Long-Term Oncological Outcomes After Laparoscopic Resection and Thermal Ablation of Colorectal Liver Metastases Within a Parenchyma-Sparing Strategy

BACKGROUND: Thermal ablation of colorectal liver metastases (CRLM) is traditionally reserved for patients who are not candidates for surgical resection, but it is increasingly applied as a parenchyma-sparing alternative. This study investigates long-term outcomes following laparoscopic resection and thermal ablation in a parenchyma-sparing treatment strategy. METHODS: Cohort study of patients with CRLM treated with laparoscopic resection or thermal ablation at Oslo University Hospital between 2007 and 2020, identified from two prospectively maintained databases. The primary endpoint was the average treatment effect on survival, estimated using inverse probability weighting to adjust for prognostic variables. Secondary endpoints included overall survival and progression-free survival. In case of recurrence of liver metastases after the study treatment, both ablation and resection were used. RESULTS: A total of 207 ablation procedures and 499 resection procedures were eligible for analysis. Five-year overall survival was 55.2% in the ablation group and 55.1% in the resection group. The estimated average treatment effect of ablation versus resection was - 0.34 months (95% confidence interval - 7.29 to 6.57; P = 0.919), indicating that treating all patients with ablation would yield an average survival of 0.34 months shorter than treating all patients with resection. CONCLUSIONS: In a parenchymal-sparing paradigm, thermal ablation yields long-term survival comparable to resection for CRLM.