Adjuvant Gemcitabine Versus Gemcitabine With Chemoradiation in Pancreatic Adenocarcinoma With R1 Resection and/or Positive Lymph Nodes

Inclusion Criteria: * Histologically confirmed resected ductal pancreatic adenocarcinoma with R1 resection and/or positive lymph nodes. * Subject should start treatment no later than 10 weeks postsurgery. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Acceptable hematology parameters: * Absolute neutrophil count ≥1500 cell/mm3 * Platelet count ≥100,000/mm3 * Hemoglobin (Hgb) ≥8.0 g/dL * Acceptable blood chemistry levels: * Aspartate aminotransferase (AST) and Alanine transaminase (ALT) ≤2.5 × upper limit of normal range (ULN) * Total bilirubin ≤ 2.5 x upper Limit of Normal (ULN) * Serum creatinine within upper limits of normal. * Cancer antigen (CA)19-9 ≤ 2.5 x upper Limit of Normal (ULN) assessed within 14 days of randomization. * No disease recurrence or metastases detected on CT/MRI assessed within 30 days of randomization. * Signed informed consent. Exclusion Criteria: * R2 resection or presence of metastatic disease. * Prior neo-adjuvant treatment or radiation therapy for pancreatic adenocarcinoma. * Any other malignancy within 5 years prior to randomization, with the exception of adequately treated in-situ carcinoma of the cervix, uteri, bladder, or nonmelanomatous skin cancer. * Active, uncontrolled infection(s) requiring systemic therapy, defined as ongoing signs/symptoms related to the infection without improvement despite appropriate treatment. * Severe, active co-morbidity, defined as follows: * Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months * Transmural myocardial infarction within the 6 months of study registration * Uncontrolled hypertension, diabetes or arrhythmia. * Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization. * Not able to take medicine orally.