Low-dose Radiotherapy Plus Chemotherapy With Gem-based Doublets and Stereotactic Radiotherapy for Advanced Pancreatic Cancer

Inclusion Criteria: * Pathologically confirmed adenocarcinoma of the pancreas * Patients with unresectable disease based on institutional standardized criteria of unresectability or patients whose disease appeared potentially resectable on axial CT imaging but were found unresectable at surgery * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. Age ≥ 18 * Patients with biliary or gastroduodenal obstruction must have drainage or surgical bypass prior to starting treatment * Patients with radiographically assessable disease * Adequate bone marrow, hepatic and renal function: -Hemoglobin \>10.0 g/dL, absolute neutrophil count \> 1.5 x 10\^9/L, platelet count \> 100 x 10\^9/L. -Aspartate transaminase (AST or SGOT) and alanine transaminase (ALT or SGPT) should be ≤ 3 x upper limit of normal (ULN). -Total bilirubin \< 2 mg/dL. Patients with elevated bilirubin due to obstruction should be stented and their bilirubin should decrease to \< 2 mg/dL prior to study entry. - Creatinine \< 3 mg/dL or Creatinine clearance \> 40 mL/min (calculated according to Cockroft and Gault) Exclusion Criteria: * Evidence of metastatic disease in the major viscera or peritoneal seeding or ascites * Gastric or duodenal obstruction * Previous peripheral neuropathy * Previous irradiation to the planned field; previous chemotherapy for pancreatic cancer * Malignancy (within the past two years) except non-melanomatous skin cancer or carcinoma in situ of the cervix, uterus, or bladder