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.