Clinical Phase II Clinical Study Evaluating the Toxicity and Efficacy of mFOLFIRINOX Associated With SBRT (Stereotactic Radiotherapy) in Patients With Unresectable Locally Advanced Pancreatic Cancer

Primary goal: Improvement of the therapeutic index by reducing the toxicity of treatment and increasing local control of the cancer process while evaluating the possibility of conversion to the surgical status. Secondary targets: * Survival rate (OS) assessment in patients treated with mFOLFIRINOX + SBRT * Assessment of quality of life using questionnaires: EQ-5D, EORTC (QLQ-C30) and pancreatic cancer-specific QLQ PAS module 26 * Early toxicity \<3 months after completion of SBRT treatment. * Percentage of local control (1-year)