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Laparoscopic Versus Open Resection for Colorectal Liver Metastases: The OSLO-COMET Randomized Controlled Trial

Fretland Åsmund Avdem MD; Dagenborg, Vegar Johansen MD; Bjørnelv, Gudrun Maria Waaler MPhil; Kazaryan, Airazat M. MD, PhD; Kristiansen, Ronny; Fagerland, Morten Wang MSc, PhD; Hausken, John MD; Tønnessen, Tor Inge MD, PhD; Abildgaard, Andreas MD, PhD; Barkhatov, Leonid MD; Yaqub, Sheraz MD, PhD; Røsok, Bård I. MD, PhD; Bjørnbeth, Bjørn Atle MD, PhD; Andersen, Marit Helen RN, PhD; Flatmark, Kjersti MD, PhD; Aas, Eline MPhil, PhD; Edwin, Bjørn MD, PhD; on behalf of the Oslo-CoMet study group
doi: 10.1097/SLA.0000000000002353
Randomized Controlled Trial: PDF Only


To perform the first randomized controlled trial to compare laparoscopic and open liver resection.

Summary Background Data:

Laparoscopic liver resection is increasingly used for the surgical treatment of liver tumors. However, high-level evidence to conclude that laparoscopic liver resection is superior to open liver resection is lacking.


Explanatory, assessor-blinded, single center, randomized superiority trial recruiting patients from Oslo University Hospital, Oslo, Norway from February 2012 to January 2016. A total of 280 patients with resectable liver metastases from colorectal cancer were randomly assigned to undergo laparoscopic (n = 133) or open (n = 147) parenchyma-sparing liver resection. The primary outcome was postoperative complications within 30 days (Accordion grade 2 or higher). Secondary outcomes included cost-effectiveness, postoperative hospital stay, blood loss, operation time, and resection margins.


The postoperative complication rate was 19% in the laparoscopic-surgery group and 31% in the open-surgery group (12 percentage points difference [95% confidence interval 1.67–21.8; P = 0.021]). The postoperative hospital stay was shorter for laparoscopic surgery (53 vs 96 hours, P < 0.001), whereas there were no differences in blood loss, operation time, and resection margins. Mortality at 90 days did not differ significantly from the laparoscopic group (0 patients) to the open group (1 patient). In a 4-month perspective, the costs were equal, whereas patients in the laparoscopic-surgery group gained 0.011 quality-adjusted life years compared to patients in the open-surgery group (P = 0.001).


In patients undergoing parenchyma-sparing liver resection for colorectal metastases, laparoscopic surgery was associated with significantly less postoperative complications compared to open surgery. Laparoscopic resection was cost-effective compared to open resection with a 67% probability. The rate of free resection margins was the same in both groups. Our results support the continued implementation of laparoscopic liver resection.

Reprints: Åsmund Avdem Fretland, MD, The Intervention Center, Oslo University Hospital, Pb. 4950 Nydalen, 0424 Oslo, Norway. E-mail:

Vegar Johansen Dagenborg and Gudrun Maria Waaler Bjørnelv contributed equally to the work.

This work was supported by South-East Norway Health Authority, grants 201135 (Å.A.F.) and 201622 (G.M.W.B.), and the Research Council of Norway, grant 218325 (V.J.D.).

Collaborators: The following are members of the Oslo-Comet study group: Davit Aghayan, Michael Bretthauer, Trond Buanes, Tor Jacob Eide, Ole Jacob Elle, Erik Fosse, Ivar P. Gladhaug, Per Steinar Halvorsen, Per Kristian Hol, Anne Catrine Martinsen, Karl Øyri (Oslo University Hospital, Oslo, Norway and University of Oslo, Oslo, Norway), Jack Gunnar Andersen, Audun E. Berstad, Kristoffer W. Brudvik, Linda Engvik, Krzysztof Grzyb, Knut Hofseth, Knut Jørgen Labori, Vinod Kumar Mishra, Henrik M. Reims, Olaug Villanger, Anne Waage (Oslo University Hospital, Oslo, Norway), Yulia Panina (University of Oslo, Oslo, Norway), Kristoffer Lassen (Oslo University Hospital, Oslo, Norway and the Arctic University of Norway, Tromsø, Norway), and Gunnvald Kvarstein (the Arctic University of Norway, Tromsø, Norway).

The authors report no conflicts of interest.

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