1-year LRFS 89.4% 95%CI[85.0-92.5]) 2-year LRFS: 85.5% 95%CI[80.4-89.3])

1. Survival after resection plus intra-operative ablation to treat colorectal liver metastases (CLM): results of an international collaborative study Serge Evrard1, Abou Diallo2, Peter Kissmeyer-Nielsen, Graeme Poston, Grégoire Desolneux1, Véronique Brouste2, Caroline Lalet2, Simone Mathoulin-Pélissier2, Frank V. Mortensen, Stefan Staettner, Ioannis Konstantidinis, Ronald DeMatteo, Michael D’Angelica, Peter Allen, William Jarnagin, Yuman Fong 1Digestive Oncology Unit, Institut Bergonié, Comprehensive Cancer Centre, Bordeaux, France; 2Clinical and Epidemiological Research Unit, Institut Bergonié, Comprehensive Cancer Centre, Bordeaux, France; 3Aarhus University Hospital, Aarhus, Denmark; 4Aintree University Hospitals, Liverpool, United Kingdom; 5Memorial Sloan-Kettering Cancer Center, New York, USA INTRODUCTION METHODS OBJECTIVES Adding intraoperative ablation to parenchymal resection to treat colorectal liver metastases (CLM) is gaining increasing acceptance in specialized HPB teams treating complex, bilobar disease. • To evaluate overall (OS), local recurrence-free (LRFS), hepatic recurrence-free (HRFS) and progression-free (PFS) survivals over three years in a multicenter study • To identify factors associated with survivals • To report complications (Clavien & Dindo) • Retrospective analyses • Adult patients with hepatic metastases from a primary colorectal cancer, • Treated between January 2001 and December 2011 with resection and intraoperative ablation by radiofrequency and/or microwaves. • Patients included from four international centers • Four survivals estimated: • Overall survival (all causes death in first 3 years) • Local-recurrence-free survival (recurrence on ablated lesion) • Hepatic recurrence-free survival (recurrence on ablated hepatic lesion or healthy liver) • Progression-free survival (all recurrences) RESULTS PATIENTS COMPLICATIONS OS LRFS HRFS PFS • 288 patients included • 62.5% male, median age 61 years • Mean size of the largest ablated lesion per patient was 15 mm (SD: 8.8), mean size of the smallest ablated lesion was 11 mm (SD: 6.8). • Median follow-up 3.17 years [95%CI(2.83-4.08)]. • 100 complications occurred • 11 Grade IV • 3 Grade V (gastrointestinal bleeding and septic shock; liver failure; and death otherwise unspecified) Median HRFS 14 months (95%CI[11-18])   Median OS 3.33y [(95%CI(3.08-4.17)] 1-year LRFS 89.4% 95%CI[85.0-92.5]) 2-year LRFS: 85.5% 95%CI[80.4-89.3]) 3-year LRFS: 81.2% 95%CI[74.9-86.1]) Median PFS 9 months (95%CI 8-11) • Factors associated with lower OS: • occurrence of complications (HR 1.93, 95%CI 1.27-2.92, p=0.002) • Factors associated with lower LRFS: • lesions ≥3 cm (HR 5.58, 95%CI 1.14-27.22, p=0.03) • Factors associated with lower HRFS: • bilateral liver metastases (HR 2.10, 95%CI[1.12-3.89], p=0.019) • presence of complications (HR 1.396, 95%CI[1.03-1.90], p=0.035) • ≥ 2 metastases treated by RFA (HR 1.435, 95%CI[1.03-2.00], p=0.033) • Factors associated with lower PFS: • synchronous liver metastases (HR 1.57, 95%CI[1.12-2.19], p=0.008) • presence of complications (HR 1.399, 95%CI[1.05-1.86], p=0.022) • pre-operative targeted therapy (HR 1.409, 95%CI[1.05-1.88], p=0.021)   • In this difficult-to-treat group, survival results were good and comparable with rates reported after resection only. • Complications are in majority minor. • IRFA complements resection, enabling to treat more patients, and offers the advantage of sparing healthy parenchyma. CONCLUSIONS