Objective To investigate the pathologic mechanism of radiofrequency ablation ( RFA ) combined with intravenous infusion of thermosensitive liposome encapsulated vinorelbine (TL-Vin) in treating liver tumors, and to analyze the effect of combination therapy on the long-term survival rate. Methods H22 liver adenocarcinoma tissue was subcutaneously implanted into ICR mice to establish the animal models. At the first experimental period, 40 mice were randomly and equally divided into 5 groups to receive different therapeutic scheme (using different TL-Vin concentrations). Twenty-four hours after the treatment the tumor specimens were collected, the necrotic areas were measured separately, and the optimal TL-Vin concentration was determined. At the second experimental period, 13 mice were randomly selected to receive treatment. Half an hour after the treatment the tumor tissues were collected and the TL-Vin concentration within the tumor was determined. At the third experimental period, 32 mice were randomly and equally divided into 4 groups, and 90 days after treatment the tumor growth curve was drawn. The survival rate was compared between each other of the groups. Results Compared with pure RFA group, TL-Vin + RFA significantly increased tumor coagulation extent (P<0.01). But free-VIN+RFA had similar tumor necrotic extent as that produced by RFA alone (P>0.05). Tumor coagulation area in TL-Vin + RFA group was bigger than that in free-VIN + RFA group at the concentration of 10 mg/kg [(341.8 ± 65.4)mm2 vs (225.3 ± 25.4)mm2, P < 0.01]. In TL-Vin group the coagulation margin was clear. The mean intratumoral Vinorelbine accumulation in TL-Vin + RFA group was 10 folds of that in free-Vin group [(1 156.5 ± 158.3)ng/ml vs (194.5 ± 52.3)ng/ml, P = 0.005]. TL-Vin +RFA had better survival result than that of RFA alone (37.6 ± 20.1 days vs. 23.4 ± 5.0 days, P=0.015), as well as than that of free-Vin + RFA [(37.6 ± 20.1)days vs (23.3 ± 1.2)days, P = 0.016]. Conclusion Thermosensitive liposomal chemotherapies (Vinorelbine) can be selectively delivered at the edge of RFA coagulation area and thus effectively increase RFA-induced tumor coagulation and prolong the end-point survival in experimental mice.

Objective To discuss the clinical application of contrast enhanced ultrasonography (CEUS) in radiofrequency ablation (RFA) treatment for residual and recurrent hepatic neoplasms. Methods A total of 517 cases of primary hepatocellular carcinoma (HCC) or hepatic metastases with residual or recurrent hepatic neoplasms after different kinds of treatment were treated with RFA. A total of 619 lesions were used as study subjects. The average size of the 290 lesions detected in 281 patients with recurrent HCC was (3.4 ± 1.5) cm. CEUS-guided RFA group included 150 cases (154 lesions in total), while conventional US-guided RFA group included 131 cases (136 lesions in total). A total of 329 lesions were detected in 236 cases with recurrent hepatic metastases, and the mean size of the lesions was (3.1 ± 1.3) cm, of which CEUS-guided RFA group included 152 cases (198 lesions in total) and conventional US-guided RFA group included 84 cases (131 lesions in total). Results In recurrent HCC, the one-month tumor necrosis rate of CEUS group and conventional US group was 96.1% and 89.7% respectively (P = 0.032), and the local recurrence rate was 9.7% and 17.6% respectively (P = 0.049). The differences between the two groups were statistically significant. In recurrent hepatic metastases , the one-month tumor necrosis rate of CEUS group and conventional US group was 88.4% and 87.0% respectively (P = 0.712), and the local recurrence rate was 16.7% and 23.7%respectively (P = 0.117). No significant differences existed between the two groups. Conclusion For the treatment of recurrent HCC, CEUS-guided radiofrequency ablation can effectively improve the early necrosis rate and decrease local recurrence rate.

Objective To assess the value of contrast-enhanced ultrasonography (CEUS) before percutaneous radiofrequency ablation (RFA) in treating patients with liver metastases. Methods A total of 267 patients with 485 liver metastatic lesions were treated with percutaneous RFA in authors ’ department during the period from July 2001 to December 2012. Among them , 180 patients with 251 lesions received CEUS examination before RFA and based on CEUS findings the treatment scheme was made (CEUS group), and other 87 patients with 234 lesions without use of preoperative CEUS were used as control group. No significant differences in clinical data existed between the two groups (P<0.05). Contrast-enhanced CT/MRI, CEUS and laboratory tests were regularly employed to evaluate the clinical results after RFA therapy. Results In CEUS group, 25.1% of the lesions (63/251) determined by CEUS were 3 mm larger than that determined by conventional US. 8.8%of the lesions (22/251) were more clear on CEUS findings. In addition, 41 new lesions were detected only on CEUS. No significant differences in early tumor necrosis rate existed between the two groups: 95.2%(239/251) vs. 92.7%(217/234)(P>0.05). The local recurrence rate of CEUS group was lower than that of the control group: 12.4% (46/234) vs. 19.7%(31/251) (P < 0.05). No significant differences in the recurrence time existed between the two groups (P > 0.05). Conclusion CEUS performed before RFA treatment for patients with liver metastases is very useful for accurately judging the size and number of the lesions, which is very helpful in making therapeutic scheme. Therefore, preoperative CEUS can significantly increase early tumor necrosis rate and decrease the local recurrence rate.