High or Standard Intensity Radiation Therapy After Gemcitabine Hydrochloride and Nab-paclitaxel in Treating Patients With Pancreatic Cancer That Cannot Be Removed by Surgery

Inclusion Criteria

• •1. Histologically or cytologically proven diagnosis of adenocarcinoma of the pancreas prior to registration
• •2. Tumor diameter ≤ 7 cm
• •3. Unresectable by radiographic criteria (pancreas protocol CT or MRI) or exploration within 30 days prior to registration.
• •4. A cell block or core biopsy must be submitted for central review and analysis of SMAD4 status as soon as possible following step 1 registration.
• •5. No distant metastases, based upon the following minimum diagnostic workup:
• •* History/physical examination within 30 days prior to registration
• •* Whole body fluorodeoxyglucose-positron emission tomography/computerized tomography (FDG-PET/CT) within 30 days prior to registration NOTE: If whole-body FDG-PET/CT is not performed, CT of the chest and CT (or MRI) of abdomen and pelvis must be obtained (imaging of abdomen and pelvis need not be repeated if already included in pancreas protocol study)
• •6. Zubrod Performance Status 0-1 within 30 days prior to registration
• •7. Age ≥ 18;
• •8. Complete blood count (CBC)/differential obtained within 14 days prior to step 1 registration, with adequate bone marrow function defined as follows:
• •* Absolute neutrophil count (ANC) ≥ 1,500 cells/mm3
• •* Platelets ≥ 100,000 cells/mm3
• •* Hemoglobin ≥ 8.0 g/dl (NOTE: The use of transfusion or other intervention to achieve Hgb ≥ 8.0 g/dl is acceptable)
• •9. Additional laboratory studies within 14 days prior to registration:
• •* carbohydrate antigen 19-9 (CA19-9); NOTE: in the event that a stent has been placed and biliary obstruction has been relieved, the CA19-9 should be drawn post stent placement
• •* Creatinine \< 2 mg/dl; Glomerular filtration rate (GFR) \> 50 mL/min (Cockroft and Gault formula)
• •* Bilirubin \< 1.5 x ULN
• •* Alanine aminotransferase (ALT) and aminotransferase (AST) ≤ 2.5 x ULN
• •* Activated partial thromboplastin time (aPTT), prothrombin time (PT) ≤1.2 x upper limit of normal (ULN)
• •10. Patient must provide study specific informed consent prior to study entry
• •11. Women of childbearing potential and male participants must practice adequate contraception during protocol treatment and for at least 6 months following treatment
• •12. For females of child-bearing potential, negative serum pregnancy test within 30 days prior to registration