Trial Evaluating Modified FOLFIRINOX and Modified FOLFOX in the Treatment of Locally Advanced or Metastatic Small Bowel Adenocarcinoma

Inclusion Criteria: * Histologically proven adenocarcinoma of the small intestine (duodenum, jejunum, ileum) * Metastatic or locally advanced unresectable tumour with curative intent * Patient who never received first-line chemotherapy * Measurable lesion according to RECIST 1.1 criteria * ECOG status \< or = 2 for patients under 70 years, or 0 or 1 for patients over 70 years * Life expectancy estimated at over 3 months * Patient over 18 years of age * Patient able to understand and sign the information and informed consent note * Women of childbearing age and men who have sex with women of childbearing age must agree to use contraception during the trial treatment and for at least 9 months after stopping the experimental treatments. Exclusion Criteria: * MSI/dMMR tumor * Adenocarcinoma of the ampulla of Vater * Neutrophils \< 1500/mm3, platelets \< 100 000/mm3 * Hemoglobin \< 9 g/dL, total bilirubin \> 1.5x normal, alkaline phosphatase \> 2.5x normal (or \>5x normal if liver metastases), creatinine clearance \> or = 40 ml/min. according to MDRD * Hypokalaemia, hypomagnesaemia and hypocalcaemia below normal, and for calcaemia, it must be corrected before enrolment. * Adjuvant chemotherapy completed less than 6 months ago * History of myocardial infarction within the last 6 months, severe coronary artery disease or severe heart failure * Severe renal failure * Peripheral sensory neuropathy with functional discomfort * Active and/or potentially severe infection or other uncontrolled conditions * Treatment with a cytochrome P450 inhibitor within 4 weeks prior to the administration of the protocol treatment (refer to paragraph 8.3 "Contraindicated treatments" of the protocol) * Patients currently undergoing treatment using St John's Wort * Treatment with brivudine within 4 weeks prior to the administration of protocol