Rare complications after lung percutaneous radiofrequency ablation: Incidence, risk factors, prevention and management

Lung microwave ablation: Post-procedure imaging features and evolution of pulmonary ground-glass nodule-like lung cancer

PURPOSE

To retrospectively examine the imaging characteristics of chest-computed tomography (CT) following percutaneous microwave ablation (MWA) of the ground-glass nodule (GGN)-like lung cancer and its dynamic evolution over time.

MATERIALS AND METHODS

From June 2020 to May 2021, 147 patients with 152 GGNs (51 pure GGNs and 101 mixed GGNs, mean size 15.0 ± 6.3 mm) were enrolled in this study. One hundred and forty-seven patients underwent MWA procedures. The imaging characteristics were evaluated at predetermined time intervals: immediately after the procedure, 24-48 h, 1, 3, 6, 12, and ≥18 months (47 GGNs).

RESULTS

This study population included 147 patients with 152 GGNs, as indicated by the results: 43.5% (66/152) adenocarcinoma in situ, 41.4% (63/152) minimally invasive adenocarcinoma, and 15.1% (23/152) invasive adenocarcinoma. Immediate post-procedure tumor-level analysis revealed that the most common CT features were ground-glass opacities (93.4%, 142/152), hyperdensity within the nodule (90.7%, 138/152), and fried egg sign or reversed halo sign (46.7%, 71/152). Subsequently, 24-48 h post-procedure, ground-glass attenuations, hyperdensity, and the fried egg sign remained the most frequent CT findings, with incidence rates of 75.0% (114/152), 71.0% (108/152), and 54.0% (82/152), respectively. Cavitation, pleural thickening, and consolidation were less frequent findings. At 1 month after the procedure, consolidation of the ablation region was the most common imaging feature. From 3 to 12 months after the procedure, the most common imaging characteristics were consolidation, involutional parenchymal bands and pleural thickening. At ≥18 months after the procedure, imaging features of the ablation zone revealed three changes: involuting fibrosis (80.8%, 38/47), consolidation nodules (12.8%, 6/47), and disappearance (6.4%, 3/47).

CONCLUSIONS

This study outlined the anticipated CT imaging characteristics of GGN-like lung cancer following MWA. Diagnostic and interventional radiologists should be familiar with the expected imaging characteristics and dynamic evolution post-MWA in order to interpret imaging changes with a reference image.

Radiofrequency ablation for stage <IIB non-small cell lung cancer: Opportunities, challenges, and the road ahead

Pulmonary carcinoma represents the second common cancer for human race while its mortality rate ranked the first all over the world. Surgery remains the primary option for early-stage non-small cell lung cancer (NSCLC) in some surgical traditions. Nevertheless, only less than half of patients are operable subjected to the limited lung function and multiple primary/metastatic lesions. Recent improvements in minimally invasive surgical techniques have made the procedure accessible to more patients, but this percentage still does not exceed half. In recent years, radiofrequency ablation (RFA), one of the thermal ablation procedures, has gradually advanced in the treatment of lung cancer in addition to being utilized to treat breast and liver cancer. Several guidelines, including the American College of Chest Physicians (ACCP), include RFA as an option for some patients with NSCLC although the level of evidence is mostly limited to retrospective studies. In this review, we emphasize the use of the RFA technique in patients with early-stage NSCLC and provide an overview of the RFA indication population, prognosis status, and complications. Meanwhile, the advantages and disadvantages of RFA proposed in existing studies are compared with surgical treatment and radiotherapy. Due to the high rate of gene mutation and immunocompetence in NSCLC, there are considerable challenges to clinical translation of combining targeted drugs or immunotherapy with RFA that the field has only recently begun to fully appreciate.

Imaging Follow-Up of Nonsurgical Therapies for Lung Cancer: AJR Expert Panel Narrative Review

Lung cancer continues to be the most common cause of cancer-related death worldwide. In the past decade, with the implementation of lung cancer screening programs and advances in surgical and nonsurgical therapies, the survival of patients with lung cancer has increased, as has the number of imaging studies that these patients undergo. However, most patients with lung cancer do not undergo surgical re-section, because they have comorbid disease or lung cancer in an advanced stage at diagnosis. Nonsurgical therapies have continued to evolve with a growing range of systemic and targeted therapies, and there has been an associated evolution in the imaging findings encountered at follow-up examinations after such therapies (e.g., with respect to posttreatment changes, treatment complications, and recurrent tumor). This AJR Expert Panel Narrative Review describes the current status of nonsurgical therapies for lung cancer and their expected and unexpected imaging manifestations. The goal is to provide guidance to radiologists regarding imaging assessment after such therapies, focusing mainly on non-small cell lung cancer. Covered therapies include systemic therapy (conventional chemotherapy, targeted therapy, and immunotherapy), radiotherapy, and thermal ablation.

Percutaneous image-guided thermal ablation of lung cancer: What is the evidence?

Thermal ablation techniques have now been used for more than twenty years in the treatment of primary lung tumours, predominantly non-small cell lung cancer (NSCLC). Although primarily used for the treatment of early-stage disease in non-surgical patients, thermal ablation is now also being used in selected patients with oligometastatic and oligoprogressive disease. This review discusses the techniques available for thermal ablation, the evidence for use of thermal ablation in primary lung tumours in early- and advanced-stage disease and compares thermal ablation to alternative treatment strategies.

Current trends in image-guided chest interventions

Interventional radiology (IR) is a rapidly expanding medical subspecialty and refers to a range of image‐guided procedural techniques. The image guidance allows real‐time visualization and precision placement of a needle, catheter, wire and device to deep body structures through small incisions. Advantages include reduced risks, faster recovery and shorter hospital stays, lower costs and less patient discomfort. The range of chest interventional procedures keeps on expanding due to improved imaging facilities, better percutaneous assess devices and advancing ablation and embolization techniques. These advances permit procedures to be undertaken safely, simultaneously and effectively, hence escalating the role of IR in the treatment of chest disorders. This review article aims to cover the latest developments in some image‐guided techniques of the chest, including thermal ablation therapy of lung malignancy, targeted therapy of pulmonary embolism, angioplasty and stenting of mediastinal venous/superior vena cava occlusion, pulmonary arteriovenous malformation treatment and bronchial artery embolization for haemoptysis.

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.

CT after Lung Microwave Ablation: Normal Findings and Evolution Patterns of Treated Lesions

Imaging-guided percutaneous ablative treatments, such as radiofrequency ablation (RFA), cryoablation and microwave ablation (MWA), have been developed for the treatment of unresectable primary and secondary lung tumors in patients with advanced-stage disease or comorbidities contraindicating surgery. Among these therapies, MWA has recently shown promising results in the treatment of pulmonary neoplasms. The potential advantages of MWA over RFA include faster ablation times, higher intra-tumoral temperatures, larger ablation zones and lower susceptibility to the heat sink effect, resulting in greater efficacy in proximity to vascular structures. Despite encouraging results supporting its efficacy, there is a relative paucity of data in the literature regarding the role of computer tomography (CT) to monitor MWA-treated lesions, and the CT appearance of their morphologic evolution and complications. For both interventional and non-interventional radiologists, it is crucial to be familiar with the CT features of such treated lesions in order to detect incomplete therapy or recurrent disease at early stage, as well as to recognize initial signs of complications. The aim of this pictorial essay is to describe the typical CT features during follow-up of lung lesions treated with percutaneous MWA and how to interpret and differentiate them from other radiological findings, such as recurrence and complications, that are commonly encountered in this setting.

Imaging of the thorax after percutaneous thermal ablation of lung malignancies

Image-guided thermal ablation is a minimally invasive treatment option for patients with early stage non-small cell lung cancer or metastatic disease to the lungs. Percutaneous ablation treats malignant tumours in situ, which precludes histopathological evaluation of the ablated tumours. Imaging studies are used as surrogates to assess technical and clinical success. Although it is not universally accepted, a common protocol for surveillance imaging includes contrast-enhanced computed tomography (CT) at 1, 3, 6, 9, 12, 18, 24 months, and yearly thereafter. Integrated 2-[¹⁸F]-fluoro-2-deoxy-d-glucose positron-emission tomography (PET)/CT imaging is recommended at 3 and 12 months and when recurrent disease is suspected. There is a complex evolution of the ablation zone on CT and PET imaging studies. The zone of ablation, initially larger than the ablated tumour, undergoes gradual involution. In the process, it may cavitate and resemble a lung abscess. Different contrast-enhancement and radionuclide uptake patterns in and around the ablation zone may indicate a wide range of diagnostic possibilities from a normal physiological response to local progression. Ultimately, the zone of ablation may be replaced by a variety of findings including linear bands of density, pleural thickening, or residual necrotic tumour. Diagnostic and interventional radiologists interpreting post-ablation imaging studies must have a clear understanding of the ablation process and imaging findings on surveillance studies. Accurate and timely recognition of complications and/or local recurrence is necessary to guide further therapy. The purpose of this article is to review imaging protocols and salient imaging findings after thermal ablation of lung malignancies.

Description of morphological evolution of lung tumors treated by percutaneous radiofrequency ablation: long term follow-up of 100 lesions with chest CT

PURPOSE

Radiofrequency ablation (RFA) is a safe and effective minimally invasive treatment for pulmonary tumors. Patterns on chest computed tomography (CT) after RFA are classified into five types; however, the follow-up has not been fully described. The objectives of this study were to describe (1) the CT pattern 3 years after RFA and (2) its evolution over 7 years.

MATERIALS AND METHODS

Lesions treated with RFA between 2009 and 2017 and with ≥3 years of follow-up CT data were included. Lesions with local recurrences were excluded from the study. The morphology of the ablation zone was classified as nodular, fibrotic, atelectatic, cavitary, and disappeared. Other initial anatomical parameters were recorded. Kruskal-Wallis or Chi-square tests were used to compare the groups.

RESULTS

One hundred lung RFA scars were included, and a retrospective longitudinal study was performed. Three years after RFA, nodular, fibrotic, atelectatic, and cavitary scars, and disappearance were observed in 49%, 36%, 5%, 3%, and 6% of the scars, respectively. Evolution over 7 years showed that the fibrosis, atelectasis, and disappearance remained stable over time, whereas 28% of nodular scars evolved into fibrotic scars. Additionally, 45% of cavitary scars evolved into nodular scars. Pleural contact was associated with disappearance, and the use of a 20-mm needle was associated with atelectasis.

CONCLUSION

Follow-up after RFA showed that fibrosis, disappearance, and atelectasis remained stable over time. Nodular scars could evolve into fibrotic scars, and cavitary scars could evolve into nodular scars.

Percutaneous thermal ablation of lung metastases from thyroid carcinomas. A retrospective multicenter study of 107 nodules. On behalf of the TUTHYREF network

PURPOSE

To determine efficacy and safety of thermal ablation (TA) for the local treatment of lung metastases of thyroid cancer.

METHODS

We retrospectively studied 47 patients from 10 centers treated by TA (radiofrequency, microwaves, and cryoablation) over 10 years. The endpoints were overall survival (OS), local efficacy, complications (CTCAE classification), and factors associated with survival. OS curves after first TA were built using the Kaplan-Meier method and compared with the log-rank test.

RESULTS

A total of 107 lung metastases during 75 sessions were treated by radiofrequency (n = 56), microwaves (n = 9), and cryoablation (n = 10). Median follow-up time after TA was 5.2 years (0.2-13.3). OS was 93% at 2 years (95% confidence interval (CI): 86-94) and 79% at 3 years (95% CI: 66-91). On univariate and multivariate analysis with a Cox model, histology was the only significant factor for OS. OS at 3 years was 94% for follicular, oncocytic, or papillary follicular variant carcinomas, compared to 59% for papillary, medullary, insular or anaplastic carcinomas (P = 0.0001). The local control rate was 98.1% at 1 year and 94.8% at 2, 3, 4, and 5 years. Morbidity was low with no major complications (grade 4 and 5 CTCAE) and no complications in 29 of 75 sessions (38.7%).

CONCLUSIONS

TA is a useful, safe and effective option for local treatment of lung metastases from thyroid carcinoma. Prolonged OS was obtained, especially for lung metastases from follicular, oncocytic, or papillary follicular variant carcinomas. Achieving disease control with TA delays the need for systemic treatment.

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.

Staged surgery for empyema and lung gangrene caused by pseudoaneurysm after radiofrequency ablation

Lung gangrene is a potentially fatal disease, and primary or staged surgery, depending on the patient's condition, is reported to be useful. We describe successful management, by staged surgery, of a rare case of empyema and lung gangrene complicating lung radiofrequency ablation. The patient, who was a diabetic with colorectal pulmonary metastases, underwent embolization of a pulmonary artery pseudoaneurysm in the right basal segment that developed after lung radiofrequency ablation. He subsequently developed lung gangrene caused by lung ischaemia, and empyema, necessitating pleural decortication followed by open-window thoracostomy. Subsequently, right basal segmentectomy was performed, with thoracostoma closure. Staged surgery might be beneficial for high-risk patients with empyema and lung gangrene caused by lung ischaemia.

Treatment of Post-Ablation Bronchopleural Fistula Using Percutaneous Synthetic Hydrogel Surgical Sealant: Initial Experience of Safety and Efficacy

Purpose Bronchopleural fistula is a rare but serious complication of lung ablation, as it is difficult to treat and is associated with a high mortality rate. Standard therapy often relies on surgical pleurodesis, which can be particularly problematic in patients with poor baseline lung function. A minimally invasive treatment option for bronchopleural fistula may offer an alternative to surgery for appropriate patients. This case series describes the technique, safety and efficacy of percutaneously administered synthetic hydrogel surgical sealant in the treatment of post-ablation bronchopleural fistula in five patients. Materials and methods Retrospective chart review was carried out in five consecutive patients identified to have had BPF after lung ablation between 2009 and 2017 who were treated with percutaneous administration of synthetic hydrogel surgical sealant using CT guidance. Results The procedure was successfully carried out in all patients without immediate complications, and complete resolution of air leak was achieved in four of five patients (80%). Up to the most recent follow-up, no evidence of delayed complications or recurrent air leak was present (follow-up range 1 week-8 years). Conclusion The authors' initial experience shows that targeted surgical sealant is a potentially safe and effective alternative treatment of post-ablation persistent air leak.

Image-guided percutaneous microwave ablation of early-stage non-small cell lung cancer

Although surgical lobectomy with systematic mediastinal lymph node evaluation is considered as the "gold standard" for management of early stage non-small cell lung cancer (NSCLC), image-guided percutaneous thermal ablation has been increasingly used for medically inoperable patients. Radiofrequency ablation (RFA) is a research-based technique that has the most studies for medically inoperable early-stage NSCLC. Other thermal ablation techniques used to treat pulmonary tumors include microwave ablation (MWA), cryoablation and laser ablation. MWA has several advantages over RFA including reduced procedural time, reduced heat-sink effect, large ablation zones, decreased susceptibility to tissue impedance, and simultaneous use of multiple antennae. This review article highlights the most relevant updates of MWA for the treatment of early-stage NSCLC, including mechanism of action, clinical outcomes, potential complications, the existing technique problems and future directions.

Safety and efficacy of thermal ablation for subpleural lung cancers

BACKGROUND

The study was conducted to assess the safety and efficacy of thermal ablation for the treatment of subpleural lung cancer.

METHODS

Eighty-nine patients with 101 subpleural lung cancers were identified between January 2012 and July 2018 in our database and included in this study. Tumors were classified as adhering to cervical, costal, diaphragmatic, and mediastinal pleurae. Lesions were categorized based on their relationship to the pleura: close to the pleura, causing pleural indentation, and involving the pleura. The complete ablation rate, local progression-free survival, complications, and associated factors were analyzed.

RESULTS

Subpleural lung cancers included lesions located under costal (n = 69), mediastinal (n = 17), cervical (n = 8), and diaphragmatic (n = 7) pleurae. The rate of complete ablation was 87.1% and the local progression-free survival rates at 3, 6, 12, and 24 months were 86%, 77%, 75%, and 64%, respectively. Tumor size was the most important factor influencing technique efficacy (P < 0.05), with a complete ablation rate of only 55.6% in lung cancers measuring > 30 mm. There were nine (10.11%) major complications, including one chest abscess, five cases of pneumothorax, and three cases of hemothorax. The occurrence of major complications was associated with increased levels of pain within 48 hours post-procedure (P < 0.05).

CONCLUSION

Local thermal ablation is a safe and effective treatment for subpleural lung cancers. Tumor size was the most significant factor affecting technique efficacy. Post-procedure pain indicated the possibility of major complications.

Expert consensus on image-guided radiofrequency ablation of pulmonary tumors: 2018 edition

Lung cancer ranks first in incidence and mortality in China. Surgery is the primary method to cure cancer, but only 20-30% of patients are eligible for curative resection. In recent years, in addition to surgery, other local therapies have been developed for patients with numerous localized primary and metastatic pulmonary tumors, including stereotactic body radiation therapy and thermal ablative therapies through percutaneously inserted applicators. Percutaneous thermal ablation of pulmonary tumors is minimally invasive, conformal, repeatable, feasible, cheap, has a shorter recovery time, and offers reduced morbidity and mortality. Radiofrequency ablation (RFA), the most commonly used thermal ablation technique, has a reported 80-90% rate of complete ablation, with the best results obtained in tumors < 3 cm in diameter. Because the clinical efficacy of RFA of pulmonary tumors has not yet been determined, this clinical guideline describes the techniques used in the treatment of localized primary and metastatic pulmonary tumors in nonsurgical candidates, including mechanism of action, devices, indications, techniques, potential complications, clinical outcomes, post-ablation surveillance, and use in combination with other therapies. In the future, the role of RFA in the treatment of localized pulmonary tumors should ultimately be determined by evidence from prospective randomized controlled trials comparing sublobar resection or stereotactic body radiation therapy.