Ablation of pulmonary malignancy: current status

Survival outcomes of radiofrequency ablation compared with surgery in patients with early-stage primary non-small-cell lung cancer: A meta-analysis

BACKGROUND

This study compared the overall survival (OS) of patients with early-stage primary non-small-cell lung cancer (NSCLC) treated with radiofrequency ablation (RFA) versus surgery.

METHODS

A systematic search was performed in MEDLINE, Embase, Cochrane Central Register, and all available Chinese databases to identify relevant publications from inception to April 2019. This meta-analysis compared hazard ratios (HRs) for OS. A multivariate fixed effects model was used to perform a meta-analysis to compare survival between treatments.

RESULTS

Six retrospective studies were included in the quantitative synthesis. Compared with surgery, RFA was associated with a similar long-term OS. The HRs and 95% confidence intervals (CIs) for 2-, 3- and 5-year OS were 1.74 [0.82, 3.71], 1.15 [0.65, 2.02] and 2.69 [0.41, 17.47], respectively, while those of the pooled data were 1.47 [0.94, 2.32] in patients with early-stage primary NSCLC.

CONCLUSIONS

RFA did not differ significantly from surgery in terms of the 5-year OS in patients with early-stage primary NSCLC. Randomized, controlled clinical trials are warranted to compare these two treatments.

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.

Non-surgical Treatments for Lung Metastases in Patients with Soft Tissue Sarcoma: Stereotactic Body Radiation Therapy (SBRT) and Radiofrequency Ablation (RFA)

BACKGROUND

Radio-frequency ablation (RFA) and Stereotactic Body Radiation Therapy (SBRT) are two emerging therapies for lung metastases.

INTRODUCTION

Aliterature review was performed to evaluate the outcomes and complications of these procedures in patients with lung metastases from soft tissue sarcoma (STS).

METHODS

After selection, seven studies were included for each treatment encompassing a total of 424 patients: 218 in the SBRT group and 206 in the RFA group.

RESULTS

The mean age ranged from 47.9 to 64 years in the SBRT group and from 48 to 62.7 years in the RFA group. The most common histologic subtype was, in both groups, leiomyosarcoma. In the SBRT group, median overall survival ranged from 25.2 to 69 months and median disease- free interval was from 8.4 to 45 months. Two out of seven studies reported G3 and one G3 toxicity, respectively. In RFA patients, overall survival ranged from 15 to 50 months. The most frequent complication was pneumothorax. Local control showed a high percentage for both procedures.

CONCLUSION

SBRT is recommended in patients unsuitable to surgery, in synchronous bilateral pulmonary metastases, in case of deep lesions and patients receiving high-risk systemic therapies. RFA is indicated in case of a long disease-free interval, in oligometastatic disease, when only the lung is involved, in small size lesions far from large vessels. Further large randomized studies are necessary to establish whether these treatments may also represent a reliable alternative to surgery.

Flexible bronchoscopy-guided microwave ablation in peripheral porcine lung: a new minimally-invasive ablation

Background

Transbronchial lung biopsy is an important approach to diagnose peripheral lung cancer, but bronchoscopy based treatment options are limited and poorly studied. A flexible bronchoscopy-guided water-cooled microwave ablation (MWA) catheter was developed to evaluate the feasibility and safety both in ex vivo and in vivo porcine models.

Methods

Using direct penetration of the catheter through the surface of ex vivo porcine lung, ablations (n=9) were performed at 70, 80, 90 W for 10 minutes. Temperatures of the catheter and 10, 15, 20 mm away from the tip were measured. Under bronchoscopy conditions in porcine lung, ablations (n=18, 6 in ex vivo and 12 in vivo) were performed at 80 W for 5 minutes. Computed tomography (CT) was acquired perioperative, 24 hours, 2 weeks, and 4 weeks post ablation. Ablation zones were excised at 24 hours and 4 weeks respectively. Long-axis diameter (Dl) and short-axis diameter (Ds) were measured and tissues were sectioned for pathological examination.

Results

In-ex vivo lung, the temperature at 20 mm removed was over 60 °C at 80 W for 288±26 seconds. The ablations under bronchoscopic conditions were successful in-ex vivo and in vivo lung. No complications occurred during the procedures. Coagulation necrosis was visible at 24 hours, and repaired fibrous tissue was seen at 4 weeks.

Conclusions

The flexible bronchoscopy-guided water-cooled MWA is feasible and safe. This early animal data holds promise of MWA becoming a potential therapeutic tool for Peripheral Lung Cancers.

Characterization of the cryoablation-induced immune response in kidney cancer patients

Cryoablation is one of treatment modalities for kidney cancer and is expected to induce strong local immune responses as well as systemic T-cell-mediated immune reactions that may lead to the regression of distant metastatic lesions. Thus, the characterization of T cell repertoire and immune environment in tumors before and after treatment should contribute to the better understanding of the cryoablation-induced anticancer immune responses. In this study, we collected tumor tissues from 22 kidney cancer patients, before cryoablation and at 3 mo after cryoablation. In addition, blood samples were collected from 14 patients at the same time points. We applied a next generation sequencing approach to characterize T cell receptor β (TCRB) repertoires using RNAs isolated from tumor tissues and peripheral blood mononuclear cells. TCRB repertoire analysis revealed the expansion of certain T cell clones in tumor tissues by cryoablation. We also found that proportions of abundant TCRB clonotypes (defined as clonotypes with ≥ 1% frequency among total TCRB reads) were significantly increased in the post-cryoablation tissue samples than those of pre-cryoablation tumor samples. Some of these TCRB clonotypes were found to be increased in peripheral blood. Expression analysis of immune-related genes in the tissues of pre- and post-cryoablation showed significantly elevated transcriptional levels of CD8⁺ , CD4⁺ , Granzyme A (GZMA), and CD11c along with a high CD8/FOXP3 ratio in the post-cryoablation tissue samples. Our findings revealed that cryoablation could induce strong immune reactions in tumors with oligoclonal expansion of antitumor T cells, which circulate systemically.

Radiofrequency ablation in primary non-small cell lung cancer: What a radiologist needs to know

Lung cancer continues to be one of the leading causes of death worldwide. In advanced cases of lung cancer, a multimodality approach is often applied, however with poor local control rates. In early non-small cell lung cancer (NSCLC), surgery is the standard of care. Only 15-30% of patients are eligible for surgical resection. Improvements in imaging and treatment delivery systems have provided new tools to better target these tumors. Stereotactic body radiation therapy (SBRT) has evolved as the next best option. The role of radiofrequency ablation (RFA) is also growing. Currently, it is a third-line option in stage 1 NSCLC, when SBRT cannot be performed. More recent studies have demonstrated usefulness in recurrent tumors and some authors have also suggested combination of RFA with other modalities in larger tumors. Following the National Lung Screening Trial (NLST), screening by low-dose computed tomography (CT) has demonstrated high rates of early-stage lung cancer detection in high-risk populations. Hence, even considering the current role of RFA as a third-line option, in view of increasing numbers of occurrences detected, the number of potential RFA candidates may see a steep uptrend. In view of all this, it is imperative that interventional radiologists be familiar with the techniques of lung ablation. The aim of this article is to discuss the procedural technique of RFA in the lung and review the current evidence regarding RFA for NSCLC.

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.

Cryoablation of lung malignancies recurring close to surgical clips following surgery: Report of three cases

Background:

Minimally ablative therapies are now available for the treatment of lung malignancies. However, selection of the appropriate technique is not always easy and requires accurate preoperative planning.

Aims:

To describe the treatment of lung tumors with cryoablation.

Settings and Design:

We report three cases of lung malignancies that recurred close to surgical clips after surgical treatment, successfully treated by cryoablation.

Materials and Methods:

An initial freezing cycle was performed for 10 min, followed by a 5-min thawing cycle, and an additional 10-min freezing cycle. A final 5-min thaw was necessary to remove the needle from the iceball formed during the freezing cycle.

Results:

The procedures were completed successfully with no signs of surgical-clip misplacement, and excellent ablation of the lesions.

Conclusion:

Cryoablation is a relatively new procedure that potentially permits the local treatment of lung tumors with minimal loss of lung parenchyma.

CT volumetric assessment of pulmonary neoplasms after radiofrequency ablation: when to consider a second intervention?

PURPOSE

To determine the minimal follow-up time point to predict therapeutic response to radiofrequency (RF) ablation of lung tumors.

MATERIALS AND METHODS

A retrospective study design was approved by the institutional review board. From January 2008 to January 2010, 78 patients (46 men and 32 women; mean age, 58.9 y) underwent computed tomography (CT)-guided percutaneous RF ablation of pulmonary malignancies. A single RF multitined electrode was used to treat 100 index tumors, 6 primary lesions, and 94 metastatic lesions. CT volumetric measurements of ablated tumors were made before ablation and 24 hours, 3-6 weeks, 3 months, 6 months, 9 months, and 12 months after ablation. An unpaired t test and Spearman rank correlation coefficient were used to analyze the volumetric changes.

RESULTS

Complete successful ablation was achieved in 80% of index tumors. The mean time to detection of tumor residue or recurrence tumor residue or recurrence was 6.7 months after ablation. In successfully ablated lesions, the mean volume before ablation was 1.81 cm(3) (standard deviation [SD], 1.71); in failed ablation lesions, the mean volume before ablation was 2.58 cm(3) (SD, 2.8) (P = .42). The earliest statistically significant follow-up time point that showed a difference in the volumetric measurements of failed and successful ablations as well as the earliest significant correlation with the 12-month point was 3 months (P = .025, Spearman R = 0.72). Secondary tumor control after repeat ablation was statistically significant for lesions ablated at a 3-month interval (four out of five lesions) (P = .04).

CONCLUSIONS

CT volumetric assessment of ablated tumors revealed that 3 months was the earliest time point that may determine the response of a pulmonary ablation or repeat intervention.

Technical and practical considerations for device selection in locoregional ablative therapy

Percutaneous ablation therapy is an essential component of contemporary interventional oncologic therapy of primary and secondary malignancies. The growing armamentarium of available ablation technologies calls for thorough understanding of the different ablation modalities to optimize device selection in individual clinical settings. The goal of the current article is to provide direction on ablative device selection by reviewing device mechanisms of action, advantages and disadvantages, and practical considerations in real-life case scenarios.

Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: systematic review of compliance with reporting standards

OBJECTIVE

To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports.

MATERIALS AND METHODS

Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated.

RESULTS

Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology.

CONCLUSION

The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology.

Radiofrequency ablation of thoracic tumours: lessons learned with ablation of 100 lesions

PURPOSE

Our aim was to analyse the results of our first 100 radiofrequency ablation (RFA) procedures, of primary (nonsmall-cell lung cancers, NSCLC) and secondary (MTS) lung cancers to assess what lessons could be learned from our experience.

MATERIALS AND METHODS

We analysed 100 lesions (mean size 23 mm) in 81 patients (25 NSCLC/56 MTS). On the basis of the clinical-radiological evolution, we analysed complete ablation (CA) versus partial ablation (PA) at the first computed tomography (CT) scan and during the follow-up (mean 23 months), time to progression (TTP) and survival. Possible predictive factors for local effectiveness and survival were sought.

RESULTS

At the first CT scan CA was obtained in 88 %; the difference between the mean diameter of lesions achieving CA and PA was significant (20 versus 38 mm; p = 0.0001). A threshold of 30 mm (p = 0.0030) and the histological type (NSCLC 75 %/MTS 94 %; p = 0.0305) were also predictive of CA. A total of 18.4 % of the CA recurred (average TTP 19 months). Survival at 1, 2 and 3 years was 84.5, 65.4 and 51.5 %, respectively. The predictors of survival at 3 years were the coexistence of other MTS (p = 0.0422) and a diameter <20 mm (p = 0.0323), but not the local effectiveness of RFA.

CONCLUSION

RFA for thoracic malignancies is accurate for lesions up to 30 mm, especially if metastatic; survival is more closely related to staging factors than to the local effectiveness of RFA.

Microwave ablation of lung tumours: single-centre preliminary experience

PURPOSE

This study was done to evaluate the feasibility, effectiveness and safety of microwave (MW) ablation of lung tumours.

MATERIALS AND METHODS

Twenty-four patients underwent percutaneous MW ablation of 26 intraparenchymal pulmonary masses. All patients were judged to be inoperable on the basis of tumour stage, comorbidities, advanced age and/or refusal to undergo surgery. Ablation was performed using a microwave generator (Evident Microwave Ablation System, Covidien Ltd., Dublin). Lesions with a diameter ≤ 3 cm were treated with a single antenna, lesions with a diameter >3 cm were treated by positioning two or more antennae, simultaneously. All patients underwent computed tomography (CT) follow-up with and without contrast administration at 1, 3 and 6 months and then yearly in combination with complete blood and metabolic tests.

RESULTS

Technical success was 100 %. No major complications were recorded. Asymptomatic grade-1 pneumothorax was recorded in 9 patients (37.5 %). One case of asymptomatic pleural effusion and one of haemoptysis, not requiring transfusion, were observed. No patients were diagnosed with a post-ablation syndrome. Complete necrosis was observed in 16 of 26 lesions (61.6 %). Partial necrosis was obtained in 30.8 % (8/26 lesions); in one case (3.8 %) a progression of the disease was recorded and in another case (3.8 %) a stability was observed.

CONCLUSIONS

Our preliminary experience may be considered in accordance with literature dates, in terms of efficacy and safety.

Study of survival in patients with malignant lung lesions treated with radiofrequency

OBJECTIVE

To report on the survival of a series of patients with primary and metastatic lung tumours treated with radiofrequency (RF). Four years ago we published our preliminary experience with the use of this technique.

MATERIALS AND METHODS

For a period of 8 years we have treated 59 patients (by means of a total of 70 procedures) with primary or metastatic pulmonary neoplastic lesions, which fulfilled inclusion criteria to perform the technique. They were in all cases non-surgical lesions that had been either previously treated or not. The technique was performed in the radiology suite, under conscious analgo-sedation. We treated primary pulmonary lesions, neoplastic recurrences, or metastases with curative or palliative intention (pain management).

RESULTS

Current global survival rate is 19 patients (32 %) with a mean of 26.61 ± 3.17 months (range: 20.38 ± 32.83) and a median of 16.00 ± 3.57 (range: 8.99-23.00). If we establish the difference between primary and metastatic tumours, mean survival is 27.62 ± 4.12 months in primary tumours (median: 16.00) vs. 24.65 ± 4.47 months in metastatic tumours (median: 16.00). When we studied the survival in those cases with a curative intent, mean survival in primary tumours was 30.97 ± 4.57 months (median: 21.00) vs. 25.14 ± 4.68 (median: 16.00) months in metastatic tumours.

CONCLUSIONS

RF ablation of lung lesions is a minimally invasive procedure that is useful in primary tumours (especially in stage I) and metastatic ones. RF has proven its usefulness in the multidisciplinary treatment of this pathology due to the low incidence of serious complications and survival obtained, considering that patients are elderly with significant comorbidity.

Microwave lung ablation complicated by bronchocutaneous fistula: case report and literature review

Microwave ablation is a developing treatment option for unresectable lung cancer. Early experience suggests that it may have advantages over radiofrequency (RF) ablation with larger ablation zones, shorter heating times, less susceptibility to heat sink, effectiveness in charred lung, synergism with multiple applicators, no need for grounding pads, and similar survival benefit. Newer microwave ablation devices are being developed and as their use becomes more prevalent, a greater understanding of device limitations and complications are important. Herein we describe a microwave lung ablation complicated by bronchocutaneous fistula (BCF) and its treatment. BCF treatment options include close monitoring, surgical closure, percutaneous sealant injection, and endoscopic plug or sealant in those who are not surgical candidates.

MR temperature imaging of nanoshell mediated laser ablation

Minimally invasive thermal therapy using high-power diode lasers is an active area of clinical research. Gold nanoshells (AuNS) can be tuned to absorb light in the range used for laser ablation and may facilitate more conformal tumor heating and sparing of normal tissue via enhanced tumor specific heating. This concept was investigated in a xenograft model of prostate cancer (PC-3) using MR temperature imaging (MRTI) in a 1.5T scanner to characterize the spatiotemporal temperature distribution resulting from nanoparticle mediated heating. Tumors with and without intravenously injected AuNS were exposed to an external laser tuned to 808 nm for 180 sec at 4 W/cm(2) under real-time monitoring with proton resonance frequency shift based MRTI. Microscopy indicated that these nanoparticles (140-150 nm) accumulated passively in the tumor and remained close to the tumor microvasculature. MRTI measured a statistically significant (p < 0.001) increase in maximum temperature in the tumor cortex (mean = 21 ± 7°C) in +AuNS tumors versus control tumors. Analysis of the temperature maps helped demonstrate that the overall distribution of temperature within +AuNS tumors was demonstrably higher versus control, and resulted in damage visible on histopathology. This research demonstrates that passive uptake of intravenously injected AuNS in PC-3 xenografts converts the tumor vasculature into a potent heating source for nanoparticle mediated ablation at power levels which do not generate significant damage in normal tissue. When used in conjunction with MRTI, this has implications for development and validation of more conformal delivery of therapy for interstitial laser ablations.

[Radiofrequency ablation for the treatment of lung neoplasms: a retrospective study of 329 cases]

背景与目的

射频消融（radiofrequency ablation, RFA）是近年来用于无法手术的肺部恶性肿瘤及肺转移瘤治疗的替代方案。本研究旨在评估肺射频消融术的安全性和临床疗效。

方法

本研究回顾性分析1999年10月-2006年7月在第四军医大学唐都医院胸腔外科进行肺部恶性肿瘤射频消融术的患者329例（其中肺部原发肿瘤237例，转移瘤92例），对其进行射频治疗后的并发症、局部进展以及1年、2年和5年总生存期的临床资料进行了研究及评价分析。

结果

行射频手术的患者术后出现的并发症包括：气胸63例（19.1%），咯血14例（死亡1例，4.2%），血胸10例（3.0%），肺炎15例（4.5%）和心包填塞3例（死亡1例，0.9%），术后30天内的死亡率为0.6%，针道肿瘤种植的患者6例（1.8%）。中位无进展时间为21.6个月。1年、2年和5年总生存率分别为68.2%、35.3%和20.1%。共有78例（23.7%）患者出现后期肿瘤局部进展。肺部肿瘤原位局部进展的患者的肿瘤包块直径大多 > 4 cm; 在肿瘤局部进展方面，肿瘤 < 3 cm的患者与直径介于3 cm-4 cm的肿瘤患者相比没有明显差异，这两组患者与直径 > 4 cm的肿瘤患者间存在明显差异。

结论

对于肺部恶性肿瘤来说，射频治疗是一种耐受性良好、疗效可靠安全的治疗方法。

Thermal ablation of lung tumors

The 5-year survival for all stages of nonsmall cell lung cancer (NSCLC) remains bleak, having increased from 13% to just 16% over the past 30 years. Despite promising results in nonoperative patients with NSCLC and pulmonary metastatic disease, thermal ablation appears to be limited by large tumor size and proximity to large vessels. This article discusses the particular challenges of performing thermal ablation in aerated lung tissue and reviews important considerations in performing ablation including treatment complications and imaging follow-up. The article compares and contrasts the three major thermal ablation modalities: radiofrequency ablation, microwave ablation, and cryoablation.

Emerging treatment options in the management of non-small cell lung cancer

Lung cancer (LC) has become the leading cancer-related cause of death in the US and in developed European countries in the last decade. Its incidence is still growing in females and in smokers. Surgery remains the treatment of choice whenever feasible, but unfortunately, many patients have an advanced LC at presentation and one-third of potentially operable patients do not receive a tumor resection because of their low compliance for intervention due to their compromised cardiopulmonary functions and other comorbidities. For these patients the alternative therapeutic options are stereotactic radiotherapy or percutaneous radiofrequency. When surgery is planned, an anatomical resection (segmentectomy, lobectomy, bilobectomy, pneumonectomy, sleeve lobectomy) is usually performed; wedge resection (considered as a nonanatomical one) is generally the accepted option for unfit patients. The recent increase in discovering small and peripheral LCs and/or ground-glass opacities with screening programs has dramatically increased surgeons' interest in limited resections. The role of these resections is discussed. Also, recent improvements in molecular biology techniques have increased the chemotherapic options for neoadjuvant LC treatment. The role and the importance of targeted chemotherapy is also discussed.