Long-term outcomes of patients with 10 or more colorectal liver metastases.

Background: Although the number of colorectal liver metastases (CLM) is decreasingly considered as a contraindication to surgery, patients with 10 CLM or more are often denied liver surgery. This study aimed to evaluate the outcome after liver surgery and to identify prognostic factors of survival in such patients.

Methods: The study population consisted of a multicentre cohort of patients with CLM (N=12 406) operated on, with intention to resect, from January 2005-June 2013 and whose data were prospectively collected in the LiverMetSurvey registry.

Results: Overall, the group ⩾10 CLM (N=529, 4.3%) experienced a 5-year overall survival (OS) of 30%. A macroscopically complete (R0/R1) resection (72.8% of patients) was associated with a 3- and 5-year OS of 61% and 39% vs 29% and 5% for R2/no resection patients (P<0.0001). At multivariate analysis, R0/R1 resection emerged as the strongest favourable factor of OS (HR 0.35 (0.26-0.48)). Other independent favourable factors were as follows: maximal tumour size <40 mm (HR 0.67 (0.49-0.92)); age <60 years (HR 0.66 (0.50-0.88)); preoperative MRI (HR 0.65 (0.47-0.89)); and adjuvant chemotherapy (HR 0.73 (0.55-0.98)). The model showed that 5-year OS rates of 30% was possible provided R0/R1 resection associated with at least an additional favourable factor.

Conclusions: Liver resection might provide long-term survival in patients with ⩾10 CLM staged with preoperative MRI, provided R0/R1 resection followed by adjuvant therapy. A validation of these results in another cohort is needed.