RAS mutation nomograms to predict prognosis after radiofrequency ablation of recurrent colorectal liver metastases

Abstract Objectives: This study was conducted to develop nomograms for predicting repeat intrahepatic recurrence (rIHR) and overall survival (OS) after radiofrequency ablation (RFA) treatment in patients with recurrent colorectal liver metastases (CLMs) after hepatectomy based on RAS mutation and clinicopathologic features. Methods: A total of 160 consecutive patients with recurrent CLMs after hepatectomy who were treated with ultrasound-guided percutaneous RFA from 2012 to 2022 were retrospectively included. Potential prognostic factors associated with rIHR and OS after RFA, identified by the competing-risks model and Cox proportional hazard model, respectively, were used to construct nomograms. The performance of each nomogram was evaluated by Harrell’s C-index and calibration curve with bootstrapping. Results: The 1-, 2-, and 3-year rIHR rates after RFA were 59%, 69%, and 74%, respectively. The 1-, 3- and 5-year OS rates were 96.2%, 66.7%, and 47.0%, respectively. Four predictive factors, RAS mutation, interval from hepatectomy to intrahepatic recurrence, carcinoembryonic antigen (CEA) level at ablation, and ablation margin, were incorporated in the rIHR nomogram with a C-index of 0.694. Five predictive factors, RAS mutation, largest CLM at hepatectomy, CEA level at ablation, extrahepatic disease, and ablation margin, were incorporated intothe OS nomogram with a C-index of 0.743. The calibration curves presented good agreement between thenomograms and actual observations. Conclusions: The established nomograms can predict the individual risk of rIHR and OS after RFA for recurrent CLMs and contribute to better individualized management. Advances in knowledge: This study highlights the predictive value of RAS mutation for rIHR and OS after RFA of recurrent CLMs.