# Does Minimally Invasive Approach Change Criteria of Allocation to Treatment Strategy in Synchronous Colorectal Metastases? An Italian National Registry-Based Analysis

## TL;DR

This study finds that combining colorectal and liver surgeries for colorectal metastases increases complications, suggesting careful patient selection is needed.

## Contribution

The study provides new insights into the risks and outcomes of combined minimally invasive colorectal and liver resections for metastases in a large registry-based analysis.

## Key findings

- Combined resections had higher complication rates despite similar conversion rates.
- Combined procedures were associated with longer operative times and less complex liver resections.
- Patient selection is critical to minimize risks in combined minimally invasive surgeries.

## Abstract

This multicenter Italian study compared minimally invasive liver resections with combined minimally invasive colorectal/liver resections for synchronous colorectal liver metastases. The addition of the colorectal procedure increased postoperative morbidity, even though conversion rates remained similar. Combined minimally invasive resections are feasible but should be limited to carefully selected patients, ideally treated in high-volume centers. Overall, minimally invasive techniques reduce some risks but do not offset the added morbidity of performing both colorectal and liver resections simultaneously, supporting the need for strict patient selection and further research on long-term outcomes.

Background/Objectives: Heterogeneity in clinical scenarios of colorectal liver metastases (CRLM) leads to the possible application of different surgical strategies. Specifically, the possibility of performing combined colorectal and liver resections for synchronous CRLM has been proposed in specific settings but its feasibility, safety and impact in minimally invasive settings remain underexplored. This study examines a multicenter Italian experience, comparing perioperative outcomes of combined (CR) versus non-combined (NCR) minimally invasive liver resections (MILR) for CRLM. Methods: Patients from the prospective multicenter registry of the Italian Group of Minimally Invasive Liver Surgery (I Go MILS) who underwent MILR for CRLM between 2016 and 2024 were included. Perioperative outcomes were compared between CR and NCR using Nearest Neighbor Matching. Results: In total, 2286 patients were analyzed, including 1879 NCR and 407 CR. CR was associated with less challenging resections (technical difficulty Kawaguchi grade III: 7.13% vs. 14.53%, p < 0.001), longer operative time (385 vs. 270 min, p < 0.001) and higher major complication rate (11.55% vs. 5.11%, p < 0.001) compared to NCR. The conversion rate was similar between the two groups (9.09% vs. 7.91%, p = 0.479). Technical complexity, operative time, conversion, low-volume hospital, and CR was an independent predictor of major complications after matching. Conclusions: CR is associated with a higher risk of postoperative complications, despite being selected for minor liver resections, confirming the impact of associated colorectal surgery in determining the postoperative risk and hence highlighting the concept that accurate preoperative patient selection is a key step in guiding treatment allocation for CRLM. Therefore, MILR does not yet justify broadening indications for combined resection beyond carefully selected patients.