Radiofrequency Ablation Combined With S-1 for Pancreatic Cancer With Liver Metastasis

Inclusion Criteria: * Karnofsky Performance Status ≥ 70 * Histologically/cytologically confirmed pancreatic adenocarcinoma. * Patients must have underwent radical resection of the pancreatic lesion, or have their locally advanced pancreatic lesion controlled after first-line chemotherapy. * At least one measurable liver metastasis by RECIST criteria must be present. * Single liver metastasis smaller than 5cm, or multiple liver metastases less than 6 lesions and smaller than 3cm for each, without metastasis to other sites. * Patients must have adequate organ functions reflected by the laboratory criteria below: Granulocytes ≥ 2,000/uL, Hemoglobin ≥ 8.0 gm/dL, Platelets ≥ 100,000/uL, Serum creatinine \< 2.0 mg/dL, Bilirubin \< 1.5 mg/dL, SGPT \< 2.5 x normal, prothrombin time \<13.5s * Prior therapy, e.g., chemotherapy, radiation, is allowed provided that at least 4 weeks washout time is given. * Patients with jaundice must have a biliary drainage decompression operation before recruitment. * Ability to understand and the willingness to sign a written informed consent. Exclusion Criteria: * Prior treatment with S-1. * Liver metastatic lesion is located at the surface of the liver, with more than 1/3 of the tumor protruding outside. * Subject has Child-Pugh grade Class C hepatic impairment, massive ascites, active gastrointestinal bleeding, severe coagulation disorder that could not be corrected, or other contraindication for radiofrequency ablation. * Tumor invasion of Cavity organs. * Known central nervous system involvement and leptomeningeal disease. * Concurrent infection requiring intravenous antibiotics. * Other serious illness or condition including cardiac disease including congestive heart failure (New York Heart Association Classification III or IV), active HIV infection/HIV disease, psychiatric disorders. * Subject has previous or concurrent cancer that is distinct in primary site or histology from pancreatic adenocarcinoma except cervical carcinoma in situ, non-melanoma carcinoma of the skin or in situ carcinoma of the bladder. Any cancer curatively treated greater than 3 years prior to entry is permitted. * Pregnant or lactating women.