SLOG vs mFOLFIRINOX as the First-line Treatment in Locally Advanced Uncresectable or Metastatic Pancreatic Cancer

Inclusion Criteria: 1. Patients must have cyto-/histologically confirmed, locally advanced unresectable or metastatic adenocarcinoma of the pancreas (mPAC). Patients who have disease measurable or evaluable on x-ray, CT scan, or physical examination are eligible. 2. Patients must have no history of prior chemotherapy for PAC, except those delivered as adjuvant setting that completed at least 6 months before documentation of recurrence by imaging study. 3. Patients with prior radiotherapy are eligible if the irradiated area does not involve the only source of measurable / evaluable disease. 4. Patients' baseline ECOG performance status must be 1. 5. Patients' life expectancy 12 weeks or greater. 6. Patients' age 20 and 80. 7. Patients with biliary obstruction and adequate drainage procedures before enrollment are eligible. 8. Patients must agree to have indwelling venous catheter implanted. 9. Women or men and their partners of reproductive potential should agree to use an effective contraceptive method. 10. All patients must be informed of the investigational nature of this study and must sign and give written informed consent. Exclusion Criteria: 1. Patients who have major abdominal surgery, radiotherapy or other investigating agents within 4 weeks are not eligible. Patients who have palliative radiotherapy for bony metastasis will be eligible 2 weeks after the completion of radiotherapy. 2. Patients with central nervous system metastasis 3. Patients with active infection 4. Pregnant or breast-nursing women 5. Patients with active cardiopulmonary disease or history of ischemic heart disease 6. Patients who have peripheral neuropathy \> Grade I of any etiology 7. Patients who have serious concomitant systemic disorders incompatible with the study, i.e. poorly controlled diabetes mellitus, auto-immune disorders, cirrhosis of the liver, and the rest will be at the discretion of in-charged investigator. 8. Patients who have other prior or concurrent malignancy except for adequately treated in situ carcinoma of cervix or adequately treated basal cell carcinoma of skin, or any malignancy remains disease-free for 3 or more years after initial curative treatment 9. Patients who are under biologic treatment for their malignancy 10. Laboratory tests (hematology, chemistry) outside specified limits: 1. WBC ≤ 3 x 10³/mm³ 2. ANC ≤ 1.5 x 10³/mm³ 3. Platelets ≤ 100.000/mm³ 4. Hb ≤ 9.0 g/dl (≤ 5.6 mmol/l) 5. GFR \< 60 mL/min 6. AST and/or ALT \> 2.5 x ULN; for patients with significant liver metastasis AST and/or ALT \> 5 x ULN 7. Total bilirubin \> 2 x ULN 8. Albumin \< 2.5 g/dL