A Meta-Analysis of Clinical Outcomes After Radiofrequency Ablation and Microwave Ablation for Lung Cancer and Pulmonary Metastases

Advances in Image-Guided Ablation Therapies for Solid Tumors

Image-guided solid tumor ablation methods have significantly advanced in their capability to target primary and metastatic tumors. These techniques involve noninvasive or percutaneous insertion of applicators to induce thermal, electrochemical, or mechanical stress on malignant tissue to cause tissue destruction and apoptosis of the tumor margins. Ablation offers substantially lower risks compared to traditional methods. Benefits include shorter recovery periods, reduced bleeding, and greater preservation of organ parenchyma compared to surgical intervention. Due to the reduced morbidity and mortality, image-guided tumor ablation offers new opportunities for treatment in cancer patients who are not candidates for resection. Currently, image-guided ablation techniques are utilized for treating primary and metastatic tumors in various organs with both curative and palliative intent, including the liver, pancreas, kidneys, thyroid, parathyroid, prostate, lung, breast, bone, and soft tissue. The invention of new equipment and techniques is expanding the criteria of eligible patients for therapy, as now larger and more high-risk tumors near critical structures can be ablated. This article provides an overview of the different imaging modalities, noninvasive, and percutaneous ablation techniques available and discusses their applications and associated complications across various organs.

A retrospective study comparing the efficacy of microwave ablation and stereotactic body radiotherapy in colorectal cancer lung metastases

The purpose of the present study was to assess and compare the efficacy of microwave ablation (MWA) and stereotactic body radiotherapy (SBRT) in the treatment of lung metastases from patients with colorectal cancer (CRC) and to identify the preferable treatment modality based on patient and tumor characteristics. Records of 118 patients with CRC with a total of 307 lung metastases who underwent SBRT or MWA between January 2015 and December 2022 were retrospectively analyzed, including the essential clinicopathological information on patients (age, sex and underlying diseases), diagnosis and treatment information [primary tumor site, levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9], imaging data [diameter of lung metastasis, location of the metastasis (i.e., whether or not the tumor was adjacent to the vessel or bronchus) and internal features] and follow-up data (postoperative therapy, complications or adverse effects and survival outcomes). For statistical analysis of the local tumor progression (LTP), disease-free survival and overall survival (OS) rates, Cox regression analysis, along with the Kaplan-Meier method adjusted using inverse probability of treatment weighting (IPTW), were performed. The median follow-up duration in the present study was 31.5 months. Multivariable Cox regression analysis revealed that the CEA level, metastasis diameter and internal features were independent predictors of OS. In the IPTW-adjusted analysis, no significant difference in the 1-year OS rate was observed between the SBRT and MWA groups (92.9 vs. 93.9%; P=0.483); however, a notable discrepancy in the treatment modalities was noted, leading to significant differences in the 2- and 3-year OS rates (65.9 vs. 57.6%, P=0.001, and 44.7 vs. 36.4%, P<0.001, respectively). A significant interaction effect for the treatment modality was observed for LTP (P=0.021). In conclusion, the present study revealed that SBRT and MWA have similar therapeutic effects in terms of prolonging the survival of patients with CRC with lung metastases; however, regarding the local control of lung metastases, MWA is associated with a number of significant advantages.

Continuous positive airway pressure is unsafe for radiofrequency ablation of lung cancer under sedation: a randomised controlled trial

OBJECTIVE

To evaluate the safety of a minimum continuous positive airway pressure of 4 cmH2O (CPAP + 4) during computed tomography (CT)-guided radiofrequency ablation (RFA) for lung malignancies under procedural sedation and analgesia (PSA).

METHODS

This was a prospective, randomised, single-blind, parallel-group, placebo-controlled trial with an open-label medical device conducted at a single tertiary university hospital in Barcelona, Spain. Forty-six patients over 18 years of age scheduled for CT-guided RFA of a malignant pulmonary tumour under PSA were randomised to receive either CPAP + 4 or a modified mask for placebo CPAP (Sham-CPAP). Exclusion criteria included contraindications for RFA, refusal to participate, inability to understand the procedure or tolerate the CPAP test, lung biopsy just prior to RFA, intercurrent diseases, or previous randomisation for additional pulmonary RFA. Primary outcomes were the percentage of patients reporting at least one serious adverse event (SAE), classification for complications from the Cardiovascular and Interventional Radiological Society of Europe (CIRSE), and Clavien-Dindo classifications for complications, hospital stay, and readmissions. Secondary outcomes included adverse events (AEs), respiratory parameters, airway management, and the local radiological efficacy of pulmonary ablation.

RESULTS

CPAP + 4 prolonged hospital stay (1.5 ± 1.1 vs. 1.0 ± 0 inpatient nights, p = 0.022) and increased the risk of AE post-RFA (odds ratio (95% CI): 4.250 (1.234 to 14.637), p = 0.021 with more pneumothorax cases (n = 5/22, 22.7% vs. n = 0/24, 0%, p = 0.019). Per-protocol analysis revealed more SAEs and CIRSE grade 3 complications in the CPAP + 4 group (23.5% vs. 0%, p = 0.036). No significant differences were found in the effectiveness of oxygenation, ventilation, or pulmonary ablation.

CONCLUSION

CPAP is unsafe during CT-guided RFA for lung cancer under PSA even at the lowest pressure setting.

TRIAL REGISTRATION

ClinicalTrials.Gov, ClinicalTrials.gov ID NCT02117908, Registered 11 April 2014, https://www.

CLINICALTRIALS

gov/study/NCT02117908 CRITICAL RELEVANCE STATEMENT: This study highlights the hazards of continuous positive airway pressure during radiofrequency ablation of lung cancer, even at minimal pressures, deeming it unsafe under procedural sedation and analgesia in pulmonary interventional procedures. Findings provide crucial insights to prioritise patient safety.

KEY POINTS

No prior randomised controlled trials on CPAP safety in percutaneous lung thermo-ablation. Standardised outcome measures are crucial for radiology research. CPAP during lung RFA raises hospital stay and the risk of complications. CPAP is unsafe during CT-guided RFA of lung cancer under procedural sedoanalgesia.

Combination of percutaneous thermal ablation and adoptive Th9 cell transfer therapy against non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the predominant malignancies globally. Percutaneous thermal ablation (PTA) has gained widespread use among NSCLC patients, with the potential to elicit immune responses but limited therapeutic efficacies for advanced-stage disease. T-helper type 9 (Th9) cells are a subset of CD4+ effector T cells with robust and persistent anti-tumor effects. This study proposes to develop PTA-Th9 cell integrated therapy as a potential strategy for NSCLC treatment.

METHODS

The therapeutic efficacies were measured in mice models with subcutaneously transplanted, recurrence, or lung metastatic tumors. The tumor microenvironments (TMEs) were evaluated by flow cytometry. The cytokine levels were assessed by ELISA. The signaling molecules were determined by quantitative PCR and Western blotting. The translational potential was tested in the humanized NSCLC patient-derived xenograft (PDX) model.

RESULTS

We find that PTA combined with adoptive Th9 cell transfer therapy substantially suppresses tumor growth, recurrence, and lung metastasis, ultimately extending the survival of mice with NSCLC grafts, outperforming both PTA and Th9 cell transfer monotherapy. Analysis of TMEs indicates that combinatorial therapy significantly augments tumor-infiltrating Th9 cells, boosts anti-tumor effects of CD8+ T cells, and remodels tumor immunosuppressive microenvironments. Moreover, combinatorial therapy significantly strengthens the regional and circulation immune response of CD8+ T cells in mice with tumor lung metastasis and induces peripheral CD8+ T effector memory cells in mice with tumor recurrence. Mechanically, PTA reinforces the anti-tumor ability of Th9 cells primarily through upregulating interleukin (IL)-1β and subsequently activating the downstream STAT1/IRF1 pathway, which could be effectively blocked by intercepting IL-1β signaling. Finally, the enhanced therapeutic effect of combinatorial therapy is validated in humanized NSCLC PDX models.

CONCLUSIONS

Collectively, this study demonstrates that combinatorial therapy displays robust and durable anti-tumor efficacy and excellent translational potential, offering excellent prospects for translation and emerging as a promising approach for NSCLC treatment.

[The role of endoscopy in the management of peripheral pulmonary nodules, part 2: Treatment]

The management of peripheral lung nodules is challenging, requiring specialized skills and sophisticated technologies. The diagnosis now appears accessible to advanced endoscopy (see Part 1), which can also guide treatment of these nodules; this second part provides an overview of endoscopy techniques that can enhance surgical treatment through preoperative marking, and stereotactic radiotherapy treatment through fiduciary marker placement. Finally, we will discuss how, in the near future, these advanced endoscopic techniques will help to implement ablation strategy.

Lung cancer among the Elderly in Denmark - A comprehensive population-based cohort study

OBJECTIVE

Lung cancer primarily occurs in the elderly with a median age at diagnosis in Denmark of 73 years. However, elderly patients are under-represented in clinical trials as well as in screening studies. In this study, we aim to characterize elderly patients with lung cancer and explore the diagnostic intensity, treatment patterns, and survival.

METHOD

Patients diagnosed with lung cancer between 2014 and 2017 according to the Danish Cancer Registry, and with clinical information in the Danish Lung Cancer Registry were included. Patient information was linked by the unique social identification number to information from Statistics Denmark.

RESULTS

We included n = 17,835 patients in this study, of whom 2,871 (16.1 %) were 80 years or older. Fewer elderly patients had lung biopsies (47 % vs 53 %) or mediastinal procedures (34 % vs 26 %), compared to the younger patients (p < 0.001). Fewer elderly patients had treatment registration (60 % vs 85 %), and fewer received treatment with curative intent (23 % vs 42 %) compared to patients younger than 80 years (p < 0.001). The elderly patients had 2.1 (CI 95 % 1.9 - 2.2) times higher odds of dying within 12 months after diagnosis than younger patients.

CONCLUSION

The diagnostic intensity among lung cancer patients aged eighty years or above is lower compared to younger patients. Being elderly is associated with not undergoing surgical treatment or treatment with curative intent. Across all treatment groups, being older than eighty years of age was associated with an adverse prognosis.

Recent advances in lung cancer research: unravelling the future of treatment

Lung cancer, a multifaceted disease, demands tailored therapeutic approaches due to its diverse subtypes and stages. This comprehensive review explores the intricate landscape of lung cancer research, delving into recent breakthroughs and their implications for diagnosis, therapy, and prevention. Genomic profiling and biomarker identification have ushered in the era of personalised medicine, enabling targeted therapies that minimise harm to healthy tissues while effectively combating cancer cells. The relationship between pulmonary tuberculosis and lung cancer is examined, shedding light on potential mechanisms linking these two conditions. Early detection methods, notably low-dose computed tomography scans, have significantly improved patient outcomes, emphasising the importance of timely interventions. There has been a growing interest in segmentectomy as a surgical intervention for early-stage lung cancer in recent years. Immunotherapy has emerged as a transformative approach, harnessing the body's immune system to recognise and eliminate cancer cells. Combining immunotherapy with traditional treatments, such as chemotherapy and targeted therapies, has shown enhanced efficacy, addressing the disease's heterogeneity and overcoming drug resistance. Precision medicine, guided by genomic profiling, has enabled the development of targeted therapies like tyrosine kinase inhibitors, offering personalised treatments tailored to individual patients. Challenges such as drug resistance and limited accessibility to advanced therapies persist, emphasising the need for collaborative efforts and innovative technologies like artificial intelligence. Despite challenges, ongoing interdisciplinary collaborations and technological advancements offer hope for a future where lung cancer is treatable and preventable, reducing the burden on patients and healthcare systems worldwide.

Transbronchial Microwave Ablation of Peripheral Lung Tumors: The NAVABLATE Study

BACKGROUND

Image-guided thermal ablation is a minimally invasive local therapy for lung malignancies. NAVABLATE characterized the safety and performance of transbronchial microwave ablation (MWA) in the lung.

METHODS

The prospective, single-arm, 2-center NAVABLATE study (NCT03569111) evaluated transbronchial MWA in patients with histologically confirmed lung malignancies ≤30 mm in maximum diameter who were not candidates for, or who declined, both surgery and stereotactic body radiation therapy. Ablation of 1 nodule was allowed per subject. The nodule was reached with electromagnetic navigation bronchoscopy. Cone-beam computed tomography was used to verify the ablation catheter position and to evaluate the ablation zone postprocedure. The primary end point was composite adverse events related to the transbronchial MWA device through 1-month follow-up. Secondary end points included technical success (nodule reached and ablated according to the study protocol) and technique efficacy (satisfactory ablation based on 1-month follow-up imaging).

RESULTS

Thirty subjects (30 nodules; 66.7% primary lung, 33.3% oligometastatic) were enrolled from February 2019 to September 2020. The pre-procedure median nodule size was 12.5 mm (range 5 to 27 mm). Procedure-day technical success was 100% (30/30), with a mean ablative margin of 9.9±2.7 mm. One-month imaging showed 100% (30/30) technique efficacy. The composite adverse event rate related to the transbronchial MWA device through 1-month follow-up was 3.3% (1 subject, mild hemoptysis). No deaths or pneumothoraces occurred. Four subjects (13.3%) experienced grade 3 complications; none had grade 4 or 5.

CONCLUSION

Transbronchial microwave ablation is an alternative treatment modality for malignant lung nodules ≤30 mm. There were no deaths or pneumothorax. In all, 13.3% of patients developed grade 3 or above complications.

An Interventional Radiologist's Guide to Lung Cancer

Lung cancer continues to be the third leading cause of cancer and the leading cause of cancer deaths. As the field of interventional oncology continues to grow, interventional radiologists are increasingly treating lung cancer patients. Involvement begins with tissue diagnosis for which biomarkers and immunohistochemistry are used to guide selective and advanced medical therapies. An interventional radiologist must be aware of the rationale behind tissue diagnosis and techniques to minimize biopsy complications. Staging is an important part of tumor board conversations and drives treatment pathways. Surgical therapy remains the gold standard for early-stage disease but with an aging population the need for less invasive treatments such as radiation therapy and ablation continue to grow. The interventionalist must be aware of the indications, techniques, and pre- and posttherapy managements for percutaneous ablation. Endovascular therapy is broadly divided into therapeutic treatment of lung cancer, which is gaining traction, and treatment of lung cancer complications such as hemoptysis. This review aims to provide a good basis for interventional radiologists treating lung cancer patients.

Advances in the Treatment of Pulmonary Nodules

BACKGROUND

Early detection and accurate diagnosis of pulmonary nodules are crucial for improving patient outcomes. While surgical resection of malignant nodules is still the preferred treatment option, it may not be feasible for all patients. We aimed to discuss the advances in the treatment of pulmonary nodules, especially stereotactic body radiotherapy (SBRT) and interventional pulmonology technologies, and provide a range of recommendations based on our expertise and experience.

SUMMARY

Interventional pulmonology is an increasingly important approach for the management of pulmonary nodules. While more studies are needed to fully evaluate its long-term outcomes and benefits, the available evidence suggests that this technique can provide a minimally invasive and effective alternative for treating small malignancies in selected patients. We conducted a systematic literature review in PubMed, designed a framework to include the advances in surgery, SBRT, and interventional pulmonology for the treatment of pulmonary nodules, and provided a range of recommendations based on our expertise and experience.

KEY MESSAGES

As such, alternative therapeutic options such as SBRT and ablation are becoming increasingly important and viable. With recent advancements in bronchoscopy techniques, ablation via bronchoscopy has emerged as a promising option for treating pulmonary nodules. This study reviewed the advances of interventional pulmonology in the treatment of peripheral lung cancer patients that are not surgical candidates. We also discussed the challenges and limitations associated with ablation, such as the risk of complications and the potential for incomplete nodule eradication. These advancements hold great promise for improving the efficacy and safety of interventional pulmonology in treating pulmonary nodules.

Emergency Surgical Intervention in Microwave Ablation-Induced Massive Lung Necrosis

Microwave ablation (MWA) has become an increasingly used procedure for the management of lung nodules in recent years. Here, we report a 33-year-old female presenting with massive pulmonary necrosis and tension pneumothorax after MWA for metastatic colon cancer. She required surgical intervention, including thoracotomy, debridement, and wedge resection, for the management of these complications.

Risk assessment of pneumothorax in colorectal lung metastases treated by percutaneous thermal ablation: a multicenter retrospective cohort study

PURPOSE

To evaluate the risk of pneumothorax in the percutaneous image-guided thermal ablation (IGTA) treatment of colorectal lung metastases (CRLM).

METHODS

Data regarding patients with CRLM treated with IGTA from five medical institutions in China from 2016 to 2023 were reviewed retrospectively. Pneumothorax and non-pneumothorax were compared using the Student's t -test, χ 2 test and Fisher's exact test. Univariate logistic regression analysis was conducted to identify potential risk factors, followed by multivariate logistic regression analysis to evaluate the predictors of pneumothorax. Interactions between variables were examined and used for model construction. Receiver operating characteristic curves and nomograms were generated to assess the performance of the model.

RESULTS

A total of 254 patients with 376 CRLM underwent 299 ablation sessions. The incidence of pneumothorax was 45.5%. The adjusted multivariate logistic regression model, incorporating interaction terms, revealed that tumour number [odds ratio (OR)=8.34 (95% CI: 1.37-50.64)], puncture depth [OR=0.53 (95% CI: 0.31-0.91)], pre-procedure radiotherapy [OR=3.66 (95% CI: 1.17-11.40)], peribronchial tumour [OR=2.32 (95% CI: 1.04-5.15)], and emphysema [OR=56.83 (95% CI: 8.42-383.57)] were significant predictive factors of pneumothorax (all P <0.05). The generated nomogram model demonstrated a significant prediction performance, with an area under the receiver operating characteristic curve of 0.800 (95% CI: 0.751-0.850).

CONCLUSIONS

Pre-procedure radiotherapy, tumour number, peribronchial tumour, and emphysema were identified as risk factors for pneumothorax in the treatment of CRLM using percutaneous IGTA. Puncture depth was found to be a protective factor against pneumothorax.

Safety and local efficacy of computed tomography-guided microwave ablation for treating early-stage non-small cell lung cancer adjacent to bronchovascular bundles

OBJECTIVES

To retrospectively evaluate the safety and efficacy of computed tomography (CT)-guided percutaneous microwave ablation in treating early-stage non-small cell lung cancer (NSCLC) adjacent to bronchovascular bundles.

METHODS

Two hundred and thirty-one patients with early-stage NSCLC who underwent CT-guided microwave ablation of the tumor were included for analysis. Among these, 66 lesions were located adjacent to the bronchovascular bundle. Achievement of the specific ablation range (defined as the ablation zone encompassing the tumor and the adjacent vessel) was assessed after ablation. Complications and tumor progression after treatment were examined and compared between the bronchovascular bundle and non-bronchovascular bundle groups.

RESULTS

A total of 231 patients were included. Overall, 1-, 2-, and 3-year local progression-free survival (LPFS) was 77.4%, 70.5%, and 63.8%, respectively. Bronchovascular bundle proximity, pure-solid tumor, tumor size, and ablation margin < 5 mm were independent risk factors for local progression in multivariate analysis. In the bronchovascular bundle group, the 1-, 2- and 3-year LPFS rates were 63.0%, 50.7%, and 43.4%, respectively; vessel proximity and specific ablation range failure were independent risk factors for local progression. Overall survival in the entire cohort was 93.0% at 1 year, 76.1% at 2 years, and 55.0% at 3 years. The incidence of postoperative complications did not significantly differ between the two groups (p > 0.05). The most common complication was pneumothorax. Severe hemoptysis did not occur.

CONCLUSION

Tumor location near the bronchovascular bundles was a significant risk factor for local progression after microwave ablation. Achieving a specific ablation range may increase LPFS for these lesions.

CLINICAL RELEVANCE STATEMENT

Achieving the specific ablation range may improve local efficacy for early-stage non-small cell lung cancer located adjacent to the bronchovascular bundle.

KEY POINTS

• Local efficacy of percutaneous microwave ablation in treating early-stage non-small cell lung cancer was affected by bronchovascular bundle proximity. • Achieving the specific ablation range may improve local efficacy for lesions located adjacent to the bronchovascular bundle.

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

PURPOSE

Radiofrequency 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.

METHODS

A 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.

RESULTS

Thirty-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).

CONCLUSIONS

Robotic 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.

Cryoablation combined with a clinical Chinese medicine for the treatment of lung cancer

Cryoablation has been clinically applied to the treatment of lung cancer, but cryoablation has the problem of incomplete tumor killing when the freezing dose is not enough, which may lead to tumor recurrence or metastasis. Therefore, cryoablation combined with other therapeutic options is usually suggested to achieve a complete cure for lung cancer. Clinical practices have shown that traditional Chinese medicine (TCM) treatment can improve the quality of life of patients with advanced lung cancer and prolong the postoperative survival time. However, the mechanism of the synergistic effect of Chinese medicine and cryotherapy, and the optimal treatment plan have not been clarified so far. Therefore, the effect of TCM particles on ice crystal growth and phase transition during cooling was investigated. In addition, we explored the optimized concentration and combination treatment sequence of TCM (lung care formula) and validated the optimal treatment protocol by establishing a mouse model of non-small cell lung cancer (NSCLC). In general, cryoablation combined with TCM is a useful treatment for lung cancer, which can effectively solve the problem of tumor recurrence after cryoablation.

Percutaneous ablation treatment in metastatic lung tumors: a single-center experience

BACKGROUND

In recent years, many studies have proven that percutaneous thermal ablation is an effective second-line treatment method with low complication rates in early-stage non-small cell lung carcinoma and lung metastases. Radiofrequency ablation and microwave ablation are commonly used for this purpose.

PURPOSE

To evaluate the factors affecting the success of the percutaneous thermal ablation treatment with technical success, complication rates, and long-term follow-up results in metastatic lung lesions.

MATERIAL AND METHODS

Computed tomography (CT)-guided percutaneous ablation was performed for 70 metastatic lung lesions in 35 patients (22 men, 13 women; mean age = 61.34 years; age range = 41-75 years). Radiofrequency ablation was performed in 53/70 (75.7%) lesions and microwave ablation in 17/70 (24.3%) lesions.

RESULTS

The technical success rate was 98.6%. Median overall survival, progression-free survival, and local recurrence-free survival of the patients were 33.9 months (range=25.6-42.1 months), 12 months (range=4.9-19.2 months), and 24.2 months (range=8.2-40.1 months), respectively. One- and two-year overall survival rates were 84% and 74%, respectively. Median progression-free survival times were 20.3 months and 11.4 months, respectively, according to the number of metastatic lung lesions being single and multiple, and the difference was statistically significant (P = 0.046). According to the number of lesions ≤3 and >3, the difference was also found statistically significant (P = 0.024) (14.3 months and 5.7 months, respectively).

CONCLUSION

In conclusion, CT-guided percutaneous thermal ablation is a safe and effective treatment method in metastatic lung lesions. The number of lesions is the most important factor in predicting treatment success.

Stereotactic body radiation therapy and thermal ablation for treatment of NSCLC: A systematic literature review and meta-analysis

RATIONALE

Stereotactic body radiation therapy (SBRT) is the standard of care for inoperable early stage non-small cell lung cancer (NSCLC). Use of image guided thermal ablation (IGTA; including microwave ablation [MWA] and radiofrequency ablation [RFA]) has increased in NSCLC, however there are no studies comparing all three.

OBJECTIVE

To compare the efficacy of IGTA (including MWA and RFA) and SBRT for the treatment of NSCLC.

METHODS

Published literature databases were systematically searched for studies assessing MWA, RFA, or SBRT. Local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) were assessed with single-arm pooled analyses and meta-regressions in NSCLC patients and a stage IA subgroup. Study quality was assessed with a modified methodological index for non-randomized studies (MINORS) tool.

RESULTS

Forty IGTA study-arms (2,691 patients) and 215 SBRT study-arms (54,789 patients) were identified. LTP was lowest after SBRT at one and two years in single-arm pooled analyses (4% and 9% vs. 11% and 18%) and at one year in meta-regressions when compared to IGTA (OR = 0.2, 95%CI = 0.07-0.63). MWA patients had the highest DFS of all treatments in single-arm pooled analyses. In meta-regressions at two and three-years, DFS was significantly lower for RFA compared to MWA (OR = 0.26, 95%CI = 0.12-0.58; OR = 0.33, 95%CI = 0.16-0.66, respectively). OS was similar across modalities, timepoints, and analyses. Older age, male patients, larger tumors, retrospective studies, and non-Asian study region were also predictors of worse clinical outcomes. In high-quality studies (MINORS score ≥ 7), MWA patients had better clinical outcomes than the overall analysis. Stage IA MWA patients had lower LTP, higher OS, and generally lower DFS, compared to the main analysis of all NSCLC patients.

CONCLUSIONS

NSCLC patients had comparable outcomes after SBRT and MWA, which were better than those with RFA.

Innovative Invasive Loco-Regional Techniques for the Treatment of Lung Cancer

Surgical resection is still the standard treatment for early-stage lung cancer. A multimodal treatment consisting of chemotherapy, radiotherapy and/or immunotherapy is advised for more advanced disease stages (stages IIb, III and IV). The role of surgery in these stages is limited to very specific indications. Regional treatment techniques are being introduced at a high speed because of improved technology and their possible advantages over traditional surgery. This review includes an overview of established and promising innovative invasive loco-regional techniques stratified based on the route of administration, including endobronchial, endovascular and transthoracic routes, a discussion of the results for each method, and an overview of their implementation and effectiveness.

Primary and Metastatic Lung Cancer: Rationale, Indications, and Outcomes of Thermal Ablation

The widespread use of imaging as well as the efforts conducted through screening campaigns has dramatically increased the early detection rate of lung cancer. Historically, the management of lung cancer has heavily relied on surgery. However, the increased proportion of patients with comorbidities has given significance to less invasive therapeutic options like minimally invasive surgery and image-guided thermal ablation, which could precisely target the tumor without requiring general anesthesia or a thoracotomy. Thermal ablation is considered low-risk for lung tumors smaller than 3 cm that are located in peripheral lung and do not involve major blood vessels or airways. The rationale for ablative therapies relies on the fact that focused delivery of energy induces cell death and pathologic necrosis. Image-guided percutaneous thermal ablation therapies are established techniques in the local treatment of hepatic, renal, bone, thyroid and uterine lesions. In the lung, and specifically in the setting of metastatic disease, the 3 main indications for lung ablation are to serve as (1) curative intent, (2) as a strategy to achieve a chemo-holiday in oligometastatic disease, and (3) in oligoprogressive disease. Following these premises, the current paper aims to review the rationale, indications, and outcomes of thermal ablation as a form of local therapy in the treatment of primary and metastatic lung disease.

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.

SPACES: Our team's experience in lung tumor microwave ablation

The standard treatment of stage I nonsmall cell lung cancer is lobectomy with systematic mediastinal lymph node evaluation. Unfortunately, up to 25% of patients with stage I nonsmall cell lung cancer are not candidates for surgery due to severe medical comorbidities (poor cardiopulmonary function). Image-guided thermal ablation is an alternative for those patients, includes radiofrequency ablation, microwave ablation (MWA), cryoablation, and laser ablation. Compared to them, MWA is a relatively new technique with some potential advantages, such as faster heating times, higher intralesional temperatures, larger ablation zones, less procedural pain, relative insensitivity to "heat sinks," and less sensitivity to tissue types. However, some advantages of MWA mentioned above (such as higher intralesional temperatures, larger ablation zones) also have potential risks and problems, and an innovative and standardized guidance system is needed to avoid and solve these risks and problems. This article combs our team's clinical experience over the past decade, summarizes a systematic and standardized guidance system, and names it SPACES (Selection, Procedure, Assessment, Complication, Evaluation, Systemic therapy). Both primary and metastatic pulmonary tumors can be efficiently treated with image-guided thermal ablation in selected candidates. The selection and use of ablation techniques should consider the size and location of the target tumor, the risk of complications, and the expertise and skills of the professionals, among which the size of the target tumor (<3 mm) is a major factor determining the success of ablation.

Image-Guided Percutaneous and Transarterial Therapies for Primary and Metastatic Lung Cancer

Lung cancer is the leading cause of cancer mortality in the world. A significant proportion of patients with lung cancer are not candidates for surgery and must resort to other treatment alternatives. Rapid technological advancements in fields like interventional radiology have paved the way for valid treatment modalities like image-guided percutaneous and transarterial therapies for treatment of both primary and metastatic lung cancer. The rationale of ablative therapies relies on the fact that focused delivery of energy induces tumor destruction and pathological necrosis. Image-guided percutaneous thermal ablation therapies are established techniques in the local treatment of hepatic, renal, bone, thyroid, or uterine lesions. In the lung, the 3 main indications for lung ablation include local curative intent, a strategy to achieve a chemoholiday in oligometastatic disease, and recently, oligoprogressive disease. Transarterial therapies include a set of catheter-based treatments that involve delivering embolic and/or chemotherapeutic agents directed into the target tumor via the supplying arteries. This article provides a comprehensive review of the various techniques available and discusses their applications and associated complications in primary and metastatic lung cancer.

Therapeutic Bronchoscopy for Lung Nodules: Where Are We Now?

Lobar resection has been the established standard of care for peripheral early-stage non-small cell lung cancer (NSCLC). Over the last few years, surgical lung sparing approach (sublobar resection [SLR]) has been compared with lobar resection in T1N0 NSCLC. Three nonsurgical options are available in those patients who have a prohibitive surgical risk, and those who refuse surgery: stereotactic body radiotherapy (SBRT), percutaneous ablation, and bronchoscopic ablation. Local ablation involves placement of a probe into a tumor, and subsequent application of either heat or cold energy, pulsing electrical fields, or placement of radioactive source under an image guidance to create a zone of cell death that encompasses the targeted lesion and an ablation margin. Despite being in their infancy, the bronchoscopic ablative techniques are undergoing rapid research, as they extrapolate a significant knowledge-base from the percutaneous techniques that have been in the radiologist's armamentarium since 2000. Here, we discuss selected endoscopic and percutaneous thermal and non-thermal therapies with the focus on their efficacy and safety.

2450-MHz microwave ablation of liver metastases under 3.0 T wide-bore magnetic resonance guidance: a pilot study

To investigate the feasibility and effectiveness of 3.0 T wide-bore magnetic resonance (MR)-guided microwave ablation (MA) of liver metastases (LM). From October 2018 to May 2020, 39 patients with 63 LM were treated with 3.0 T wide-bore MR-guided 2450-MHz MA therapy. The procedure parameters, technical success, complications, biochemical index changes, local tumor response, local tumor progression (LTP), 12-month disease-free survival (DFS) and 12-month overall survival (OS) were recorded and analyzed. The mean tumor maximum diameter and total procedure time were 3.0 cm and 55.2 min, respectively. Technical success was 100%, but 5 cases (12.8%) had grade-1 complications. Alanine transaminase, aspartate transaminase and total bilirubin showed a slight transient increase on day 3 (P < 0.05) and returned to normal by day 30 (P > 0.05). The complete ablation rates for ≤ 2.5 and > 2.5 cm lesions were 100% and 92.5%, respectively. During the median follow-up of 12.0 months, the LTP rate was 4.8% (3/63), and the 12-month DFS and OS rates were 61.3% and 92.2%, respectively. 3.0 T wide-bore MR-guided MA for LM is a safe and effective approach, especially for small LM.

Percutaneous local tumor ablation vs. stereotactic body radiotherapy for early-stage non-small cell lung cancer: a systematic review and meta-analysis

BACKGROUND

Percutaneous local tumor ablation (LTA) and stereotactic body radiotherapy (SBRT) have been regarded as viable treatments for early-stage lung cancer patients. The purpose of this study was to compare the efficacy and safety of LTA with SBRT for early-stage non-small cell lung cancer (NSCLC).

METHODS

PubMed, Embase, Cochrane library, Ovid, Google scholar, CNKI, and CBMdisc were searched to identify potential eligible studies comparing the efficacy and safety of LTA with SBRT for early-stage NSCLC published between January 1, 1991, and May 31, 2021. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were applied to estimate the effect size for overall survival (OS), progression-free survival (PFS), locoregional progression (LP), and adverse events.

RESULTS

Five studies with 22,231 patients were enrolled, including 1443 patients in the LTA group and 20,788 patients in the SBRT group. The results showed that SBRT was not superior to LTA for OS (HR = 1.03, 95% CI: 0.87-1.22, P = 0.71). Similar results were observed for PFS (HR = 1.09, 95% CI: 0.71-1.67, P = 0.71) and LP (HR = 0.66, 95% CI: 0.25-1.77, P = 0.70). Subgroup analysis showed that the pooled HR for OS favored SBRT in patients with tumors sized >2 cm (HR = 1.32, 95% CI: 1.14-1.53, P = 0.0003), whereas there was no significant difference in patients with tumors sized ≤2 cm (HR = 0.93, 95% CI: 0.64-1.35, P = 0.70). Moreover, no significant differences were observed for the incidence of severe adverse events (≥grade 3) (OR = 1.95, 95% CI: 0.63-6.07, P = 0.25) between the LTA group and SBRT group.

CONCLUSIONS

Compared with SBRT, LTA appears to have similar OS, PFS, and LP. However, for tumors >2 cm, SBRT is superior to LTA in OS. Prospective randomized controlled trials are required to determine such findings.

INPLASY REGISTRATION NUMBER

INPLASY202160099.

Up-to-date evidence on image-guided thermal ablation for metastatic lung tumors: a review

The aim of this review was to summarize the latest evidence on image-guided thermal ablation therapies for lung metastases. PubMed was used to search for relevant articles that reported the oncological outcomes of thermal ablation for metastatic lung tumors, and those published in 2010 or later were selected for review. Ablative therapies were applied for lung metastases from various types of primary tumors, but most commonly colorectal ones. Radiofrequency ablation (RFA) was the most evaluated technique, followed by microwave ablation (MWA). The local control rates of ablative therapies were generally favorable, approximately 80–90% in many studies. Representative studies demonstrated promising overall survival rates of approximately 50% or higher 5 years after ablation for lung metastases from colorectal cancer or mixed types of primary tumors. Nevertheless, the survival outcomes varied depending on the type of primary tumor and background factors of patients such as other metastases and comorbidities. Several studies had aimed to compare the outcomes of various ablative therapies such as RFA, MWA, and cryoablation; however, conclusive data are not yet available to determine the most appropriate ablation modality for lung metastases. Further data accumulation is needed, especially for long-term outcomes and comparisons with other therapies.

Long term survival after multiple microwave ablations for colorectal cancer lung metastases: A case report

Colorectal cancer is one of the leading causes of cancer-associated morbidity and mortality in the world, with lower survival rates when metastases are present. We present a case of a 69-year-old man, diagnosed with metastatic rectal cancer to the lungs in 2015. Over the course of 5 years, he was treated with 4 microwave ablation procedures to both his lungs. Despite this, he does not have any local recurrence or any symptoms since he was first diagnosed 7 years ago. This case highlights the potential for microwave ablation to be used for curative intent in pulmonary metastases in colorectal cancer as an alternative to more invasive and complex procedures such as metastasectomies or lung resection, as well as the benefit of using microwave ablation for disease control to improve patients’ quality of life.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

ERS International Congress 2021: highlights from Assembly 8 Thoracic Surgery and Lung Transplantation

The thoracic surgery and lung transplantation assembly of the European Respiratory Society (ERS) is delighted to present the highlights from the 2021 International ERS Congress. We have selected four sessions that discussed recent advances across a wide range of topics: including digital health surveillance in thoracic surgery, emerging concepts in pulmonary metastasectomy, advances in mesothelioma care, and novel developments in lung graft allocation and monitoring. The sessions are summarised by early career members in close collaboration with the assembly faculty. We aim to give the reader an update on the highlights of the conference in the fields of thoracic surgery and lung transplantation.

Microwave ablation via a flexible catheter for the treatment of nonsurgical peripheral lung cancer: A pilot study

Background

Endobronchial microwave ablation via flexible catheter offers the potential for local therapy for inoperable peripheral lung cancer. The study aimed to evaluate the feasibility and safety of navigation bronchoscopy‐guided water‐cooled microwave ablation catheter for nonsurgical peripheral lung cancer.

Methods

This was a prospective single arm pilot study. Patients with early stage or multiple primary peripheral lung cancer who were nonsurgical candidates for surgery were enrolled in the study. Bronchoscopic microwave ablation was performed via a flexible water‐cooled microwave ablation antenna under the guidance of navigation bronchoscopy. Radial probe endobronchial ultrasound combined with fluoroscopy was used to confirm the position. Treatment outcomes were evaluated based on follow‐up chest CT and positron emission tomography scans. Primary endpoints were technical success and safety. Secondary endpoints were complete ablation rate, 2‐year local control rate, and progression‐free survival.

Results

Thirteen patients were enrolled in the study from April 2018 to July 2019. A total of 19 sessions of microwave ablation were performed on 14 tumors under the guidance of navigation bronchoscopy. The technical success was 100%. Treatment‐related complications occurred in two patients. The complete ablation rate was 78.6% (11/14). The 2‐year local control rate was 71.4%. Median progression‐free survival was 33 months for all patients.

Conclusions

In this pilot study, bronchoscopic microwave ablation appears to be feasible with acceptable occurrence of complication in the treatment of peripheral lung cancer under the guidance of navigation bronchoscopy.

Advances and controversies in the management of early stage non-small cell lung cancer

Complete resection continues to be the gold standard for the treatment of early-stage lung cancer. The landmark Lung Cancer Study Group trial in 1995 established lobectomy as the minimum intervention necessary for the management of early-stage non-small cell lung cancer, as it was associated with lower recurrence and metastasis rates than sublobar resection and lower postoperative morbidity and mortality than pneumonectomy. There is a growing tendency to perform sublobar resection in selected cases, as, depending on factors such as tumor size, histologic subtype, lymph node involvement, and resection margins, it can produce similar oncological results to lobectomy. Alternative treatments such as stereotactic body radiotherapy and radiofrequency ablation can also produce good outcomes in inoperable patients or patients who refuse surgery.

Role of surgical resection and its alternative local therapy for pulmonary metastasis of colorectal cancer

We reviewed surgical and alternative treatments for pulmonary metastasis of colorectal cancer, focusing on recent reports. The standard treatment for pulmonary metastasis of colorectal cancer is pulmonary resection, if resectable, despite the fact that the metastasis is hematogenous to distant organs. Guidelines in several countries, including Japan, have described pulmonary resection as a useful option because of the favorable long-term prognosis reported in various studies pertaining to pulmonary resection. The indications for pulmonary resection have been reviewed in several studies; additionally, the number of metastases, pretreatment carcinoembryonic antigen value, and disease-free interval from the primary resection to pulmonary recurrence have been proposed. However, no consensus has been reached to date. Contrastingly, recent advances in chemotherapy have remarkably improved the outcome of distant metastases, indicating that it is time to reconsider the significance of local treatment, including pulmonary resection. In addition to surgical resection, minimally invasive therapies, such as stereotactic body radiation therapy and radiofrequency ablation have been developed as local treatments for pulmonary metastases, and their long-term results have been reported. Prospective controlled trials and large-scale data analyses are needed to determine the best local treatment for pulmonary metastases and to find the appropriate indication for each treatment.

Current Management of Oligometastatic Lung Cancer and Future Perspectives: Results of Thermal Ablation as a Local Ablative Therapy

A growing body of evidence shows improved overall survival and progression-free survival after thermal ablation in non-small cell lung carcinoma (NSCLC) patients with a limited number of metastases, combined with chemotherapy or tyrosine kinase inhibitors or after local recurrence. Radiofrequency ablation and microwave ablation are the most evaluated modalities, and target tumor size <3 cm (and preferably <2 cm) is a key factor of technical success and efficacy. Although thermal ablation offers some advantages over surgery and radiotherapy in terms of repeatability, safety, and quality of life, optimal management of these patients requires a multidisciplinary approach, and further randomized controlled trials are required to help refine patient selection criteria. In this article, we present a comprehensive review of available thermal ablation modalities and recent results supporting their use in oligometastatic and oligoprogressive NSCLC disease along with their potential future implications in the emerging field of immunotherapy.

The ECLIPSE Study: Efficacy of cryoablation on metastatic lung tumors with a 5-year follow-up

INTRODUCTION

The ECLIPSE study aimed to assess the feasibility and efficacy of cryoablation for local tumor control in patients with pulmonary metastatic disease over five years of follow-up.

METHODS

ECLIPSE was a prospective, multicenter, single-arm study which included patients treated with cryoablation if they had 1-5 metastatic lung tumors, each with a diameter of ≤ 3.5 cm. Patients were followed up over the course of five years. The primary endpoint was local tumor control, both per tumor and per patient; secondary endpoints included cancer-specific survival, overall survival (OS), and quality of life. Quality of life was assessed using the Karnofsky Performance Score, the Eastern Cooperative Oncology Group Performance Score, and the Short Form-12 health survey.

RESULTS

The study included 40 patients across 4 sites (3 US and 1 European). A total of 60 metastatic pulmonary tumors were treated with 48 cryoablation procedures. Overall local tumor control rates were 87.9% (29/33) and 79.2% (19/24) per tumor, and 83.3% (20/24) and 75.0% (15/20) per patient, at 3 and 5 years respectively. A total of 5 treated patients demonstrated local progression throughout the duration of the study. Disease specific survival rate was of 74.8% at 3 years and 55.3% at 5 years while overall survival at 3 and 5 years were of 63.2% and 46.7% respectively. Patient quality of life scores did not reach statistical significance.

CONCLUSIONS

Cryoablation is an effective means of long-term local tumor control in patients with metastatic pulmonary tumors.

Percutaneous lung and liver CT-guided ablation on swine model using microwave ablation to determine ablation size for clinical practice

PURPOSE

Microwave ablation (MWA) provides an effective treatment of lung and liver tumors but suffers from a lack of reproducibility of ablation size among currently available technologies. In-vitro evaluations are far removed from clinical practices because of uninfused tissue. This study is in-vivo preclinical testing of a new MWA system on swine lungs and liver.

MATERIALS AND METHODS

All ablations were performed under CT guidance and multiple algorithms were tested with a power of 50, 75, and 100 W for durations of 3, 5, 8, 10, and 15 min. A 3 D-evaluation of the ablation zone was carried out using enhanced-CT. The sphericity index, coefficients of variation, and energy efficiency (which corresponds to the volume yield according to the power supplied) were calculated.

RESULTS

Fifty liver and 48 lung ablations were performed in 17 swine. The sphericity index varies from 0.50 to 0.80 for liver ablations and from 0.40 to 0.69 for lung ablations. The coefficient of variation was below 15% for 4/5 and 4/8 protocols for lung and liver ablations, respectively. The energy efficiency seems to decrease with the duration of the ablation from 0.60 × 10^-3 cm³/J (75 W, 3 min) to 0.26 × 10^-3 cm³/J (100 W, 15 min) in the liver and from 0.57 × 10^-3 cm³/J (50 W, 10 min) to 0.42 × 10^-3 cm³/J (100 W, 12 min) in the lungs.

CONCLUSION

A shorter treatment time provides the best energy efficiency, and the best reproducibility is obtained for a 10 min treatment duration. The system tested provides an interesting reproducibility in both lung and liver measurements. Our results may help interventional radiologists in the optimal selection of treatment parameters.

Society of Interventional Radiology Multidisciplinary Position Statement on Percutaneous Ablation of Non-small Cell Lung Cancer and Metastatic Disease to the Lungs: Endorsed by the Canadian Association for Interventional Radiology, the Cardiovascular and Interventional Radiological Society of Europe, and the Society of Interventional Oncology

PURPOSE

To state the Society of Interventional Radiology's position on the use of image-guided thermal ablation for the treatment of early stage non-small cell lung cancer, recurrent lung cancer, and metastatic disease to the lung.

MATERIALS AND METHODS

A multidisciplinary writing group, with expertise in treating lung cancer, conducted a comprehensive literature search to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 63 studies, including existing systematic reviews and meta-analysis, retrospective cohort studies, and single-arm trials were identified. The expert writing group developed and agreed on 7 recommendations on the use of image-guided thermal ablation in the lung.

CONCLUSION

SIR considers image-guided thermal ablation to be an acceptable treatment option for patients with inoperable Stage I NSCLC, those with recurrent NSCLC, as well as patients with metastatic lung disease.

Alternative methods for local ablation-interventional pulmonology: a narrative review

OBJECTIVE

To discuss and summarise the background and recent advances in the approach to bronchoscopic ablative therapies for lung cancer, focusing on focal parenchymal lesions.

BACKGROUND

This series focusses on the challenges highlighted by increasing recognition of the prognostically more favourable oligometastatic disease rather than the more frequent, but prognostically poor, high tumour burden metastatic disease. While surgery, stereotactic body radiation therapy (SBRT), and trans-thoracic percutaneous ablative techniques such as microwave (MWA) and radiofrequency ablation (RFA) are well recognised options for selected cases of pulmonary oligometastasis, bronchoscopic approaches to pulmonary tumour ablation are becoming realistic alternatives. An underlying tenet driving research and implementation in this domain is that percutaneous ablative techniques are obliged to traverse the pleura leading to a high rate of pneumothorax, and risks also goes up for peri-vascular lesions. Historically low yield bronchoscopic targeting of isolated peripheral tumors have significantly improved by incorporating multi-modality high resolution imaging and processing, including navigation planning and real-time image guidances (ultrasound, electromagnetic navigation, cone-beam CT). Combining advanced image guidance with ablative technology adaptations for bronchoscopic delivery opens up the options for high dose local ablative therapies that may reduce transthoracic complications and provide palliative to curative options for limited stage primary and oligometastatic diseases.

METHODS

We conduct a narrative review of the literature summarizing the history of bronchoscopic tumor ablation approaches, technical details including biologic rational for their uses, and current evidence for each modality, as well as investigations into future applications. Because of the relative paucity of prospective studies, we have been very inclusive in our inclusion of experiences from the published clinical databases.

CONCLUSIONS

Whilst surgical resection and SBRT remain the current mainstay of curative therapies for peripheral cancers, in the foreseeable future, developments and further research will see bronchoscopic ablative therapies become viable lung sparing alternatives in those deemed suitable. The future is bright.

Thermal ablation in non-small cell lung cancer: a review of treatment modalities and the evidence for combination with immune checkpoint inhibitors

Lung cancer is the leading cause of cancer death worldwide, with approximately 1.6 million cancer related deaths each year. Prognosis is best in patients with early stage disease, though even then five-year survival is only 55% in some groups. Median survival for advanced non-small cell lung cancer (NSCLC) is 8–12 months with conventional treatment. Immune checkpoint inhibitor (ICI) therapy has revolutionised the treatment of NSCLC with significant long-term improvements in survival demonstrated in some patients with advanced NSCLC. However, only a small proportion of patients respond to ICI, suggesting the need for further techniques to harness the potential of ICI therapy. Thermal ablation utilizes the extremes of temperature to cause tumour destruction. Commonly used modalities are radiofrequency ablation (RFA), cryoablation and microwave ablation (MWA). At present thermal ablation is reserved for curative-intent therapy in patients with localized NSCLC who are unable to undergo surgical resection or stereotactic ablative body radiotherapy (SABR). Limited evidence suggests that thermal ablative modalities can upregulate an anticancer immune response in NSCLC. It is postulated that thermal ablation can increase tumour antigen release, which would initiate and upregulated steps in the cancer immunity cycle required to elicit an anticancer immune response. This article will review the current thermal ablative techniques and their ability to modulate an anti-cancer immune response with a view of using thermal ablation in conjunction with ICI therapy.

Society of Interventional Radiology Quality Improvement Standards on Percutaneous Ablation of Non-Small Cell Lung Cancer and Metastatic Disease to the Lungs

PURPOSE

To provide guidance on quality improvement thresholds for outcomes and complications of image-guided thermal ablation for the treatment of early stage non-small cell lung cancer, recurrent lung cancer, and metastatic disease.

MATERIALS AND METHODS

A multidisciplinary writing group conducted a comprehensive literature search to identify studies on the topic of interest. Data were extracted from relevant studies and thresholds were derived from a calculation of 2 standard deviations from the weighted mean of each outcome. A modified Delphi technique was used to achieve consensus agreement on the thresholds.

RESULTS

Data from 29 studies, including systematic reviews and meta-analyses, retrospective cohort studies, and single-arm trials were extracted for calculation of the thresholds. The expert writing group agreed on thresholds for local control, overall survival and adverse events associated with image-guided thermal ablation.

CONCLUSION

SIR recommends utilizing the indicator thresholds to review and assess the efficacy of ongoing quality improvement programs. When performance falls above or below specific thresholds, consideration of a review of policies and procedures to assess for potential causes, and to implement changes in practices, may be warranted.

ENB-guided microwave ablation combined with uniportal VATS for multiple ground glass opacities

BACKGROUND

An increasing number of patients are being diagnosed with multiple ground glass opacities (GGOs), but a consensus on the treatment of these patients is still lacking. The aim of this study was to investigate the safety and feasibility of a novel technique, electromagnetic navigation bronchoscopy (ENB)-guided microwave ablation combined with uniportal video-assisted thoracoscopic surgery (Uni-VATS), in patients with multiple GGOs.

METHODS

The clinical, radiographic, surgical, and pathological data of patients with multiple GGOs who underwent ENB-guided microwave ablation combined with Uni-VATS from October 2018 to December 2019 were reviewed.

RESULTS

Eleven patients with multiple GGOs underwent ENB-guided microwave ablation combined with Uni-VATS, including 6 males and 5 females with a mean age of 61.3±5.1 (53-68) years. Thirty-seven lesions were observed in the 11 patients, 21 of which were microwave ablated and 16 of which were surgically resected. Only one patient developed postoperative pneumothorax and subcutaneous emphysema and was successfully discharged from the hospital after symptomatic treatment. The success rate and efficiency of microwave ablation under ENB guidance were 100%, with no other serious complications or procedure-related deaths occurring. No local metastasis or recurrence occurred in any patients during the follow-up period.

CONCLUSIONS

ENB-guided microwave ablation combined with Uni-VATS is safe and feasible in patients with multiple GGOs suspected of having multiple primary lung cancers, and may represent an alternative approach for more patients, particularly patients who cannot tolerate the simultaneous resection of multiple tumors.

Computerized tomography-Guided Microwave Ablation of Patients with Stage I Non-small Cell Lung Cancers: A Single-Institution Retrospective Study

Objectives:

The objective of the study was to retrospectively investigate the safety and efficacy of computerized tomography-guided microwave ablation (MWA) in the treatment of Stage I non-small cell lung cancers (NSCLCs).

Material and Methods:

This retrospective, single-center study evaluated 21 patients (10 males and 11 females; mean age 73.8 ± 8.2 years) with Stage I peripheral NSCLCs treated with MWA between 2010 and 2020. All patients were surveyed for metastatic disease. Clinical success was defined as absence of FDG avidity on follow-up imaging. Tumor growth within 5 mm of the original ablated territory was defined as local recurrence. Welch t-test and Fisher’s exact test were used for univariate analysis. Hazard ratio (HR) and odds ratio (OR) were determined using Cox regression and Firth logistic regression. Significance was P < 0.05. Data are expressed as mean ± standard deviation.

Results:

Ablated tumors had longest dimension 17.4 ± 5.4 mm and depth 19.7 ± 15.1 mm from the pleural surface. Median follow-up was 20 months (range, 0.6–56 months). Mean overall survival (OS) following lung cancer diagnosis or MWA was 26.2 ± 15.4 months (range, 5–56 months) and 23.7 ± 15.1 months (range, 3–55 months). OS at 1, 2, and 5 years was 67.6%, 61.8%, and 45.7%, respectively. Progression-free survival (PFS) was 19.1 ± 16.2 months (range, 1–55 months). PFS at 1, 2, and 5 years was 44.5%, 32.9%, and 32.9%, respectively. Technical success was 100%, while clinical success was observed in 95.2% (20/21) of patients. One patient had local residual disease following MWA and was treated with chemotherapy. Local control was 90% with recurrence in two patients following ablation. Six patients (28.6%) experienced post-ablation complications, with pneumothorax being the most common event (23.8% of patients). Female gender was associated with 90% reduction in risk of death (HR 0.1, P = 0.014). Tumor longest dimension was associated with a 10% increase in risk of death (P = 0.197). Several comorbidities were associated with increased hazard. Univariate analysis revealed pre-ablation forced vital capacity trended higher among survivors (84.7 ± 15.2% vs. 73 ± 21.6%, P = 0.093). Adjusted for age and sex, adenocarcinoma, and neuroendocrine histology trended toward improved OS (OR: 0.13, 0.13) and PFS (OR: 0.88, 0.37) compared to squamous cell carcinoma.

Conclusion:

MWA provides a safe and effective alternative to stereotactic brachytherapy resulting in promising OS and PFS in patients with Stage I peripheral NSCLC. Larger sample sizes are needed to further define the effects of underlying comorbidities and tumor biology.

Interventional Pulmonology: A Brave New World

Interventional pulmonology is a dynamic and evolving field in respiratory medicine. Advances have improved the ability to diagnose and manage diseases of the airways. A shift toward early detection of malignant disease has generated a focus on innovative diagnostic techniques. With patient populations living longer with malignant and benign diseases, the role for interventional bronchoscopy has grown. In cancer groups, novel immunotherapies have improved the prospects of clinical outcomes and reignited a focus on optimizing patient performance status to enable access to anticancer therapy. This review discusses current and emerging diagnostic modalities and therapeutic approaches available to manage airway diseases.

Lung radiofrequency ablation: post-procedure imaging patterns and late follow-up

•

RFA is an effective minimally invasive treatment for selected patients with primary and secondary lung tumors.

•

We described the expected imaging features after RFA of lung tumors, and their frequency over time after the procedure.

•

Radiologists should be familiar with these features in order to avoid misinterpretation and inadequate treatments.

•

These normal post-procedure imaging features must be considered in future post-ablation follow-up protocols.

Purpose

To describe expected imaging features on chest computed tomography (CT) after percutaneous radiofrequency ablation (RFA) of lung tumors, and their frequency over time after the procedure.

Methods

In this double-center retrospective study, we reviewed CT scans from patients who underwent RFA for primary or secondary lung tumors. Patients with partial ablation or tumor recurrence during the imaging follow-up were not included. The imaging features were assessed in pre-defined time points: immediate post-procedure, ≤4 weeks, 5−24 weeks, 25−52 weeks and ≥52 weeks. Late follow-up (3 and 5 years after procedure) was assessed clinically in 48 patients.

Results

The study population consisted of 69 patients and 144 pulmonary tumors. Six out of 69 (9%) patients had primary lung nodules (stage I) and 63/69 (91 %) had metastatic pulmonary nodules. In a patient-level analysis, immediately after lung RFA, the most common CT features were ground glass opacities (66/69, 96 %), consolidation (56/69, 81 %), and hyperdensity within the nodule (47/69, 68 %). Less than 4 weeks, ground glass opacities (including reversed halo sign) was demonstrated in 20/22 (91 %) patients, while consolidation and pleural thickening were detected in 17/22 patients (77 %). Cavitation, pneumatocele, pneumothorax and pleural effusions were less common features. From 5 weeks onwards, the most common imaging features were parenchymal bands.

Conclusions

Our study demonstrated the expected CT features after lung RFA, a safe and effective minimally invasive treatment for selected patients with primary and secondary lung tumors. Diagnostic and interventional radiologists should be familiar with the expected imaging features immediately after RFA and their change over time in order to avoid misinterpretation and inadequate treatments.

Survival Benefit of Radiofrequency Ablation with Intratumoral Cisplatin Administration in a Rabbit VX2 Lung Tumor Model

PURPOSE

This study evaluated the survival benefit of a combination therapy with radiofrequency ablation (RFA) and intratumoral cisplatin (ITC) administration for lung tumors by using a rabbit VX2 tumor model.

MATERIALS AND METHODS

Experiments were approved by the institutional animal care committee. VX2 tumor suspension was injected into the lungs of Japanese white rabbits under CT guidance to create a lung tumor model. Thirty-two rabbits bearing a transplanted VX2 lung tumor were randomly assigned to four groups of eight: control (untreated); RFA alone; ITC alone; and RFA with ITC. All treatments were performed one week after tumor transplantation. Kaplan-Meier survival curves were compared by the log-rank test.

RESULTS

The median survival time was 24.5 days (range 17-33 days) in the control group, 40 days (30-80 days) in the RFA alone group, 31.0 days (24-80 days) in the ITC alone group, and not reached (53-80 days) in the RFA with ITC group. The median survival was significantly longer with the RFA/ITC combination compared to the control group (P < 0.001), RFA alone (P = 0.034), and ITC alone (P = 0.004). The survival time after RFA alone was also significantly longer than that of the control group (P < 0.001). There was no significant difference in tumor size or the rate of pneumothorax between each group.

CONCLUSION

RFA prolonged the survival of rabbits with lung VX2 tumors when combined with ITC.

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.

Microwave Ablation Versus Wedge Resection for Stage I Non-small Cell Lung Cancer Adjacent to the Pericardium: Propensity Score Analyses of Long-term Outcomes

Objective

The present study has compared the long-term outcomes between performing wedge resection (WR) and microwave ablation (MWA) as first-line treatment of stage I non–small cell lung cancer (NSCLC) patients with tumors adjacent to the pericardium.

Materials and Methods

Between January 2014 and December 2018, a total of 223 consecutive patients with T1N0 NSCLC underwent first-line treatment by WR (n = 155) or image-guided lung MWA (n = 68). This study has compared the progression-free survival (PFS) and overall survival (OS) rates between the two treatments before and after propensity score matching. Subgroup analysis of these outcomes was conducted based on the distance from the pericardium.

Results

The median follow-up time was 47 months. Propensity matching yielded 56 pairs of patients. In the two matched groups, the PFS rates in the WR group at 3 and 5 years were 66.0% and 56.0% and 54.0% and 36.0%, respectively, in the MWA group (P = 0.029). Meanwhile, the corresponding OS rates for the WR group at 3 and 5 years were 81.0% and 72.0% and 60.0% and 55.0% in the MWA group, respectively (P = 0.031). Subgroup analysis, done according to the treatment modality, indicated that local tumor recurrence and PFS for NSCLCs that were close but not contiguous to the pericardium were different from those contiguous to the pericardium (P = 0.018 and P = 0.025, respectively).

Conclusion

WR provided better long-term tumor control and OS compared to MWA for stage I NSCLC adjacent to the pericardium as a first-line treatment. MWA can be considered as an alternative option for high-risk and inoperable patients, particularly for tumors that were not contiguous to the pericardium.

Long-Term Outcomes in Percutaneous Radiofrequency Ablation for Histologically Proven Colorectal Lung Metastasis

Introduction

To evaluate the long-term outcome of image-guided radiofrequency ablation (RFA) when treating histologically confirmed colorectal lung metastasis in terms of overall survival (OS), progression-free survival (PFS) and local tumour control (LTC).

Materials and Methods

Retrospective single-centre study. Consecutive RFA treatments of histologically proven lung colorectal metastases between 01/01/2008 and 31/12/14. The primary outcome was patient survival (OS and PFS). Secondary outcomes were local tumour progression (LTP) and complications. Prognostic factors associated with OS/ PFS were determined by univariate and multivariate analyses.

Results

Sixty patients (39 males: 21 females; median age 69 years) and 125 colorectal lung metastases were treated. Eighty percent (n = 48) also underwent lung surgery for lung metastases. Mean metastasis size (cm) was 1.4 ± 0.6 (range 0.3–4.0). Median number of RFA sessions was 1 (1–4). During follow-up (median 45.5 months), 45 patients died (75%). The estimated OS and PFS survival rates at 1, 3, 5, 7, 9 years were 96.7%, 74.7%, 44.1%, 27.5%, 16.3% (median OS, 52 months) and 66.7%, 31.2%, 25.9%, 21.2% and 5.9% (median PFS, 19 months). The LTC rate was 90% with 6 patients developing LTP with 1-, 2-, 3- and 4-year LTP rates of 3.3%, 8.3%, 10.0% and 10.0%. Progression-free interval < 1 year (P = 0.002, HR = 0.375) and total number of pulmonary metastases (≥ 3) treated (P = 0.037, HR = 0.480) were independent negative prognostic factors. Thirty-day mortality rate was 0% with no intra-procedural deaths.

Conclusion

The long-term OS and PFS following RFA for the treatment of histologically confirmed colorectal lung metastases demonstrate comparable oncological durability to surgery.

Electronic supplementary material

The online version of this article (10.1007/s00270-020-02623-1) contains supplementary material, which is available to authorized users.