SBRT for Close or Positive Margins After Resection of Pancreatic Adenocarcinoma

Inclusion Criteria:

* Histologically or cytologically proven adenocarcinoma of the pancreas that has been resected with a close (\<2.5mm) or positive margin based on surgical and pathological findings.
* Subjects will be staged according to the 2010 AJCC staging system (Appendix E) with pathologic stage T1-4, N0-1 being eligible; and have a primary tumor of the pancreas (i.e., pancreatic head, neck, uncinate process, body/tail
* PTV must be encompassed in a reasonable SBRT "portal" as defined by the treating radiation oncologist
* Karnofsky performance status \> 70 (ECOG 0-1)
* Age \> 18
* Estimated life expectancy \> 12 weeks
* Patient must have adequate renal function as defined by serum creatinine\<1.5mg/dl obtained within 28 days prior to registration
* Patient must have adequate hepatic function as defined by total bilirubin \<1.5 xIULN(institutional upper limit of normal) and either SGOT or SGPT \<2.5xIULN, obtained within 28 days prior to registration.
* Patient must be able to swallow enteral medications. Patient must not require a feeding tube. Patient must not have intractable nausea or vomiting, GI tract disease resulting in an inability to take oral medication, malabsorption syndrome, or uncontrolled inflammatory bowel disease (Chron's, ulcerative colitis).
* Ability to provide written informed consent
* Patient must not have uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, history of myocardial infarction or cerebrovascular accident within 3 months prior to registration, uncontrolled diarrhea, or psychiatric illness/social situations that would limit compliance with study requirements.
* Patient must not be pregnant because of the risk of harm to the fetus. Nursing women may participate only if nursing is discontinued, due to the possibility of harm to nursing infants from the treatment regimen. Women/men of reproductive potential must agree to use an effective contraception method.

Exclusion Criteria:

* Non-adenocarcinomas, adenosquamous carcinomas, islet cell carcinomas, cystadenomas, cystadenocarcinomas, carcinoid tumors, duodenal carcinomas, distal bile duct, and ampullary carcinomas are not eligible.
* Evidence of distant metastasis on upright chest x-ray (CXR), computed tomography (CT) or other staging studies
* Subjects with recurrent disease
* Prior radiation therapy to the upper abdomen or liver
* Prior chemotherapy
* Subjects in their reproductive age group should use an effective method of birth control. Subjects who are breast-feeding, or have a positive pregnancy test will be excluded from the study
* Any co-morbidity or condition of sufficient severity to limit full compliance with the protocol per assessment by the investigator
* Concurrent serious infection
* Previous or current malignancies of other histologies within the last 5 years, with the exception of cervical carcinoma in situ, adequately treated basal cell or squamous cell carcinoma of the skin, and treated low-risk prostate cancer.