Radiofrequency Ablation For Pulmonary Metastases Research Articles

Robotic versus freehand CT-guided radiofrequency ablation of pulmonary metastases: a comparative cohort study

PurposeRadiofrequency ablation (RFA) is a curative treatment option for small lung metastases, which conventionally involves multiple freehand manipulations until the treating electrode is satisfactorily positioned. Stereotactic and robotic guidance has been gaining popularity for liver ablation, although has not been established in lung ablation. The purpose of this study is to determine the feasibility, safety, and accuracy of robotic RFA for pulmonary metastases, and compare procedures with a conventional freehand cohort.MethodsA single center study with prospective robotic cohort, and retrospective freehand cohort. RFA was performed under general anesthesia using high frequency jet ventilation and CT guidance. Main outcomes were (i) feasibility/technical success (ii) safety using Common Terminology Criteria for Adverse Events (iii) targeting accuracy (iv) number of needle manipulations for satisfactory ablation. Robotic and freehand cohorts were compared using Mann–Whitney U tests for continuous variables, and Fisher’s exact for categorical variables.ResultsThirty-nine patients (mean age 65 ± 13 years, 20 men) underwent ablation of 44 pulmonary metastases at single specialist cancer center between July 2019 and August 2022. 20 consecutive participants underwent robotic ablation, and 20 consecutive patients underwent freehand ablation. All 20/20 (100%) robotic procedures were technically successful, and none were converted to freehand procedures. There were 6/20 (30%) adverse events in the robotic cohort, and 15/20 (75%) in the freehand cohort (P = 0.01). Robotic placement was highly accurate with 6 mm tip-to-target distance (range 0–14 mm) despite out-of-plane approaches, with fewer manipulations than freehand placement (median 0 vs. 4.5 manipulations, P < 0.001 and 7/22, 32% vs. 22/22, 100%, P < 0.001).ConclusionsRobotic radiofrequency ablation of pulmonary metastases with general anesthesia and high frequency jet ventilation is feasible and safe. Targeting accuracy is high, and fewer needle/electrode manipulations are required to achieve a satisfactory position for ablation than freehand placement, with early indications of reduced complications.

Clinical outcomes and prognostic factors of cone-beam CT-guided radiofrequency ablation for pulmonary metastases in colorectal cancer patients.

Radiofrequency ablation (RFA) has been increasingly used for the treatment of pulmonary metastases in various malignancies. A retrospective analysis was performed to establish the safety and efficacy of cone-beam computed tomography (CBCT)-guided RFA in patients with metastatic colorectal cancer between 2016 and 2019, and the prognostic factors of local tumor control were assessed. A total of 31 patients with colorectal cancer underwent 48 sessions of lung RFA. The mean diameter of metastases targeted for RFA was 11mm (range: 4-32), and the RFA was technically successful in 43 sessions (90%). There were 14 complications (29%), the majority of which required no intervention, with no cases of mortality. The median follow-up duration from RFA in the surviving 29 patients was 18.0months. Only two patients (6%) died of disease progression, and the 3-year overall survival rate was 91% (95% CI: 83-99). Local tumor progression (LTP) of the RFA site was observed in 27%, and the LTP-free survival rates at 1 and 2years were 81% (95% CI: 70-82) and 64% (95% CI: 50-77), respectively. Multivariate analysis showed that the progression of extra-RFA sites and the presence of extrapulmonary metastasis were independent prognostic factors significantly associated with LTP at RFA site. Lung RFA using CBCT guidance is a comparatively safe and effective option for the treatment of lung metastases from colorectal cancer. However, the control of extrapulmonary metastases should be accompanied by combined or sequential systemic treatment and local treatment.

Artificial pneumothorax improves radiofrequency ablation of pulmonary metastases of hepatocellular carcinoma close to mediastinum

BackgroundTo investigate the feasibility, safety and efficacy of percutaneous radiofrequency ablation (RFA) of pulmonary metastases from hepatocellular carcinoma (HCC) contiguous with the mediastinum using the artificial pneumothorax technique.MethodA total of 40 lesions in 32 patients with pulmonary metastases from HCC contiguous with the mediastinum accepted RFA treatment from August 2014 to May 2018 via the artificial pneumothorax technique. After ablation, clinical outcomes were followed up by contrast enhanced CT. Technical success, local tumor progression (LTP), intrapulmonary distant recurrence (IDR), and adverse events were evaluated. Overall survival (OS) and local tumor progression free survival (LTPFS) were recorded for each patient.ResultsThe tumor size was 1.4 ± 0.6 cm in diameter. RFA procedures were all successfully performed without intra-ablative complications. Technical success was noted in 100% of the patients. Five cases of LTP and 8 cases of IDR occurred following the secondary RFA for treatment. Slight pain was reported in all patients. No major complications were observed. The 1, 2, and 3-year LTPFS rates were 90.6, 81.2, and 71.8%, and the 1, 2, and 3-year OS rates were 100, 100 and 87.5%, respectively.ConclusionArtificial pneumothorax adjuvant RFA is a feasible, safe, and efficient method for treatment of pulmonary metastases from HCC contiguous with the mediastinum.

Risk factors for local tumor progression after RFA of pulmonary metastases: a matched case-control study.

Curative treatment of oligometastatic pulmonary disease aims at eradication of all metastases. Radiofrequency ablation (RFA) has been shown to be an efficient method and the frequency of local tumor progression (LTP) should be minimized. The objective of this study was to determine the morphological and treatment-related risk factors for LTP after RFA of pulmonary metastases. All patients treated with RFA for pulmonary metastases from 2002 to 2014 were reviewed. All LTPs from 2011 to 2014 were individually matched on the basis of tumor size, number, and histology. In total, 48 LTPs and 112 controls were blindly analyzed for morphological factors including vicinity of bronchus and vessels as well as treatment-related factors such as the size of the ablation zone and ablation margins. In the simple regression analysis, the significant predictive variables were ≤ 5-mm distance to a large bronchus (OR = 4.94; p = 0.0095) or large vessel (OR = 7.09; p < 0.001), minimal ablation margin (≤ 5 mm (OR = 42.67; p < 0.001), and a central-peripheral ablation offset/ablation zone size > 0.36 (OR = 13.83; p = 0.013). In the multiple regression model, only a minimal ablation margin ≤ 5 mm remained a significant risk factor for LTP. Only the minimal ablation margin remains significant in the multiple regression analysis; the other factors are presumably surrogates of an insufficient ablation margin. Improvement of lung RFA outcomes can probably be obtained by immediate post RFA evaluation of ablation margins to ensure a minimal ablation margin of at least 5 mm. • A distance < 5 mm to a bronchus or vessel of over 3 mm diameter is associated with insufficient ablation margin and thus risk factors for local tumor progression after pulmonary radiofrequency ablation. • A minimal ablation margin of > 5 mm after pulmonary RFA is associated with significantly less local tumor progression and should be looked for at the end of treatment session before needle removal in order to decrease local tumor progression. • Tumor location, pleural contact, occurrence of intra-alveolar hemorrhage, pulmonary atelectasis, and pneumothorax are not associated with an increased risk of local tumor progression.

Erector Spinae Plane Block for Computed Tomographic Scan Guidance Percutaneous Radiofrequency Ablation of Pulmonary Metastasis: Three Cases.

Erector Spinae Plane Block for Computed Tomographic Scan Guidance Percutaneous Radiofrequency Ablation of Pulmonary Metastasis: Three Cases.

Effectiveness and safety in radiofrequency ablation of pulmonary metastases from HCC: a five years study.

Hepatocellular carcinoma (HCC) is a frequent tumor that may be treated with radiofrequency thermal ablation (RFA). RFA has been used with success also in treatment of pulmonary metastases from a wide range of primitive tumors, especially colorectal. Previous studies have shown that RFA con be used in treating HCC pulmonary metastases. Purpose of our study was a retrospective evaluation of overall survival and complication rates of percutaneous CT-guided radiofrequency ablation of pulmonary metastases from hepatocellular carcinoma (HCC). Data were collected from 40 CT-guided ablation sessions performed on 42 lesions in 26 patients (16M and 10 F; mean age 62.5years) with pulmonary metastases from HCC (size range 0.3-4cm, mean diameter 1.4 ± 0.98cm) from February 2012 to December 2017. All patients, as in advanced stage of illness (stage C), were treated according to Barcelona Clinic Liver Cancer (BCLC) criteria, with Sorafenib. They had no active HCC foci in the liver and no more than three metastases in the lung. Patients did not discontinue medical therapy with Sorafenib and pulmonary relapses were treated up to three times. In two patients two lesions were treated during the same procedure. Each lesion was ablated under CT guidance. Follow-up contrast-enhanced CT at 1, 3, 6, 12-month and every 6months after treatment were reviewed. A total of 42 metastatic lung lesions from HCC in 26 patients (57% male, 43% female) were treated with CT-guided radiofrequency thermal ablation procedures. Immediate radiofrequency ablation-related complications (subtle pneumothorax) were observed in 9 of 40 procedures (22.5%). Only one patient developed a pneumothorax requiring drainage tube insertion (2.5%). No other major complications occurred. Moreover, no significant worsening of pulmonary function was observed. In all patients the overall survival rates were 88.5% at 1year, 69.8% at 3years and 26.2% at 5years. Our retrospective assessment confirmed that percutaneous CT-guided radiofrequency thermal ablation in 23 patients with pulmonary metastases from HCC represents an effective and safe alternative treatment option in patients not considerable as potential candidates to surgery.

Safety and efficacy of radiofrequency ablation for pulmonary metastases in metastatic colorectal cancer patients: A single center experience.

141 Background: Radiofrequency ablation (RFA) has been increasingly used for the treatment of pulmonary metastases from several types of malignancies. Methods: A retrospective analysis was performed for the safety and efficacy of percutaneous RFA in patients with metastatic colorectal cancer between October 2016 and June 2019 as well as assessing prognostic factors of local tumor control. Results: RFA was carried out for 48 lung metastases in 31 consecutive colorectal cancer patients. Male was 17 patients (55%), and the median age at RFA was 61 years (range, 42-81). The mean diameter of metastases targeted for RFA was 12 mm (range, 4-32), and 17 tumors (35%) were located in a sub-pleural or deep position. Although five cases (10%) were failed due to immediate complications, there was no procedure-related death. In terms of immediate complication, a total of 12 cases (25%) had events including nine pneumothorax (percutaneous drain in four), one pleural effusion, and two hemoptysis (ICU care in one). Delayed complications were lung abscess and diaphragm injury in each one patient, respectively. At the time of analysis, the median follow-up duration from RFA was 12.0 months (interquartile range, 6.5-23.1). Only two patients (6%) died of disease progression, and 3-year overall survival rate was 85.5% (95% CI, 75.5-95.5). RFA site progression was observed in 11 patients (23%), and 1-year and 2-year progression-free survival rates were 71.5% (95% CI, 58.7-84.3) and 56.6% (95% CI, 42.6-70.6), respectively. Multivariate analysis showed that extra-pulmonary progression (hazard ratio 17.49; p = 0.023) was only one independent prognostic factor associated with RFA site progression after adjusting for confounding factors including sex, age, performance, tumor size, location, contact with the vessel, last chemotherapy response, and duration. Conclusions: RFA is a comparatively safe and effective option for the treatment of small-sized lung metastases; however, the control of extra-pulmonary metastases should be accompanied for effective local control.

Immune Mechanisms After Radiofrequency Ablation of Pulmonary Metastases From Colorectal Cancer Origin

Immune Mechanisms After Radiofrequency Ablation of Pulmonary Metastases From Colorectal Cancer Origin

Radiofrequency ablation of pulmonary metastases from sarcoma: single-center retrospective evaluation of 46 patients

This retrospective, single-center study evaluated radiofrequency (RF) ablation for pulmonary metastases of sarcoma. Forty-six patients with sarcoma (144 pulmonary metastases) underwent 88 RF ablation sessions. Data regarding local tumor progression, efficacy, procedural adverse events (AEs; National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0), overall survival (OS), and OS-associated prognostic factors were retrospectively evaluated using univariate analyses. Local progression occurred in 22 of 144 tumors (15.3%). Primary and secondary efficacy rates were 83.5 and 90.0% at 1year and 76.3 and 81.4% at 2years, respectively. Seventy-three grade 1 AEs, 33 grade 2 AEs, and no grade≥3 AEs were observed. Twenty-eight patients (60.9%) remained alive and 18 died, yielding 1-, 2-, and 3-year OS rates of 80.6, 70.1, and 47.1% (median survival time, 31.7months). Univariate analysis revealed extrapulmonary metastasis (P=0.005), noncurative RF ablation (P=0.009), and a post-RF ablation disease-free interval of ≤12months (P=0.015) as significant negative prognostic factors. RF ablation is safe, offers good local control, and may be a viable treatment option for pulmonary metastasis of sarcoma.

Single Center Prospective Phase II Trial of CT-guided Radiofrequency Ablation for Pulmonary Metastases from Colorectal Cancer (SCIRO-1401).

The present single center prospective phase II clinical trial is designed to evaluate the efficacy and safety of percutaneous radiofrequency (RF) ablation for colorectal lung metastases. Patients who have colorectal lung metastases without extrapulmonary metastases are included in this study. The primary endpoint is 3-year overall survival (OS) after RF ablation. The secondary endpoints are the prevalence of adverse events within 4 weeks, local tumor progression rate, 1- and 5-year OS, cause-specific survival, and relapse-free survival. The recruitment of patients commenced in July 2014, and the enrolment of 45 patients is intended over the 3 years of study period.

Long-term results of percutaneous radiofrequency ablation of pulmonary metastases: a single institution experience.

Surgical resection of pulmonary metastases is considered as a therapeutic procedure in selected cases. However, many patients are unable to tolerate surgical intervention due to comorbidities and/or poor pulmonary reserve, also related to repeated parenchymal resections. Considering this scenario, we decided to investigate the role of radiofrequency ablation (RFA). The outcomes of all patients that underwent RFA for lung metastases, during the period 2003-2013, were analysed. The primary end-points were overall survival (OS) and local progression-free survival (LPFS). Secondary end-point was the analysis of possible risk factors affecting OS and LPFS. Ninety-nine RFAs were performed on 61 patients (38 men, 23 women, median age of 74 years). Fourteen patients were treated for two or more lesions, for a total of 86 lesions. Twelve lesions were treated up to three times. The median lesion diameter was 2 cm. The majority of patients were affected by lung metastases from colorectal cancer (47.5%). All procedures were successfully completed. One death occurred, whereas the morbidity rate was 11% (8% pneumothorax requiring chest drainage). At a median follow-up of 28 months, the 1-, 3-, 5-year OS (LPFS) rates were 94.8% (86.3%), 49.0% (70.3%) and 44.5% (68.3%), respectively. No significant correlation was found, using univariate and multivariate analysis, between OS and age, gender, histology of primary cancer (colon versus others), type of approach (computed tomography versus ultrasonography guidance), number of treated lesions (1 vs >1), disease-free interval (from primary tumour to first lung metastases) (1-35 vs >35 months), previous lung resections (yes versus no), whereas a tendency towards better OS was observed, by applying univariate analysis, for a lesion of <3 cm (P = 0.051) and for the presence of local disease 1 month after treatment (P = 0.056), however, without a statistically significant difference. With regard to LPFS, lesion dimensions (P = 0.005) and the presence of local disease 1 month after treatment (P < 0.001) were found to be significant risk factors, in both univariate and multivariate analyses. RFA appears as a feasible and safe procedure, with an acceptable morbidity, offering the possibility to safely repeat the treatment on the same lesion. RFA can be considered a valid option for the local control of lung metastases, in patients not eligible for surgery, especially those with lesions smaller than 3 cm.

Radiofrequency ablation for pulmonary metastases from esophageal squamous cell carcinoma.

138 Background: Radiofrequency ablation (RFA) is increasingly being used for the treatment of intrathoracic malignancies. Although RFA has been found to be promising in the treatment of lung metastases from some types of neoplasms, little is known concerning its clinical significance in the treatment of pulmonary metastasis from esophageal squamous cell carcinoma (ESCC). This retrospective study evaluated the feasibility, safety, and effectiveness of computed tomography-guided RFA for pulmonary metastasis from ESCC. Methods: Of 322 patients with ESCC underwent esophagectomy at Kumamoto University Hospital between January 2007 and May 2015, 23 cases had pulmonary recurrence. Selection criteria for CT-guided RFA for pulmonary metastasis were as follows: (i) there were no distant metastases except for pulmonary lesions, when there were extrapulmonary recurrences that had to be controlled by additional therapies; (ii) there were up to three pulmonary tumors; (iii) the number of pulmonary tumors did not increase over a certain period while receiving pre-RFA chemotherapy; (iv) the metastatic lesions were not adjacent to major pulmonary vessels, major bronchi, or the heart. 17 patients who underwent CT-guided RFA for metachronous pulmonary metastasis from ESCC were included in this study. Results: Correct placement of the ablation device into the target tumor proved to be feasible in all tumors (100%). The mean visual analog scale score, with values that ranged from 0 (no pain) to 10 (worst pain possible), was 1. This suggested that this procedure was well tolerated. No procedure-related deaths occurred. A pneumothorax needing drainage was a major complication in two patients. 6 patients died of recurrent disease. The predicted 1- and 2-year overall survival rates after lung RFA were 78.8% and 46.7%, respectively. Conclusions: Percutaneous computed tomography-guided RFA yielded relatively high levels of local control in patients with pulmonary metastases from ESCC and was associated with an acceptable level of complications. It was concluded that a prospective study will be necessary to evaluate the effectiveness of a combination of systemic therapy and RFA for ESCC lung metastases.

A prospective clinical trial of radiofrequency ablation for pulmonary metastases

Pulmonary oligometastases can be treated by local treatment options, such as resection, radiofrequency ablation (RFA), and radiotherapy, in selected patients. In the present study, 67 patients with 115 pulmonary metastases were treated, and all the lesions were treated by RFA and followed with a computed tomography scan. The local control, overall survival (OS), progression-free survival (PFS) and treatment-related toxicity were observed. Median follow-up duration after the initial RFA was 24 months (range, 3-39 months). The median PFS from RFA was 14 months [95% confidence interval (CI), 11.6-16.4]. The 6-, 12- and 18-month PFS rates were 82.1, 55.7 and 27.5%, respectively. The median OS rate from RFA was 24 months (95% CI, 18.2-29.8). The 1-, 2- and 3-year OS rates were 83.6, 46.3 and 14.3%, respectively. Primary tumor was significantly correlated to PFS and OS on multivariate analysis, and other variates showed no significance. Therefore, RFA is safe for patient treatment and can be considered as a promising treatment option for patients with pulmonary metastases.

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.

Abstract No. 372 - Percutaneous radiofrequency ablation for pulmonary metastases from esophageal cancer: retrospective evaluation of 21 patients

Abstract No. 372 - Percutaneous radiofrequency ablation for pulmonary metastases from esophageal cancer: retrospective evaluation of 21 patients

Radiofrequency Ablation for Pulmonary Metastases from Gastrointestinal Cancers

The lung is one of the most common targets of metastases from gastrointestinal (GI) cancers. Surgical treatment (i.e., metastasectomy) is an accepted therapeutic option for pulmonary metastases from GI cancers. However, surgery may be contraindicated in advanced stages of cancer, compromised lung function, and/or comorbidities. This issue has prompted the search for innovative and less invasive ways of treating pulmonary metastases. Image-guided radiofrequency ablation (RFA) has attracted great interest as a minimally invasive approach against intrathoracic malignancies. In this technique, radiofrequency energy is applied via a needle electrode inserted into the target tissue. As the cells are agitated by the applied energy, they release heat, causing denaturation and cell death. Recently, this technique has been used on patients with pulmonary metastatic disease arising from GI cancers such as colorectal cancer, esophageal cancer, and hepatocellular carcinoma, as well as on patients with primary lung cancer. The present review updates the clinical outcomes and advances in RFA therapy of lung metastases from GI cancers.

Radiofrequency ablation for pulmonary metastases from esophageal squamous cell carcinoma

Radiofrequency ablation (RFA) is increasingly being used for the treatment of intrathoracic malignancies. Although RFA has been found to be promising in the treatment of lung metastases from some types of neoplasms, little is known concerning its clinical significance in the treatment of pulmonary metastasis from esophageal squamous cell carcinoma (ESCC). This retrospective study evaluated the feasibility, safety, and effectiveness of computed tomography-guided RFA for pulmonary metastasis from ESCC. A series of 10 ESCC patients with 17 pulmonary tumors were included. Correct placement of the ablation device into the target tumor proved to be feasible in all tumors (100%). The mean visual analog scale score, with values that ranged from 0 (no pain) to 10 (worst pain possible), was 1. This suggested that this procedure was well tolerated. No procedure-related deaths occurred. A pneumothorax needing drainage was a major complication in two patients. Local control of ablated tumor lasting for at least 1 year was achieved in 10 (83%) of 12 assessable tumors. Although locoregional recurrences developed in two tumors, these lesions could be recontrolled by repeat treatment with RFA. Three patients died of recurrent disease. The predicted 1- and 2-year overall survival rates after lung RFA were 77.8% and 62.2%, respectively. Percutaneous computed tomography-guided RFA yielded relatively high levels of local control in patients with pulmonary metastases from ESCC and was associated with an acceptable level of complications. It was concluded that a prospective study will be necessary to evaluate the effectiveness of a combination of systemic therapy and RFA for ESCC lung metastases.

Percutaneous Radiofrequency Ablation for Pulmonary Metastases from Hepatocellular Carcinoma: Results of a Multicenter Study in Japan

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.

Local progression after radiofrequency ablation for pulmonary metastases

Local treatment for pulmonary metastases is considered to be a reasonable treatment option in patients with oligometastatic disease. Percutaneous radio frequency ablation (RFA) has been reported as an alternative to surgery. Results of RFA for local control of pulmonary metastases were evaluated. All consecutive patients treated with RFA for pulmonary metastases (2004-2009) were included. RFA was performed percutaneously under computed tomographic guidance. Follow-up was scheduled at 1, 3, and 6 months after treatment and every 6 months thereafter. Major outcome parameters were local and any-site progression, complications, and survival. Ninety pulmonary metastases were treated, in 46 patients at 65 sessions. Many patients had recurrent metastases after previous surgery (n = 36 of 46). Pneumothorax occurred in 34% (chest drain in 25%) and major complications in 6%. After median follow-up of 22 months (range, 2-65 months), 25 local progressions occurred after RFA; the 2-year local progression rate per lesion was 35%. Overall survival at 3 years was 69%. Notwithstanding its relatively low morbidity, follow-up after RFA for pulmonary metastases shows a considerable rate of local progression. The role of local ablation techniques for long-term disease control in oligometastatic disease is discussed.

Pathologic Assessment of Radiofrequency Ablation of Pulmonary Metastases

To evaluate pathologically the effectiveness of radiofrequency (RF) ablation in the treatment of pulmonary metastases. Patients with multiple pulmonary metastases scheduled for surgical resection were prospectively enrolled. Patients underwent RF ablation of one percutaneously accessible tumor and within 2-4 weeks underwent surgical resection of the ablated tumor and any additional lesions. Resected tumors all were assessed by routine light microscopy, and selected tumors were assessed by immunohistochemistry with MIB1 and proliferative cell nuclear antigen (PCNA). Relationship of ablation zone to the tumor and viability of the ablated tumors were assessed. Nine patients (four men and five women) 46-76 years of age were included in the study. Four patients had metastatic colorectal carcinoma, and five patients had metastases from soft tissue sarcomas. Ablated tumors ranged from 1.0-3.0 cm in diameter. Each target lesion was completely encompassed by the ablation zone. All tumor tissue within the ablation zone showed characteristic changes of coagulative necrosis with hematoxylin and eosin staining. Tumors showed preservation of MIB1 staining but loss of PCNA protein staining. RF ablation resulted in complete coagulative necrosis of all the pulmonary metastases treated in the study. Although this series is small, it provides histologic support for RF ablation as an effective treatment for selected pulmonary metastases.