In some cases, curative liver resection can be contraindicated because lesions are bilobar, and the extent of the planned liver resection is too large that could induce postoperative liver failure. Treatment of the lesions located in the future liver remnant can be achieved using tools for local destruction. Cryotherapy of liver metastases has been firstly used in this indication [20], but in situ recurrence rate was elevated. To date, radiofrequency ablation (RFA) is preferred [21].

RFA can be performed either percutaneously or intraoperatively. Different types of needle electrode can be used to treat liver metastases. The area of necrosis induced by RFA should be larger than the size of the tumor, by 1 cm, similar to the surgical margin obtained after surgical resection. Tumors of less than 3 cm located in the future remnant liver are currently the better indication of RFA. Indeed, in case tumor of 3 cm or more, oncologic results remain uncertain with the increased risk of in situ local recurrence [22].

If the future remnant liver after liver resection is too small to provide sufficient postoperative liver function, preoperative selective portal vein embolization has been proposed to induce ipsilateral atrophy and contralateral hypertrophy of the future remnant liver, thus preventing postoperative liver failure [23]. Following embolization, a liver resection judged primarily impossible, due to insufficient volume of remnant liver, is feasible in 60 % of cases, with mortality and morbidity rates comparable to those observed following liver resections without embolization. In case of bilobar lesions, induced liver regeneration or hypertrophy can be associated with an accelerated increase in the size of metastases located in the non-embolized liver [24]. Whether preoperative chemotherapy should be stopped after the embolization to avoid to decrease the hypertrophy of the liver or continued to control the disease during the time interval between the embolization and the hepatectomy is still debated [25–27].

Multiple bilobar liver metastases are often considered as unresectable. In selected cases, bilobar liver metastases can be resected in two stages. The first stage includes the resection or local destruction of lesions located in the future remnant liver which is in most cases the left liver. The second hepatectomy is generally a right or an extended right hepatectomy. During the first procedure, a right portal vein ligation can be performed if the volume of the left lobe is judged to be insufficient. Although this strategy can only be proposed in selected patients with unresectable liver metastases, oncologic outcome can be close to those observed in patients’ resectable liver metastases [28].

Recurrence limited to the liver following previous hepatic resection occurs in 25–50 % of cases and may be amenable to repeat resection [29]. Postoperative mortality and morbidity do not differ from those reported after a first resection, and the mean survival approaches 2 years. Hepatic recurrences should therefore be resected whenever technically feasible.

In case of resectable liver metastases, preoperative chemotherapy can be administered to decrease the risk of recurrence, to test the chemosensitivity of the tumor, to guide the choice for postoperative treatment, and to facilitate the resection. One randomized trial [30] has recently showed that perioperative chemotherapy decreases the risk of recurrence after liver resection for resectable colorectal liver metastases (see Chap. 13).

In case of unresectable liver metastases, chemotherapy is initially the sole treatment that can be proposed. During the past decade, the introduction of new cytotoxic agents (camptothecin and oxaliplatin) and targeted therapies (bevacizumab and cetuximab) has led to increase the response rate and survival of patients with advanced colorectal cancer [31–36]. In patients with unresectable liver metastases, in case of tumor shrinkage during chemotherapy, curative liver resection may be considered. Several retrospective studies have showed that oncologic outcome of patients operated of initially unresectable liver metastases downstaged by chemotherapy may be good even in case of initial large hepatic involvement. Recurrence rate is close to 80 % and remains elevated in these patients, and 5-year survival rate can range from 25 to 35 % [20, 37, 38].

In most recent studies, in-hospital mortality rates vary from 0 to 5 % and are strongly influenced by intraoperative blood loss, preoperative liver function, and extent of liver resection [4]. Reversible postoperative complications are observed in 25–40 % of patients. Morbidity after hepatic resection is usually due to transient liver failure, hemorrhage, sub-phrenic abscesses, or biliary fistula. The mean hospital stay after liver surgery ranges from 10 to 15 days in the absence of complications.

Recent studies suggest that administration of preoperative chemotherapy could increase the risk of liver resection for colorectal liver metastases. Morbidity rate may be slightly increased in patients who have received a preoperative chemotherapy [14–16]. The impact of preoperative chemotherapy on postoperative mortality after liver resection is debated, and to date, only one study has reported that chemotherapy could increase the mortality after liver resection. In this study, the mortality rate was increased in patients who had lesions of chemotherapy associated steatohepatitis [15].

Liver resection of colorectal metastases is associated with 3- and 5-year survival rates close to 40 % and 30 %, respectively. After resection, recurrences are observed in two-thirds of patients and involve the liver in 50 % of cases.

Several studies have assessed factors influencing survival. Risk factors of recurrence have been identified using multivariate analysis on two large series of more than 1,000 patients [7–9]: age, size of the largest metastasis, elevated CEA level, stage of the primary tumor and lymph node involvement, disease-free interval <12 months, number of liver nodules, and involved surgical margin. However, these studies did not take into account the potential impact of associated treatment and in particular the administration of chemotherapy.

Response to chemotherapy is a very strong prognosis factor of survival in patients operated of colorectal liver metastases [39–42].