This is a Phase II open study, not randomized with a neoadjuvant therapy,combination of Gemcitabine (1,000 mg/m2/week) with Erlotinib (100mg/day) (3 cycles of 4 weeks), followed by gemcitabine (300 mg/m2/week) combined with Erlotinib (100mg/day) and radiotherapy (45 Gy / day fr180 cGy) (5 cycles of 1 week) in patients with resectable pancreatic adenocarcinoma to assess the percentage of R0 resections. They have planned a total of 21 visits.

Inclusion Criteria:

• Able to sign the inform consent form
• Age between 18-75 years
• Subject has not undergone any chemotherapy or radiotherapy previously
• Functional status o-1 (ECOG scale)
• Satisfy all radiological inclusion criteria (MSCT performed 28 days before the treatment starts and a centralized evaluation)
• Patients with a cytologically confirmed diagnosis of pancreatic adenocarcinoma(preferably by EUS)
• Appropriate analytical as inclusion criteria (7 days before the treatment starts):
• bone marrow status: neutrophils ≥ 1,500x10^9/L; platelets ≥ 100x10^9/L; hemoglobin ≥ 9g/dL.
• INR ≤ 1.5 and PTT ≤ 1.5 x upper range of normal.
• Bilirubin ≤ 5 mg/dL
• Albumin> 34 g/L
• Renal function: creatinine ≤ 1.5 mg/dL and creatinine clearance> 50ml/min

Exclusion Criteria:

• patients treated with any of the study's drugs
• patients who has develop other primary tumors in 5 years prior to the inclusion at the clinical trial, except for cervix carcinoma in situ or basal cell skin cancer which have been treated properly.
• significant clinical cardiovascular disease: stroke (≤ 6 months before the study inclusion), heart attack (≤ 6 months before inclusion), unstable ango pectoris, congestive heart failure second grade or higher of the New York Heart Association (NYHA) or serious cardiac arrhythmia requiring medication, uncontrolled hypertension
• Total o partial bowel obstruction
• Chronic diarrhea
• Current treatment with another investigational drug or participation in another clinical trial within 30 days prior to inclusion.
• Known hypersensitivity to any of the study drugs or their components
• Currently o recent therapeutic treatment (opposite to prophylactic) with oral or parenteral anticoagulants (full dose) or thrombolytic agents. Patients who receive (or are candidates to receive) anticoagulants for prophylaxis of cardiovascular risk, should continue (or begin) treatment at baseline
• Thromboembolic event history or bleeding in the 6 months prior to treatment.
• Evidence of bleeding diathesis or coagulopathy.
• Serious problems in wounds healing, ulcers or bone fractures.
• Major surgery, open biopsy or significant traumatic injury 28 days before treatment.
• Any other disease, metabolic disorder, physical examination findings or clinical laboratory that provides reasonable evidence for suspecting a disease or condition for which it is contraindicated or patient an experimental drug at high risk of experiencing complications related to treatment .
• Patients undergoing with organ allografts requiring immunosuppressive treatment.
• Pregnant or breastfeeding woman. It requires a negative pregnancy test (serum or urine) within 7 days before previous to treatment.
• Men and women of childbearing potential (including women who have had their last menstrual period in less than 2 years) not using effective contraception precautions
• Positive HIV status
• Addiction to alcohol or other drugs
• Known liver cirrhosis