International Multi-centric Minimally Invasive Liver Resection for Colo-Rectal Liver Metastases (SIMMILR-CRLM)

Abstract

Background: The Study: of International Multi-centered Minimally Invasive Liver Resection (SIMMILR) is a study of ColoRectal Liver Metstases (CRLM) from 6 international centers.

Materials and Methods: Resections were divided by the approach used: Open liver resection (OLR), Laparoscopic liver resection (LLR) and Robotic liver resection (RLR). Patients with  ≥  3 tumors measuring  ≥ 5cm were excluded, and any remaining heterogeneity found was further analyzed after propensity score matching (PSM) to decrease any potential bias.

Results: A total of 1,064 hepatectomies were done at 6 centers. After exclusion criteria and PSM, 142 patients were in each arm of the OLR vs. LLR group and 22 in the OLR vs. RLR and 21 in the LLR vs. RLR groups. Blood loss, hospital stay, and morbidity rates were all highly statistically significantly increased in the OLR group, 636mL vs. 353mL, 9 vs. 5 days and 25% vs. 6%, respectively (p<0.001). Only blood loss was significantly decreased when RLR was compared to OLR and LLR, 250mL vs 597mL, and  778 mL vs. 224 mL, p<0.008 and p<0.04, respectively. Overall survival (OS) and recurrence free survival (RFS) was not statistically different regardless of operative approach.

Conclusion: LLR seems to result in decreased blood loss, hospital stay and morbidity rates when compared to OLR. RLR has decreased blood loss without an increase in operative times when compared to both OLR and LLR. This Study on an International Multi-centric cohort of Minimally Invasive Liver Resection (SIMMILR) indicates that minimally invasive approaches for CRLM that follow the Milan Criteria may have short term advantages that do not appear to significantly change overall and recurrence free survival, but larger studies comparing robotic resections to both OLR and LLR are still needed.