Oncological Adequacy of R1 Vascular Margin in Minimally Invasive Liver Surgery for Hepatocellular Carcinoma and Colorectal Liver Metastases: A Meta-analysis.

BACKGROUND

The concept of tumor-vessel detachment (R1 vascular [R1v]), has recently gained attention within the minimally invasive (MI) setting, but its oncological adequacy remains poorly defined. This meta-analysis aims to assess the outcomes of MI-R1v hepatectomy for hepatocellular carcinoma (HCC) and colorectal liver metastases (CLM).

PATIENTS AND

METHODS

A literature search was conducted in MEDLINE, Embase, and Cochrane Library to identify studies reporting local recurrence (LR) rates following MI-R1v for HCC and CLM. Secondary outcomes included the extent of hepatectomy (major versus parenchyma-sparing), tumor burden (monofocal versus multifocal), intrahepatic recurrence, and overall survival (OS).

RESULTS

In total, eight studies comprising 839 patients (410 HCC and 429 CLM) were included. In HCC, LR rates were comparable between R1v and R0 (5.6% versus 7.9%; odds ratio [OR] 1.2, 95% confidence interval [CI] 0.25-6.1; p = 0.79), whereas in CLM, LR was higher after R1v (12.3% versus 6.4%; OR 3.4, 95% CI 1.10-10.54; p = 0.03). Robotic and laparoscopic R1v resections showed similar LR rates in both HCC (2.8% versus 4.8%; p = 0.82) and CLM (15% versus 12%; p = 0.08). No significant differences were observed between MI-R1v and MI-R0 resections in terms of extent of hepatectomy, tumor burden, intrahepatic recurrence, or OS in either group.

CONCLUSIONS

The comparable LR rates suggest that the R1v approach is oncologically acceptable for HCC in the MI setting, supporting its use when R0 cannot be achieved without a major hepatectomy. The higher LR rates in R1v for CLM resections require cautious patient selection and further standardization. Prospective studies are needed to define clear oncological benchmarks for MI-R1v procedures.