Gemcitabine/Capecitabine Followed by SBRT in Pancreatic Adenocarcinoma

Inclusion Criteria:

* Histologically or cytologically proven adenocarcinoma of the pancreas
* Subjects will be staged according to the 2010 AJCC staging system 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
* Tumor must be deemed to be borderline resectable or locally advanced by radiographic criteria defined by Varadhachary et al.26 Final CT confirmation of surgical staging/eligibility will be by two expert pancreatic surgeons
* Disease confined to locoregional site confirmed by FDG-PET/CT or CT and diagnostic staging laparoscopy to ensure no occult peritoneal implants
* Disease must be encompassed in a reasonable SBRT "portal" as defined by the treating radiation oncologist
* Measurable disease on imaging studies (MRI, CT, FDG-PET/CT or physical exam), including maximum diameter/dimension, must be present for assessment of response
* 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 bone marrow function as defined by absolute neutrophil count\>1500/mcl and platelets\>100,000/mcl, obtained within 28 days prior to registration
* Patient must have adequate hepatic function as defined by total bilirubin \<1.5 x IULN(institutional upper limit of normal) and either SGOT or SGPT \<2.5x IULN, 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).
* Diabetes must be controlled prior to FDG-PET/CT scanning (blood glucose \<200 mg/dL)
* 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.