Radiofrequency ablation for unresectable colorectal hepatic metastases: Prognostic factors and the effect of postoperative chemotherapy on survival.

Abstract

581 Background: Radiofrequency ablation (RFA) is a recognized treatment modality in the management of patients with colorectal cancer liver metastasis (CRCLM). Our goal was to assess factors affecting long-term survival of patients undergoing RFA of CRCLM. Methods: We prospectively evaluated patients with unresectable CRCLM that underwent laparoscopic RFA. Patients were assessed pre- and postoperatively using triphasic computed tomography (CT) and intraoperatively using laparoscopic ultrasound. All information was entered into an IRB approved database. Pre-operative predictors were identified using Cox modeling. Postoperative chemotherapy was analyzed for its affect on survival. Results: 312 patients underwent 397 RFA sessions from 1999 to 2010. Patients averaged 2.7 lesions, with a dominant diameter of 3.4 cm and a preoperative CEA of 76. 28% had preoperative extrahepatic disease. Median survival on Kaplan-Meier analysis was 32 months, with 3 and 5 years survivals of 44% and 22%, respectively. The following were statistically significant on univariate and multivariable analysis: number of tumors (hazard ratio (HR) of 1.13 per tumor p=0.0002), dominate tumor diameter (HR 1.14 per cm p=0.03), pre-operative CEA (HR of 1.002 per one point rise p<.0001), and pre-operative extrahepatic disease (HR 1.4 p=0.05). Post-operative chemotherapy was shown to improve survival after controlling for the presence of new disease in follow-up. Conclusions: To our knowledge, this is both the largest and longest follow-up of RFA for unresectable CRCLM. The number and size of tumors, and preoperative CEA value are strong predictors of survival whereas pre-operative extrahepatic disease had mild impact on survival. Post-operative chemotherapy was shown to improve survival after controlling for other factors.