A6: Resection versus Resection with Ablation: Analysis from the Colorectal Liver Operative Metastasis International Collaborative

Introduction: Thermal ablation has recently become a key therapy for the treatment of colorectal liver metastasis (CLM). However, the role of ablation in combination with resection has not yet been firmly established. We hypothesize that in patients with CLM, those who undergo liver resection with ablation (RA) have similar outcomes compared with those who undergo liver resection alone.


Methods:

We reviewed a multicenter international database of 906 surgical procedures for CLM from 5 high volume hepatobiliary surgical units.  Patients undergoing RA (n=100) were matched based on number of lesions using a 2:1 balanced propensity score analysis with those having resection alone (n=200).  Our primary outcomes were overall survival (OS) and disease-free survival (DFS).


Results: With a median follow up of 70.9 months, the resection and RA group had 5-year OS of 40.1% and 33.7% and median OS of 46.3 and 39.7 months (p=0.06), respectively.  For the resection and RA groups, the 5-year DFS was 25.5% and 8.9% and median DFS was 17.3 and 13.0 months (p=0.077), respectively. Using a multivariate Cox proportional hazards regression model, treatment approach was not associated with OS (p=0.51) or DFS (p=0.34). While higher number of lesions, larger tumor size, and R1 margin status were all associated with worse OS (p=< 0.05), only higher number of lesions was associated with worse DFS (p=< 0.05).  The majority of recurrences from the RA group were intra-hepatic when compared to the resection group (57% vs 38%, p=0.02).  Although there was a higher rate of Clavien-Dindo grade 3/4 complications in the RA group compared to the resection group (49% vs 26%, p=0.01), this was not associated with differences in OS or DFS.


Conclusions: Treatment approach was not significantly associated with OS or DFS, while tumor biology and margin status played an important role.  Patients treated with ablation had higher locoregional recurrences.  Prospective research on the quality and effectiveness of thermal ablation combined with hepatic resection is warranted.