Abstract:  

Objective  To investigate the clinical value of circulating tumor cells （CTCs） in evaluating the prognostic value in patients with metastatic colorectal cancer undergoing microwave ablation. Methods  A total of 29 patients who received microwave ablation for hepatic metastases from colorectal cancer at the Second Hospital of Nanjing from January 2014 to May 2018 were enrolled in this study. Preoperative and postoperative blood samples from these patients were tested for CTCs. CTCs values and clinical data of the 29 cases were analyed. The data was analyzed by Chi square test or Fisher exact test, and the survival analysis was performed by Kaplan-Meier method and Log-rank test. Results  The short-term efficacy of microwave ablation for local lesions in 29 patients was assessed by imaging. The short-term outcome was complete ablation in 8 patients， partial ablation in 16 patients and progressive ablation in 5 patients. An increase in CTCs values after microwave ablation was found （Z=-2.489， P=0.013）. While， age， sex， synchronous colorectal liver metastasis or not， left or right colorectal cancer and the change of CTC values after microwave ablation were no statistically significant （P＞0.05）. The shortterm effect of local liver metastases in patients with CTCs ＜7/ml after microwave ablation was better than that in patients with CTCs ≥7/ml, and the difference was statistically significant （P=0.031）. The median overall survival（OS） of 29 patients was 30.0 months （95％CI： 10.7-49.3 months）. The median OS of patients under 60 years old were better than those aged 60 and above（P=0.008）. The median OS in patients with left colon cancer was better than that in patients with right colon cancer（P=0.028）. The patients with microwave ablation only have worse survival than combined treatment（P=0.001）. But gender， simultaneous or heterogeneous liver metastasis， elevated CTCs and postoperative CTCs／ml were not associated with median OS （P＞0.05）. Conclusion  Microwave ablation is an effective method for local treatment of colorectal cancer with liver metastases. Monitoring the number of CTCs before and after treatment may be helpful to evaluate the shortterm curative effects.

Key words:  , Colorectal cancer">Colorectal cancer')">">, Circulating tumor cell, Microwave ablation