Testing Higher Dose Radiation Therapy for Locally Advanced Pancreatic Cancer

Inclusion Criteria: * At time of enrollment, the patient must have received 4-6 months of active chemotherapy with FOLFIRINOX or NALIRIFOX or gemcitabine/nab-paclitaxel. Patients are permitted to receive more than 1 type of chemotherapy for toxicity reasons, but not for disease progression. "Active chemotherapy" refers to time on chemotherapy not counting treatment breaks (i.e. if a patient had 1 month of chemotherapy followed by 1 month break, this would count as 1 month chemotherapy). Study registration must occur within 45 days of last day of chemotherapy cycle * BASELINE PRE-ENTRY CHEMOTHERAPY REQUIREMENTS: * Pathologically (histologically or cytologically) proven diagnosis of pancreatic ductal adenocarcinoma * Locally advanced unresectable disease (as defined per the National Comprehensive Cancer Network \[NCCN\] guidelines and institutional tumor board review) * Patients must have baseline pre-chemotherapy scans for staging. Options include: CT chest/abdomen/pelvis, CT chest/MRI abdomen/pelvis, CT chest/CT pelvis/MRI abdomen, or PET/CT performed prior to enrollment * Age ≥ 18 years * Performance status Eastern Cooperative Oncology Group (ECOG) 0-2 * Required initial laboratory values: All laboratory values must be obtained any time prior to initiation of chemotherapy up to 30 days post initiation of chemotherapy * Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 x upper limit of normal (ULN) * BASELINE CA19-9 AND BILIRUBIN REQUIREMENTS: The pur…