In this randomized phase II/III trial, we aim to test an exclusive concomitant chemoradiotherapy for patients with non resectable esophageal cancer with a dose escalation up to 66Gy on the primary tumor as well as the involved nodes using a 3D conformal technique combined with a 40 Gy elective nodal irradiation on lymph node stations (as defined by the RTOG) with a risk of microscopic involvement ≥ 20%.