Capecitabine, Bevacizumab, and Radiation Therapy Followed By Gemcitabine and Bevacizumab in Treating Patients With Locally Advanced Pancreatic Cancer That Cannot Be Removed By Surgery

Inclusion Criteria:

* Histologically confirmed adenocarcinoma of the pancreas

  * Locally advanced disease
  * Unresectable disease
* All malignant disease must be encompassable within a single irradiation field
* Radiographically assessable disease
* Patients with biliary or gastroduodenal obstruction are eligible provided drainage or surgical bypass was performed prior to initiation of study treatment
* No evidence of gastric outlet obstruction
* No evidence of duodenal invasion on CT scan
* No evidence of metastatic disease in the major viscera
* No peritoneal seeding or ascites
* Performance status - Zubrod 0-1
* Granulocyte count ≥ 1,500/mm\^3
* Platelet count ≥ 100,000/mm\^3
* No evidence of bleeding diathesis
* ALT \< 3 times upper limit of normal
* Bilirubin \< 2.0 mg/dL
* INR ≤ 1.5
* No evidence of coagulopathy
* Creatinine clearance \> 50 mL/min
* Urine protein \< 1,000 mg by 24-hour urine collection (for patients with proteinuria ≥ 1+ by dipstick or urinalysis OR urine protein:creatinine ratio ≥ 1.0)
* No myocardial infarction within the past 6 months
* No unstable angina within the past 6 months
* No arterial thromboembolic events within the past 6 months, including any of the following:

  * Transient ischemic attack
  * Cerebrovascular accident
  * Clinically significant peripheral artery disease
* No unstable symptomatic arrhythmia requiring medication (e.g., chronic atrial arrhythmia \[i.e., atrial fibrillation or paroxysmal supraventricular tachycardia\])

  * Patients with an atrial arrhythmia are eligible provided the condition is well controlled on stable medication
* No New York Heart Association class II-IV congestive heart failure
* No history of arteriovenous malformation
* No history of aneurysm
* No uncontrolled hypertension (i.e., blood pressure \> 160/90 mm Hg with medication)
* No other clinically significant cardiac disease
* No AIDS
* No significant infection
* No known hypersensitivity to Chinese hamster ovary cell products or other recombinant human antibodies
* Not pregnant
* No nursing during and for ≥ 3-4 months after completion of study treatment
* Negative pregnancy test
* Fertile patients must use effective contraception during and for ≥ 3-4 months after completion of study treatment
* No history of gastrointestinal fistula or perforation
* No other malignancy within the past two years except nonmelanoma skin cancer or carcinoma in situ of the cervix, uterus, or bladder
* No significant traumatic injury within the past 4 weeks
* No serious nonhealing wound or ulcer
* No current healing fracture
* No known or suspected dihydropyrimidine dehydrogenase deficiency
* No other medical condition that would preclude study participation
* No concurrent interleukin-11
* No prior chemotherapy for pancreatic cancer
* More than 2 years since prior chemotherapy for another malignancy
* No prior radiotherapy to the planned irradiation field
* No concurrent intensity modulated radiotherapy
* No other concurrent radiotherapy
* See Disease Characteristics
* More than 4 weeks since prior major surgical procedure or open biopsy
* More than 1 week since prior fine needle aspiration or core biopsy
* No prior organ transplantation
* No concurrent major surgical procedure
* More than 30 days since prior and no concurrent cimetidine

  * Concurrent ranitidine or a drug from another anti-ulcer class allowed
* More than 4 weeks since prior and no concurrent sorivudine or brivudine
* No concurrent warfarin during chemoradiotherapy

  * Concurrent warfarin allowed beginning 2 weeks after completion of chemoradiotherapy
  * Concurrent low molecular weight heparin allowed (at any time during study participation)
* No other concurrent investigational agents
* No other concurrent cytotoxic agents