Radiofrequency Ablation In Patients Research Articles

Rate of Recurrence of Non-Small Cell Lung Cancer in Patients Treated with Percutaneous Ablation

Background: Percutaneous ablation therapy as a treatment for non-small cell lung cancer (NSCLC) has been increasingly utilized. There is little data on long term efficacy. Because of this we reviewed the rate of recurrence of all ablation procedures done at our institution for the last 6 years. Methods: A total of 36 patients underwent 43 percutaneous procedures from July 2008 until January 2014 at our institution. There were 9 patients treated with radiofrequency ablation (RFA) and 27 treated withmicrowave ablation (MWA) for Stage I NSCLC. Each patient was reviewed to determine if there was a recurrence, the time to recurrence and the characteristics of the original cancer possibly predisposing the procedure to failure. Results: There were 8 recurrences in 9 patients undergoing RFA occurring at a median time of 842 days (range 425 - 1568) after their procedure. MWA was utilized in 27 patients for 34 procedures with 11 patients experiencing recurrences at a median time of 487 days (range 168 - 845). The median follow up time for the RFA patients was 1631 days (4.46 years) and for the MWA patients 751 days (2.06 years). Of the RFA recurrences, 5 involved systemic spread of their cancer and 3 were limited to site recurrences only. Of the MWA recurrences, 5 involved systemic spread of their cancer, 2 had chest wall recurrences and 4 were limited to site recurrences only.

Predictors of Response to Endoscopic Therapy of Barrettʼs High-Grade Dysplasia (HGD) and Intramucosal Cancer (IMC)

Purpose: Modalities of endoscopic therapy of Barrett's HGD and IMC include endoscopic mucosal resection (EMR), radiofrequency ablation (RFA), cryotherapy and argon plasma coagulation (APC). Although these are highly effective in most patients for eradication of dysplasia, some patients continue to have small areas of residual Barrett's or continue to progress to HGD or cancer. Our aims were to assess eradication rates of Barrett's metaplasia and dysplasia as well as factors which predict complete eradication. Methods: Review of prospectively collected database of patients who underwent endoscopic therapy for Barrett's dysplasia or IMC from 2006 to 2011. Patients who underwent EMR only excluded. Variables such as age, race, sex, BMI, alcohol use, smoking, diabetes, hypertension, hyperlipidemia, medication use were analyzed. Endoscopic data included length of Barrett's segment, hiatal hernia size, number of endoscopies and biopsy results. Results: Among 118 patients included, there were 60 patients in RFA and 58 patients in cryotherapy group. Compared to RFA patients, cryotherapy patients were found to be older and were more likely to have never used alcohol. In addition, they had longer treatment period and higher number of treatment sessions (table 1). Patients with RFA were more likely to have complete eradication of dysplasia (100% vs. 90%; p=0.012). There were no other significant differences between two groups. PREDICTORS: There was complete eradication of Barrett's in 72 patients (61%). There was Barrett's without dysplasia in 40 patients (33.8 %). Six patients had persistent HGD or progression to cancer (5%). On univariable analysis, subjects who had eradication of metaplasia had a longer treatment period (months 32.8± 20 vs 23.3±18.8, p=0.011) and follow-up time (months 36.8±21.5 vs. 25.9±18.7; p=0.006). There were no other significant differences. After adjusting for all variables in the model, subjects who had RFA had 3-fold higher odds of having eradication of metaplasia than those who had cryotherapy (odds ratio [OR] 2.9; 95% confidence interval [CI] 1.1-7.7; p = 0.031). In addition, for every 1 month increase in the EGD followup time, the odds of having complete metaplasia eradication increased by 4% (OR 1.04; 95% CI 1.01-1.07; p= 0.002). Younger age was associated with eradication of metaplasia/dysplasia (66.7± 10.6 vs. 75.8±9.3 years p=0.042). In addition, EMR and RFA were associated with eradication of metaplasia/dysplasia while patients without eradication were more likely to have had cryotherapy or APC/band ligation.Table 1: Endoscopic therapyConclusion: Endoscopic therapy is highly effective in eradication of Barrett's HGD and IMC. RFA with or without EMR and younger age are predictors for complete eradication of BE.

Recurrence of Esophageal Intestinal Metaplasia and Dysplasia: Porfimer Sodium Photodynamic Therapy versus Radiofrequency Ablation

Purpose: Both porfimer sodium photodynamic therapy (Ps-PDT) and radiofrequency ablation (RFA) are effective endoscopic ablation modalities used to eradicate esophageal intestinal metaplasia with or without dysplasia/neoplasia among patients with Barrett's Esophagus (BE). The aim of this study is to compare the time to recurrence of intestinal metaplasia and dysplasia between PDT and RFA among patients with BE. Methods: This was a retrospective, observational study using a large database of patients treated with Ps-PDT and RFA in a tertiary referral center. Information collected included age, gender, race, history of smoking, histology of statin use, NSAID use, previous treatments, length of Barrett's segment, date of follow-up visit, procedures and biopsy results. The primary endpoint of this study was the recurrence of IM among patients who achieved complete remission of IM (CRIM). We used Kaplan-Meier analysis, Wilcoxon rank sum test and Cox proportional hazards regression models to assess and compare time to recurrence of IM and dysplasia between PDT and RFA. Results: A total of 233 patients were included in this study. Of those, 103 patients had RFA while 130 patients had Ps-PDT between August 2001 and June 2012. 77% (n=180) of patients achieved remission of IM. After a median follow-up time of 14.3 months, the rate of recurrence was similar among patients with RFA compared to PDT (36.4% vs. 48.1%). There was no significant difference in the likelihood of experiencing disease recurrence following normal biopsy between PDT and RFA patients in either single variable analysis (RR: 1.44, P=0.15) or multivariable analysis (RR: 1.26, P=0.42). Kaplan-Meier curves for time to recurrence of intestinal metaplasia/neoplasia for PDT and RFA is shown in Figure 1. In these patients who experienced freedom from dysplasia, the risk of recurrence of dysplasia did not differ significantly between the two treatment groups in single variable analysis (RR: 1.15, P=0.63) or multivariable analysis (RR: 1.09, P=0.78).Fig 1: Kaplan-Meier curves for time to recurrence of intestinal metaplasia/neoplasia.Conclusion: Among patient with BE, there was no significant difference in disease recurrence between patients treated with RFA compared to Ps-PDT when controlling of age, gender, race, BE length, baseline histology, and use of NSAIDs or statins. Disclosure - Dr. Waseem David - Research Fellow: Pinnacle Biologics, Grant/Research Support This research was supported by an industry grant from Pinnacle Biologics

Higher Rates of Remission of Esophageal Intestinal Metaplasia Using Photodynamic Therapy Compared to Radiofrequency Ablation

Purpose: There are few data comparing the efficacy of porfimer sodium photodynamic therapy (Ps-PDT) and radiofrequency ablation (RFA) in achieving complete remission of intestinal metaplasia (CRIM) or dysplasia (CRD). The aim of this study was to highlight the differences in time to CRIM and time to CRD among patient treated with Ps-PDT compared to RFA. Methods: This was a retrospective, observational study of patients with BE (+/- dysplasia) treated at a tertiary care center with Ps-PDT or RFA. Information of interest was collected regarding baseline characteristics (age, gender, race, history of smoking, histology, previous statin use, previous NSAID use, previous treatments [EMR, PDT, RFA, APC], length of Barrett's segment), and followup characteristics (date of follow-up visit, procedures performed, biopsy results, complications). The primary endpoint of this study was the occurrence of the first normal biopsy after starting treatment with either RFA or Ps-PDT (CRIM). We used Kaplan-Meier analysis, Wilcoxon rank sum test and Cox proportional hazards regression models to compare and assess time to CRIM and CRD. Results: A total of 233 patients were included in this study. Of those, 103 patients had RFA while 130 patients had Ps-PDT between August 2001 and June 2012. The median follow-up time after first Ps-PDT or RFA treatment was 14.3 months. Patients who underwent RFA were younger (median age 65 years vs. 71 years; p<0.001) and less likely to have a history of smoking (67% vs. 82%, p= 0.017). There was no difference in other variables between both groups. Median time to CRIM was 8.8 months in patients with RFA compared to 2.3 months in patients with Ps-PDT. Patients who were treated with Ps-PDT were more likely to experience a normal biopsy than patients who were treated with RFA (RR 2.42' P<0.001), and this result remained consistent in multivariable analysis (RR 2.67; P<0.001). Kaplan-Meier cumulative incidences CRIM are shown in Figure 1 for RFA patients and Ps-PDT patients separately.FigureConclusion: When treating patient with BE +/- dysplasia, the rate of CRIM is higher in patients treated with Ps-PDT compared to RFA, when controlling for patient age, gender, baseline histology, BE length, use of statins and NSAIDs. Head to head studies may be needed to better quantify this difference and its potential implications. Disclosure - Dr. Waseem David - Research Fellow: Pinnacle Biologics, Grant/Research Support. This research was supported by an industry grant from Pinnacle Biologics.

Higher Rates of Remission of Esophageal Intestinal Metaplasia Using Photodynamic Therapy Compared to Radiofrequency Ablation

Purpose: There are few data comparing the efficacy of porfimer sodium photodynamic therapy (Ps-PDT) and radiofrequency ablation (RFA) in achieving complete remission of intestinal metaplasia (CRIM) or dysplasia (CRD). The aim of this study was to highlight the differences in time to CRIM and time to CRD among patient treated with Ps-PDT compared to RFA. Methods: This was a retrospective, observational study of patients with BE (+/- dysplasia) treated at a tertiary care center with Ps-PDT or RFA. Information of interest was collected regarding baseline characteristics (age, gender, race, history of smoking, histology, previous statin use, previous NSAID use, previous treatments [EMR, PDT, RFA, APC], length of Barrett's segment), and follow-up characteristics (date of follow-up visit, procedures performed, biopsy results, complications). The primary endpoint of this study was the occurrence of the first normal biopsy after starting treatment with either RFA or Ps-PDT (CRIM). We used Kaplan-Meier analysis, Wilcoxon rank sum test and Cox proportional hazards regression models to compare and assess time to CRIM and CRD. Results: A total of 233 patients were included in this study. Of those, 103 patients had RFA while 130 patients had Ps-PDT between August 2001 and June 2012. The median follow-up time after first Ps-PDT or RFA treatment was 14.3 months. Patients who underwent RFA were younger (median age 65 years vs. 71 years, p<0.001) and less likely to have a history of smoking (67% vs. 82%, p=0.017). There was no difference in other variables between both groups. Median time to CRIM was 8.8 months in patients with RFA compared to 2.3 months in patients with Ps-PDT. Patients who were treated with Ps-PDT were more likely to experience a normal biopsy than patients who were treated with RFA (RR: 2.42, P<0.001), and this result remained consistent in multivariable analysis (RR: 2.67, P<0.001). Kaplan-Meier cumulative incidences CRIM are shown in Figure 1 for RFA patients and Ps-PDT patients separately.FigureConclusion: When treating patient with BE +/- dysplasia, the rate of CRIM is higher in patients treated with Ps-PDT compared to RFA, when controlling for patient age, gender, baseline histology, BE length, use of statins and NSAIDs. Head to head studies may be needed to better quantify this difference and its potential implications. Disclosure - Dr. Waseem David - Research fellow: Pinnacle Biologics, Grant/Research Support. This research was supported by an industry grant from Pinnacle Biologics.

Efficacy of laparoscopic radiofrequency ablation for the treatment of patients with small solitary colorectal liver metastasis

Although radiofrequency ablation (RFA) has been incorporated to the treatment algorithm of patients with unresectable colorectal liver metastasis (CLM), its utility in patients with resectable disease has not been well studied. The aims of this study were to define the clinical profile of patients with a solitary CLM who underwent laparoscopic RFA and to analyze their oncologic outcomes. Between 2000 and 2011, 44 patients underwent laparoscopic RFA and 60 patients resection of solitary CLM ≤3 cm. Data were analyzed from a prospectively maintained institutional review board-approved database using Student's t test, Chi-square, and Kaplan-Meier tests. The indications for RFA were patient decision in 61% (n = 27), comorbidities in 34% (n = 15), and intraoperative findings in 5% (n = 2). In comparison with the resection group, RFA patients had a greater American Society of Anesthesiologists score (3.0 ± 0.1 vs 2.6 ± 0.1, respectively; P = .002), more frequent incidence of cardiopulmonary comorbidities (60% vs 38%, respectively; P = .045), and tumors located deeper in the liver parenchyma (39% vs 12%) that would have required a formal lobectomy. The 2groups were otherwise similar for age, gender, carcinoembrradyogenic antigen, synchronous versus metachronous presentation of CLM, tumor size, and tumor and nodal status of primary colorectal cancer. The local recurrence rate was 18% after RFA and 4% after resection (P = .012). The overall Kaplan-Meier, cancer-specific, 5-year survival was 47% for RFA and 57% for resection (P = .464). Median disease-free survival was 25 months after RFA and 22 months after resection (P = .973). Our results suggest that laparoscopic RFA might spare a number of patients at greater risk with a small solitary CLM the risk of morbidity from a formal liver resection. Furthermore, laparoscopic RFA might also be acceptable as the first line of therapy for patients with tumors that otherwise would have required a formal lobectomy or open resection. Nevertheless, the local recurrence rate of RFA should be kept in mind and the patients followed closely to treat failures promptly.

Contrast-enhanced US-guided Radiofrequency Ablation of Hepatocellular Carcinoma

PurposeContrast-enhanced ultrasound (US) has been shown to be an efficient imaging modality in guiding radiofrequency (RF) ablation of hepatocellular carcinomas (HCC). The purpose of the present study was to assess the usefulness of contrast-enhanced US in guiding RF ablation in patients with early-stage HCC that was not clearly visible on grayscale US or noncontrast computed tomography (CT). Materials and MethodsDuring a 17-month period, contrast-enhanced US–guided RF ablation was performed in 14 patients with 19 early-stage lesions that were poorly defined on grayscale US and noncontrast CT. Contrast-enhanced US was repeated after 30 minutes, and complete ablation was defined as absence of any arterial-phase enhancement within the ablated lesion. Patients were followed periodically with clinical evaluation, liver function tests, α-fetoprotein measurement, and multiphasic CT or magnetic resonance (MR) imaging for a minimum of 1 year after ablation to look for local recurrence or disease progression. Survival probability was estimated with the Kaplan–Meier method. ResultsComplete tumor ablation was achieved in all 19 lesions, with no evidence of residual or recurrent tumor in the ablated areas after a mean follow-up of 16 months. No major complications were observed in any patient. However, new lesions developed in other parts of the liver on follow-up scans in three patients, and were accordingly treated with RF ablation. Two patients died of disease progression or liver failure within the 1-year follow-up. ConclusionsFor early-stage HCCs not well visualized on unenhanced US or CT, contrast-enhanced US provides an additional tool to guide RF ablation.

Complementary Use of Resection and Radiofrequency Ablation for the Treatment of Colorectal Liver Metastases: An Analysis of 395 Patients

Liver resection and radiofrequency ablation (RFA) are two surgical options in the treatment of patients with colorectal liver metastases (CLM). The aim of this study was to analyze patient characteristics and outcomes after resection and RFA for CLM from a single center. Between 2000 and 2010, 395 patients with CLM undergoing RFA (n = 295), liver resection (n = 94) or both (n = 6) were identified from a prospective IRB-approved database. Demographic, clinical and survival data were analyzed using univariate and multivariate analyses. RFA patients had more comorbidities, number of liver tumors and a higher incidence of extrahepatic disease compared to the Resection patients. The 5-year overall actual survival was 17 % in the RFA, 58 % in the Resection group (p = 0.001). On multivariate analysis, multiple liver tumors, dominant lesion >3 cm, and CEA >10 ng/ml were independent predictors of overall survival. Patients were followed for a median of 20 ± 1 months. Liver and extrahepatic recurrences were seen in 69 %, and 29 % of the patients in the RFA, and 40 %, and 19 % of the patients in the Resection group, respectively. In this large surgical series, we described the characteristics and oncologic outcomes of patients undergoing resection or RFA for CLM. By having both options available, we were able to surgically treat a large number of patients presenting with different degrees of liver tumor burden and co-morbidities, and also manage liver recurrences in follow-up.

Editorial Comment: The present and future of thermal ablation for lung cancer

In this issue of the European Journal of Cardiothoracic Surgery, Dr Baisi et al. [1] from Milan have summarized some of the literature regarding the use of thermal ablation for pulmonary tumours. They have also described some of their own personal experience with 26 cases. Their primary discussion has focused on the use of radiofrequency ablation, and to a lesser extent, on microwave ablation. They have, however, omitted discussion of other ablative technologies such as cryoablation and irreversible electroporation [2, 3]. Although these other technologies have been reported to a lesser extent, the myriad of different approaches to thermal ablation attests to the ever-changing selection of available treatments for high-risk operable and medically inoperable patients with lung cancer. Although most reports of ablation involve the use of percutaneous approaches, a group from Japan has reported the use of a bronchoscopic approach to ablation [4]. As experience with technologies such as electromagnetic navigation evolve, the fusion of these techniques may lead to a future where small cancers are diagnosed and then treated by bronchoscopy alone. On the other hand, the use of thermal ablation has declined, particularly in academic medical centres. There are a number of reasons for this. The primary reason has been the implementation of stereotactic body radiation therapy (SBRT) programmes in many hospitals, and the excellent results from several phase I and II trials for lung cancer [5]. Radiofrequency ablation (RFA) for the most part has been performed in the community setting, primarily by interventional radiologists. Unlike surgeons or radiation oncologists, radiologists do not generally evaluate patients pre-therapy, or participate in the long-term follow-up, and are generally not stakeholders in multidisciplinary tumour board discussions. For this reason, thermal ablation studies have involved smaller numbers of patients, tended to consist of a mixture of patients with primary and secondary lung tumours, and have generally involved shorter followup periods. On the other hand, the benefits of SBRT have been overstated when compared with both surgery and thermal ablation. With respect to surgery, it has been stated that local control rates are excellent and approach that of lobectomy, which is simply not true as the definitions of local control have been different for surgical and SBRT studies [6]. For ablation, it has been commented that SBRT is safer and associated with a lower morbidity rate. Although the rate of pneumothorax is high with RFA, the actual incidence of grade 3 and higher adverse events, using Common Terminology Criteria Definitions, is lower than that reported for SBRT [5, 7]. Another issue when comparing these three general approaches (surgery, thermal ablation, and SBRT) is that studies have generally involved dissimilar risk patient groups. A recent propensitymatched analysis compared preoperative risk factors in patients from three cooperative group studies involving sublobar resection, SBRT or RFA [8]. Interestingly, SBRT patients had the best, and the RFA patients had the most impaired baseline pulmonary function. Differences with inclusion criteria, and end-point definition between single-arm studies for different treatment modalities, support the need for randomized trials to compare these different approaches for lung cancer. Currently, a phase III study is underway in the USA comparing SBRT with sublobar resection for highrisk operable patients with lung cancer [9]. Further prospective studies are also needed to evaluate the optimal approach, and patient selection for thermal ablation.

Comparison of resection and ablation for hepatocellular carcinoma: A cohort study based on a Japanese nationwide survey

The treatment of choice for early or moderately advanced hepatocellular carcinoma (HCC) with good liver function remains controversial. We evaluated the therapeutic impacts of surgical resection (SR), percutaneous ethanol injection (PEI), and radiofrequency ablation (RFA) on long-term outcomes in patients with HCC. A database constructed on the basis of a Japanese nationwide survey of 28,510 patients with HCC treated by SR, PEI, or RFA between 2000 and 2005 was used to identify 12,968 patients who had no more than 3 tumors (≤ 3 cm) and liver damage of class A or B. The patients were divided into SR (n=5361), RFA (n=5548), and PEI groups (n=2059). Overall survival and time to recurrence were compared among them. Median follow-up was 2.16 years. Overall survival at 3 and 5 years was respectively 85.3%/71.1% in the SR group, 81.0%/61.1% in the RFA, and 78.9%/56.3% in the PEI. Time to recurrence at 3 and 5 years was 43.3%/63.8%, 57.2%/71.7%, and 64.3%/76.9%, respectively. On multivariate analysis, the hazard ratio for death was significantly lower in the SR group than in the RFA (SR vs. RFA:0.84, 95% confidence interval, 0.74-0.95; p=0.006) and PEI groups (SR vs. PEI:0.75, 0.64-0.86; p=0.0001). The hazard ratios for recurrence were also lower in the SR group than in the RFA (SR vs. RFA:0.74, 0.68-0.79; p=0.0001) and PEI groups (SR vs. PEI:0.59, 0.54-0.65; p=0.0001). Our findings suggest that surgical resection results in longer overall survival and time to recurrence than either RFA or PEIin patients with HCC [corrected].

Cryotherapy after Radiofrequency Ablation (RFA) Failure in Patients with Barrettʼs Dysplasia

Purpose: Radiofrequency ablation (RFA) is an increasingly used form of endoscopic treatment in patients with Barrett's esophagus (BE) with dysplasia or early adenocarcinoma (ACA). Treatment failures (patients with persistent Barrett's disease despite RFA) are offered salvage treatment using cryotherapy. The aim of this study was to determine the treatment response of cryotherapy in patients with persistent BE dysplasia after RFA ablation. Methods: We reviewed a large, prospectively-collected database of BE ablation procedures performed from 2000-2011. The patients treated with Cryotherapy (using liquid nitrogen or carbon dioxide) for persistent BE dysplasia RFA ablation were analyzed. Patients' demographics, initial BE segment length, total number of RFA sessions, RFA ablation response, cryotherapy procedure details, and cryotherapy treatment response were recorded. Results: We analyzed approximately 412 patients treated with RFA for BE dysplasia since 2003. cryotherapy was performed in 11 patients with persistent BE dysplasia despite RFA ablation therapy were included in our study analysis. Their mean age was 72 (range 60-85) years and all were male. The mean BE segment was 4.8 (range 1-12) cm. Pre-RFA, 7 patients (63.6%) had BE-HGD (high grade dysplasia) and 4 patients (36.4%) had BELGD (low grade dysplasia) prior to receiving RFA ablation. The mean number of RFA treatments was 3.2 (range 1-9). After RFA of the 7 BE-HGD patients, the HGD was unchanged in 4 (57%), down-graded to LGD in 2 (29%) or BE No dysplasia in 1 (14%). After RFA of 4 LGD patients, 1 progressed to BE-HGD while other 3 had persistent LGD. These failed RFA patients are all undergoing cryotherapy (mean 1.8 treatments; range 1-4, thus far). Cryotherapy treatments targeted 1-3 sites (mean 2.25) using 4-10 cycles (mean 7) of 10-20 seconds freeze time (mean 15.4 seconds). Post cryotherapy, esophageal biopsies were available in 8 (72%) patients (4 BEHGD, 3 BE-LGD, 1 BE-no dysplasia). Among them, complete dysplasia eradication was seen in 1 (25%) patient with BE-HGD and 1 (33%) patient with BE-LGD (see Table). In remaining patients, the BE dysplasia severity has remain unchanged.Table: No Caption available.Conclusion: The number of patients undergoing cryotherapy for persistent BE disease after RFA ablation is low. Cryotherapy has shown fair response among refractory BE with dysplasia (LGD and HGD) that failed prior RFA ablation. In the remaining patients, cryotherapy treatment will continue. Future studies are needed to better define the role of cryotherapy for the endoscopic treatment of BE with dysplasia. Disclosure: Dr. Patel - None. Ms. Hemminger - None. Dr. Wolfsen - Consultant for CSA Medical, Mauna Kea Tech, BARRx.

Traitement d’une tumeur rénale et préservation néphronique impérative : étude comparative des données périopératoires et des résultats à moyen terme de la néphrectomie partielle et de la radiofréquence

To compare morbidity, oncological and functional outcomes of percutaneous radiofrequency ablation (RFA) and partial nephrectomy in indications of renal tumor treatment with imperative nephron-sparing procedure. Between January 2005 and December 2010, 50 consecutive patients were referred in our center for NP or RFA for a renal tumor with either a renal function impairment defined as estimated glomerular filtration (eGFR) less than 60 mL/min/1.73 m(2), and/or solitary kidney and/or bilateral tumors. Perioperative outcomes were compared. Thirty-six PN and 14 RFA were performed. RFA patients were older (79.2 vs. 62.5 years old), had a higher ASA score (3 vs. 2), a lower RENAL score (6 vs. 7.5) and a lower rate of tumor on solitary kidney or bilateral tumors (P=0.009). Overall complications (29.4% vs. 6.3%), transfusions (20.6% vs. 0) and longer hospital stay (9 vs. 3 days) were more likely to occur in the NP group. During a median follow-up of 22 months (4.3-53.7), eGFR decrease was similar between the two groups (P=0.34). On multivariate analysis, PN was associated with an increased occurrence of overall complications (OR=14.09, P=0.02) but with a similar eGFR decrease. No patient died. For patients with an indication of treatment of renal tumor and imperative nephron-sparing procedure, RFA seems to provide low morbidity and comparable functional outcomes as partial nephrectomy. Our limited follow-up does not permit to conclude on oncologic data.

Short-term efficacy of ultrasound-guided percutaneous ethanol injection enhanced single needle radiofrequency ablation in the treatment of liver cancer

Objective To investigate the short-tern efficacy of ultrasound-guided percutaneous ethanol injection (PEI) enhanced single needle radiofrequency ablation ( RFA) in the treatment of liver cancer.Methods The clinical data of 71 patients who were admitted to the Xijing Hospital from June 2010 to June 2011 were retrospectively analyzed.All patients were divided into the RFA group (25 patients ) and RFA + PEI group (46 patients).In the RFA group,the needle of RFA was injected into the tumor for coagulation with the guidence of ultrasound.In the RFA + PEI group,95％ ethanol was injected into the tumor with the guidence of ultrasound,and then RFA was performed.The tumor necrosis volumes of the 2 groups were assessed by contrast-enhanced ultrasound at 2 weeks after RFA.The relationship between the average RFA energy and volume of ethanol applied and necrosis volume was analyzed.All data were analyzed by using the chi-square test,t test and Pearson correlation coefficient.Results The volume of coagulative necrosis of the RFA group was (22 ± 17) cm3,which was significantly smaller than (55 ± 44) cm3 of the RFA + PEI group (t =3.85,P ＜ 0.05 ).In the RFA + PEI group,the volume of ethanol injected was positively correlated with the volume of coagulative necrosis (r =0.615,t =5.86,P ＜ 0.05 ),but negatively correlated with the treatment efficacy ( r =- 0.709,t =- 7.52,P ＜ 0.05 ).The amount of required energy was positively correlated with the volume of coagulative necrosis (r =0.884,t =14.13,P ＜0.05 ),whereas no significant correlation was detected between the amount of required energy and the treatment efficacy ( r =- 0.225,t =- 1.72,P ＞ 0.05 ).The equation for calculating the volume of ethanol required was conducted:Y =2.526X - 2.693 [ Y:volume of ethanol required ( ml),X:diameter of the tumor (cm) ].Three patients in the RFA + PEI group were complicated by transient pain,flushing and cardiac acceleration after the operation,and the symptoms were alleviated by symptomatic treatment.The levels of transaninase were increased in the 3 groups,and then back to normal at 2 weeks after the treatment.No complications such as hepatic rupture,intestinal perforation,bile leakage or tumor implantation were detected in the 2 groups.The levels of alphafetoprotein (AFP) were significantly decreased.The AFP expressions of 20 patients (80％) in the RFA group and 39 patients (85％) in the RFA + PEI group changed to negative,with no significant difference between the 2 groups ( x2 =0.42,P ＞ 0.05 ).Conclusion PEI helps to increase the volume of coagulative necrosis and to reduce the energy requirement of routine RFA,and enhances the efficacy of single needle RFA. Key words: Liver neoplasms; Ultrasound guidence; Percutaneous ethanol injection; Radiofrequency ablation, single needle

Long-Term Outcomes of Renal Tumor Radio Frequency Ablation Stratified by Tumor Diameter: Size Matters

Renal tumor size influences the efficacy of radio frequency ablation but identification of confident size cutoffs has been limited by small numbers and short followup. We evaluated tumor size related outcomes after radio frequency ablation for patients with adequate (greater than 3 years) followup. We identified 159 tumors treated with radio frequency ablation as primary treatment. Disease-free survival was defined as the time from definitive treatment to local recurrence, detection of metastasis or the most recent imaging showing no evidence of disease. Patients were evaluated with contrast enhancing imaging preoperatively, and at 6 weeks, 6 months and at least annually thereafter. Median tumor size was 2.4 cm (range 0.9 to 5.4) with a median followup of 54 months (range 1.5 to 120). Renal cell carcinoma was confirmed in 72% of the 150 tumors that had pre-ablation biopsy (94%). The 3 and 5-year disease-free survival was comparable at 92% and 91% overall, and was dependent on tumor size, being 96% and 95% for tumors smaller than 3.0 cm and 79% and 79%, respectively, for tumors 3 cm or larger (p=0.001). Most failures (14 of 18) were local, either incomplete ablations or local recurrences. This is an intent to treat analysis and, therefore, includes patients ultimately found to have benign tumors, although outcomes were comparable in patients with cancer. Radio frequency ablation treatment success of the small renal mass is strongly correlated with tumor size. Radio frequency ablation provides excellent and durable outcomes, particularly in tumors smaller than 3 cm. Of tumors 3 cm or larger, approximately 20% will recur such that alternative treatment techniques should be considered. However, most treatment failures are local and are often successfully treated with another ablation session.

Long‐Term Efficacy of Single Procedure Remote Magnetic Catheter Navigation for Ablation of Ischemic Ventricular Tachycardia: A Retrospective Study

Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long-term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open-irrigated-tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long-term success as freedom from VT upon follow-up. There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long-term success in RMN group: after a median of 13 (range 1-34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long-term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time.

POSTER PRESENTATIONS

POSTER PRESENTATIONS

Focal atrial tachycardia originating from the distal portion of the left atrial appendage: characteristics and long-term outcomes of radiofrequency ablation

The characteristics and response to ablation therapy of focal atrial tachycardia (AT) originating from the distal portion of left atrial appendage (LAAd) are still not quite clear up to now. The goal of this study is to characterize electrocardiographic and electrophysiological features and radiofrequency ablation (RFA) outcomes in patients with focal AT originating from the LAAd. Fourteen patients (2.1%) (mean age, 25 ± 10 years; nine women; mean symptom duration, 5 ± 5 years) undergoing RFA of focal AT originating from the LAAd were included out of 668 RFA patients. Activation mapping was performed. P waves were classified as negative, positive, isoelectric, or biphasic. Tachycardia that was incessant in all, demonstrated a characteristic P-wave morphology and endocardial activation pattern: P wave was negative in leads I and aVL, highly positive in the inferior leads, and broad and positive in lead V₁. Radiofrequency ablation was acutely successful in 13 of 14 patients. The endocardial activation time of the successful RFA sites was 47.1 ± 4.3 ms before the onset of P wave. There were no complications in any of the 14 patients and long-term success was achieved in 13 of 13 successful RFA patients during follow-up (5 ± 2 years). The LAAd is an uncommon site of origin for focal AT (2.1% incidence). In this case series, focal ATs originating from the LAAd had typical electrophysiological and electrocardiographic characteristics. Focal ablation yielded high acute success rate with low rate of recurrence during follow-up.

Mortality and complication rates of percutaneous ablative techniques for the treatment of liver tumors: a systematic review

Reported rates of major complications and mortality of radiofrequency ablation (RFA), microwave ablation (MWA) and percutaneous ethanol injection (PEI) for the treatment of liver tumours were substantially heterogeneous among studies. The aim was to analyse the mortality and major complication rates of percutaneous RFA, PEI and MWA. MEDLINE and EMBASE search from January 1982 to August 2010. Randomised clinical trials and observational studies, age >18, more than 50 patients for each technique analysed, studies reporting mortality and major complications were included. Random effects model was performed, with assessment for heterogeneity and publication bias. Thirty-four studies including 9531, 1185, and 1442 patients for RFA, MWA, and PEI, respectively were included. For all ablative techniques pooled proportion mortality rate was 0.16% (95% confidence interval [CI], 0.10-0.24). Pooled mortality rate associated with RFA, PEI and MWA was 0.15% (0.08-0.23), 0.59% (0.14-1.3) and 0.23% (0.0-0.58) respectively. Pooled proportion of major complications was 3.29% (2.43-4.28). Major complication rates associated with RFA, MWA, and PEI was 4.1% (3.3-5.1), 4.6% (0.7-11.8) and 2.7% (0.28-7.4) respectively. Percutaneous RFA, PEI and MWA can be considered safe techniques for the treatment of liver tumours.

Percutaneous Sonographically Guided Radio Frequency Ablation of Hepatocellular Carcinoma

The purposes of this study were to evaluate the causes of mistargeting during percutaneous sonographically guided radio frequency ablation in patients with hepatocellular carcinoma and to determine factors affecting the feasibility of a second ablation session. This study received Institutional Review Board approval, and informed consent was waived. Among 2213 percutaneous sonographically guided radio frequency ablations performed in our hospital, we searched for mistargeting cases and analyzed the causes of mistargeting. To determine which factors affected the feasibility of a second ablation session, univariate and multivariate analyses were performed. Forty-one cases of mistargeting occurred during the first ablation session, and 4 cases occurred during the second session. Of the 41 patients with mistargeted hepatocellular carcinomas during the first session, 39 who underwent replanning sonography were able to be analyzed for causes of mistargeting. The most common cause of mistargeting was confusion with cirrhotic nodules (87.2% [34 of 39]), followed by poor conspicuity of the hepatocellular carcinoma (69.2% [27 of 39]), a poor sonic window (28.2% [11 of 39]), a poor electrode path (7.7% [3 of 39]), and inaccurate electrode placement (2.6% [1 of 39]). Artificial ascites (P = .035) and the presence of more than 3 mistargeting causes (P = .017) were independent factors affecting feasibility. The most common cause of mistargeting was confusion with cirrhotic nodules, followed by poor conspicuity of the hepatocellular carcinoma, a poor sonic window, a poor electrode path, and inaccurate electrode placement. The use of artificial ascites and the presence of more than 3 mistargeting causes were factors affecting the feasibility of a second radio frequency ablation session.

Comparison of radiofrequency ablation and transarterial chemoembolization for hepatocellular carcinoma within the Milan criteria: A propensity score analysis

Radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) are used to treat hepatocellular carcinoma (HCC). This study was designed to compare the long-term survival of HCC patients within the Milan criteria who underwent RFA or TACE. In all, 315 RFA patients and 215 TACE patients with HCC within the Milan criteria were analyzed. Propensity scores were generated to select matched patients. For the propensity model, 101 patients were selected from each arm of the study. Independent prognostic predictors were determined with the Cox proportional hazards model. The long-term survival was significantly better for the RFA group in the univariate survival analysis (P = 0.048). In the Cox model, the following were identified as independent predictors of poor prognosis (TACE was not): age > 69 years (P = 0.026), serum α-fetoprotein level > 20 ng/mL (P = 0.003), ascites (P < 0.001), Eastern Cooperative Oncology Group performance status ≥ 1 (P = 0.004), total tumor volume (TTV) > 8.2 cm³ (P = 0.020), and vascular invasion (P = 0.023). With similar baseline patient characteristics generated in the propensity score model, there was no significant difference in the long-term survival rates of the 2 groups of patients. A subgroup analysis showed that among patients with a TTV < 11 cm³, the RFA group had significantly better long-term survival than the TACE group (P = 0.032). In conclusion, TACE and RFA lead to comparable long-term survival rates for HCC patients within the Milan criteria. Patients with a smaller TTV (<11 cm³) are likely to benefit more from RFA treatment. Further studies are needed to compare RFA and TACE in patients with early-stage cancers.