BACKGROUND: Combined intra-operative ablation and resection (CARe) is proposed to treat extensive colorectal liver metastases (CLM). This multicenter study was conducted to evaluate overall survival (OS), local recurrence-free survival (LRFS), hepatic recurrence-free survival (HRFS) and progression-free survival (PFS), to identify factors associated with survival, and to report complications.MATERIALS AND METHODS: Four centers combined retropectively their clinical experiences regarding CLM treated by CARe. CLM characteristics, pre- and post-operative chemotherapy regimens, surgical procedures, complications and survivals were analyzed.RESULTS: Of the 288 patients who received CARe, 210 (73%) had synchronous and 255 (88%) had bilateral CLM. Twenty-two patients (8%) had extrahepatic disease. Median follow-up was 3.17 years (95%CI 2.83-4.08). Median OS was 3.33 years (95%CI 3.08-4.17) and 5-year OS was 37% (95%CI 29-45). One- and 5-year LRFS from ablated lesions were 87.9% (95%CI 83.3-91.2) and 78.0% (95%CI 71-83), respectively. Median HRFS and PFS were 14 months (95%CI 11-18) and 9 months (95%CI 8-11), respectively. One hundred patients experienced complications: 29 grade I, 68 grade II-III-IV, and three deaths. In the multivariate models adjusted for center, the occurrence of complications was confirmed as a major independent factor associated with 3-year OS (HR 1.80; P = 0.008). Five-year OS was 25.6% (95%CI 14.9-37.6) for patients with complications and 45% (95%CI 33.3-53.4) for patients without.CONCLUSIONS: Recent strategies facing advanced CLM include non-anatomic resections, portal-induced hypertrophy of the future remnant liver and aggressive medical preoperative treatments. CARe has the qualities of an approach that allows effective tumor clearance while maintaining good tolerance for the patient.