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Purpose: To retrospectively assess the feasibility, safety, and efficacy of artificial carbon dioxide (CO 2 ) pneumothorax for computed tomography (CT) fluoroscopy-guided percutaneous radiofrequency (RF) ablation of hepatocellular carcinoma (HCC)., Materials and Methods: This study included 26 sessions of 24 patients in whom the creation of artificial CO 2 pneumothorax was attempted to avoid the transpulmonary route during CT fluoroscopy-guided percutaneous RF ablation of HCC between April 2011 and December 2017. In these 26 sessions, 29 HCCs (mean tumor diameter: 12 mm, range: 6-22 mm) were treated., Results: Adequate lung displacement after induction of artificial CO 2 pneumothorax was achieved in 23 of the 26 sessions (88.5%). In the remaining three sessions, transpulmonary RF ablation, transthoracic extrapulmonary RF ablation after switching to an artificial pleural effusion procedure, or RF ablation with electrode insertion in the caudal-cranial oblique direction was performed. No major complications were found. Among the 29 treated tumors, one (3.4%) showed local progression, and the other 28 (96.6%) were completely ablated at the last follow-up (mean follow-up period: 39.3 months, range: 7-78 months)., Conclusion: Artificial CO 2 pneumothorax for CT fluoroscopy-guided percutaneous RF ablation appeared to be a feasible, safe, and useful therapeutic option for HCC., (© 2021. Japan Radiological Society.)

Purpose: This multicenter phase I/II study evaluated the safety, feasibility, and initial efficacy of radiofrequency ablation (RFA) for small malignant renal tumors., Methods: Thirty-three patients were enrolled in the study. A single session of RFA was performed in patients with a renal tumor of 1-3 cm in greatest diameter, with the exception of lesions adjacent to the renal hilum. The primary endpoint was the safety of renal RFA, and the secondary endpoints were its feasibility and initial efficacy for local control, as well as the incidence and grade of adverse events. Clinical efficacy was evaluated by CT scans within 1 week and at a further 4 weeks after the procedure using the criteria adapted from the Response Evaluation Criteria in Solid Tumors., Results: The RFA procedure was completed in 100% (95% confidence interval [CI] 89-100%) of all 33 patients. There were no severe adverse events (0% [95% CI 0-11%]). Among the 33 patients, a complete response, partial response, progressive disease, and stable disease were seen in 28 (85%), 0 (0%), one (3%), and one (3%) patient(s), respectively, with a tumor response rate of 85% [95% CI 68-95%]). Three patients (9%), including one ineligible patient (3%), were not evaluable. Out of 30 evaluable patients, a complete response was achieved in 28 (93%)., Conclusion: The current multicenter trial revealed that RFA is a safe, feasible, and effective treatment for small malignant renal tumors in patients who are not candidates for surgery.

Purpose: The purpose of this study was to evaluate altered pulmonary function retrospectively after RFA., Methods: This retrospective study comprised 41 ablation sessions for 39 patients (22 men and 17 women; mean age, 64.8 years). Vital capacity (VC) and forced expiratory volume in 1 s (FEV(1)) at 1 and 3 months after RFA were compared with the baseline (i.e., values before RFA). To evaluate the factors that influenced impaired pulmonary function, univariate analysis was performed by using multiple variables. If two or more variables were indicated as statistically significant by univariate analysis, these variables were subjected to multivariate analysis to identify independent factors., Results: The mean VC and FEV(1) before RFA and 1 and 3 months after RFA were 3.04 and 2.24 l, 2.79 and 2.11 l, and 2.85 and 2.13 l, respectively. The values at 1 and 3 months were significantly lower than the baseline. Severe pleuritis after RFA was identified as the independent factor influencing impaired VC at 1 month (P = 0.003). For impaired FEV(1) at 1 month, only severe pleuritis (P = 0.01) was statistically significant by univariate analysis. At 3 months, severe pleuritis (VC, P = 0.019; FEV(1), P = 0.003) and an ablated parenchymal volume ≥20 cm(3) (VC, P = 0.047; FEV(1), P = 0.038) were independent factors for impaired VC and FEV(1)., Conclusions: Pulmonary function decreased after RFA. RFA-induced severe pleuritis and ablation of a large volume of marginal parenchyma were associated with impaired pulmonary function.

Purpose: To retrospectively investigate the incidence of and risk factors for phrenic nerve injury after radiofrequency (RF) ablation of lung tumors., Materials and Methods: The study included 814 RF ablation procedures of lung tumors. To evaluate the development of phrenic nerve injury, chest radiographs obtained before and after the procedure were examined. Phrenic nerve injury was assumed to have developed if the diaphragmatic level was elevated after the procedure. To identify risk factors for phrenic nerve injury, multiple variables were compared between cases of phrenic nerve injury and randomly selected controls by using univariate analyses. Multivariate analysis was then performed to identify independent risk factors., Results: Evaluation of phrenic nerve injury from chest radiographs was possible after 786 procedures. Evidence of phrenic nerve injury developed after 10 cases (1.3%). Univariate analysis revealed that larger tumor size (≥ 20 mm; P = .014), proximity of the phrenic nerve to the tumor (< 10 mm; P < .001), the use of larger electrodes (array diameter or noninsulated tip length ≥ 3 cm; P = .001), and higher maximum power applied during ablation (≥ 100 W; P < .001) were significantly associated with the development of phrenic nerve injury. Multivariate analysis demonstrated that the proximity of the phrenic nerve to the tumor (< 10 mm; P < .001) was a significant independent risk factor., Conclusions: The incidence of phrenic nerve injury after RF ablation was 1.3%. The proximity of the phrenic nerve to the tumor was an independent risk factor for phrenic nerve injury., (Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.)

The present report describes three cases of a bronchiolitis obliterans organizing pneumonia (BOOP)-like reactive pneumonitis following radiofrequency (RF) ablation for lung cancer. The incidence of BOOP-like reactive pneumonitis after RF ablation at the authors' institution was estimated to be approximately 0.4% (three of 840 sessions). The patients presented with nonspecific symptoms. Computed tomography images showed consolidation or ground-glass opacity in a peripheral-dominant distribution and/or patchy air-space opacities. The disease was nonresponsive to antibiotic therapy but responded favorably to pulse therapy of steroids. BOOP-like reactive pneumonitis should be recognized as a complication following lung RF ablation., (Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.)

The aim of the present study was to assess the diagnostic usefulness of Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the prediction of local recurrence of malignant lung tumors by analyzing the pre-radiofrequency ablation (RFA) maximal standardized uptake value (SUV(max)). We performed a historical cohort study of consecutive malignant lung tumors treated by RFA from January 2007 to May 2008 at Okayama University Hospital. We selected only lung tumors examined by PET/CT within 90 days before RFA and divided them (10 primary and 29 metastatic) into 3 groups according to their tertiles of SUV(max). We calculated recurrence odds ratios in the medium group and the high group compared to the low group using multivariate logistic analysis. After we examined the relationship between SUV(max) and recurrence in a crude model, we adjusted for some factors. Tumors with higher SUV(max) showed higher recurrence odds ratios (medium group; 1.84, high group; 4.14, respectively). The tumor size also increased the recurrence odds ratio (2.67); we thought this was mainly due to selection bias because we excluded tumors less than 10mm in diameter. This study demonstrated the pre-RFA SUV(max) in PET/CT may be a prognostic factor for local recurrence of malignant lung tumors.

The application of radiofrequency ablation for the treatment of lung cancer by our group at Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences began in June 2001, and in the present report, we review our 10-year experience with this treatment modality at Okayama University Hospital. The local efficacy of radiofrequency ablation for the treatment of lung cancer depends on tumor size and the type of electrode used, but not on tumor type. An important factor for the prevention of local failure may be the acquisition of an adequate ablative margin. The combination of embolization and radiation therapy enhances the local efficacy. Local failure may be salvaged by repeating the radiofrequency ablation, particularly in small tumors. Survival rates after radiofrequency ablation are quite promising for patients with clinical stage I non-small cell lung cancer and pulmonary metastasis from colorectal cancer, hepatocellular carcinoma, and renal cell carcinoma. The complications caused by radiofrequency ablation can be treated conservatively in the majority of cases. However, attention should be paid to rare but serious complications. This review shows that radiofrequency ablation is a promising treatment for patients with lung cancer.

Objective: This study aimed at retrospectively evaluating the outcomes of radiofrequency ablation of clinical stage I non-small cell lung cancer., Methods: This study was carried out on 50 nonsurgical candidates (29 men and 21 women; mean age, 74.7 years) with clinical stage I (IA, n = 38; IB, n = 12) histologically proven non-small cell lung cancer. A total of 52 tumors were treated with 52 ablation sessions. Radiofrequency ablation was performed percutaneously under computed tomography fluoroscopic guidance. The outcomes of radiofrequency ablation were evaluated, including toxicity, local efficacy, and patient survival. Toxicity was evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0. Local efficacy was evaluated by using computed tomography scan with a contrast medium. The overall, cancer-specific, and disease-free survivals were estimated with Kaplan-Meier analysis., Results: Grade 2 and 3 adverse events occurred after 6 (12%) and 3 (6%) of the 52 sessions, respectively. The median follow-up period was 37 months. Local progression was observed in 16 (31%) of the 52 tumors. The median survival time was 67 months. The overall, cancer-specific, and disease-free survivals were 94%, 100%, and 82% at 1 year, 86%, 93%, and 64% at 2 years, and 74%, 80%, and 53% at 3 years, respectively., Conclusions: Radiofrequency ablation of clinical stage I non-small cell lung cancer was minimally invasive and provided promising patient survival, although the local efficacy needs to be improved., (Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Purpose: To retrospectively evaluate technical success, effectiveness, complications, patient survival, and prognostic factors with percutaneous radiofrequency (RF) ablation for pulmonary metastases resulting from hepatocellular carcinoma (HCC)., Materials and Methods: Thirty-two patients from six institutions were included, with a total of 83 pulmonary metastases treated in 65 sessions. RF ablation was always performed percutaneously with computed tomography (CT) guidance. Primary endpoints were technical success and technique effectiveness. Technique effectiveness was evaluated based on sequential follow-up CT images. Secondary study endpoints were complications, patient survival, and determination of prognostic factors. Complications were classified as major or minor. Prognostic factors were determined by analyzing multiple variables with the log-rank test., Results: Technical success rate was 100%. Primary technique effectiveness rates were 92% each at 1, 2, and 3 years. Major and minor complications occurred after 16 (25%) and 23 (35%) of the 65 sessions, respectively. The median follow-up period was 20.5 months. Overall survival rates were 87% at 1 year and 57% each at 2 and 3 years (median and mean survival times, 37.7 mo and 43.2 mo, respectively). Significantly better survival rates were obtained in cases of (i) no viable intrahepatic recurrence (P < .001), (ii) Child-Pugh class A disease (P < .001), (iii) absence of liver cirrhosis (P < .001), (iv) absence of hepatitis C virus infection (P = .006), and (v) α-fetoprotein level of 10 ng/mL or lower (P = .007) at the time of RF ablation., Conclusions: RF ablation appears effective, with an acceptable safety profile, in selected patients with pulmonary metastases resulting from HCC., (Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.)

This report describes seven cases in which a pneumothorax was artificially created for relief from severe pain that occurred during radiofrequency (RF) ablation of peripheral lung tumors. In this procedure, the multitined probe surrounding the lesion was advanced into the chest, displacing the tines and the peripheral tumor away from the parietal pleura and the chest wall and resulting in pain relief in one patient; in the remaining patients, an intravenous catheter was also introduced, followed by the administration of carbon dioxide (CO(2)) into the space between the tumor and the parietal pleura. The pain decreased considerably immediately after this procedure. No complication related to the creation of the artificial pneumothorax was observed. Creation of an artificial pneumothorax is a safe and effective method for pain relief., (Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.)

The present report describes four cases of brachial nerve injury caused by percutaneous radiofrequency (RF) ablation of lung cancer. All the tumors were located in the lung apex. The patients developed symptoms indicative of a low brachial plexus injury during RF ablation or as long as 7 days afterward. These symptoms partially receded over time. The indications of RF ablation in patients with apical lung cancer should be carefully determined because of the risk of brachial nerve injury associated with the procedure., (Copyright 2010 SIR. Published by Elsevier Inc. All rights reserved.)

Objective: : To retrospectively evaluate the effect of tumor type on local control by radiofrequency ablation in the lungs., Materials and Methods: : This study included 252 lung tumors (mean size, 13.5mm) in 105 patients (73 men and 32 women; mean age, 66.6 years) who underwent radiofrequency ablation with a multitined expandable electrode. Those tumors comprised five tumor types: primary lung cancer (n=35) and pulmonary metastases from colorectal cancer (n=117), lung cancer (n=23), renal cell carcinoma (n=49), and hepatocellular carcinoma (n=28). Local control was evaluated with contrast-enhanced computed tomography. The overall local control rates were estimated as well as those for each tumor type using the Kaplan-Meier analysis. Local control rates for a given tumor type were compared with those for the four other types. Then, multivariate multilevel analysis was performed using the variables of tumor type, tumor size, contact with a vessel or bronchus, and procedure period., Results: : The overall local control rates were 97%, 86%, 81%, and 76% at 6, 12, 18, and 24 months, respectively. Local control rates varied among the tumor types, and metastatic colorectal cancer showed significantly (P=.023) higher local control rates than those of the four other types. However, multivariate analysis indicated that the relative risk of local progression for a given tumor type was comparable to the risks for the four other types., Conclusion: : Tumor type per se did not significantly influence local control., (Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.)

We describe a case of pulmonary artery (PA) pseudoaneurysm related to radiofrequency ablation (RFA) of lung tumor. We performed RFA for a pulmonary epithelioid hemangioendothelioma directly adjacent to a branch of the PA. Seventeen days later, the patient complained of hemoptysis. A chest CT image revealed PA pseudoaneurysm. Transcatheter coil embolization was performed 59 days after RFA. Although PA pseudoaneurysm is rare, with an incidence of 0.2% (1/538 sessions) at our institution, it should be recognized as a risk when treating lung tumors adjacent to a branch of the PA.

Purpose: To determine which lung metastases are most likely to be treated effectively with a single radiofrequency (RF) application (defined as two separate applications of RF energy at a single electrode position) with a multitined expandable electrode with arrays 2 cm in diameter., Materials and Methods: The authors retrospectively evaluated 88 lung metastases (mean long-axis diameter, 0.9 cm) in 36 patients (20 men and 16 women; mean age, 57 years) treated with a single RF application with a multitined expandable electrode with arrays 2 cm in diameter. Based on follow-up computed tomographic examinations, the technique effectiveness rates were estimated with Kaplan-Meier analysis. Multiple variables were analyzed with the log-rank test to determine risk factors for local progression. Then, the technique effectiveness rates were again estimated when considering only metastases without risk factors and compared with those of other tumors., Results: The median follow-up period was 13.2 months (range, 6.0-24.7 months). Tumor size greater than 1.0 cm (P = .033) and contact with the bronchus with an inner diameter of at least 2 mm (P = .047) were the significant risk factors for local progression. The technique effectiveness rates for metastases 1.0 cm or smaller that were not in contact with the bronchus (n = 59) were 96% at 1 year and at 2 years; those rates were significantly (P = .010) higher than those in other tumors (n = 29)., Conclusions: A single RF application with a multitined expandable electrode with arrays 2 cm in diameter is most likely to suffice in small (

The present study was performed to clarify the effect of hypertonic saline infusion into the lung parenchyma on radiofrequency ablation (RFA) of the lungs. A total of 20 ablation zones were created in 3 pigs. The ablation zones were divided into 3 groups. Group 1 (n=6) consisted of ablation zones created by applying smaller radiofrequency (RF) power without saline infusion; group 2 (n=5) zones were created by applying greater RF power without saline infusion;and group 3 (n=9) zones were created by applying greater RF power with saline infusion. The techniques of saline infusion included administration of hypertonic saline 1 ml before RFA, followed by continuous administration at a rate of 1 ml/min during the first 2 min after the initiation of RFA. The ablation parameters and coagulation necrosis volumes were compared among the groups. Group 3 had a tendency toward smaller mean impedance than group 1 (p=0.059) and group 2 (p=0.053). Group 3 showed significantly longer RF application time than group 2 (p=0.004) and significantly greater maximum RF power than group 1 (p=0.001) and group 2 (p=0.004). Group 3 showed significantly larger coagulation necrosis volume (mean, 1,421mm3) than group 2 (mean, 858 mm3, p=0.039) and had a tendency toward larger necrosis volume than group 1 (mean, 878 mm3, p=0.077). Although this small study had limited statistical power, hypertonic saline infusion during RFA appeared to enlarge coagulation necrosis of the lung parenchyma.

The authors describe two cases of needle-tract seeding after percutaneous radiofrequency (RF) ablation for lung cancer. Needle biopsy was performed immediately before RF ablation in one case. In both cases, RF ablation was performed with a single internally cooled electrode, which was removed without cauterizing the electrode tract. The seeding nodule appeared 4 or 7 months after RF ablation and was then completely treated with a repeat RF ablation.

Purpose: To retrospectively evaluate the role of repeat radiofrequency (RF) ablation for local progression of lung tumors in local tumor control., Materials and Methods: From June 2001 to February 2007, the authors treated 797 lung tumors (primary lung cancer, n=66; metastatic lung neoplasm, n=731; mean tumor size, 1.7 cm) in 295 patients with RF ablation. After RF ablation, patients were followed-up with contrast-enhanced chest computed tomography at 1, 3, 6, 9, and 12 months and thereafter at 6-month intervals. Local progression was observed in 117 of the 797 lung tumors. Fifty repeat RF ablation sessions were performed for 56 tumors (primary lung cancer, n=9; metastatic lung neoplasm, n=47; mean tumor size, 2.7 cm) in 46 patients (33 men, 13 women; mean age, 59.6 years). Repeat RF ablation was not performed for the remaining 61 locally progressing tumors because it was not presumed to provide survival benefit. For all 797 tumors, the overall primary and secondary technique effectiveness rates (TERs) after the first RF ablation were compared with each other. To determine the risk factors for local control with repeat RF ablation, multiple variables were analyzed. Next, local control with repeat RF ablation was evaluated for tumors with and tumors without risk factors., Results: The overall secondary TERs were significantly higher than the overall primary TERs (P<.00001). Tumor size of at least 2 cm at the first RF ablation (P=.045) and contact with bronchi (P=.045) or vessels (P=.048) were risk factors for local control with repeat RF ablation. The secondary TERs after the first RF ablation were 94% at 1 year, 68% at 2 years, and 55% at 3 years for tumors without risk factors and 60% at 1 year and 40% at 2 years for tumors with at least one risk factor. Among the 50 repeat RF ablation sessions, pneumothorax occurred in 13 sessions (26%), one of which necessitated chest tube placement; pleural effusion occurred in nine sessions (18%), all of which resolved spontaneously. Thermal injury of the brachial plexus occurred after one session., Conclusions: Repeat RF ablation improved the overall local control outcomes. In particular, it offered an opportunity to salvage tumors that had no risk factors but nevertheless progressed locally after the first RF ablation. Conversely, tumors with risk factors were not controlled sufficiently even after repeating the procedure.

The purpose of this study was to investigate the relationship between pleural temperature and pneumothorax or pleural effusion after radiofrequency (RF) ablation of lung tumors. The pleural temperature was measured immediately outside the lung surface nearest to the tumor with a fiber-type thermocouple during 25 ablation procedures for 34 tumors in 22 patients. The procedures were divided into two groups depending on the highest pleural temperature: P-group I and P-group II, with highest pleural temperatures of <40 degrees C and >/=40 degrees C, respectively. The incidence of pneumothorax or pleural effusion was compared between the groups. Multiple variables were compared between the groups to determine the factors that affect the pleural temperature. The overall incidence of pneumothorax and pleural effusion was 56% (14/25) and 20% (5/25), respectively. Temperature data in five ablation procedures were excluded from the analyses because these were affected by the pneumothorax. P-group I and P-group II comprised 10 procedures and 10 procedures, respectively. The incidence of pleural effusion was significantly higher in P-group II (4/10) than in P-group I (0/10) (p = 0.043). However, the incidence of pneumothorax did not differ significantly (p = 0.50) between P-group I (4/10) and P-group II (5/10). Factors significantly affecting the pleural temperature were distance between the electrode and the pleura (p < 0.001) and length of the lung parenchyma between the electrode and the pleura (p < 0.001). We conclude that higher pleural temperature appeared to be associated with the occurrence of pleural effusion and not with that of pneumothorax.

Introduction: Local treatment that includes surgical resection of metastatic pulmonary tumors is controversial because of the biologic features and invasiveness of these tumors. We report our experience with a premeditated treatment involving combined computed tomography-guided radiofrequency ablation and surgical resection in three patients with metastatic pulmonary tumors., Methods: Three patients underwent radiofrequency ablation in conjunction with surgical resection. The first was a 67-year-old man with pulmonary metastases of bronchial adenoid cystic carcinoma. We performed partial resection of five tumors in the right lung and ablated a tumor in the left lung. The second was a 66-year-old man with pulmonary metastases of renal cell carcinoma. He underwent radiofrequency ablation for three tumors in the right upper and middle lobes, and right lower lobectomy for tumors in that lobe. The third was a 55-year-old man with pulmonary metastases of high-grade sarcoma of the right thigh. We performed partial resection of five tumors in the left lung and ablated a tumor in the right lung., Results: Two patients had metastatic lesions on both sides of the lung; we performed surgical resection on one side and radiofrequency ablation contralaterally to avoid bilateral thoracotomy. The third patient underwent surgical resection and radiofrequency ablation to avoid highly invasive right pneumonectomy. All patients survived for more than 1(1/2) years after combination therapy., Conclusions: Premeditated treatment involving a combination of radiofrequency ablation and surgical resection can be a useful option in patients with metastatic pulmonary tumors, improving curability and avoiding highly invasive procedures.

Objective: Our objective was to evaluate the outcomes of radiofrequency ablation for nonsurgical candidates with clinical stage I non-small cell lung cancer., Methods: This study was carried out on 20 nonsurgical candidates (11 men and 9 women; mean age, 75.6 years) with clinical stage I (IA, n = 14; IB, n = 6) non-small cell lung cancer. All patients were deemed nonsurgical candidates because of poor pulmonary function (n = 7), poor cardiac function (n = 3), poor performance status (n = 4), or refusal to undergo surgery (n = 6). The mean long-axis tumor diameter was 2.4 cm. Twenty patients underwent 23 percutaneous ablation sessions, including 3 repeat sessions for the treatment of local progression. The outcomes of radiofrequency ablation were retrospectively evaluated., Results: Procedural complications included pneumothorax (n = 13 [57%]) and pleural effusion (n = 4 [17%]). One case of pneumothorax required chest tube placement. The median follow-up period was 21.8 months. Local progression was observed in 7 (35%) patients a median of 9.0 months after the first session. The local control rates were 72% at 1 year, 63% at 2 years, and 63% at 3 years. The mean survival time was 42 months. The overall survivals and cancer-specific survivals were 90% and 100% at 1 year, 84% and 93% at 2 years, and 74% and 83% at 3 years, respectively., Conclusions: Treating clinical stage I non-small cell lung cancer with one or more radiofrequency ablation sessions provided promising outcomes in terms of survival, although the rate of local progression was relatively high. A prospective study with a larger population and longer follow-up is warranted.

Purpose: To retrospectively evaluate the midterm outcomes (eg, safety, local efficacy, and survival) after radiofrequency (RF) ablation for pulmonary metastases from colorectal cancer., Materials and Methods: Twenty-seven patients (19 men and eight women; mean age, 61.6 years) with 49 pulmonary metastases (mean long axis diameter, 1.5 cm) from colorectal cancer underwent 41 percutaneous computed tomography (CT)-guided RF ablation sessions. Follow-up examinations were performed with CT by using contrast medium administration in all patients; positron emission tomography was performed in five patients. The safety of the procedure, local tumor control, and patient survival were evaluated. Multiple variables were analyzed to determine prognostic factors., Results: Pneumothorax occurred after 20 of the 41 sessions (49%), three of which necessitated chest tube placement. A small pleural effusion was found after six of the 41 sessions (15%). No major hemorrhagic event was observed. None of the patients died due to the procedure. The median follow-up period was 20.1 months (range, 11.2-47.7 months). The primary and secondary technique effectiveness rates were 72% and 85%, respectively, at 1 year, 56% and 62% at 2 years, and 56% and 62% at 3 years. The overall survival rates after RF ablation were 96% at 1 year, 54% at 2 years, and 48% at 3 years. The presence of extrapulmonary metastasis was determined to be a prognostic factor (P = .001)., Conclusions: The midterm outcomes of percutaneous RF ablation for colorectal pulmonary metastases appear promising. The presence of extrapulmonary metastasis had an adverse effect on survival after RF ablation.

Purpose: The authors retrospectively evaluated the safety and effectiveness of percutaneous radiofrequency ablation of lung tumors close to the heart or aorta., Materials and Methods: Forty-two tumors (mean diameter, 25 mm +/- 16; range, 5-73 mm) located less than 10 mm from the heart or aorta were treated with radiofrequency ablation in 47 sessions. Lung tumors were classified into two groups according to their distance from the heart or aorta: group A (n = 27) comprised tumors at a distance of 1-9 mm; group B (n = 15) comprised contiguous tumors (distance, 0 mm). The safety and technique effectiveness of the procedure, defined as no evidence of local tumor progression, were evaluated., Results: Radiofrequency ablation was feasible for all the 42 tumors. Procedural complications included asymptomatic pleural effusion (n = 5), small pneumothorax (n = 11), pneumothorax that necessitated chest tube placement (n = 4), and lung abscess (n = 1). No complications related to the specific tumor location, such as the accidental insertion of the electrode into the heart or aorta, pericardial effusion, arrhythmia, or cardiac infarction, occurred. The overall primary technique effectiveness rate was 75.8%, 45.9%, and 45.9% at 6, 12, and 24 months, respectively. This rate in group A (94.7%, 69.3%, and 69.3% at 6, 12, and 24 months, respectively) was significantly (P < .001) higher than that in group B (42.9% and 8.6% at 6 and 12 months, respectively)., Conclusions: Radiofrequency ablation of lung tumors close to the heart or aorta was safely performed. The local control of tumors contiguous to the heart or aorta was considerably lower compared with the tumors that were close but not contiguous to these structures.

We report the clinical experience of radiofrequency ablation followed by radiation therapy for large primary lung tumors. Two patients with large primary lung tumors were treated with combined radiofrequency ablation and radiation therapy, and good local control was observed. Combined radiofrequency ablation and radiation therapy that involves minimally invasive techniques appears to be promising for the treatment of large lung tumors.

We describe two cases of intractable pneumothorax that were attributed to a bronchopleural fistula (BPF) after radiofrequency ablation of lung tumors. In both cases, radiofrequency ablation induced necrosis of the lung tissue between the pleural space and the bronchus. The bronchopleural fistula formed after sloughing of the necrotic tissue. Management of the bronchopleural fistula was quite challenging, requiring frequent treatments, including pleurodesis, endobronchial management, and/or surgical repair. In one of the patients, air leakage persisted despite these efforts, and the patient died of acute pneumonia 52 days after the procedure. Although it is rare, with an incidence of 0.6% (2/334) at our institution, intractable pneumothorax due to bronchopleural fistula should be recognized as a risk associated with radiofrequency ablation of lung tumors.

Purpose: The present study was performed to evaluate the effect of pulmonary artery embolization on radiofrequency (RF) ablation of normal porcine lungs., Materials and Methods: RF ablation zones (n=34) were created in the normal lungs of five domestic pigs (five zones in each of the first two pigs and eight zones in each of the remaining three pigs) with an expandable multitined electrode with use of bilateral thoracotomy. RF ablation was performed without pulmonary artery embolization (group 1, n=8), immediately after embolization (group 2, n=11), 15 minutes after embolization (group 3, n=7), and 30 minutes after embolization (group 4, n=8) with degradable starch microspheres. Among them, 12 ablation zones were excluded from this study because they were considerably limited by the presence of the pleura or large bronchi. The remaining 22 zones were included (n=7, n=5, n=4, and n=6 in groups 1, 2, 3, and 4, respectively). Coagulation necrosis volumes in the ablation zones were measured and compared among the groups., Results: Coagulation necrosis volumes were 0.9+/-0.5 cm3, 2.1+/-0.4 cm3, 2.1+/-1.0 cm3, and 1.9+/-0.6 cm3 in groups 1, 2, 3, and 4, respectively. Groups 2-4 showed significantly larger coagulation volumes than group 1 (P=.012, P=.023, and P=.010 in groups 2, 3, and 4, respectively)., Conclusion: Pulmonary artery embolization contributed to larger volumes of coagulation necrosis after RF ablation of normal lungs.

Purpose: To retrospectively evaluate the incidence of and risk factors for pneumothorax, pleural effusion, and chest tube placement for pneumothorax after radiofrequency (RF) ablation of lung tumors., Materials and Methods: Institutional review board approval was obtained, with waiver of informed consent. This retrospective study comprised 224 ablation sessions for 392 tumors in 142 patients (92 men, 50 women; mean age, 64.0 years). Multiple variables were analyzed by using the Student t test or the Mann-Whitney U test for numerical values and by using the chi(2) test or the Fisher exact test for categorical values in order to assess risk factors for pneumothorax, pleural effusion, and chest tube placement for pneumothorax., Results: The incidence of pneumothorax, pleural effusion, and chest tube placement for pneumothorax was 52% (117 of 224 sessions), 19% (42 of 224 sessions), and 21% (24 of 117 sessions), respectively. For pneumothorax, risk factors included male sex (P = .030), no history of pulmonary surgery (P < .001), a greater number of tumors ablated (P < .001), involvement of the middle or lower lobe (P = .008), and increased length of the aerated lung traversed by the electrode (P = .014). For pleural effusion, risk factors included the use of a cluster electrode (P = .008), decreased distance to the nearest pleura (P = .040), and decreased length of the aerated lung traversed by the electrode (P = .019). For chest tube placement for pneumothorax, risk factors included no history of pulmonary surgery (P = .002), the use of a cluster electrode (P < .001), and involvement of the upper lobe (P < .001)., Conclusion: Pneumothorax and pleural effusion can occur after RF ablation in patients with lung tumors, and chest tube placement for pneumothorax is sometimes required., ((c) RSNA, 2006.)

A 56-year-old man had a lung metastasis from hepatocellular carcinoma 4.7 cm x 3.4 cm in size located directly adjacent to the pulmonary hilar vessels. The tumor was treated with radiofrequency ablation combined with earlier bronchial arterial chemoembolization and subsequent radiation therapy. A complete remission of the tumor has been observed for 6 months since completion of therapy. Considering that complete treatment of such an intermediate-sized tumor adjacent to the large vessels is usually difficult with radiofrequency ablation alone, this result suggests a possible role for combined therapy for pulmonary neoplasms.

We quantitatively evaluated total and individual renal function by technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) renal scintigraphy before and after radiofrequency ablation (RFA) of renal tumors. Eleven patients who underwent Tc-99m MAG3 renal scintigraphy 1 week before and after RFA were evaluated (7 men and 4 women; age range: 23-83 years; mean age: 60.6 years). Five patients had solitary kidneys, and five had normally or minimally functioning contralateral kidneys. One patient had a renal cell carcinoma in the contralateral kidney. One patient with a solitary kidney underwent RFA a second time for a residual tumor. In patients with a solitary kidney, MAG3 clearance decreased after 5 of 6 RFAs, and in patients with a normally functioning contralateral kidney, MAG3 clearance decreased after 4 of 5 RFAs, but no significant differences were observed between before and after treatments. In addition to the total MAG3 clearance, the split MAG3 clearance was evaluated in patients with a normally functioning contralateral kidney. MAG3 clearance decreased in 4 of 5 treated kidneys, while it adversely increased in the contralateral kidneys after 4 of 5 RFAs. No significant differences, however, were observed between before and after treatments. The results of our study revealed no significant differences in sCr, BUN, CCr, or MAG3 clearance between pre- and post-RFA values. These results support data regarding the functional impact and safety of renal RFA in published reports. We evaluated total and individual renal function quantitatively using Tc-99m MAG3 renal scintigraphy before and after treatment. This scintigraphy was very useful in assessing the effects of RFA on renal function.

Institutional review board approval and patient informed consent were obtained. Radiofrequency ablation in a total of 10 sessions was performed for each mediastinal lymph node metastasis from esophageal cancer that had a mean largest diameter of 2.2 cm +/- 0.6 (standard deviation) in seven male patients (mean age, 59 years). During ablation, cooling and temperature of the tracheal mucosa were monitored in the proper position in eight of the 10 sessions; in the other two sessions, monitoring was not done because of tracheal stenosis (perforation resulted). Three of the four lymph nodes that were 2.0 cm or smaller in largest diameter showed no evidence of local progression for at least 1 year since ablation; all three of the nodes greater than 2.0 cm in largest diameter progressed within 6 months. The 1-year survival rate was 60%; the median survival time was 13 months. Radiofrequency ablation may be effective for local control of small metastatic mediastinal lymph nodes, and cooling and temperature monitoring of the tracheal mucosa in the proper position may prevent thermal tracheal damage., (RSNA, 2005)

Recent technological development has allowed expanding applications of radiofrequency ablation (RFA) for malignant tumor therapy. We report a case with a spinal metastatic tumor treated with combination of percutaneous vertebroplasty (PVP) that provides pain relief and spinal stabilization and RFA. A 68-year-old male who had undergone resection of left ureteric carcinoma was referred to our hospital with lower back pain due to the fifth lumbar (L5) vertebral metastatic tumor. Conventional radiation therapy was discontinued because of pneumonia. One year later, the patient was admitted again with weakness of the right knee and foot and severe pain of the back and the right lower extremity. Radiographs demonstrated a compressive fracture of the L5 vertebra predominantly on the right side. CT and MRI showed a tumor of the L5 body invading the right pedicle, the intervertebral foramen, and the retroperitoneal space. RFA was performed in the ventral part of the L5 body, and then around the right L5/the first sacral intervertebral foramen. Temperature and time for ablation ranged from 74 degrees C to 95 degrees C and from 11 min. to 30 min., respectively. Next, PVP was performed by the right transpedicular approach. Bone cement was injected into the L5 body and the pedicle by an amount of 3.0 ml in total without technical complications. Postoperatively, visual analogue scale demonstrated decreased pain degree from 10 cm to 5.4 cm. Combined treatment with RFA and PVP is a feasible and promising procedure for spinal metastatic tumors. Further evaluation is necessary to confirm its long-term efficacy.

Purpose: To determine the effectiveness of computed tomography (CT)-guided radiofrequency (RF) ablation of malignant thoracic tumors., Materials and Methods: CT-guided RF ablations of 99 malignant thoracic tumors (3-80 mm in largest diameter; mean, 19.5 mm) were performed in 35 patients in 54 sessions. Ablation was performed with an RF generator by using a single internally cooled electrode. Tumors were both primary (three lesions) and secondary (pulmonary or pleural metastases, 96 lesions). Follow-up was 1-17 months (mean, 7.1 months). Follow-up CT and histopathologic examinations were evaluated. Univariate analysis was performed with the Fisher exact test, and Welch t test was used to evaluate differences between group means. P <.05 represented a significant difference. The maximal diameter of each residual tumor or local recurrence or the proportion of primary lesions of pulmonary metastatic tumors with recurrence after RF ablation were analyzed. Complications, management, and outcomes of the complications were recorded., Results: The appearance of each ablation zone, including the target tumor and surrounding normal lung parenchyma, showed involution at follow-up CT. Local recurrence was demonstrated histopathologically or radiologically in nine tumors. The other 90 tumors showed no growth progression at follow-up CT. Probable complete coagulation necrosis obtained with initial RF ablation was achieved in 91% (90 of 99) of the tumors. The mean maximal diameter of the nine tumors (19.6 mm +/- 7.7 [SD]) was not significantly different (P =.994) from that of the other 90 tumors (19.5 mm +/- 13.0). Primary lesions of those nine metastatic tumors varied and did not demonstrate a specific tendency. Complications included pneumothorax, fever higher than 37.5 degrees C, hemoptysis, cough, pleural effusion, abscess formation, and hemothorax. The overall complication rate was 76% (41 of 54 sessions)., Conclusion: RF ablation seems to be a promising treatment for malignant thoracic tumors., (Copyright RSNA, 2004)

We performed radiofrequency ablation (RFA) for 14 patients with hepatocellular carcinoma (HCC) between May 2001 and March 2002. The underlying hepatic disease was type C liver cirrhosis in all patients. Seven patients had a solitary lesion, and 7 patients had multiple lesions. RFA was chosen for the primary tumor in 5 cases and for a recurrent tumor in 9 cases. Three cases of well differentiated HCC were included. Transcatheter arterial embolization (TAE) was performed in 10 cases simultaneously. Nine patients received RFA under general anesthesia (open laparotomy: 5 cases, transthoracic: 1 case, CT guided: 2 cases, US guided: 1 case) and 5 patients under local anesthesia (CT guided: 2 cases, US guided: 3 cases). RFA was performed for 12 minutes in each session and the mean number of sessions per patient was 3.2. Excellent ablation was achieved in all cases according CT evaluation, and no additional therapy was needed. No recurrences have been found in any cases so far. RFA for HCC achieved excellent therapeutic effect in combination with other therapies as multimodal therapy.