Comparison of the therapeutic efficacy between systemic chemotherapy with and without radiofrequency ablation for colorectal cancer liver metastases: A propensity score matching study

Objective: To compare therapeutic efficacy between systemic chemotherapy (SC) alone and preoperative SC followed by radiofrequency ablation (SC+RFA) in patients with colorectal cancer liver metastases (CRLM).Methods: This study identified a cohort of patients with CRLM after treatment between 2010 and 2016. Patients who received SC+RFA were compared with SC patients by propensity score matching. Overall survival (OS) and intrahepatic progression -free survival (PFS) were compared using stratified log -rank test. The outcomes after SC and SC+RFA were also assessed in patient subgroups. Results: This study identified 338 patients with CRLM who had underwent SC and had different response to chemotherapy, including non-progressive disease (non -PD) or progressive disease (PD). Of this cohort, 64 patients in SC+RFA group were matched by propensity score to 64 patients who received SC alone. Compared with SC cohort, the SC+RFA cohort yielded better OS (HR, 0.403; 95% CI, 0.271-0.601) and PFS (HR, 0.190; 95% CI, 0.113-0.320). The estimated OS rates at 1, 3 and 5 years were 93.8%, 51.6% and 15.6% for SC+RFA group and 81.3%, 26.6% and 10.9% for SC group (p<0.001). The cumulative PFS rates at 1, 3, and 5 years were 43.8 %, 14.1% and 3.1% for the SC+RFA group and 1.6%, 0 and 0% for SC group (p<0.0001). In subgroup analysis, compared with patients with PD response, patients with non -PD response could gain better PFS (HR, 0.207; 95% CI, 0.121-0.354) and OS (HR, 0.390; 95% CI, 0.246-0.617).Conclusions: RFA was associated with improved OS and intrahepatic PFS in CRLM patients with preoperative SC,especially in non -PD response subgroup after SC.Advances in knowledge: The addition of RFA was advo-cated for CRLM patients with preoperative SC. This study will provide important reference and evidence to better perform the management of unresectable CRLM.