Efficacy of Treatment on Liver Metastases by Contrast Enhanced Ultrasonography-Guided Percutaneous Radiofrequency Ablation

Objective To evaluate the clinical application and the efficacy of contrast enhanced ultrasonography(CEUS)-guided percutaneous radiofrequency ablation(RFA) in patients with liver metastases.Methods Total 136 patients with 219 liver metastatic tumors,which were detected by CEUS before RFA therapy,were analyzed retrospectively.The diamter of tumors was(3.2±1.2) cm.Among them,the largest tumor more than 3 cm in diameter were found in 48.5%(66 patients),and 57.4%(78 patients) were with solitary metastasis.Enhanced CT and(or) MRI,and laboratory tests were applied to evaluate the outcomes after RFA treatment by regular follow-up.Results Tumors were not detected by conventional ultrasonography in two cases,and 47.0%(63/134) of the patients with the largest tumor were 0.3 cm larger by CEUS than by conventional ultrasonography.More 40 tumors were detected in 18.4%(25/136) patients by CEUS.Follow-up ranged from 3 to 68 months(median time of 12 months).Early tumor necrosis rate one month after therapy was 98.2%(215/219 tumors).The incidence of local recurrence,new intrahepatic metastasis,and extrahepatic metastasis was 16.9%(23/136),38.2%(52/136),and 8.8%(12/136),respectively.Local recurrence and new intrahepatic metastasis happened 2-25 months(median time of 6 months) after treatment.Local recurrence rates of the largest tumors ≥ 3 cm and tumor 3 cm was 22.7% and 11.4%,respectively(P=0.079).The rate of new intrahepatic metastasis for the solitary metastasis cases was significantly lower than that for multiple metastases cases(25.6% versus 55.2%,P=0.000).The 1-,2-,3-year survival rates were 82.5%,64.3%,and 50.1%,and the 1-,2-,3-year local recurrence free survival rates were 67.7%,53.8%,and 38.3%,respetively.Patients with solitary metastasis survived longer than that with multiple metastases(P=0.034).Conclusion Patients with liver metastases treated by CEUS-guided percutaneous RFA can get better survival rate,and CEUS is of much value for clinic application.