Impact of resection margins for colorectal liver metastases in laparoscopic and open liver resection: a propensity score analysis.

Background: There is no clear consensus over the optimal width of resection margin for colorectal liver metastases (CRLM), with evolving definitions alongside the advances on the management of the disease. In addition, data on the impact of resection margin after laparoscopic liver resection are still scarce.

Methods: Prospectively maintained databases of patients undergoing open or laparoscopic CRLM resection in 7 European tertiary hepatobiliary referral centres were reviewed. After propensity score matching (PSM), the influence of 1 mm and wider margins on OS and DFS were evaluated in open and laparoscopic cohorts.

Results: After PSM, 648 patients were comparable in each group. The incidence of positive margins (< 1 mm) was similar in open and laparoscopic groups (17% vs 13%, p = 0,142). Margins < 1 mm were associated with shorter RFS in open (12 vs 26 months, p = 0.042) and in laparoscopic group (13 vs 23, p = 0,002). Margins < 1 mm were associated with shorter OS in open (36 vs 57 months, p = 0.027), but not in laparoscopic group (49 vs 60, p = 0,177). Subgroups with margins ≥ 1 mm (1-4 mm, 5-9 mm, ≥ 10 mm) presented similar RFS in open (p = 0,251) or laparoscopic cohorts (p = 0.117), as well as similar OS in open (p = 0.295) or laparoscopic cohorts (p = 0.908). In the presence of liver recurrence, repeat liver resection was performed in 70 (30%) patients in the open group and 88 (48%) in the laparoscopic group (p < 0.001).

Conclusions: Our study suggests that a positive resection margin (less than 1 mm) width does not impact OS after laparoscopic resection of CRLMs as it does in open liver resection. However, a positive margin continues to affect RFS in open and laparoscopic resection. Wider margins than 1 mm do not seem to improve oncological results in open or laparoscopic surgery.