Introduction : Synchronous open liver resection of colorectal cancer liver metastasis has demonstrated safety, efficacy and feasibility in several studies. Nevertheless, still oncologic safety and perioperative outcome of synchronous minimally invasive liver resection in colorectal cancer liver metastasis remain unclear.

Methods : From January 2006 to June 2017, we reviewed synchronous liver resection in colorectal cancer liver metastasis patients in Severance hospital. We exclude hybrid resection. Eventually, 391 patients were investigated.

Results : Total 66 patients underwent pure minimally invasive approach for liver resection and primary cancer operation. On the other hand, 325 patients was performed open liver resection. Between two group, length of stay(LOS, 14.7 days vs 9.7 days) and imaging liver metastasis lesion numbers( 3.9 vs 1.5) and final pathologic liver metastasis number (3.8 vs 1.4), tumor size (2.8 cm vs 1.9 cm) were statistically higher in open group. In survival analysis, minimally approach for liver resection group was more favorable than open resection group in overall survival (mean 87.9 months vs 110.9 months, p=0.011) and disease free survival( mean 40.6 months vs 59.3 months.p= 0.033). After propensity score matching, LOS of still longer in open resection group in statistically significance. In survival analysis, there were no differences between two groups.

Conclusions : Syncrhonous minimally invasive liver resection for colorectal cancer liver metastasis is safe and fesasible with benefit of short LOS. In terms of oncologic outcome, minimally invasive liver resection was not inferior to open liver resection. In selected patients, minimally invasive approach for liver metastasis resection synchronously should be considered.