Stereotactic Radiotherapy in Locally Advanced Pancreatic Cancer With Different Biological Effective Doses

Inclusion Criteria:

* Cytologically or histologically verified pancreatic adenocarcinoma
* Imaging examinations confirmed locally advanced pancreatic cancer
* No previous radiotherapy, chemotherapy, immunotherapy or targeted therapy
* ECOG of 0 to1
* Age of 18 years or older
* Adequate bone marrow function, defined as: Absolute neutrophil count (ANC) ≥ 1.5×10\^9 cells/L, leukocyte count≥ 3.5×10\^9 cells/L, platelets ≥ 70×10\^9 cells/L, hemoglobin ≥ 8.0 g/dl
* Adequate liver and renal, defined as: Albumin \> 2.5 g/dL, total bilirubin \< 3 mg/dL, creatinine \< 2.0 mg/dL, AST\<2.5 × ULN (Upper Limit of Normal) (0-64U/L), ALT\<2.5 × ULN (0-64U/L)
* Adequate blood clotting function, defined as: international normalized ratio (INR) \< 2 (0.9-1.1)
* Ability of the research subject or authorized legal representative to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

* Previously receiving radiotherapy, immunotherapy or targeted therapy
* Evidences of metastatic disease confirmed by chest CT or PET-CT
* ECOG ≥2
* Age \<18 years
* Secondary malignancy
* Abnormal results of blood routine examinations and liver and kidney and coagulation tests
* Patients with active inflammatory bowel diseases or peptic ulcer
* Gastrointestinal bleeding or perforation within 6 months
* Uncontrolled infection requiring IV antibiotics, antivirals, or antifungals
* Medical history of symptomatic congestive heart failure: New York Heart Association Class III to IV
* Medical history of respiratory insufficiency
* Women who are pregnant or breastfeeding
* Participation in another clinical treatment trial
* Inability of the research subject or authorized legal representative to understand and the willingness to sign a written informed consent document