Adjuvant FOLFIRI Based-chemotherapy After Resection of CLM Responding to Preoperative FOLFIRI

Inclusion Criteria: * Histologically proven resected metachronous CLM with curative intent that could not be treated with perioperative oxaliplatin-based chemotherapy for oncologic or tolerability reasons. For this study, metachronous CLM is defined as liver recurrence occurring more than 12 months after treatment of the primary colorectal cancer. * No more than 10 treated CLM at surgery * At least 2 cycles and no more than 8 cycles of preoperative FOLFIRI based chemotherapy ± targeted therapy. * Preoperative FOLFIRI based chemotherapy ± targeted therapy administered no more than 12 weeks before surgery * R0/R1resection ± radiofrequency ablation with curative intent of all liver deposits with no macroscopic residual liver disease * Objective response to preoperative therapy defined as complete or partial radiological response and/or major or complete pathologic response * No extrahepatic or residual liver disease on baseline work-up including thoraco-abdominal CT scan within 6 weeks after surgery. 1 non-specific lung nodule of less than 10 mm in maximum diameter is not considered as extra-hepatic metastases * Primary tumor (or liver metastasis) of CRC must be characterized for RAS and BRAF status * No contraindication to FOLFIRI based chemotherapy * Patients must be 18 years old or older * A WHO performance status of 0 or 1 * Participants must be affiliated to a social security scheme Exclusion Criteria: * Palliative/R2 resection of CLM * 10 lesions or more treated at the time of surgery * Patients undergoing only radiofrequency ablation of all liver deposit (this situation precludes the assessment of pathologic response to preoperative chemotherapy) * Extra-hepatic or residual metastasis of CRC * Absence of objective response to therapy (radiological or pathological response ) * Inflammatory bowel disease * Known UGT1A1\*28 allele homozygosity * complete absence of dihydropyrimidine dehydrogenase (DPD) activity (blood uracil level ≥ 150 ng/ml * Contraindications to investigational medicinal products (irinotecan, 5-FU, folinic acid) and to auxiliary medicinal products (ondansetron, methylprednisolone) * Persistent toxicity ≥ grade 1 related to preoperative FOLFIRI based chemotherapy * Known pregnancy (pregnancy test for women of childbearing) or breastfeeding women