Stereotactic Radiosurgery and Metformin in Patients With Borderline-Resectable or Locally-Advanced Pancreatic Cancer

Inclusion Criteria: * Subjects must be able to provide written informed consent * Histologically and/or cytologically confirmed adenocarcinoma of the pancreas, clinical stage T1-4, N0-1, M0 * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * Hemoglobin ≥ 9.0 g/dl * Alkaline phosphatase \< 3 x upper limit of normal (ULN) * Albumin \> 2.5 g/dL * Absolute neutrophil count ≥ 1500/mm\^3 * Platelet count ≥ 75,000/mm\^3 * Total bilirubin \< 1.5 x upper limit of normal (ULN) * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\]) ≤ 2.5 x institutional upper limit of normal * Alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) ≤ 2.5 x institutional upper limit of normal * Creatinine ≤ 1.5 * Borderline-resectable or locally-advanced pancreatic cancer (based upon impression of the surgical oncologist, in conjunction with radiologic consultations) as defined per the Alliance consensus : * Borderline-resectable * An interface between the primary tumor and superior mesenteric vein (SMV)/portal vein measuring 180 degrees or greater of the circumference of the vein wall * Short-segment occlusion of the SMV/portal vein but with suitable vessel proximal and distal to the obstruction to allow safe resection and reconstruction * Short-segment interface (of any degree) between the tumor and the hepatic artery with normal artery proximal and distal to the interface that is amenable to resection and arterial…