Study of Stereotactic Body Radiation Therapy for Patients After Radical Resection of Pancreatic Cancer With Advanced Stages (T3 or N1)

Inclusion Criteria:

1. Male/Female subjects, age ≥ 18 years and ≤ 75 years old at the time informed consent is signed
2. Pathologically confirmed pancreatic adenocarcinoma or mixed-type pancreatic carcinoma (adenocarcinoma predominantly)
3. The operation must be radical resection (R0), with all margins negative.
4. Eastern Cooperative Oncology Group (ECOG) score: 0-2
5. Without large volume ascites or pleural effusion

6. Lab tests:

   a Complete blood cell count: HGB≥100g/L, WBC≥4×109/L, PLT≥100×109/L b Liver function: Total bilirubin≤3 x upper limit of normal range (ULN) with direct bilirubin within normal range, alanine aminotransferase (ALT) / aspartate aminotransferase (AST)≤3 c Renal function: Creatine≤1.5 x ULN or creatine clearance≥60 ml/min

7. Heart and lung function well (Eject function>55%)
8. Females of child-bearing potential must demonstrate a negative serum pregnancy test result at screening confirmed by local negative urine pregnancy dipstick within 72 hours prior to the first dose of Gemcitabine.
9. At least 30 days from major surgery before randomization, with full recovery
10. Understand and voluntarily sign an informed consent document prior to any study related assessments/procedures are conducted
11. Able to adhere to the study visit schedule and other protocol requirements

Exclusion Criteria:

1. Margin positive resections (R1 or R2)
2. Resection of recurrence pancreatic cancer
3. Other types of pancreatic cancer (non-adenocarcinoma)
4. Subjects with severe complications, can't tolerate chemotherapy in 4-12 weeks after surgery
5. Subjects with severe bone marrow suppression
6. Subjects with a history of severe lung diseases (interstitial lung disease, sarcoidosis, silicosis, idiopathic pulmonary fibrosis, pulmonary hypersensitivity pneumonitis), severe liver diseases (active hepatitis, liver cirrhosis), renal dysfunction, uncontrolled diabetes and hypertension, or multiple and severe allergies which may lead to serious complications
7. Subjects with severe heart diseases (congested heart failure, systematic coronary disease, uncontrolled arrhythmia, or myocardial infarction in 6 months)
8. Under treatment with steroids for a long time
9. Subjects with early recurrence of pancreatic cancer before initiation of chemotherapy
10. Subjects with diarrhea and infection (body temperature >38.5℃)
11. Subjects who was enrolled into another clinical study or finished another clinical study within the previous 4 weeks prior to randomization
12. Pregnant or nursing women
13. Subjects with other type of malignancies, except of curated basal cell carcinoma and carcinoma in situ of cervix which finished treatments more than half one year ago
14. Subjects having any significant medical condition, laboratory abnormality, or psychiatric illness that would prevent them from participating in the study
15. Any condition that confounds interpreting data from the study