Efficacy and Tolerance Evaluation in FOLFIRINOX Dose Adjusted in Elderly Patients With a Metastatic Pancreatic Cancer

METHODOLOGY : Phase II study, opened, multicentric MAIN OBJECTIVE : The main objective is the simultaneous evaluation of the objective rate of answer and toxicity of her(it) of the protocol FOLFIRINOX administered to doses adapted at patients of 70 and more years old. SECONDARY OBJECTIVE : * Efficiency evaluation; * Tolerance evaluation; * Quality of Life (QoL) and clinical profit. STATISTICAL ANALYSIS: An analysis in two stages is planned, according to the method of Bryant and Day with a risk ß 5 % to reject wrongly an effective treatment and of acceptable toxicity and a risk a=10 % to accept wrongly a not rather effective or too toxic treatment. The study will be considered as successful if: * we obtain at least 11 tumoral answers and * maxi 30 patients on 72 are in loss of autonomy (decrease of their ADL). * All the patients who will have received at least an injection will be eligible for the evaluation of the toxicity * The evaluation of the efficiency will be made after 3 cures at least unless early termination where the scanner will be anticipated. * All the toxicity will be increased according to criteria of toxicity NCI-CTC v4.0. * The evaluation of the tumoral answer (CR, PR and SD) will be made according to the criteria RECIST-v1.1.