R1vasc surgery for colorectal liver metastases

Surgical resection remains the gold standard for the treatment of colorectal liver metastases (CLM). The goal for successful surgery is to pursue the optimal balance between oncological radicality and adequate future liver remnant (FLR). The impact of surgical margin is under active debate since many years, and it remains controversial when the disease burden is high or when the tumor is deeply located. The strategy of a large parenchymal sacrifice, limiting the possibility of a future re-resection and risking leaving an inadequate FLR, rather than challenging tumor exposure with potentially increased local recurrence rates, is becoming a relevant issue. Parenchymal-sparing surgery (PSS) strategy, taking profit of the ultrasound guidance, allows to remove the tumors minimizing the sacrifice of functioning parenchyma. This policy has been pushed beyond the classic oncological criteria, introducing the tumor-vessel detachment (R1vasc surgery) in order to further maximize the parenchyma sparing. This finding makes feasible conservative surgery for patients generally candidate to major hepatectomies or staged procedures with comparable oncological results and better perioperative outcome, redefining the role of surgical margins.