Criteria:

1. Existence of active double cancer
2. The patient suffered from severe drug allergy
3. Sever complications (interstitial pneumonia, heart failure, renal failure, liver failure, ileus, incontrollable diabetes mellitus, and so on)
4. Any active infections exist.
5. Pregnancy
6. Severe mental disorder
7. Others