R1 Margins in Colorectal Liver Metastasis Surgery: A New Perspective

Microscopically positive margins (R1) after colorectal liver metastasis resection indicate worse outcomes but require context for interpretation regarding recurrence and repeat surgeries.

• Among 1,060 patients, R1 margins occurred in 21.5% and were linked to a higher crude risk of recurrence or death, with a hazard ratio of 1.34 after adjustments.
• Isolated liver recurrence was less frequent in R1 cases (31.1%) compared to R0 (47.6%), while liver plus extrahepatic recurrence was more common (26.2% vs 18.6%).
• Fewer patients with R1 margins underwent repeat hepatectomy (16.4% vs 31.4%), especially node-negative patients (10.5% vs 39.7%).

Surgeons should recognize that R1 status reflects nuanced prognostic implications rather than just a technical failure.