Radiofrequency ablation treatment for renal cell carcinoma: early clinical experience

OBJECTIVE: To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). MATERIALS AND METHODS: The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43-73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow-up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. RESULTS: All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1-5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17-33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). CONCLUSION: The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs.     

Radiofrequency Ablation Combined with Renal Arterial Embolization for the Treatment of Unresectable Renal Cell Carcinoma Larger Than 3.5 cm: Initial Experience

The purpose of the study was to evaluate the feasibility, safety, and therapeutic effects of the combination of renal arterial embolization and radiofrequency (RF) ablation to reinforce the anticancer effect on renal cell carcinomas (RCCs) measuring 3.5 cm or larger. This study was undertaken to evaluate this combined therapy on large RCCs-based tumor geometry. Eleven patients with 12 RCCs 3.5 cm or larger in diameter (3.5–9.0 cm) underwent combined therapy. Two were exophytic tumors, and the remaining 10 tumors had components extending into the renal sinus fat. Tumor vessels were selectively embolized in nine patients and the renal artery was completely embolized in two patients with polyvinyl alcohol or ethanol mixed with iodized oil. RF ablation was percutaneously done under the computed tomographic (CT)–fluoroscopic guidance. Response to treatment was evaluated by dynamic contrast-enhanced CT and magnetic resonance (MR) imaging. Tumor enhancement was eliminated after a single RF session in nine tumors (75%), after two sessions in two tumors (17%), and after four sessions in one tumor (8%). Both exophytic tumors (100%) and 7 of 10 tumors having components in the renal sinus fat (70%) were completely ablated with a single RF session. All tumors remained controlled during a mean follow-up period of 13 months and showed significant reduction in tumor sizes (5.2 ± 1.7 cm to 3.6 ± 1.4 cm, p < 0.001). A delayed abscess developed in the ablated lesion in a patient, which was percutaneously drainaged. Combined therapy as described in this report is a feasible, relatively safe, and promising treatment method for large RCCs regardless of tumor geometry.     

Interventional Management of a Renal Cell Carcinoma by Radiofrequency Ablation with Tagging and Cooling

Over the last few years, percutaneous radiofrequency (RF) ablation has been successfully established as a viable treatment modality for small peripheral renal cell carcinoma (RCC). This technique is limited by central tumor location and tumor size. We report the interventional management of a 5.3 cm mixed RCC with central and exophytic parts by combining the RF ablation with embolization, tagging, and retrograde, as well as anterograde cooling. The potential pitfalls of complex hybrid interventions for treating RCC are discussed.     

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.     

Percutaneous radiofrequency ablation with a multiple-electrode switching-generator system

PURPOSE: To determine the feasibility and safety of treating 35 hepatic tumors with a multiple-electrode switching-generator radiofrequency (RF) ablation system. MATERIALS AND METHODS: The authors performed a retrospective review of percutaneous RF ablation procedures in 35 hepatic tumors ranging in diameter from 0.9 to 3.8 cm and involving 22 patients. Tumors smaller than 2 cm were ablated with a single electrode, and larger tumors were ablated with two or three electrodes depending on tumor size and location of initial electrode placement. Electrodes were positioned 1-2 cm apart to create an intratumoral configuration that maximized index tumor coverage. Computed tomography or magnetic resonance imaging was performed within 24 hours of ablation. The ablation volume, maximum ablation size, and maximum tumor size were compared among the three electrode groups by using analysis of variance. If the global P value with analysis of variance was statistically significant (P<.05), post hoc testing for pairwise comparisons was performed by using the Bonferroni correction to adjust for multiple comparisons. Complications were defined according to the SIR reporting standards for image-guided tumor ablation. RESULTS: Ten tumors were treated with one electrode, 16 were treated with two electrodes, and nine were treated with three electrodes. The mean and median maximum sizes of the tumors ablated with one, two, and three electrodes were 1.2 and 1.1 cm, 2.7 and 2.8 cm, and 3.2 and 3.4 cm, respectively. The mean and median ablation volumes with two electrodes (40.9 and 31.9 cm3, respectively) and three electrodes (59.3 and 48.2 cm3, respectively) were significantly greater than that with one electrode (11.7 and 8.6 cm3, respectively; P相似文献   

Percutaneous radiofrequency ablation of renal tumors: technique, complications, and outcomes

PURPOSE: To report the safety, technical success, and effectiveness of percutaneous radiofrequency (RF) ablation for renal tumors. MATERIALS AND METHODS: The authors retrospectively reviewed the medical records and imaging studies of 29 consecutive patients (18 men, 11 women; mean age, 65 +/- 2.62 years) with 30 renal tumors (mean diameter, 3.5 +/- 0.24 cm) who underwent percutaneous RF ablation at their institution from September 2001 to March 2004. All procedures were performed with computed tomography guidance with general anesthesia, and all patients were admitted to the hospital for overnight observation. Technical success, complications, and their management were recorded. Technique effectiveness was assessed by imaging and clinical follow up. RESULTS: Overall, 88 overlapping ablations were performed (mean, 2.6 +/- 0.16 ablations per tumor per session) in 34 sessions. There were four major complications (12%). Three patients had gross hematuria and urinary obstruction, all were successfully treated. One patient had persistent anterior abdominal wall weakness. There were also two minor complications (6%) without significant clinical sequelae. One patient had gross hematuria which resolved spontaneously, another patient had transient paresthesia of the anterior abdominal wall. There were no significant changes in renal function after RF ablation. The intent of RF ablation was eradication of the primary tumor in 27 patients and treatment of gross hematuria in the other two. Technical success was achieved in all cases. Follow-up images were available for 26 patients. The primary tumor was completely ablated in 23 of 24 patients (96%) in whom eradication of the primary tumor was attempted (follow up period: mean, 10 months, median 7 months). The two patients treated for hematuria remained asymptomatic for 6 and 27 months each. CONCLUSION: Percutaneous RF ablation for renal tumors is safe and well tolerated. High technical success rates are expected. Early reports of the technique's effectiveness are promising.     

Percutaneous radiofrequency ablation of renal tumors: midterm results in 16 patients

PURPOSE: To evaluate the outcome of 16 patients after percutaneous radiofrequency ablation of renal tumors. MATERIALS AND METHODS: Sixteen patients (nine women, seven men; mean age, 61+/-9 years) with 24 unresectable renal tumors (mean volume, 4.3+/-4.3 cm3) underwent CT-guided (n=20) or MR imaging-guided (n=4) percutaneous radiofrequency ablation using an expandable electrode (Starburst XL, RITA Medical Systems, Mountain View, CA) with a 150-W generator. The initial follow-up imaging was performed within 1-30 days after RF ablation, then at 3-6 month intervals using either CT or MRI. Residual tumor volume and coagulation necrosis was assessed, and statistical correlation tests were obtained to determine the strength of the relationship between necrosis volume and number of ablations. RESULTS: Overall, 97 overlapping RF ablations were performed (mean, 3.5+/-1.5 ablations per tumor) during 24 sessions. Five or more RF ablations per tumor created significant larger necrosis volumes than 1-2 (p=.034) or 3-4 ablations (p=.020). A complete ablation was achieved in 20/24 tumors (primary technical success, 83%; mean volume of coagulation necrosis: 10.2+/-7.2 cm3). Three of four residual tumors were retreated and showed complete necrosis thereafter. Three major complications (one percuatneous urinary fistula and two ureteral strictures) were observed after RF ablation. No further clinically relevant complications were observed and renal function remained stable. During a mean follow-up of 11.2 months (range, 0.2-31.5), 15/16 patients (94%) were alive. Only one patient had evidence of local recurrent tumor. CONCLUSION: The midterm results of percutaneous RF ablation for renal tumors are promising and show that RF ablation is well-suited to preserve renal function.     

MR imaging follow-up after percutaneous radiofrequency ablation of renal cell carcinoma: findings in 18 patients during first 6 months

PURPOSE: To prospectively evaluate the magnetic resonance (MR) imaging findings seen within the first 6 months after radiofrequency (RF) thermal ablation of renal cell carcinoma (RCC). MATERIALS AND METHODS: After providing written informed consent, 18 patients (17 men, one woman; mean age, 71.2 years) with RCC underwent MR imaging-guided percutaneous RF thermal ablation, which was performed by using protocols approved by a comprehensive cancer center protocol committee and the institutional review board for human investigation. The study was Health Insurance Portability and Accountability Act compliant. Follow-up unenhanced T2-weighted MR images and unenhanced and gadolinium-enhanced T1-weighted MR images were acquired immediately, 2 weeks, 3 months, and 6 months after ablation. Thermal ablation zone size was analyzed, and contrast-to-noise ratios (CNRs) were calculated from the signal amplitudes of the thermal ablation zone, perirenal fat, and normal renal cortex on the MR images. Statistical analyses were performed by using the paired Student t test. P < .05 was considered to indicate statistical significance. RESULTS: The mean follow-up time was 16.1 months (range, 6.0-41.2 months). The mean sizes of the thermal ablation zones were 6.8, 7.0, 6.1, and 4.7 cm2, respectively, at immediate, 2-week, 3-month, and 6-month follow-up MR imaging examinations. Thermal ablation zones were uniformly hypointense and had a surrounding bright rim on T2-weighted images and were predominantly hyperintense on T1-weighted images. Thin rim enhancement with central hypointensity was noted on the gadolinium-enhanced images. Gadolinium-enhanced T1-weighted and unenhanced T2-weighted MR images showed significantly higher CNRs than unenhanced T1-weighted MR images. Residual tumor was detected after RF thermal ablation in two cases and was best seen on unenhanced T2-weighted and gadolinium-enhanced T1-weighted MR images. CONCLUSION: After initially increasing in size within the first 2 weeks, renal RF thermal ablation zones involuted during the remainder of the MR imaging follow-up period.     

Radiofrequency ablation with internally cooled versus perfused electrodes for the treatment of small hepatocellular carcinoma in patients with cirrhosis

PURPOSE: To compare the results of radiofrequency (RF) ablation with internally cooled electrodes (ICEs) versus perfused electrodes (PEs) in patients with cirrhosis with small (相似文献   

Radiofrequency Ablation,Cryoablation, and Microwave Ablation for T1a Renal Cell Carcinoma: A Comparative Evaluation of Therapeutic and Renal Function Outcomes

PurposeTo compare the therapeutic and renal function outcomes of radiofrequency (RF) ablation, cryoablation, and microwave (MW) ablation for treatment of T1a renal cell carcinoma (RCC).Materials and MethodsA retrospective assessment of 297 patients (mean age 72 years range 24–90 years) with biopsy-proven RCC treated with image-guided percutaneous thermal ablation was performed between October 2006 and December 2016. Mean tumor size was 2.4 cm; mean radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, hilar tumor touching the main renal artery or vein, and location relative to polar lines; Preoperative Aspects and Dimensions Used for an Anatomical; and c-centrality scores were 6.0, 7.0, and 2.8, respectively. Assessments of adverse events, treatment efficacy, and therapeutic outcomes were performed among RF ablation, cryoablation, and MW ablation. The 2-year disease-free, metastatic-free, and cancer-specific survival rates were tabulated. Estimated glomerular filtration rate was used to assess for treatment related changes in renal function.ResultsA total of 297 T1aN0M0 biopsy-proven RCCs measuring 1.2–3.9 cm were treated with computed tomography–guided RF ablation (n = 244, 82%), cryoablation (n = 26, 9%), and MW ablation (n = 27, 9%). There were no significant differences in patient demographics among the 3 groups (P = .09). Technical success rates were similar among the 3 treatments (P = .33). Primary efficacy at 1 month postablation was more likely to be achieved with RF ablation and MW ablation than with cryoablation. At 2 years’ follow-up, there was no local recurrence, metastatic progression, or RCC-related death observed in the 3 groups. There was no significant change in estimated glomerular filtration rate among the 3 ablation groups compared with baseline at 2-year follow-up (P = .71).ConclusionRF ablation, cryoablation, and MW ablation are equivalent at 2 years for treatment of T1a RCC for therapeutic outcome, stability of renal function, and low adverse event rate.     

Risk factors for occurrence of local tumor progression after percutaneous radiofrequency ablation for lung neoplasms

PURPOSE: To examine the characteristics of lung tumors for which radiofrequency (RF) ablation therapy is effective, and to determine what RF ablation parameters are effective for obtaining complete coagulation of the entire ablation zone with a single RF ablation session. MATERIALS AND METHODS: Computed tomography (CT)-guided RF ablation of lung tumors was performed on 82 lesions in 34 patients between April 2003 and May 2005. Tumor characteristics and ablation parameters, including tumor size, location, and depth, and ablation duration, power deployed during ablation, and temperatures achieved were analyzed with regard to local tumor progression. RESULTS: In all, 103 RF ablation sessions were performed on 82 tumors. As a procedure-related complication, pneumothorax occurred in 27 procedures. During the mean follow-up period of 10 months (range, 6-28 months), local tumor progression occurred in 18 (22.0%) of the 82 ablated tumors (3 months after RF ablation in 10, 6 months after RF ablation in 5, 9 months after RF ablation in 1, and 12 months after RF ablation in 2). Mean local progression-free duration was 8.7 +/- 4.5 months (range, 3-28 months). The frequency of local tumor progression was significantly correlated with size, whereas other variables had no statistical association. In tumors with a diameter > or =2.5 cm, only the period of ablation during the initial session was significantly correlated with subsequent local tumor progression (P = 0.000002, chi-square test). CONCLUSION: A long duration of RF ablation is desirable for large lung tumors. The success of RF ablation is dependent upon tumor size. RF ablation treatment is most effective for lesions < 2.5 cm.     

Radio-frequency ablation of renal cell carcinoma: early clinical experience

PURPOSE: To report the authors' early experience with radio-frequency (RF) ablation of renal cell carcinoma. MATERIALS AND METHODS: Twenty-four percutaneous RF ablation treatments for nine tumors were performed in eight patients with renal cell carcinoma. Indications included coexistent morbidity, previous surgery, or solitary kidney in patients with a life expectancy shorter than 10 years. Smaller (3 cm) and/or central lesions (n = 6) were treated with cluster or multiple electrodes. Patients returned for a second treatment when follow-up imaging depicted tumor enhancement. Follow-up imaging was performed at 1 and 3 months and then at 6-month intervals, with a mean follow-up of 10.3 months. Seven patients were alive at least 6 months after their initial treatment. RESULTS: All five exophytic tumors were free of enhancement. One of three central tumors was free of enhancement. One tumor had both central and exophytic components and was free of enhancement. Three tumors were 3 cm or smaller and free of enhancement. Of the six tumors larger than 3 cm, four were free of enhancement. CONCLUSION: Percutaneous RF ablation is a promising treatment for select patients with renal cell carcinoma. The ultimate role of this modality will continue to evolve and warrants further study.     

Percutaneous US-guided RF thermal ablation for malignant renal tumors: preliminary results in 13 patients

Minimally invasive treatment for small renal cell carcinoma (RCC) can be necessary in selected patients and, anyway, is desirable. In situ ablation techniques, including RFA, have been developed. The aim of this study is to evaluate the feasibility, safety and short-term local effectiveness of percutaneous US-guided RFA in a small series, as well as mid-term patient outcome. Thirteen patients with a total of 18 tumors (17 small lesions, 35 mm in size or less, and a larger one, 75 mm in size) underwent 19 RFA sessions. Seven patients had a solitary kidney, and three suffered from VHL disease, too. We treated four lesions in a patient with a bilateral tumor. In another patient, three lesions were ablated. Seventeen tumors were RCC; one was a metastasis from lung cancer. Eight lesions were parenchymal, six exophytic, two parenchymal/exophytic, one parenchymal/central and one central. A monopolar RF system with multitined expandable electrode needles was used. The 35-mm lesion underwent two sessions; the 75-mm lesion was treated with transcatheter arterial embolization before RFA. Tumors with complete loss of contrast enhancement at short-term CT (or MR) were considered successfully treated. Percutaneous US-guided RFA was always feasible without major complications. The success rate after a single treatment in tumors less than 35 mm in size was 88.2% (15/17) and rose to 94.1% (16/17) after the second treatment of the largest lesion. After a mean 14-month follow-up, no successfully treated lesions recurred locally. Only the patient with metastasis from lung cancer died from disease progression in a further location, while all other patients are alive, with renal function still sufficient to avoid dialysis. US guidance allows an easy and safe percutaneous approach for RFA of small non-parahilar RCC. The treatment is locally effective and can be proposed as a minimally invasive therapy for patients with contraindications to surgery or to those expressing an informed consent. Based on the results of this study and of the literature, mid-term results on the clinical usefulness are very encouraging.Presented at ECR 2003.     

Angiomyolipoma with minimal fat: differentiation from renal cell carcinoma at biphasic helical CT

PURPOSE: To compare various computed tomographic (CT) features of angiomyolipoma (AML) with minimal fat with those of size-matched renal cell carcinoma (RCC). MATERIALS AND METHODS: Eighty-one patients (19 with AML with minimal fat [mean diameter, 2.8 cm; range, 1.5-4.5 cm] and 62 with RCC [mean diameter, 3.1 cm; range, 1.8-4.5 cm]) who had undergone biphasic CT (ie, CT with unenhanced, corticomedullary, and early excretory phase scanning) were evaluated. Two reviewers who were unaware of the diagnosis retrospectively recorded tumor attenuation on unenhanced scans, enhancement characteristics (ie, homogeneity of enhancement, amount of enhancement, enhancement pattern over time), tumor margin, location of tumor center, intratumoral calcification, perinephric changes, and patient age and sex. The predictive value of each CT finding was determined by using multivariate logistic regression analysis. RESULTS: Homogeneous enhancement (observed in 79% of AMLs vs 5% of RCCs; odds ratio, 37) and prolonged enhancement pattern (observed in 58% of AMLs vs 10% of RCCs; odds ratio, 42) were valuable predictors for differentiating AML with minimal fat from RCC at multivariate analysis (P <.05 for both). When both CT findings were used as a criterion for differentiating AML from RCC, positive and negative predictive values were 91% (10 of 11 tumors) and 87% (61 of 70 tumors), respectively. Fifty-three percent of AMLs versus 13% of RCCs showed high tumor attenuation on unenhanced scans (P =.04), whereas RCCs showed greater mean enhancement than AMLs (114 HU +/- 44 [SD] vs 73 HU +/- 30 in corticomedullary phase and 66 HU +/- 24 vs 49 HU +/- 20 in early excretory phase) and a male predominance (male-to-female ratio, 50:12 vs 8:11; P =.001). CONCLUSION: Biphasic helical CT may be useful in differentiating AML with minimal fat from RCC, with homogeneous tumor enhancement and prolonged enhancement pattern being the most valuable CT findings.     

Intermediate Outcomes and Predictors of Efficacy in the Radiofrequency Ablation of 100 Pathologically Proven Renal Cell Carcinomas

PurposeTo determine oncologic outcomes and predictors of primary efficacy, including RENAL nephrometry scores (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines), after percutaneous radiofrequency (RF) ablation of proven renal cell carcinoma (RCC).Materials and MethodsPatients who underwent percutaneous computed tomography– and ultrasound-guided RF ablation for histologically proven RCC from 2004 to 2011 were evaluated. Clinical data, pathologic findings, technical details, and outcomes were reviewed. Univariate and multivariate logistic regression analysis was performed to determine predictors of primary technique effectiveness and complications. Local tumor progression–free, metastasis-free, and overall survival were calculated. One hundred RCC lesions underwent 115 RF ablation sessions in 84 patients. Median follow-up was 24 months (mean, 27 mo; range, 1–106 mo).ResultsEfficacy of RF ablation was defined per International Working Group of Image-Guided Tumor Ablation criteria. Total, primary, and secondary technique effectiveness rates were 95% (95 of 100), 86% (86 of 100), and 9% (nine of 100), respectively. Primary efficacy was associated with size (P < .001), proximity to collecting system (P = .001), RENAL nephrometry score (P < .001), and number of ablation zones (P < .001). Complications occurred in 13% of patients, without procedure-related deaths. The median 2.1-year local progression–free, metastasis-free, disease-specific, and overall survival rates were 86%, 98.7%, 100%, and 97.6%, respectively.ConclusionsPercutaneous image-guided RF ablation for RCC provides excellent intermediate oncologic control. Location, size, proximity to the collecting system, low RENAL nephrometry score, and number of ablation zones predict primary efficacy.     

Radiofrequency ablation of hepatocellular carcinoma: treatment success as defined by histologic examination of the explanted liver

PURPOSE: To retrospectively evaluate the effectiveness of radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) by using histologic examination of the explanted liver. MATERIALS AND METHODS: The study was approved by the medical center Institutional Review Board, with waiver of informed consent. Forty-seven HCC nodules in 24 patients (18 men, six women; age range, 33-71 years; mean age, 56 years) were treated with single or double RF ablation sessions prior to liver transplantation. Histologic data from hematoxylin-eosin staining of explanted liver specimens were retrospectively reviewed to determine treatment success, which was defined as the absence of residual or recurrent viable carcinoma cells at treatment site. Tumor size and the presence of large (> or =3 mm) abutting vessels that were observed during imaging were tested as potential predictors of treatment success or failure (Fisher exact test). In patients who underwent postablation computed tomographic (CT) or magnetic resonance (MR) imaging within 3 months prior to transplantation (21 patients with 44 tumors), imaging results were analyzed for sensitivity and specificity of residual or recurrent tumor by using histologic data as the reference standard. RESULTS: Thirty-five (74%) of 47 ablated tumors, including 29 (83%) of 35 tumors less than 3 cm, were found to be successfully treated on the basis of histologic findings after a mean interval of 7.5 months between RF ablation and transplantation. Nodules that were successfully treated had mean maximal diameter of 2.0 cm, and nodules that were unsuccessfully treated had mean maximal diameter of 3.1 cm (P=.014). Seven (47%) of 15 perivascular lesions were successfully treated whereas 28 (88%) of 32 nonperivascular lesions were successfully treated (P <.01). Imaging correlation showed 100% (33 of 33) specificity and 36% (four of 11) sensitivity of postablation CT and MR imaging for the depiction of residual or recurrent tumor. CONCLUSION: Histologic evidence directly validates RF ablation as an effective treatment of small (<3 cm) HCC.     

Percutaneous CT-guided radiofrequency ablation of renal neoplasms: factors influencing success

OBJECTIVE: The objective of our study was to evaluate the success rate for radiofrequency ablation of renal tumors and to determine the risk of serious complications. CONCLUSION: No serious complications occurred after 27 CT-guided radiofrequency ablation sessions in 22 patients. In total, no residual tumor was detected on follow-up contrast-enhanced CT or MRI 1-35 months (mean, 7 months) after final tumor ablation in 20 (91%) of 22 patients. Two patients with residual viable tumor deferred further treatment. Complete tumor ablation was achieved after a single treatment session in 83% of patients, and in 8% of patients after subsequent ablation sessions. Size was the major determinant for achieving tumor eradication with a single session of ablation, with all 11 tumors 3 cm or smaller being completely ablated after one session. Tumor location, histology, and the presence of renal disease did not correlate with treatment success. Contrast-enhanced CT performed immediately after ablation is reliable to exclude residual viable tumor. CT-guided radiofrequency ablation of renal tumors is safe and has a high rate of success in the treatment of small renal tumors, with no evidence of recurrence at midterm follow-up of treated patients.     

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.     

Renal Tumors: Technical Success and Early Clinical Experience with Radiofrequency Ablation of 18 Tumors

Purpose To evaluate the feasibility, safety, and technical efficacy of image-guided radiofrequency ablation (RFA) for the treatment of small peripheral renal tumors and to report our early results with this treatment modality. Methods Twenty-two RFA sessions for 18 tumors were performed in 11 patients with renal tumors. Indications included coexistent morbidity, high surgical or anesthetic risk, solitary kidney, and hereditary predisposition to renal cell carcinoma. Ten patients had CT-guided percutaneous RFA performed on an outpatient basis. One patient had open intraoperative ultrasound-guided RFA. Technical success was defined as elimination of areas that enhanced at imaging within the entire tumor. With the exception of one patient with renal insufficiency who required gadolinium-enhanced MRI, the remaining patients underwent contrast-enhanced CT for post-treatment follow-up assessment. Follow-up was performed after 2–4 weeks and then at 3, 6, 12 months, and every 12 months thereafter. Results Fourteen (78%) of 18 tumors were successfully ablated with one session. Three of the remaining four tumors required two sessions for successful ablation. One tumor will require a third session for areas of persistent enhancement. Mean patient age was 72.82 ± 10.43 years. Mean tumor size was 1.95 ± 0.79 cm. Mean follow-up time was 10.91 months. All procedures were performed without any major complications. Conclusions Our early experience with percutaneous image-guided radiofrequency ablation demonstrates it to be a feasible, safe, noninvasive, and effective treatment of small peripheral renal tumors.     

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.