Introduction : Multiple colorectal liver metastases (CRLM) with bilateral intrahepatic main vascular contacts are generally considered unresectable or at least amenable to staged procedures in selected cases. We present perioperative and long term results of our series of patients with bilateral contacts with hepatic veins at the hepatocaval confluence (ZoneH) or with 1?and 2?order of portal branch (ZoneP) treated in a single step: the one stage hepatectomy (OSH).

Methods : 597 consecutive patients undergoing liver resection for CRLM between June 2002 and January 2017 were reviewed. Seventy-nine patients carrier of multiple (≥4) CRLM with bilateral ZoneH and ZoneP contact submitted to OSH were analyzed.

Results : 16 (20%) patients received new devised surgical intervention (SERPS, transversal hepatectomy, mini-mesohepatectomies, liver tunnels). Twelve(15%) patients received vascular reconstruction. Seven(9%) patients underwent major hepatectomy associated with limited resection. Sixty patients had at least one lesion detached from a ZoneH and ZoneP. Sixty-two patients(78%) had a thoraco-phenolaparotomy incision. Seven patients (9%) had an associated colon resection. Median number of resected CRLMs was 10(4-48), 28(35%) patients had >10 nodules. Eight(10%) patients were R0, 14(18%) R1 vascular , 57(72%) R1parenchimal. Mortality and morbidity rates were 3,8% and 33%. Five-year survival was 22% (median overall survival 30 months). Overall recurrence rate was 84%(63 patients), 22 patients have liver only recurrence, 5 have extrahepatic only disease, 35 have combined intrahepatic and extrahepatic recurrence. Re hepatectomy was performed in 77 %(17/22 patients) of patients with liver only recurrence. Cut surface recurrence occurred in 14 patients(18%).

Conclusions : OSH is a valuable alternative to staged procedures.