Neoadjuvant Modified FOLFIRINOX and Stereotactic Body Radiation Therapy in Borderline Resectable Pancreatic Adenocarcinoma

Inclusion Criteria: * Histologically confirmed pancreatic adenocarcinoma * Borderline resectable pancreatic adenocarcinoma, determined centrally by review of a diagnostic CT scan and/or MRI scan with contrast by a dedicated surgical oncologist and radiologist, or as determined by EUS, and defined according to the NCCN consensus guidelines * ECOG Performance Status of 0-1 * Age \> 18 * Laboratory parameters as follows: * Absolute neutrophil count \>=1,500/uL * Platelet count \>=100,000/uL * Hemoglobin \>=9 g/dL * Creatinine \<1.5 X ULN or estimated GFR \>30 ml/min * Bilirubin =\<1.5 X ULN * AST and ALT =\<3 X ULN * Negative pregnancy test in women of childbearing potential * Able to have fiducials placed in the pancreas * Patients who received chemotherapy \>5 years ago for malignancies other than pancreatic cancer are eligible Exclusion Criteria: * Evidence of extrapancreatic disease on diagnostic imaging (CT, MRI, or PET scan), or laparoscopy, including nodal involvement beyond the peripancreatic tissues and/or distant metastases * Evidence of invasion into the duodenum or stomach, as determined by EGD/EUS * Prior treatment (chemotherapy, biological therapy, or radiotherapy) for pancreatic cancer * Prior treatment with oxaliplatin, irinotecan, fluoruouracil or capecitabine * Major surgery within 4 weeks of study entry * Other concurrent anticancer therapies * Other malignancy within the past five years (exceptions include basal cell carcinoma of the skin, cervical carcinoma in situ, and non-metastatic prostate cancer) * Evidence of second malignancy at the time of study entry * Interstitial pneumonia or extensive and symptomatic interstitial fibrosis of the lung * Grade 2 or greater sensory peripheral neuropathy * Uncontrolled seizure disorder, active neurological disease, or known CNS disease * Significant cardiac disease, including the following: unstable angina, New York Heart Association class II-IV congestive heart failure, myocardial infarction within six months prior to study enrollment * Pregnant or nursing * Other medical condition or reason that, in the opinion of the investigator, would preclude study participation