Wei Jun Fan

Noninvasive treatment of malignant bone tumors using high-intensity focused ultrasound

High‐intensity focused ultrasound (HIFU) is a new, noninvasive technique with potential to ablate and inactivate tumors. Treatment of solid tumors with HIFU has been reported. In this study, the safety and effects of HIFU in the clinical therapy of malignant bone tumors were assessed.

Comparison of microwave ablation and multipolar radiofrequency ablation in vivo using two internally cooled probes.

OBJECTIVE The objective of our study was to compare the effectiveness of microwave ablation (MWA) and multipolar radiofrequency ablation (RFA) in vivo using two internally cooled probes. MATERIALS AND METHODS MWA (n=24) was performed by simultaneous application of double internally cooled-shaft antennae. Three power settings (60, 70, and 80 W) were used. Multipolar RFA (n=16) was also performed by simultaneously using two internally cooled bipolar applicators (lengths: 3-cm T30 and 4-cm T40) at 60 and 80 W. Probe spacing was 2 cm. Each power setting was applied for eight ablations with a 10-minute duration for each. The cooled-shaft probes were inserted approximately 7 cm into the liver parenchyma of seven adult Wuzhishan pigs under ultrasound guidance, and ablations were performed in various segments of porcine liver. The long-axis diameter (Dl), short-axis diameter (Ds) and the ratio Ds/Dl for each ablation was measured. Temperature curves at 0, 2, and 3 cm from the middle of the two probes and the time to reach 60°C at 0 cm from the parallel central line between the two probes were recorded. RESULTS The long-axis diameter and short-axis diameter for all the power settings of MWA were significantly larger than that of both kinds of multipolar RFA (p<0.05). The rates of temperature rise to 60°C at 0 cm from the parallel central line between the two probes for all MWA power settings were significantly faster compared with RFA. CONCLUSION MWA, by the simultaneous application of double antennae, can generate a larger ablation zone, in vivo, compared with multipolar RFA.

Comparison of microwave ablation and multipolar radiofrequency ablation, both using a pair of internally cooled interstitial applicators: Results in ex vivo porcine livers

Purpose: To compare the effectiveness of microwave ablation (MWA) and multipolar radiofrequency ablation (RFA) in ex vivo porcine livers, in both cases using a pair of internally cooled interstitial applicators. Materials and methods: MWA was performed on ex vivo porcine livers (n = 60) using a pair of simultaneously powered, internally cooled shaft interstitial antennae. Four power settings were used: 50 W, 60 W, 70 W and 80 W (n = 15 per setting). Multipolar RFA was also performed on ex vivo porcine livers (n = 30), also using a pair of simultaneously powered, internally cooled shaft interstitial bipolar applicators. This was performed for two applicator types T30 (3 cm length) and T40 (4 cm length) at a manufacturer prescribed power of 60 W and 80 W, respectively (n = 15 per applicator). Spacing between the two probes was 2 cm in all cases. Each power setting was applied for 15 ablations for 10 min each. The long-axis diameter (Dl), short-axis diameter (Ds) and the ratio Ds/Dl for each ablation were measured. Temperature data were recorded at 10 positions. Temperature curves were recorded at 3 locations, as well as the time required for the temperature to rise to 50°C. Results: Dl and Ds for all the power settings of MWA were significantly larger than that of both kinds of multipolar RFA (P < 0.05). The rates of temperature to rise to 50°C in all the MW ablations power settings were significantly faster than those in both multipolar RF ablations. Conclusion: MWA by the simultaneous application of double antennae may be more advantageous for treating larger liver tumour than multipolar RFA.

Osteosarcoma: Limb salvaging treatment by ultrasonographically guided high-intensity focused ultrasound

The purpose of this study was to prospectively evaluate the use of ultrasonographically guided high-intensity focused ultrasound (HIFU) in the salvage of limbs in patients with osteosarcoma. Seven patients underwent HIFU ablation. Laboratory and radiologic examinations were performed after intervention. Changes in symptoms and survival time were noted at follow-up. No severe complications were observed, and preexisting severe pain disappeared in patients treated with HIFU. Alkaline phosphatase did not show statistically significant changes before and after HIFU treatment, although Alkaline phosphatase did change 1 mo and 2 mo after HIFU. Complete response [amp1]of the tumor was achieved in 3 patients with osteosarcoma. Partial response was achieved in another 3 patients treated with HIFU. Pulmonary metastasis was noted in only one patient 5 mo after HIFU. The median survival time was 68 months. All patients were alive 3 yrs after HIFU treatment. Five patients were alive at follow-up visits after 5 yrs. One patient died from cachexia and infection after 4 yrs, another patient died of cardiac arrestttack after 4 yrs. Three patients died of lung dysfunction from pulmonary metastases after 5 yrs. The five-year survival rate was 71.4%. The authors concluded that HIFU ablation was a safe and feasible method of treatment of osteosarcome which salvages the limb, but large-scale randomized clinical trials are necessary for confirmation.

CT-guided percutaneous microwave ablation of adrenal malignant carcinoma: preliminary results.

Microwave ablation has recently been developed as a safe and effective treatment for a variety of tumors. The authors evaluated the safety and efficacy of computed tomography (CT)‐guided percutaneous microwave ablation of adrenal malignant tumors.

Percutaneous CT-Guided Radiofrequency Ablation as Supplemental Therapy After Systemic Chemotherapy for Selected Advanced Non–Small Cell Lung Cancers

OBJECTIVE The purpose of this study is to evaluate the safety and efficacy of percutaneous CT-guided radiofrequency ablation (RFA) as a supplemental therapy after systemic chemotherapy for selected patients with advanced non-small cell lung cancer (NSCLC). MATERIALS AND METHODS We retrospectively reviewed the medical records of 220 patients with advanced NSCLC who were treated with platinum-doublet chemotherapy between January 2000 and January 2012. Among them, 49 patients underwent RFA as a supplemental therapy for tumors in partial response or stable diseases after first-line chemotherapy. The progression-free survival (PFS) was evaluated by Kaplan-Meier method. RESULTS There were nine women and 40 men (median age, 60 years; range, 24-82 years), including 28 patients with stage IIIb cancer and 21 with stage IV cancer. All 49 patients (partial response, 23 patients; stable disease, 26 patients) underwent 67 RFA sessions for 61 targeted tumors after systemic chemotherapy. There were no procedure-related deaths. Pneumothorax requiring chest tubes developed in eight sessions (11.9%). Thirty-one patients (63.3%) had complete response, 12 patients (24.5%) had partial response, six patients (12.2%) had stable disease, and no patients had progressive disease. The median follow-up period was 19 months (range, 6-34), and the median PFS was 16 weeks (95% CI, 14.5-17.5). CONCLUSION Percutaneous CT-guided RFA can be performed as a feasible minimally invasive supplemental therapy with satisfactory PFS after systemic chemotherapy for patients with advanced NSCLC.

Percutaneous CT-guided radiofrequency ablation for unresectable hepatocellular carcinoma pulmonary metastases

Purpose: This study aimed to evaluate the safety and efficacy of percutaneous CT-guided radiofrequency ablation (RFA) for unresectable hepatocellular carcinoma pulmonary metastases (HCCPM) and to identify the prognostic factors for survival. Materials and methods: We reviewed the medical records of 320 patients with HCCPM treated between January 2005 and January 2012. Among them, 29 patients with 68 lesions of unresectable HCCPM underwent 56 RFA sessions. Safety, local efficacy, survival and prognostic factors were evaluated. Survival was analysed using the Kaplan-Meier method. Univariate analyses were evaluated by the log-rank test. Results: Pneumothorax requiring chest tube placement occurred in five (8.9%, 5/56) RFA sessions. During the median follow-up period of 23 months (range 6–70), 18 patients (62.1%, 18/29) died of tumour progression and 11 (37.9%, 11/29) were alive. The 1-, 2- and 3-year overall survival rates were 73.4%, 41.1% and 30%, respectively. The median progression-free survival was 18 months (95% confidence interval (CI) 9.8–26.2) and the median overall survival time was 21 months (95%CI, 9.7–32.3). The maximum tumour diameter ≤3 cm (p = 0.002), the number of pulmonary metastases ≤3 (p = 0.014), serum AFP level ≤400 ng/mL (p = 0.003), and the controlled status of intrahepatic tumour after lung RFA (p = 0.001) were favourable prognostic factors for overall survival. Conclusions: Our study indicates that percutaneous CT-guided RFA, as an alternative treatment procedure to pulmonary metastasectomy, can be a safe and effective therapeutic option for unresectable HCCPM.

CT-guided percutaneous microwave ablation of liver metastases from nasopharyngeal carcinoma

PURPOSE To access efficacy of percutaneous microwave ablation (MWA) of liver metastases from nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS From March 2007 to June 2012, 18 consecutive patients with NPC and liver metastases (15 men and three women; average age, 45.7 y; age range, 31-61 y) received computed tomography (CT)-guided percutaneous MWA treatment. A total of 27 ablations were performed involving 24 liver metastatic lesions in 18 patients with NPC. Average patient follow-up after ablation was 22.4 months (range, 2-52 mo). The average number of liver metastases per patient was 1.3 (range, 1-4 lesions), with lesion diameters ranging from 1.9 cm to 4.2 cm. Evaluation was then performed to assess percentage of complete necrosis, local tumor progression, and safety. RESULTS Technical success was achieved in all 27 MWA procedures performed. During follow-up, new metastatic lesions developed in four of 18 patients. Of these, two were liver metastases, and were successfully treated with repeat WMA. Only two major complications were observed: pneumothorax in a patient with an ablation pathway involving the thorax and postprocedural pain in two other patients. A median overall survival time of 41.4 months was observed (range, 2-50 mo); three of 18 patients died during follow-up. CONCLUSIONS CT-guided MWA is safe and offers an effective treatment alternative for local tumor control in selected patients with liver metastases from NPC.

Evaluation of transarterial chemoembolization combined with percutaneous ethanol ablation for large hepatocellular carcinoma

AIM To assess the effects of combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol ablation (PEA) in patients with large hepatocellular carcinoma (HCC). METHODS A total of 63 patients with unresectable large HCC were treated with TACE followed by PEA. The largest dimension of the tumors ranged from 5.3 cm to 17.8 cm. The survival rates, acute effects, toxicity and prognostic factors were analyzed. RESULTS The cumulative survival rates at 1, 3 and 5 years were 59.4%, 28.4% and 15.8%, respectively (a median survival of 27.7 mo). Tumor area was reduced by more than 50% in 30 (47.6%) cases. In 56 cases with increased α-fetoprotein (AFP) values, AFP level was declined by more than 75%. The combined therapy was generally well tolerated. Only two patients died from variceal bleeding associated with the therapy. The Cox proportional hazards model showed that the number of tumors, the tumor margin and the ethanol dose were independent prognostic factors. CONCLUSION The combined TACE and PEA therapy is a promising approach for unresectable large HCC.

Microwave ablation: Results with three different diameters of antennas in ex vivo bovine and in vivo porcine liver

PURPOSE To evaluate the ablation ranges and temperature rising rates of three microwave antenna with different diameters in vitro bovine and in vivo porcine livers. MATERIALS AND METHODS In vitro and in vivo study, microwave ablations (MWA) were induced at a power output of 70 W for 5, 8, and 10 min; a total of 54 and 36 ablations were performed, respectively. Temperature measurements were performed in the 70 W/10 min group with 3 different microwave antennas. RESULTS In vitro study, the long axis diameter for the 16G microwave antenna was longer than the 15G (P < 0.05) and 14G microwave antennae (P < 0.05). The sphericity index for the 14G and 15G microwave antennae was higher than the 16G microwave antenna (P < 0.05 for both). In the in vivo study, the short- and long-axis diameters, and sphericity index were not statistically different between the 14G, 15G, and 16G groups. The temperature data were not statistically different in both studies. CONCLUSIONS Although the thin microwave antenna had a longer long-axis diameter and a lower sphericity index in vitro study, the thin microwave antenna achieved the same ablation effect in vivo application. MWA has several advantages, and the thin microwave antenna decreases the puncture risk and complication rate. Thus, a thin microwave antenna (15G and 16G) is beneficial in clinical applications and will have a significant influence in the development of MWA.