Radiofrequency ablation combined with chemoembolization for the treatment of hepatocellular carcinomas 5 cm or smaller: risk factors for local tumor progression

PURPOSE: To investigate the risk factors for local tumor progression after radiofrequency (RF) ablation combined with chemoembolization for the treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 255 HCC lesions 5 cm or less in maximum diameter were treated by RF ablation in 173 patients within 2 weeks after chemoembolization was performed. Therapeutic response was evaluated by contrast medium-enhanced computed tomography studies. The disappearance of tumor enhancement was considered to indicate complete necrosis. Local tumor progression was defined by the appearance of enhanced tumor adjacent to the zone of ablation. The risk factors for local tumor progression after RF ablation were retrospectively assessed by univariate and multivariate analyses. RESULTS: All tumors showed complete necrosis after RF ablation. Local tumor progression was found in 18 of the 255 lesions (7%) during a mean follow-up period of 23 months (range, 1-63 months). The cumulative local tumor progression rate was 12% at 5 years. Larger tumor (3.1-5 cm), infiltrating tumor, and previous treatments were found to increase the risk of local tumor progression in univariate and multivariate analyses. CONCLUSIONS: The combination of chemoembolization with RF ablation is an effective treatment to control HCC lesions. The factors identified in the present study may help to predict the therapeutic response.     

Repeat radiofrequency ablation for local progression of lung tumors: does it have a role in local tumor control?

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.     

Percutaneous radiofrequency ablation of lung neoplasms: initial therapeutic response

PURPOSE: To evaluate the feasibility, safety, and initial therapeutic effect of radiofrequency (RF) ablation in the treatment of unresectable malignant lung tumors. MATERIALS AND METHODS: Fifty-four lung neoplasms in 31 patients were treated with RF ablation. Thirteen tumors were primary lung cancers and 41 were pulmonary metastases. Tumor sizes ranged from 0.7 to 6.0 cm, with a mean size of 2.7 +/- 1.3 cm. After the RF electrode was placed in the tumor with computed tomographic (CT) fluoroscopic guidance, RF energy was applied. Initial therapeutic response was evaluated by (18) F fluorodeoxyglucose positron emission tomography (FDG-PET) and contrast-enhanced CT. The disappearance of FDG uptake on PET images and tumor enhancement on CT images were considered to indicate complete tumor necrosis. Complete necrosis rates were evaluated according to tumor size and type (primary or secondary lung neoplasm). RESULTS: RF ablation was technically successful in all lesions. Complete necrosis was achieved in 32 of the 54 tumors (59%) after initial RF session. There was a significant difference in the rate of complete tumor necrosis between tumors 3 cm or less and tumors larger than 3 cm (69% vs. 39%; P <.05). Tumor type did not influence complete necrosis rates. Lung abscesses developed in two patients with large tumors. CONCLUSION: Lung RF ablation is a feasible, relatively safe, and promising treatment for unresectable lung neoplasms. Tumor size is an important factor in achieving complete tumor necrosis.     

Tumor Seeding Following Lung Radiofrequency Ablation: A Case Report

Lung radiofrequency (RF) ablation was performed for the treatment of a primary lung cancer measuring 2.5 cm in maximum diameter in a 78-year-old man. A contrast-enhanced computed tomography (CT) study performed 3 months after RF ablation showed incomplete ablation of the lung tumor and the appearance of a chest wall tumor 4.0 cm in maximum diameter that was considered to be the result of needle-tract seeding. RF ablation was performed for the treatment of both the lung and the chest wall tumors. Although tumor enhancement was eradicated in both of the treated tumors, follow-up CT studies revealed diffuse intra-pulmonary metastases in both lungs 2 months after the second RF session. He is currently receiving systemic chemotherapy.     

Computed tomography-guided re-radiofrequency ablation for unresectable lung tumor with local progression previously treated with the same procedure

Purpose  The aim of this study was to evaluate the technical success, complications, and effectiveness of re-radiofrequency (re-RF) ablation for recurrent lung tumors previously treated with RF ablation. Materials and methods  Reenlargement at the site of ablation seen on follow-up computed tomography (CT) is defined as local progression. CT-guided re-RF ablation was performed during 11 treatment sessions (mean tumor size 2.6 cm diameter) in 10 patients. The treated lesions consisted of five recurrences of primary lung cancer and six metastatic lung tumors from the esophagus (n = 2), bladder (n = 2), kidney (n = 1), and colon (n = 1). Results  At 3 of the 11 treatment sessions there were no relapses; at 8 of the 11 sessions local progression was seen at a median of 7 months (range 3–17 months). The local progression rate was significantly higher for tumors >2.5 cm (P < 0.05). Minor complications included pneumothorax not requiring drainage (n = 3), subcutaneous emphysema (n = 1), and self-limited hemoptysis (n = 2). Conclusion  Re-RF ablation for lung tumors was feasible without any major complications. Although our study comprised only a few cases with a short follow-up period, patients with re-RF ablation were at higher risk of local progression.     

Adrenal neoplasms: CT-guided radiofrequency ablation--preliminary results

PURPOSE: To evaluate initial experience with radiofrequency (RF) ablation of adrenal neoplasms. MATERIALS AND METHODS: Thirteen adrenal masses in 12 patients (bilateral metastases in one patient) were treated with computed tomography (CT)-guided percutaneous RF ablation. Eleven adrenal lesions were metastases (five from lung cancer, four from renal cell carcinoma, and two from melanoma); one lesion was a pheochromocytoma and one was an aldosteronoma. There were 10 men and two women (average age, 58 years; range, 40-77 years) in the study; average adrenal mass diameter was 3.9 cm (range, 1-8 cm). Average number of RF applications per adrenal mass was 2.7 (range, 1-5 applications); average time per application was 7.8 minutes (range, 4-13 minutes). An internally cooled single electrode was used in five sessions; an internally cooled cluster electrode was used in eight sessions. RESULTS: Average follow-up was 11.2 months (range, 1-46 months). Eleven of 13 lesions were treated successfully with RF ablation after one session. Successful treatment was defined as lack of enhancement of the treated region on follow-up CT images and resolution of the biochemical abnormality in two patients. In two patients with large adrenal lesions (4 and 8 cm in diameter), enhancement of residual tissue was observed after one treatment session; this finding was indicative of residual tumor. One patient with thrombocytopenia that resulted from chemotherapy had a small hematoma, but no transfusion was required. No patient developed hypertension during the RF application. No patient with metastases had recurrent tumor at the treated site, and this lack of recurrence indicated effective local control; 11 patients had progression of metastatic disease at extraadrenal sites. CONCLUSION: Preliminary data suggest that CT-guided RF ablation is an effective technique for local control of adrenal neoplasms.     

Image-guided radiofrequency ablation of Bosniak category III or IV cystic renal tumors: initial clinical experience

The purpose of this study was to assess the efficacy of image-guided radiofrequency (RF) ablation of cystic renal tumors. Between November 2005 and August 2007, computed tomography (CT) or ultrasound-guided RF ablation was performed in nine patients with 14 Bosniak category III (n = 5) or IV (n = 9) cystic renal tumors using an internally cooled RF ablation system. We evaluated the number of sessions, cycles and duration of energy application, treatment results, lesion size change, and complications. Together the cystic renal tumors required 15 sessions and 23 cycles of energy application. The duration of energy application per one tumor ablation ranged from 1 to 12 min (mean 6 min). The last follow-up CT indicated complete coagulation of 14/14 (100%) lesions. None of these tumors had recurred within 1-19 months (mean 8 months). The maximum diameter of the cystic renal tumors was significantly reduced from 2.5 +/- 0.6 cm before ablation to 1.7 +/- 0.7 cm at the last follow-up CT (P < 0.01). Complications were pneumothorax (n = 2), inguinal paresthesia (n = 1), and arteriovenous fistula (n = 1). Image-guided RF ablation is an effective treatment for Bosniak category III or IV cystic renal tumors, which might need relatively shorter duration of energy application than purely solid renal tumors of the same size.     

Recurrent hepatocellular carcinoma: percutaneous radiofrequency ablation after hepatectomy

PURPOSE: To evaluate the therapeutic efficacy and safety of percutaneous radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) in the liver after hepatectomy. MATERIALS AND METHODS: Forty-five patients with 53 recurrent HCC tumors in the liver underwent percutaneous RF ablation with ultrasonographic guidance. All patients had a history of hepatic resection for HCC. The mean diameter of recurrent tumors was 2.1 cm (range, 0.8-4.0 cm). All patients were followed up for at least 10 months after ablation (range, 10-40 months; mean, 23 months). Therapeutic efficacy and complications were evaluated with multiphase helical computed tomography (CT) at regular follow-up visits. Overall and disease-free survival rates were calculated. RESULTS: At follow-up CT after initial RF ablation, 11 (21%) of 53 ablated HCC tumor sites showed residual tumor or local tumor progression. After additional RF ablation, complete ablation of 46 (87%) of 53 tumors was attained. Also at initial follow-up CT, before either additional RF ablation or other treatment was performed, 21 (47%) of 45 patients were found to have 41 new HCC tumors at other liver sites. Of these, nine tumors in eight patients were treatable with a second application of RF ablation. Overall survival rates at 1, 2, and 3 years were 82%, 72%, and 54%, respectively. No deaths or complications requiring further treatment occurred as a result of RF ablation. CONCLUSION: Percutaneous RF ablation is an effective and safe method for treating recurrent HCC in the liver after hepatectomy, with a good overall patient survival rate.     

Percutaneous Radiofrequency Ablation for Pulmonary Metastases from Esophageal Cancer: Retrospective Evaluation of 21 Patients

PurposeTo evaluate retrospectively outcomes after radiofrequency (RF) ablation for pulmonary metastases from esophageal cancer.Materials and MethodsThis study included 21 consecutive patients who met inclusion criteria (all men; mean age, 66.0 y) and had pulmonary metastases from esophageal cancer. There were 31 tumors (mean size, 1.7 cm) that were treated with 27 planned ablation sessions. At the initial RF ablation sessions, 3 patients had viable extrapulmonary recurrences, and 18 patients had viable recurrences confined to the lung. Primary study endpoints included patient survival and the determination of prognostic factors. Secondary endpoints included local efficacy and safety of the treatment. The log-rank test was used to identify prognostic factors. Adverse events were evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0.ResultsMedian follow-up duration after the initial RF ablation was 22.4 months (range, 6.2–76.1 mo). Estimated overall survival rates were 85.7% at 1 year, 54.8% at 2 years, and 38.4% at 3 years after the initial RF ablation session. The presence of viable extrapulmonary recurrences at the initial RF ablation session was an unfavorable prognostic factor (P < .001). Local tumor progression was observed in 25.8% (8 of 31) of tumors and occurred 2.6–10.0 months (median, 4.8 mo) after RF ablation. Grade 3 adverse events occurred in 7.4% (2 of 27) of sessions, including pleural effusion requiring chest tube placement and pneumoderma requiring surgical intervention. No grade 4 or greater adverse events occurred.ConclusionsRF ablation is a promising treatment option for patients with pulmonary metastases from esophageal cancer.     

Influence of large peritumoral vessels on outcome of radiofrequency ablation of liver tumors

PURPOSE: The effect of large vessels (>/=3 mm) contiguous to hepatic tumors was evaluated with respect to clinical tumor recurrence rates after radiofrequency (RF) ablation. MATERIALS AND METHODS: The first 105 malignant liver tumors treated by RF ablation therapy at our institution with pathologic analysis or a minimum of 6 months of clinical follow-up were reviewed. The original pretreatment imaging studies were reviewed by a radiologist who was blinded to the cases, and, based on lesion contiguity to vessels of at least 3 mm, the lesions were categorized as perivascular or nonperivascular. Treatment outcomes with respect to local tumor recurrence between these two groups were then compared. Logistic regression analysis was performed to take into account other variables and to determine whether this categorization was an independent predictor of treatment outcome. RESULTS: There were 74 nonperivascular tumors and 31 perivascular tumors. Mean tumor size was 2.4 cm and mean follow-up was 11.3 months. Residual or locally recurrent tumors were documented in 20 of 105 cases (19%). In the nonperivascular group, five of 74 (7%) had either incompletely treated tumor (manifested within 6 months) or local recurrence beyond 6 months. In the perivascular group, 15 of 31 (48%) had incompletely treated or locally recurrent tumor (P <.001). Subanalysis of lesion size (61 tumors 4 cm), tumor type (40 hepatocellular carcinomas, 48 colorectal metastases, and 17 other metastases), access (53 intraoperative, 52 percutaneous), and RF device (45 Radiotherapeutics electrodes, 18 Rita electrodes, and 42 Radionics electrodes) showed similar results. Multivariate logistic regression analysis showed that presence or absence of a large peritumoral vessel is an independent, and the dominant, predictor of treatment outcome. CONCLUSION: The presence of vessels at least 3 mm in size contiguous to hepatic tumors is a strong independent predictor of incomplete tumor destruction by RF ablation. Modified ablation strategies should be considered to improve destruction of these tumors.     

Risk Factors for Local Progression after Percutaneous Radiofrequency Ablation of Lung Tumors: Evaluation Based on a Review of 147 Tumors

Purpose

To retrospectively evaluate risk factors related to incomplete computed tomography (CT)–guided radiofrequency (RF) ablation of metastatic and primary lung tumors.

Therapeutic response assessment of percutaneous radiofrequency ablation for hepatocellular carcinoma: utility of contrast-enhanced agent detection imaging

PURPOSE: To assess the utility of contrast-enhanced agent detection imaging (ADI) in the assessment of the therapeutic response to percutaneous radiofrequency (RF) ablation in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Ninety patients with a total of 97 nodular HCCs (mean, 2.1+/-1.3 cm; range, 1.0-5.0 cm) treated with percutaneous RF ablation under the ultrasound guidance were evaluated with contrast-enhanced ADI after receiving an intravenous bolus injection of a microbubble contrast agent (SH U 508A). We obtained serial contrast-enhanced ADI images during the time period from 15 to 90 s after the initiation of the bolus contrast injection. All of the patients underwent a follow-up four-phase helical CT at 1 month after RF ablation, which was then repeated at 2-4 month intervals during a period of at least 12 months. The results of the contrast-enhanced ADI were compared with those of the follow-up CT in terms of the presence or absence of residual unablated tumor and local tumor progression in the treated lesions. RESULTS: On contrast-enhanced ADI, technical success was obtained in 94 (97%) of the 97 HCCs, while residual unablated tumors were found in three HCCs (3%). Two of the three tumors that were suspicious (was not proven) for incomplete ablation were subjected to additional RF ablation. The remaining one enhancing lesion that was suspicious of a residual tumor on contrast-enhanced ADI was revealed to be reactive hyperemia at the 1-month follow-up CT. Therefore; the diagnostic concordance between the contrast-enhanced ADI and 1-month follow-up CT was 99%. Of the 94 ablated HCCs without residual tumors on both the contrast-enhanced ADI and 1-month follow-up CT after the initial RF ablation, five (5%) had CT findings of local tumor progression at a subsequent follow-up CT. CONCLUSION: Despite its limitations in predicting local tumor progression in the treated tumors, contrast-enhanced ADI is potentially useful for evaluating the early therapeutic effect of percutaneous RF ablation for HCCs.     

Magnetic resonance-guided percutaneous radiofrequency ablation of renal cell carcinomas: a pilot clinical study

OBJECTIVE: The objective of this study was to assess the feasibility and efficacy of magnetic resonance imaging-(MRI) guided percutaneous radiofrequency (RF) ablation of renal cell carcinomas (RCC). SUBJECTS AND METHODS: Twelve patients with RCC (63 to 82 years old) were treated with RF ablation in an interventional 0.2-Tesla open MR unit. Tumor sizes varied from 1.6 cm to 3.9 cm in maximum diameter (tumor volumes 1.9 cm3 to 28.7 cm3). RF procedures were entirely performed in the MR suite. For positioning of the MR-compatible RF-electrode, near real-time MR fluoroscopy by means of rapid gradient echo sequences (acquisition time approximately 2 seconds) was used. Monitoring of ablation was obtained by intermittent imaging with T1- and T2-weighted spin echo sequences. RESULTS: Accurate placement of the RF electrodes was possible in all cases using near real-time MR fluoroscopy. Eleven of 12 patients were successfully treated within 1 single session; 1 patient had to be retreated for tumor relapse at 13 months follow up. Mean number of electrode repositionings under MR guidance during 1 session was 1.7; ablation time ranged between 12 and 28 minutes. Mean duration of 1 treatment session was 5 hours. Coagulation volumes ranged from 7.3 cm3 up to 30.2 cm3. All patients now appear to be disease-free with a mean follow up of 10.3 months (range, 3-23 months). CONCLUSION: MRI-guided RF ablation of RCC in an interventional MR unit is safe and feasible. Fast MR imaging is a convenient method for rapid positioning of MR-compatible RF electrodes. MR monitoring of ablation procedure with T2-weighted imaging allows for immediate assessment of coagulation extent.     

Radiofrequency Ablation for Ground-Glass Opacity–Dominant Lung Adenocarcinoma

PurposeTo evaluate retrospectively the clinical utility of lung radiofrequency (RF) ablation for the treatment of ground-glass opacity (GGO)–dominant lung adenocarcinoma.Materials and MethodsFrom August 2004 through May 2012, 33 consecutive patients (14 men and 19 women; mean age, 71.1 y; age range, 46–84 y) with 42 lung tumors having ≥ 50% GGO component received lung RF ablation. The mean maximum tumor diameter was 1.6 cm ± 0.9 (range, 0.7–4.0 cm). Feasibility, safety, local tumor progression, and survival were evaluated.ResultsFor the 42 RF sessions, after RF electrodes were placed in each target tumor, planned ablation protocols were completed in all sessions (100%; 42 of 42). No deaths related to the RF procedure occurred. Major and minor complication rates were 4.8% and 23.8%, respectively. Local tumor progression developed in 6 tumors (14.3%; 6 of 42) during a mean follow-up of 42 months ± 23 (range, 5–92 mo). Four of six tumors with local progression were controlled by repeated RF ablation. No evidence of disease was achieved in 31 of 33 patients (93.9%) at the end of the follow-up period. All but one patient (who died of brain hemorrhage) are alive today. Overall and cancer-specific survival rates were 100% and 100% at 1 year, 96.4% (95% confidence interval [CI], 77.5%–99.5%) and 100% at 3 years, and 96.4% (95% CI, 77.5%–99.5%) and 100% at 5 years, respectively.ConclusionsLung RF ablation is a feasible, safe, and useful therapeutic option to control GGO-dominant lung adenocarcinoma.     

Five-year survival following radiofrequency ablation of small, solitary, hepatic colorectal metastases

PURPOSE: Radiofrequency (RF) ablation is an increasingly accepted treatment for nonsurgical candidates with a limited number of colorectal hepatic metastases. RF ablation is most effective in tumors smaller than 4.0 cm. This report describes 5-year survival in patients with single tumors with a maximum diameter of 4 cm. MATERIALS AND METHODS: Forty of 291 patients (14%; 24 men, 16 women; mean age, 67 years; age range, 34-86 y) with no or treated extrahepatic disease were identified who were not candidates for resection and who had a minimum follow-up of 6 months. Sixteen had undergone hepatic resection and two had undergone lung resection and lung ablation. Thirty-two (80%) received chemotherapy. Thirty-five were treated under general anesthesia and five under conscious sedation. Our standard ablation protocol used internally water-cooled electrodes introduced percutaneously with ultrasonography and computed tomography guidance and monitoring. Follow-up data were obtained from primary care physicians or oncologists. RESULTS: Mean tumor diameter was 2.3 cm (range, 0.8-4.0 cm). There were two successfully treated systemic complications: a chest infection and an exacerbation of asthma. There were no local complications. Mean follow-up was 38 months (range, 6-132 months). The median survival duration and 1-, 3-, and 5-year survival rates were 59 months and 97%, 84%, 40%, respectively, after ablation; and 63 months, 100%, 88%, and 54%, respectively, from the diagnosis of liver metastases. History of liver resection did not impact survival. CONCLUSIONS: RF ablation of solitary liver metastases 4 cm or smaller can be performed with minimal morbidity and results in excellent long-term survival, approaching that of surgical resection, even in patients who are not surgical candidates.     

Protecting the ureter during radiofrequency ablation of renal cell cancer: a pilot study of retrograde pyeloperfusion with cooled dextrose 5% in water

PURPOSE: To describe early experience with cooled dextrose 5% in water (D5W) solution retrograde pyeloperfusion during radiofrequency (RF) ablation of renal cell carcinoma (RCC) within 1.5 cm of the ureter with respect to feasibility, safety, and incidence of residual/recurrent tumor in proximity to the cooled collecting system. MATERIALS AND METHODS: Between November 2004 and April 2007, 17 patients underwent 19 RF ablation sessions of RCCs within 1.5 cm of the ureter during cooled D5W pyeloperfusion (nine men, eight women; mean tumor size, 3.5 cm; mean age, 73 y; mean distance to ureter, 7 mm). RF ablation was performed with pulsed impedance control current. The records and imaging studies of patients treated with this technique were reviewed for demographics, indication, technique, complications, and tumor recurrence. RESULTS: All 19 RF ablation and ureteral catheter placement procedures were technically successful. No patient developed a ureteral stricture or hydronephrosis during a mean of 14 months of follow-up (range, 4-32 months). Three patients had residual tumor on the first follow-up imaging study, but all three tumors were completely ablated after a second RF ablation session. No complications or deaths occurred. No recurrent tumor was seen anywhere in the treated tumors, and there was complete ablation of the tumor margin in proximity to the collecting system. CONCLUSIONS: RF ablation of RCC within 1.5 cm of the ureter is feasible with cooled D5W retrograde pyeloperfusion and is not associated with reduced efficacy, ureteral injury, or early recurrence.     

Thoracic tumors treated with CT-guided radiofrequency ablation: initial experience

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.     

Percutaneous radiofrequency ablation for inoperable non-small cell lung cancer and metastases: preliminary report

PURPOSE: To assess technical feasibility, efficacy, and complications of percutaneous computed tomography (CT)-guided transthoracic radiofrequency (RF) ablation for treating inoperable non-small cell lung cancer (NSCLC) and lung metastases. MATERIALS AND METHODS: Twenty-six patients with 27 NSCLCs and four patients with five lung metastases underwent RF ablation with cooled-tip electrodes with CT guidance. Patients were not candidates for surgery because of either advanced-stage disease (n = 20) and/or comorbid processes (n = 4) or refusal to undergo surgery (n = 6). The procedure was performed with the intent to cure in 10 (33%) patients with stage I tumors and as palliative therapy in 20 (67%) patients. Contrast material-enhanced CT was performed immediately, 1 month, and then every 3 months after RF ablation to evaluate the response to therapy. Time to death for each patient was calculated with Kaplan-Meier analysis, and the effect of tumor size and the extent of coagulation necrosis on time to death were determined. RESULTS: Complete necrosis was attained in 12 (38%) of 32 lesions; partial (>50%) necrosis, in the remaining 20 (62%) lesions. Tumor size was a major discriminator in achieving complete necrosis. Complete necrosis was attained in all six (100%) tumors smaller than 3 cm but only in six (23%) of 26 larger tumors (P <.05). Mean survival of patients with complete necrosis (19.7 months) was significantly better than that of patients with partial necrosis (8.7 months) (P <.01). There were three (in 30 patients, 10%) major complications, which included acute respiratory distress syndrome, and two pneumothoraces that required thoracostomy. CONCLUSION: RF ablation appears to be a safe and promising procedure for the treatment of inoperable NSCLC and metastases.     

Percutaneous radiofrequency ablation of renal cell carcinoma: preliminary results

PURPOSE: To report early results in percutaneous radiofrequency ablation (RFA) of renal cell carcinoma with an expandable RF probe. MATERIAL AND METHODS: In 14 patients (9 male, mean age 67.9 +/- 9.9 years) CT-guided percutaneous radiofrequency ablation of 15 renal cell carcinomas was performed using an expandable LeVeen probe (diameter 2-4 cm) and a 200-watt generator under general anesthesia and CT control. Tumors exceeding a diameter of 3 cm (n=6) were embolized within 24 h prior to RFA. Average tumor size was 3.0 +/- 1.0 cm. RESULTS: RFA was technically successful in all patients, resulting in a mean size of necrosis of 3.7 +/- 0.7 cm. With the exception of one reno-cutaneous fistula, which was successfully treated conservatively, no major complications were observed. No local recurrence was observed (follow-up: 13.9 +/- 12.4 months) while extrarenal tumor progression occurred in four patients. CONCLUSION: Our preliminary data suggest that nephron sparing percutaneous RFA of renal tumors with an expandable RF probe is safe and effective.     

Sonazoid-enhanced sonography for guiding radiofrequency ablation for hepatocellular carcinoma: better tumor visualization by Kupffer-phase imaging and vascular-phase imaging after reinjection

Purpose  The purpose of this study was to assess the usefulness of contrast harmonic sonography with a newly developed sonographic contrast agent as a means of guidance for percutaneous radiofrequency (RF) ablation of hepatocellular carcinoma (HCC). Materials and methods  A total of 52 consecutive HCC lesions in 42 patients with HCC who underwent percutaneous RF ablation were included in this study. Altogether, 40 lesions in 35 patients were untreated HCC, and 12 lesions in 7 patients were local tumor progression of an HCC that had already been treated by other methods. We investigated tumors by Kupffer-phase imaging and vascular-phase imaging after reinjection. We performed RF ablation guided by Sonazoid-enhanced sonography using Kupffer-phase imaging and vascular-phase imaging after reinjection. Results  Conventional sonography identified 30 (57%) of 52 HCCs, whereas Sonazoid-enhanced sonography detected 50 (96%) of 52 HCCs (P < 0.01, McNemar’s χ² test). Complete ablation was achieved at a single session in 48 of 50 tumors. Conclusion  Sonazoid-enhanced sonography is a useful technique for guiding RF ablation of HCCs, even when treating local progression of a previously treated HCC.