The Impact of KRAS Status on Long-Term Outcomes After Thermal Ablation and Hepatic Resection for Liver-Only Colorectal Metastases: A New Clue for Tailoring Surgical Strategy on Tumor Biology?

Introduction: KRAS mutation is a negative prognostic factor for colorectal liver metastases (CRLM). Thermal ablation (TA) is considered a valid alternative to liver resection (LR) for CRLM in selected cases. This study aims to investigate the influence of KRAS status on long-term outcomes of TA during LR. Materials and Methods: This is a retrospective analysis of patients undergoing surgery for CRLM in two hepatobiliary centers. Patients were divided into two groups: LR or LR + TA, and long-term results were investigated according to KRAS status. Results: 220 patients were included, of whom 74 (33.6%) were KRAS mutated. TA was performed in association with LR in 42 mutated (mKRAS) tumors (56.7%). Multivariate analysis in mKRAS patients showed that synchronous disease (p = 0.014), performing TA (p = 0.044), performing two or more TA (p = 0.032), and N2 status (p < 0.001) were independently associated with DFS. TA was more frequently associated with a liver-only recurrence, both in mutated and wt tumors, but with a higher risk in mKRAS (p = 0.013 vs. p = 0.048). Conclusion: CRLM surgical treatment should be tailored to KRAS status because TA may potentially be less effective in mutated patients during surgical resection. This is even more important in the case of multiple ablations.