A Phase I Dual Dose Escalation Study of Radiation and Nab-Paclitaxel in Patients With Unresectable and Borderline Resectable Pancreatic Cancer

Inclusion Criteria: * Pathologically confirmed adenocarcinoma of the pancreas. * Unresectable disease or borderline resectable disease assessed by a multidisciplinary panel of pancreas surgeon, medical and radiation oncologist, and a radiologist. Criteria defining unresectable and borderline resectable patients will be based on the NCCN Guidelines (v 1.2014): Unresectable * Greater than 180 degrees of SMA encasement * Any celiac abutment * Unreconstructible SMV/portal occlusion * Aortic invasion or encasement * Nodal metastases beyond the field of resection Borderline resectable * Venous involvement of the SMV/portal vein demonstrating tumor abutment with impingement and narrowing of the lumen * Encasement of the SMV/portal vein but without encasement of the nearby arteries * Short-segment venous occlusion resulting from either tumor thrombus or encasement with suitable proximal and distal vessel for reconstruction/grafting. * Gastroduodenal artery encasement up to the hepatic artery with either short segment encasement or direct abutment of the hepatic artery, without extension to celiac axis * Tumor abutment to SMA but not to exceed greater than 180 degrees of circumferential vessel wall * Age \> 18 years. * ECOG performance status of ≤ 1. * Adequate organ function defined as follows: absolute neutrophil count of ≥ 1500/mm3, platelets ≥ 100,000/mm3, serum creatinine ≤ 2 mg/dl, total bilirubin ≤ 3, (with relief of biliary obstruction if present (PTC tube or endobiliary stent) and AST \< 5 times the upper limit of normal. * Patients of reproductive potential must agree to use an effective contraceptive method during participation in this trial and for 6 months after the trial. * Patients must be able to provide written informed consent. Exclusion Criteria: * Distant metastatic disease. * Prior history of abdominal radiation therapy. * Prior systemic therapy for pancreatic cancer. * Prior or simultaneous malignancy within the past 2 years (other than cutaneous squamous or basal cell carcinoma, melanoma in situ, thyroid carcinoma, or low-risk prostate cancer). In-situ carcinoma is allowed. * Serious uncontrolled concomitant systemic disorders or psychiatric condition that would interfere with the safe delivery of protocol therapy. * Treatment with an investigational anti-cancer agent within 4 weeks prior to enrollment into the study. * Pregnant women, women planning to become pregnant and women that are nursing