Ablation for the Management of Pulmonary Malignancies

Lung Cryoablation: Patient Selection, Techniques, and Postablation Imaging

Image-guided percutaneous lung ablation has become increasingly common in the treatment of non-small cell lung cancer (NSCLC) and oligometastatic disease in recent years. Among the available techniques are well-described heat-based techniques, such as lung radiofrequency or microwave ablation, and lung cryoablation (LCA), based on the use of extreme cold to cause tissue necrosis. Although it is the least used of the three ablative techniques available for lung ablation, LCA has inherent characteristics that render it the preferred technique in certain situations. Due to the nature of cryoablation, the collagen extracellular matrix of the tissue adjacent to the ablation site is preserved during the intervention. Additionally, cryoablation may allow more precise imaging monitoring of the ablation zone compared with heat-based techniques. These intrinsic advantages potentially establish LCA as the preferred ablative technique for treating lung tumors located near sensitive vital structures, such as the heart, pulmonary hilum, pulmonary arteries, aorta, main bronchi, and pleura. The authors discuss the basic principles of LCA; the indications and contraindications of the technique; and the technical details of the treatment, including the expected findings and periprocedural complications. A standardized scheme for post-cryoablation imaging follow-up is proposed, detailing the expected findings of complete response and signs of tumor persistence and recurrence and specifying the differences seen with heat-based ablative techniques. ©RSNA, 2025 Supplemental material is available for this article. See the invited commentary by Parvinian and Eiken in this issue.

Hybrid Approaches to Local Management of Pulmonary Metastatic Disease

With increasingly effective systemic therapies for stage IV disease, the addition of local control strategies for a subset of patients with limited metastatic disease has contributed to improved disease control and life prolongation. While surgery has been the mainstay strategy for local control, stereotactic ablative body radiation and percutaneous ablation techniques are alternate methods that have been demonstrated to be safe and effective and offer options to those patients who are unresectable, inoperable, or who do not desire surgery. A hybrid approach combining surgery and radiotherapy can maximize the ability to treat more lesions.

Efficacy and safety of microwave ablation and its synergistic potential in the treatment of early-stage non-small cell lung cancer

Lung cancer remains the primary cause of cancer-related mortality globally. In the case of early-stage non-small cell lung cancer (NSCLC), surgical resection, such as lobectomy and sub-lobectomy, continues to be the established standard treatment. However, for patients with insufficient cardiopulmonary function and multiple comorbidities who are unable to undergo surgical resection, nonoperative local therapies, including radiotherapy and thermal ablation, are preferred. In recent years, microwave ablation (MWA) has gained popularity for treating early-stage NSCLC due to its high heating efficiency, good tissue conductance, and heat conduction capabilities. This review provides a comprehensive summary of the current efficacy and safety data regarding MWA for early-stage NSCLC and discusses the potential benefits of combining MWA with other therapies.

The Latest on Lung Ablation

Lung cancer is the second most common cancer in both men and women. Despite smoking cessation efforts and advances in lung cancer detection and treatment, long-term survival remains low. For early-stage primary lung carcinoma, surgical resection offers the best chance of long-term survival; however, only about one-third of patients are surgical candidates. For nonsurgical candidates, minimally invasive percutaneous thermal ablation therapies have become recognized as safe and effective treatment alternatives, including radiofrequency ablation, microwave ablation, and cryoablation. Lung ablation is also an acceptable treatment for limited oligometastatic and oligorecurrent diseases. This article discusses the technologies and techniques available for tumor ablation of thoracic malignancies, as well as new treatments on the horizon.

Update on Image-Guided Thermal Lung Ablation: Society Guidelines, Therapeutic Alternatives, and Postablation Imaging Findings

Percutaneous image-guided thermal ablation (IGTA) has been endorsed by multiple societies as a safe and effective lung-preserving treatment for primary lung cancer and metastases involving the lung and chest wall. This article reviews the role of IGTA in the care continuum of patients with thoracic neoplasms and discusses strategies to identify the optimal local therapy considering patient and tumor characteristics. The advantages and disadvantages of percutaneous thermal ablation compared to surgical resection and stereotactic body radiotherapy are summarized. Principles of radiofrequency ablation, microwave ablation, and cryoablation, as well as the emerging use of transbronchial thermal ablation, are described. Specific considerations are presented regarding the role of thermal ablation for early-stage non-small cell lung cancer (NSCLC), multifocal primary NSCLC, pulmonary metastases, salvage of recurrent NSCLC after surgery or radiation, and pain palliation for tumors involving the chest wall. Recent changes to professional society guidelines regarding the role of thermal ablation in the lung, including for treatment of oligometastatic disease, are highlighted. Finally, recommendations are provided for imaging follow-up after thermal ablation of lung tumors, accompanied by examples of expected postoperative findings and patterns of disease recurrence.

Imaging following thermal ablation of early lung cancers: expected post-treatment findings and tumour recurrence

Thermal ablation is a minimally invasive technique that is growing in acceptance and popularity in the management of early lung cancers. Although curative resection remains the optimal treatment strategy for stage I pulmonary malignancies, percutaneous ablative treatments may also be considered for selected patients. These techniques can additionally be used in the treatment of oligometastatic disease. Thermal ablation of early lung tumours can be achieved using several different techniques. For example, microwave ablation (MWA) and radiofrequency ablation (RFA) utilise extreme heat, whereas cryoablation uses extremely cold temperatures to cause necrosis and ultimately cell death. Typically, post-ablation imaging studies are performed within the first 1-3 months with subsequent imaging performed at regular intervals to ensure treatment response and to evaluate for signs of recurrent disease. Surveillance imaging is usually undertaken with computed tomography (CT) and integrated positron-emission tomography (PET)/CT. Typical imaging findings are usually seen on CT and PET/CT following thermal ablation of lung tumours, and it is vital that radiologists are familiar with these appearances. In addition, radiologists should be aware of the imaging findings that indicate local recurrence following ablation. The objective of this review is to provide an overview of the expected post-treatment findings on CT and PET/CT following thermal ablation of early primary lung malignancies, as well as describing the imaging appearances of local recurrence.

Image-guided percutaneous ablation for the treatment of lung malignancies: current state of the art

Image-guided percutaneous lung ablation has proven to be a valid treatment alternative in patients with early-stage non-small cell lung carcinoma or oligometastatic lung disease. Available ablative modalities include radiofrequency ablation, microwave ablation, and cryoablation. Currently, there are no sufficiently representative studies to determine significant differences between the results of these techniques. However, a common feature among them is their excellent tolerance with very few complications. For optimal treatment, radiologists must carefully select the patients to be treated, perform a refined ablative technique, and have a detailed knowledge of the radiological features following lung ablation. Although no randomized studies comparing image-guided percutaneous lung ablation with surgery or stereotactic radiation therapy are available, the current literature demonstrates equivalent survival rates. This review will discuss image-guided percutaneous lung ablation features, including available modalities, approved indications, possible complications, published results, and future applications.

Video-assisted thoracoscopic surgery as the gold standard for lung cancer surgery

Surgical resection remains the only effective means of cure in the vast majority of patients with early-stage lung cancer. It can be performed via a traditional open approach (particularly thoracotomy) or a minimally invasive approach. VATS is 'keyhole' surgery in the chest, and was first used for lung cancer resection in the early 1990s. Since then, a large volume of evolving clinical evidence has confirmed that VATS lung cancer resection offered proven safety and feasibility, better patient-reported post-operative outcomes, less surgical trauma as quantified by objective outcome measures and equivalent or better survival than open surgery. This has firmly established VATS as the surgical approach of choice for early-stage lung cancer today. Although impressive new non-surgical lung cancer therapies have emerged in recent years, VATS is also being constantly rejuvenated by the development of 'next generation' VATS techniques, the refinement of VATS sublobar resection for selected patients, the utilization of bespoke post-operative recovery programmes for VATS and the synthesis of VATS into multi-modality lung cancer therapy. There is little doubt that VATS will remain as the gold standard for lung cancer surgery for the foreseeable future.

Imaging of Novel Oncologic Treatments in Lung Cancer Part 2: Local Ablative Therapies

Conventional approaches to the treatment of early-stage lung cancer have focused on the use of surgical methods to remove the tumor. Recent progress in radiation therapy techniques and in the field of interventional oncology has seen the development of several novel ablative therapies that have gained widespread acceptance as alternatives to conventional surgical options in appropriately selected patients. Local control rates with stereotactic body radiation therapy for early-stage lung cancer now approach those of surgical resection, while percutaneous ablation is in widespread use for the treatment of lung cancer and oligometastatic disease for selected other malignancies. Tumors treated with targeted medical and ablative therapies can respond to treatment differently when compared with conventional therapies. For example, after stereotactic body radiation therapy, radiologic patterns of posttreatment change can mimic disease progression, and, following percutaneous ablation, the expected initial increase in the size of a treated lesion limits the utility of conventional size-based response assessment criteria. In addition, numerous treatment-related side effects have been described that are important to recognize, both to ensure appropriate treatment and to avoid misclassification as worsening tumor. Imaging plays a vital role in the assessment of patients receiving targeted ablative therapy, and it is essential that thoracic radiologists become familiar with these findings.

Bronchoscopically Delivered Thermal Vapor Ablation of Human Lung Lesions

BACKGROUND

The discovery that early diagnosis can reduce the mortality of lung cancer provides firm evidence that early surgical intervention is effective. However, surgical resection is available only to those who are healthy enough to tolerate the procedure. Vapor ablation may provide an additional method of treating the lung cancer patient, and has been studied in humans for emphysema treatment. In swine, we previously demonstrated that bronchoscopically delivered thermal vapor ablation (BTVA) could be accurately applied, was uniform, anatomically confined, and was tolerated by the animal. To provide evidence that BTVA may be a feasible method of treatment in humans, and since human and swine lungs have differing airway and segmental anatomy, we extended our studies to deceased human lungs to determine if anatomically confined and uniform ablations could be obtained with levels of energy comparable with our swine and human emphysema studies.

METHODS

We obtained fresh, deceased human lungs and performed BTVA with increasing energy in subsegmental regions of lung containing tumors as well as non-tumor-containing areas in order to determine if uniform ablations with sharp boundaries could be obtained in human lung.

RESULTS

We found that all ablations were anatomically contained. The frequency of uniform ablation effect was dependent on the total energy delivered and was achieved at a greater frequency than those with sharp boundaries. If a lung tumor was contained within the anatomy of the subsegment, the ablation zone completely surrounded the tumor.

CONCLUSION

We conclude that BTVA may have a future role in the treatment of lung cancer and should be investigated further in clinical trials.

Microwave Ablation in the Management of Colorectal Cancer Pulmonary Metastases

PURPOSE

To review outcomes following microwave ablation (MWA) of colorectal cancer pulmonary metastases and assess predictors of oncologic outcomes.

METHODS

Technical success, primary and secondary technique efficacy rates were evaluated for 50 patients with 90 colorectal cancer pulmonary metastases at immediate, 4-8 weeks post-MWA and subsequent follow-up CT and/or ¹⁸F-FDG PET/CT. Local tumor progression (LTP) rate, LTP-free survival (LTPFS), cancer-specific and overall survivals were assessed. Complications were recorded according to SIR classification.

RESULTS

Median follow-up was 25.6 months. Median tumor size was 1 cm (0.3-3.2 cm). Technical success, primary and secondary technique efficacy rates were 99, 90 and 92%, respectively. LTP rate was 10%. One-, 2- and 3-year LTPFS were: 93, 86 and 86%, respectively, with median LTPFS not reached. Median overall survival was 58.6 months, and median cancer-specific survival (CSS) was not reached. One-, 2- and 3-year overall and CSS were 94% and 98, 82 and 90%, 61 and 70%, respectively. On univariate analysis, minimal ablation margin (p < 0.001) and tumor size (p = 0.001) predicted LTPFS, with no LTP for minimal margin ≥ 5 mm and/or tumor size < 1 cm. Pleural-based metastases were associated with increased LTP risk (p = 0.002, SHR = 7.7). Pre-MWA CEA level > 10 ng/ml (p = 0.046) and ≥ 3 prior chemotherapy lines predicted decreased CSS (p = 0.02). There was no 90-day death. Major complications rate was 13%.

CONCLUSIONS

MWA with minimal ablation margin ≥ 5 mm is essential for local control of colorectal cancer pulmonary metastases. Pleural-based metastases and larger tumor size were associated with higher risk of LTP. CEA level and pre-MWA chemotherapy impacted CSS.

Ablation therapy of non-colorectal cancer lung metastases: retrospective analysis of tumour response post-laser-induced interstitial thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA)

PURPOSE

To retrospectively compare the local tumour response and survival rates in patients with non-colorectal cancer lung metastases post-ablation therapy using laser-induced thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA).

MATERIAL AND METHODS

Retrospective analysis of 175 computed tomography (CT)-guided ablation sessions performed on 109 patients (43 males and 66 females, mean age: 56.6 years). Seventeen patients with 22 lesions underwent LITT treatment (tumour size: 1.2-4.8 cm), 29 patients with 49 lesions underwent RFA (tumour size: 0.8-4.5 cm) and 63 patients with 104 lesions underwent MWA treatment (tumour size: 0.6-5 cm). CT scans were performed 24-h post-therapy and on follow-up at 3, 6, 12, 18 and 24 months.

RESULTS

The overall-survival rates at 1-, 2-, 3- and 4-year were 93.8, 56.3, 50.0 and 31.3% for patients treated with LITT; 81.5, 50.0, 45.5 and 24.2% for patients treated with RFA and 97.6, 79.9, 62.3 and 45.4% for patients treated with MWA, respectively. The mean survival time was 34.14 months for MWA, 34.79 months for RFA and 35.32 months for LITT. In paired comparison, a significant difference could be detected between MWA versus RFA (p = 0.032). The progression-free survival showed a median of 23.49 ± 0.62 months for MWA,19.88 ± 2.17 months for LITT and 16.66 ± 0.66 months for RFA (p = 0.048). The lowest recurrence rate was detected in lesions ablated with MWA (7.7%; 8 of 104 lesions) followed by RFA (20.4%; 10 of 49 lesions) and LITT (27.3%; 6 of 22 lesions) p value of 0.012. Pneumothorax was detected in 22.16% of MWA ablations, 22.73% of LITT ablations and 14.23% of RFA ablations.

CONCLUSION

LITT, RFA and MWA may provide an effective therapeutic option for non-colorectal cancer lung metastases with an advantage for MWA regarding local tumour control and progression-free survival rate.

Pulmonary radiofrequency ablation (Part 1): current state

The risks involved in surgical treatment and conventional radiotherapy in patients with early lung cancer or lung metastases often make these treatments difficult to justify. However, on the other hand, it is also unacceptable to allow these lesions to evolve freely because, left untreated, these neoplasms will usually lead to the death of the patient. In recent years, alternative local therapies have been developed, such as pulmonary radiofrequency ablation, which has proven to increase survival with a minimal risk of complications. There are common recommendations for these treatments, and although the specific indications for using one technique or another have yet to be established, there are clearly defined situations that will determine the outcome of the treatment. It is important to know these situations, because appropriate patient selection is essential for therapeutic success. This article aims to describe the characteristics and constraints of pulmonary radiofrequency ablation and to outline its role in thoracic oncology in light of the current evidence.

Radiofrequency ablation in the management of advanced stage thymomas: a case report on a novel multidisciplinary therapeutic approach

We describe in this report a case of successful radiofrequency ablation of an unresectable stage III-type B3 thymoma, and we discuss the role of this novel approach in the management of patients with advanced stage thymoma. The patient, a 59-year-old Caucasian male underwent neoadjuvant chemotherapy with only a slight reduction of the mass. Subsequently, an explorative sternotomy and debulking were performed; before closing the thorax, radiofrequency ablation of the residual tumor was carried out and a partial necrosis of the mass was achieved. A further percutaneous radiofrequency ablation was performed subsequently, obtaining complete necrosis of the lesion. Successively, the patient underwent adjuvant radiotherapy. As a result of this multidisciplinary treatment, complete and stable response was obtained. It is hard to say which of the single treatments had the major impact on cure; nevertheless, the results obtained suggest that radiofrequency ablation must be taken into account for the treatment of advanced stage thymomas, and its effectiveness must be further assessed in future studies.

Interventional radiology in the diagnosis and treatment of diseases of the breast: a historical review and future perspective based on currently available techniques

OBJECTIVE

The topic of imaging-guided breast interventions spans more than 30 years. Radiologists pioneered procedures such as needle or wire localization and ultrasound and stereotactic-guided biopsy. Using recently developed devices and technology, the opportunity exists to treat lesions of the breast with minimally invasive imaging-guided techniques.

CONCLUSION

Breast imagers and interventional radiologists, along with our surgical and oncologic colleagues, are best qualified to participate together in the research and development of these procedures.

Evolution of the ablation region after magnetic resonance-guided high-intensity focused ultrasound ablation in a Vx2 tumor model

OBJECTIVES

Volumetric magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU) is a completely noninvasive image-guided thermal ablation technique. Recently, there has been growing interest in the use of MR-HIFU for noninvasive ablation of malignant tumors. Of particular interest for noninvasive ablation of malignant tumors is reliable treatment monitoring and evaluation of response. At this point, there is limited evidence on the evolution of the ablation region after MR-HIFU treatment. The purpose of the present study was to comprehensively characterize the evolution of the ablation region after volumetric MR-HIFU ablation in a Vx2 tumor model using MR imaging, MR temperature data, and histological data.

MATERIALS AND METHODS

Vx2 tumors in the hind limb muscle of New Zealand White rabbits (n = 30) were ablated using a clinical MR-HIFU system. Twenty-four animals were available for analyses. Magnetic resonance imaging was performed before and immediately after ablation; MR temperature mapping was performed during the ablation. The animals were distributed over 7 groups with different follow-up lengths. Depending on the group, animals were reimaged and then killed on day 0, 1, 3, 7, 14, 21, or 28 after ablation. For all time points, the size of nonperfused areas (NPAs) on contrast-enhanced T1-weighted (CE-T1-w) images was compared with lethal thermal dose areas (ie, the tissue area that received a thermal dose of 240 equivalent minutes or greater [EM] at 43°C) and with the necrotic tissue areas on histology sections.

RESULTS

The NPA on CE-T1-w imaging showed an increase in median size from 266 ± 148 to 392 ± 178 mm(2) during the first day and to 343 ± 170 mm(2) on day 3, followed by a gradual decrease to 113 ± 103 mm(2) on day 28. Immediately after ablation, the NPA was 1.6 ± 1.4 times larger than the area that received a thermal dose of 240 EM or greater in all animals. The median size of the necrotic area on histology was 1.7 ± 0.4 times larger than the NPA immediately after ablation. After 7 days, the size of the NPA was in agreement with the necrotic tissue area on histology (ratio, 1.0 ± 0.2).

CONCLUSIONS

During the first 3 days after MR-HIFU ablation, the ablation region increases in size, after which it gradually decreases in size. The NPA on CE-T1-w imaging underestimates the extent of tissue necrosis on histology in the initial few days, but after 1 week, the NPA is reliable in delineating the necrotic tissue area. The 240-EM thermal dose limit underestimates the necrotic tissue area immediately after MR-HIFU ablation. Reliable treatment evaluation techniques are particularly important for noninvasive, image-guided tumor ablation. Our results indicate that CE-T1-w imaging is reliable for MR-HIFU treatment evaluation after 1 week.

[Change of ERCC1 expression of residual VX2 squamous carcinoma cells in rabbit lung after radiofrequency ablation]

背景与目的

残存肿瘤是影响射频消融（radiofrequency ablation, RFA）治疗肺恶性肿瘤效果的重要因素，联合铂类药物化疗是减少残存肿瘤的重要手段之一。核苷酸切除修复交叉互补基因1（excision repair cross-complementation group 1, ERCC1）的表达水平是影响铂类药物化疗效果的重要因素之一。RFA治疗后残存肿瘤会发生一些生物学特性变化，但有关ERCC1表达变化的研究尚无报道。本研究旨在探讨RFA治疗后兔肺内残存VX2鳞癌细胞ERCC1表达水平的变化。

方法

应用组织块悬液注射法建立兔VX2鳞癌肺内移植瘤模型。58只荷瘤新西兰白兔随机分为对照组（n=10）和RFA组（n=48）。在RFA治疗时，通过控制电极展开范围、输出功率、治疗时间的方法，造成肿瘤残存。应用免疫组织化学方法检测残存肿瘤细胞在不同时间点ERCC1表达的阳性率。

结果

RFA组残存肿瘤组织ERCC1表达阳性率在1 d-5 d呈一过性升高（53.7%±1.6% & 32.9%±2.5%），5 d后恢复至对照组水平。

结论

因在RFA治疗后1 d-5 d内残存肿瘤细胞ERCC1表达增高，在此期间给予铂类药物化疗可能效果不佳。

Ki 67 is an independent predictive biomarker of cancer specific and local recurrence-free survival after lung tumor ablation

BACKGROUND

The objective of this work was to evaluate the feasibility of histopathological analysis of tissue extracted on multitined electrodes and assess whether tissue characteristics can be used as biomarkers of oncologic outcomes after lung tumor radiofrequency (RF) ablation.

METHODS

Treatment-related data regarding RF ablation of lung malignancies at our institution was collected using a Health Insurance Portability and Accountability Act-compliant ablation database. Institutional review board waiver was obtained for this study. Immunohistochemical analysis of tissue extracted from the electrodes after lung tumor RF ablation was performed for proliferation (Ki-67) and apoptosis (caspase-3). Patient, tumor demographics, and ablation parameters were recorded. Local tumor progression-free survival (LPFS), disease-specific survival (DSS), and overall survival (OS) were assessed using Kaplan-Meier methodology. Multivariate analysis determined factors affecting these oncological outcomes.

RESULTS

A total of 47 lung tumors in 42 patients were ablated; 30 specimens were classified as coagulation necrosis (CN) and 17 as Ki-67-positive (+) tumor cells (viable). Tumor sizes were similar in the CN and Ki-67+ groups (P = 0.32). Median LPFS was 10 versus 16 months for Ki-67+ and CN groups, and 1-year LPFS was 34 and 75 %, respectively (P = 0.003). Median OS was 20 and 46 months (P = 0.12), and median DSS was 20 and 68 months (P = 0.01) for the Ki-67 + and CN groups, respectively. Identification of Ki-67+ tumor cells more than tripled the risk of death from cancer [hazard ratio (HR) = 3.65; 95 % confidence interval (95 % CI), 1.34-9.95; P = 0.01] and tripled the risk of local tumor progression (LTP) (HR = 3.01; 95 % CI, 1.39-6.49; P = 0.005).

CONCLUSIONS

Ki-67+ tumor cells on the electrode after pulmonary tumor RF ablation is an independent predictor of LTP, shorter LPFS, and DSS.

Treatment of pulmonary colorectal metastases by radiofrequency ablation

We evaluated the local tumor control and the survival benefit achieved with radiofrequency ablation (RFA) for nonoperable lung metastases in 45 patients with colorectal cancer. Median survival from the time of RFA was 46 months. One-, 2- and 3-year local tumor progression (LTP)-free survival rates were 92%, 77%, and 77%, respectively. RFA offers very good local control in patients with pulmonary metastases from colorectal cancer.

BACKGROUND

Radiofrequency ablation has emerged as a potential, lung function-preserving treatment of colorectal lung metastases.

PATIENTS AND METHODS

Forty-five patients with colorectal pulmonary metastases underwent computed tomography-guided RFA from December 2004 to June 2010. A baseline posttreatment scan was obtained 4-6 weeks after RFA and follow-up imaging studies every 3 months thereafter were obtained and compared to evaluate the tumor progression at site of ablation or elsewhere. The primary end points were LTP-free survival and overall survival from RFA procedure. The Kaplan-Meier method was used to analyze the end points. A Cox proportional hazard model with robust inference was used to estimate the associations between baseline factors and survival end points.

RESULTS

Sixty-nine metastases were ablated in 45 patients. Tumor size ranged from 0.4 to 3.5 cm. The median number of metastases ablated per patient was 1 (range, 1-3). Median follow-up after RFA was 18 months. Median survival from the time of RFA was 46 months (95% confidence interval [CI], 27.8-47.3). One-, 2- and 3-year overall survival rates from the time of RFA were 95% (95% CI, 82%-99%), 72% (95% CI, 52%-85%), and 50% (95% CI, 26%-71%), respectively. Nine of 69 lesions (13%) progressed and 4 were retreated with no progression after second RFA. Median time to progression was not reached. LTP-free survival from RFA was 92% (95% CI, 82%-97%) at 1 year, 77% (95% CI, 58%-88%) at 2 years, and 77% (95% CI, 58%-88%) at 3 years.

CONCLUSION

Radiofrequency ablation of lung metastases is an effective minimally invasive, parenchymal-sparing technique that has very good local control rates in patients with pulmonary metastases from colorectal cancer, with LTP-free survival of 77% at 3 years.