Clinical Study Of Percutaneous Radiofrequency Ablation Of Liver Tumors Guided By Ultrasound

Purpose:Aim of this study is to explore the pattern for intrahepatic recurrence and the prognostic factors affecting tumor-free survival after percutaneous radiofrequency ablation (RFA) for liver tumor. Meanwhile, make a summary of possible complication after radiofrequency ablation for tumor so that proper measures can be taken in advance to improve the therapeutic long-time effect.Materials and methods:Retrospective analysis of clinical documents and image examinations of223patients, with342primary or secondary liver tumors who were treated with percutaneous cool-tip radiofrequency ablation guided by ultrasound in Tianjin Cancer Hospital and Institute from2009to2014. We evaluated the complication incidence, the cumulative disease-free survival rate of overall intrahepatic recurrence, local tumor progression (LTP) and intrahepatic distal recurrence (IDR). Thirteen and seven risk factors were reviewed for significant tie-in correlation with local tumor progression and intrahepatic distal recurrence, respectively. Cumulative disease-free survival was estimated by using the univariate analysis Kaplan-Meier model and the difference significance comparison was evaluated by using Log-rank test, while multivariate analyses using a stepwise Cox proportional regression model to search for independently significant risk factors.Results:For the223patients with342lesions, the ablation technique success rate was100%,25patients suffered from complications after radiofrequency ablation. The difference in hydrothorax rate between sub diaphragmatic and nonsubdiaphragmatic tumors was significant (x2=18.93, P=0.001). Hydrothorax incidence was rising as the tumor got closer to the diaphragm.There were197patients with primary hepatocellular carcinoma suffer RFA and263patients experience surgery, no significant incidence difference in each recurrence pattern was detected between this too groups. But complications of operation is significantly higher than RFA(x2=17.463, P=0.001). There were197patients with primary hepatocellular carcinoma and26patients with liver metastases; the complete ablation rate was100%assessed with contrast-enhanced image examinations. There were58patients with primary hepatocellular carcinoma and14patients with liver metastasis, had intrahepatic distal recurrence,6patients with primary hepatocellular carcinoma and3patients with liver metastases had local tumor progression occurrence. For the group of hepatocellular carcinoma, the incidence of overall recurrence, local tumor progression and intrahepatic distal recurrence was32.5%(64/197),3.0%(6/197), and29.4%(58/197).Univariate. and multi-univariate analysis showed that significant factors for local tumor progression were: tumor size≥3cm (RR=0.09,95%CI0.02--0.51, P=0.006), and insufficient safe margin were the most significant sole factor (RR=207.48,95%CI9.56-4505.18, P=0.001). For ablated lesions lack of safe margin, patients would have local tumor progression in early near future, with a median recurrence time (10.6+2.0) months. Only the degrees of hepatocellular carcinoma was the significant risk factor for intrahepatic distal recurrence (RR=0.45,95%CI0.21--0.97; P=0.041<0.05).For the group of liver metastases, the incidence of overall recurrence, local tumor progression and intrahepatic distal recurrence was65.4%,13.9%and53.8%, respectively. The cumulative disease-free survival rate was60.3%,94.2%and65.5%at1year,15.7%,77.9%and18.5%at2years, respectively. No significant factor was detected for local tumor progression by multi-univariate analysis. Significant factors for intrahepatic distant recurrence were: patient ag≥65years and tumor histological origin. Patients with single small liver metastasis from colorectal tumor would have better local-regional treatment and long-time disease-free survival than that with liver metastases from non-colorectal origin.Conclusion:Ultrasound guided radiofrequency ablation was a comprehensive and safe minimally invasive treatment method for primary or secondary liver tumors. Accurate localization of needle and proper real-time monitoring by ultrasound would benefit the therapeutic effectiveness and overcome unfavorable factors, such as large tumor and difficult location to puncture. Local tumor progression could almost always occur during the first12months after ablation, especially for the ablated areas without safe margin in image examinations, so patients at risk of local tumor progression should be closely monitored in first years and secondary complete ablation could still be effective for those recurrent lesions; intraphepatic distal recurrence occurs more than local tumor progression and it could occur at any time earlier during the first2years post-ablation or later on. Furthermore, regular long-time surveillance is essential for early detection and eradication of intrahepatic distal recurrence.