Impact of timing and cycles of systemic chemotherapy on survival outcome of colorectal liver metastases patients treated by percutaneous microwave ablation

Abstract

Purpose: The aim of this retrospective study is to determine the optimal timing and number of cycles of systemic chemotherapy in patients with colorectal liver metastases (CLM) treated by ultrasound-guided percutaneous microwave ablation (PMWA). Materials and methods: In total 199 patients with 318 CLM, median number of tumours one per patient and median maximum size of tumours 3.0 cm, treated by PMWA combined with or without systemic chemotherapy were included in our study. Chemotherapy was administered pre-ablatively in 148 of those patients (74.4%), and post-ablatively in 142 (73.6%). Chemotherapy regimens included FOLFOX/XELOX, FOLFIRI/XELIRI, and sequential monotherapy. Prognostic factors were evaluated by univariate and multivariate analyses, using log-rank test and Cox proportional hazards model, respectively. Results: The estimated 5-year rates of progression free survival (PFS) and overall survival (OS) were 10.1% and 27.9%, respectively. The number of CLM (P = 0.003), maximum size of CLM (P < 0.001) and topography (P = 0.030) were independent prognostic factors for PFS of patients with CLM while age (P = 0.002), maximum size of CLM (P = 0.006) and post-ablative chemotherapy (P = 0.046) for OS. In further analysis, CLM patients receiving more than six cycles of post-ablative chemotherapy had significantly better OS (P = 0.015) than those without post-ablative chemotherapy. Conclusion: This study revealed chemotherapy administered after (more than six cycles) PMWA improved the OS of CLM patents. And, PMWA was a safe procedure in view of the absence of procedure-related death and low rate of major complications.