Endobronchial tumor debulking with a flexible cryoprobe for immediate treatment of malignant stenosis

Cryodebulking to Relieve Critical Airway Narrowing Due to a Central Airway Tumor at the Carina: A Case Report and Literature Review

Central airway tumors presenting as critical airway stenosis is a medical emergency. Employing a cryoprobe, we successfully debulked a central airway tumor, providing rapid relief to a patient who came to the emergency room with severe breathlessness, hemoptysis, and respiratory failure. The current report underscores the efficacy of cryodebulking as an immediate and minimally invasive technique and a compelling alternative to conventional heat-based therapies.

Utility and Safety of Bronchoscopic Cryotechniques-A Comprehensive Review

Cryosurgical techniques are employed for diagnostic and therapeutic bronchoscopy and serve as important tools for the management of pulmonary diseases. The diagnosis of interstitial lung disease requires multidisciplinary team discussions after a thorough assessment of history, physical exam, computed tomography, and lung-function testing. However, histological diagnosis is required in selected patients. Surgical lung biopsy has been the gold standard but this can be associated with increased morbidity and mortality. Transbronchial lung cryobiopsy is an emerging technique and multiple studies have shown that it has a high diagnostic yield with a good safety profile. There is wide procedural variability and the optimal technique for cryobiopsy is still under investigation. There is emerging data that demonstrate that cryobiopsy is safe and highly accurate in the diagnosis of thoracic malignancies. Furthermore, cryorecanalization procedures are a useful adjunct for the palliation of tumors in patients with central airway obstruction. One should keep in mind that these procedures are not free from complications and should be carried out in a specialized center by a trained and experienced bronchoscopy team. We present a review of the literature on the diagnostic and therapeutic utility of bronchoscopy-guided cryosurgical procedures and their safety profile.

Clinical Outcomes of Bronchoscopic Cryotherapy for Central Airway Obstruction in Adults: An 11-Years' Experience of a Single Center

BACKGROUND

Although bronchoscopic cryotherapy (BC) is a pragmatic modality for recanalization of central airway obstruction (CAO), the risk of complications, such as bleeding, remains a concern. This study aimed to present the clinical outcomes of BC and evaluate the factors associated with its complications.

METHODS

In this retrospective study, we reviewed the medical records of patients who underwent BC for CAO at the Asan Medical Center, South Korea. Most sessions were conducted via flexible bronchoscopy under moderate sedation. A multivariate logistic regression analysis was used to identify the factors associated with the success rate and complications.

RESULTS

BC was performed in 262 sessions in 208 patients between January 2009 and December 2020. The most common cause of cryotherapy was recanalization of the endobronchial tumor related CAO (233/262, 88.9%). More than partial re-establishment of airway patency was achieved in 211 of 233 (90.6%) sessions. The success rate did not differ significantly in the multivariate logistic regression analysis. The most common complication was intrabronchial bleeding (78/233, 35.5%); however, severe bleeding occurred only in one case (0.4%). Univariate and multivariate logistic regression analyses revealed that diabetes mellitus (odds ratio [OR] = 2.820, P = 0.011), respiratory failure before BC (OR = 3.546, P = 0.028), and presence of distal airway atelectasis (OR = 0.417, P = 0.021) were independently associated with moderate to severe intrabronchial bleeding, while the histologic type of tumor was not related to bleeding. BC for CAO caused by blood clot or foreign body was successful in most cases, and there were no complications.

CONCLUSION

BC is an efficient and relatively safe intervention for patients with CAO. Our findings suggest that diabetes, respiratory failure before BC, and the absence of distal airway atelectasis may be risk factors of moderate to severe intrabronchial bleeding.

Malignant Central Airway Obstruction: What's New?

Malignant central airway obstruction (MCAO) is a debilitating and life-limiting complication that occurs in an unfortunately large number of individuals with advanced intrathoracic cancer. Although the management of MCAO is multimodal and interdisciplinary, the task of providing patients with prompt palliation falls increasingly on the shoulders of interventional pulmonologists. While a variety of tools and techniques are available for the management of malignant obstructive lesions, advancements and evolution in this therapeutic venue have been somewhat sluggish and limited when compared with other branches of interventional pulmonary medicine (e.g., the early diagnosis of peripheral lung nodules). Indeed, one pragmatic, albeit somewhat uncharitable, reading of this article's title might suggest a wry smile and shug of the shoulders as to imply that relatively little has changed in recent years. That said, the spectrum of interventions for MCAO continues to expand, even if at a less impressive clip. Herein, we present on MCAO and its endoscopic and nonendoscopic management-that which is old, that which is new, and that which is still on the horizon.

Successful removal of distal persistent foreign body airway with CO2 cryotherapy in a child

We report a case of a nine-year-old boy with clinical evidence of foreign body (FB) aspiration with 3 months of delay in diagnosis. The bronchoscopy found soft tissue FB with surrounding inflamed granulation tissue at the entrance to the lateral segmental bronchus. Repeated attempts to remove the FB with flexible forceps were unsuccessful due to friable FB and granulation tissue. Ablation of the granulation tissue using nitrous oxide cryotherapy was then successfully performed and the distal and organic FB was extracted. Early diagnosis is important for minimizing granulation tissue development which complicates FB removal. Cryotherapy with a flexible bronchoscope is an option if organic FB cannot be removed using conventional bronchoscopic instrumentation.

Association between blood pressure and the risk of biopsy-induced endobronchial hemorrhage during bronchoscopy

BACKGROUND

Hemorrhage is one of the most common complications of bronchoscopy. Although several hemorrhage risk factors have been proposed, it remains unclear whether blood pressure affects the onset of biopsy-induced endobronchial hemorrhage.

METHODS

We conducted a retrospective cohort study of 643 consecutive adults with lung cancer over an approximately 4-year period (from January 2014 to February 2018) at a large tertiary care hospital. Patients were divided into the hemorrhage group and the non-hemorrhage group based on endobronchial biopsy (EBB) findings. The association between systolic pressure (SP), diastolic pressure (DP), mean arterial pressure (MAP), pulse pressure (PP), PP to DP ratio (PP/DP) and the risk of EBB-induced hemorrhage was evaluated using multivariate regression analysis and smooth curve fitting adjusted for potential confounding factors.

RESULTS

The EBB-induced bleeding incidence was 37.8% (243/643) in our cohort. An independent association was found between PP/PD and the EBB-induced hemorrhage risk (per 1 SD, adjusted odds ratio, 0.788; 95% confidence interval, 0.653-0.951). The multivariate regression analysis performed using quartiles of PP/DP revealed that lower level of PP/DP ratio was related to a higher risk of EBB-induced hemorrhage (P for trend <0.05) after adjustment for potential confounders. However, no association was observed between SP, DP, MAP, PP and EBB-induced hemorrhage.

CONCLUSIONS

Low PP/DP was the independent risk factor for biopsy-induced endobronchial hemorrhage during bronchoscopy in patients with lung cancer.

[Interventional bronchoscopy-an overview]

Die Bronchoskopie stellt neben der Lungenfunktion und der radiologischen Bildgebung das wichtigste Diagnostikum bei Patienten mit Atemwegs- und Lungenerkrankungen dar. Aufgrund des kombinierten Einsatzes flexibler und starrer Bronchoskope kommt sie heutzutage aber auch zunehmend als endoskopisches Therapieverfahren bei pulmonalen Erkrankungen in Frage. Bei thorakalen Tumoren kann die interventionelle Bronchoskopie sowohl in palliativer als auch kurativer Intention zum Einsatz kommen. Neben der bronchoskopischen Tumorbehandlung rückten in den letzten Jahren zunehmend die Techniken der endoskopischen Lungenvolumenreduktion in den Fokus. Darüber hinaus bieten sich Therapiemöglichkeiten für Asthma und chronische Bronchitis sowie bei Atemwegsstenosen und -fisteln.

Effects of bronchial thermoplasty and cryoablation on airway smooth muscle

Background:

The effectiveness of bronchial thermoplasty (BT) has been reported in patients with severe asthma. This study compared the effects of BT and cryoballoon ablation (CBA) therapy on the airway smooth muscle (ASM).

Methods:

Eight healthy male beagle dogs were included in this experiment. In the preliminary experiment, one dog received BT treatment for both lower lobe bronchus, another dog received CBA treatment for 7 s on the upper and lower lobe of right bronchus, and 30 s on the left upper and lower lobe. The treatments were performed twice at an interval of 1 month. In subsequent experiments, the right lower lobe bronchus was treated with BT, and the left lower lobe bronchus was treated with CBA. The effects of treatment were observed after 1 (n = 3) month and 6 months (n = 3). Hematoxylin-eosin staining, Masson trichrome staining, and immunohistochemical staining were used to compare the effects of BT and CBA therapy on the ASM thickness, collagen fibers synthesis, and M3 receptor expression after treatment. One-way analysis of variance with Dunnett post hoc test was used to analyze the differences among groups.

Results:

In the preliminary experiment, the ASM ablation effect of 30-s CBA was equivalent to that of 7-s CBA (ASM thickness: 30.52 ± 7.75 μm vs. 17.57 ± 15.20 μm, P = 0.128), but the bronchial mucociliary epithelium did not recover, and large numbers of inflammatory cells had infiltrated the mucosal epithelium at 1-month post-CBA with 30-s freezing. Therefore, we chose 7 s as the CBA treatment time in our follow-up experiments. Compared with the control group (35.81 ± 11.02 μm), BT group and CBA group (13.41 ± 4.40 μm and 4.81 ± 4.44 μm, respectively) had significantly decreased ASM thickness after 1 month (P < 0.001). Furthermore, the ASM thickness was significantly lower in the 1-month post-CBA group than in the 1-month post-BT group (P = 0.015). There was no significant difference in ASM thickness between the BT and CBA groups after six months (9.92 ± 4.42 μm vs. 7.41 ± 7.20 μm, P = 0.540). Compared with the control group (0.161 ± 0.013), the average optical density of the ASM M3 receptor was significantly decreased in 6-month post-BT, 1-month post-CBA, and 6-month post-CBA groups (0.070 ± 0.022, 0.072 ± 0.012, 0.074 ± 0.008, respectively; all P < 0.001). There was no significant difference in the average optical density of ASM M3 receptor between the BT and CBA therapy groups after six months (P = 0.613).

Conclusions:

CBA therapy effectively ablates the ASM, and its ablation effect is equivalent to that of BT with a shorter onset time. A neural mechanism is involved in both BT and CBA therapy.

Overview of Interventional Pulmonology for Radiologists

Interventional pulmonology is a growing field specializing in minimally invasive procedures of the mediastinum, lungs, airways, and pleura. These procedures have both diagnostic and therapeutic indications and are performed for benign and malignant diseases. Endobronchial US has been combined with transbronchial needle aspiration to extend tissue sampling beyond the airways and into the lungs and mediastinum. Recent innovations extending the peripheral access of bronchoscopy include electromagnetic navigational bronchoscopy and thinner bronchoscopes. An important indication for therapeutic bronchoscopy is the relief of central airway obstruction, which may be severe and life threatening. Techniques for restoring patency of the central airways include mechanical debulking and multiple modalities for ablation, stent placement, and balloon bronchoplasty. Bronchoscopic lung volume reduction improves quality of life in certain patients with severe emphysema and is an important less invasive alternative to lung volume reduction surgery. Bronchial thermoplasty is likewise a nonpharmacologic treatment in patients with severe uncontrolled asthma. Many of these procedures have unique selection criteria that require precise evaluations at preprocedure imaging. Postprocedure imaging is also essential in determining outcome success and the presence of complications. Radiologists should be familiar with these procedures as well as the relevant imaging features in both planning and later surveillance. Evolving techniques that may become more widely available in the near future include robotic-assisted bronchoscopy, bronchoscopic transparenchymal nodule access, transbronchial cryobiopsy, ablation of early-stage cancers, and endobronchial intratumoral chemotherapy. An invited commentary by Wayne et al is available online. ^©RSNA, 2021.

Combination of the Archimedes Navigation System and cryobiopsy in diagnosis of diffuse lung disease

OBJECTIVE

To evaluate the efficacy of the Archimedes Navigation System (Broncus Medical, San Jose, CA, USA) for guidance during transbronchial cryobiopsy and the incidence of complications in patients with diffuse lung disease.

METHODS

High-resolution computed tomography and transbronchial cryobiopsy were used to evaluate eight patients with diffuse lung disease. The Archimedes Navigation System was used before cryobiopsy to obtain the best path with which to avoid large vessels. Three to five cryobiopsy specimens were taken from each sampled segment.

RESULTS

Preoperative planning using the Archimedes Navigation System was successfully performed on all eight patients. The probe-to-pleura distance was approximately 10 mm. No cases of pneumothorax occurred, one patient developed moderate bleeding, two developed minor bleeding, and five developed minimal bleeding that stopped spontaneously. A final diagnosis was obtained for seven patients, and ongoing follow-up was being conducted for the last patient at the time of this writing.

CONCLUSIONS

This is the first report of combining navigation technology with cryobiopsy to diagnose diffuse lung disease. The Archimedes Navigation System, which provides real-time guidance, is helpful in pre-cryobiopsy planning and diagnosis of diffuse lung disease. Moreover, this system can reduce the pneumothorax rate and bleeding risk by avoiding large vessels.

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.

Focal therapy for localized cancer: a patent review

INTRODUCTION

Conventional cancer treatments such as radical surgery and systemic therapy targeting the organ or organ system might have side effects because of damage to the surrounding tissue. For this reason, there is a need for new instruments that focally treat cancer.

AREAS COVERED

This review provides a comprehensive overview of the patent literature on minimally and noninvasive focal therapy instruments to treat localized cancer. The medical section of the Google Patents database was scanned, and 128 patents on focal therapy instruments published in the last two decades (2000-2021) were retrieved and classified. The classification is based on the treatment target (cancer cell or network of cancer cells), treatment purpose (destroy the cancerous structure or disable its function), and treatment means (energy, matter, or a combination of both).

EXPERT OPINION

We found patents describing instruments for all groups, except for the instruments that destroy a cancer cell network structure by applying matter (e.g. particles) to the network. The description of the different treatment types may serve as a source of inspiration for new focal therapy instruments to treat localized cancer.

Endobronchial treatment of benign endobronchial neoplasms: Our 10 years of experience

Background

The aim of the study was to assess the safety, efficacy, complications, and long-term outcomes of endobronchial treatment for benign endobronchial tumors.

Methods

A total of 53 patients (39 males, 14 females; mean age: 53.7 years; range, 12 to 83 years) with the diagnosis of benign endobronchial neoplasms in our center between November 2010 and September 2019 were retrospectively analyzed. Data including demographic and clinical characteristics of the patients and treatment outcomes were examined.

Results

Tumors regressed in all patients with argon plasma coagulation, diode laser and electrocautery, which was combined with cryotherapy in some cases. Complications were observed in five (9%) patients. Major complications were atrial fibrillation in two patients and respiratory failure requiring mechanical ventilation in one patient. Minor complications were minimal bleeding in two patients. The response was very good in 39 (74%) patients and good in 12 (23%) patients. There was no significant difference in the residual tissue formation requiring cryotherapy among the endobronchial treatment modalities (p>0.05). The five-year survival rate was 94%. No endobronchial treatment-related mortality was observed in any of the patients.

Conclusion

Endobronchial treatment modalities including diode laser, electrocautery, and argon plasma coagulation combined with or without cryotherapy are effective and safe in the treatment of benign endobronchial tumors.

Therapeutic bronchoscopy for central airway diseases

Over the past century rigid bronchoscopy has been established as the main therapeutic means for central airway diseases of both benign and malignant aetiology. Its use requires general anaesthesia and mechanical ventilation usually in the form of manual or high-frequency jet ventilation. Techniques applied to regain patency of the central airways include mechanical debulking, thermal ablation (laser, electrocautery and argon plasma coagulation) and cryo-surgery. Each of these techniques have their advantages and limitations and best results can be attained by combining different modalities according to the type, location and extent of the airway blockage. If needed, deployment of airway endoprostheses (stents), as either fixed-diameter silicone or self-expandable metal stents, may preserve the airways patency often at the cost of several complications. Newer generation of customised stents either three-dimensional printed or drug-eluting stents constitute a promise for improved safety and efficacy results in the near future. Treating central disease of benign or malignant aetiology, foreign body aspiration or massive bleeding in the airways requires a structured approach with combined techniques, a dedicated team of professionals and experience to treat eventual complications. Specific training and fellowships in interventional pulmonology should therefore be offered to those who wish to specialise in this field.

Cryodebulking of endobronchial hamartoma via fibreoptic bronchoscopy and literature review

Endobronchial hamartoma is a rare tumour. We report a 65-year-old woman with a history of recurrent pneumonia. Bronchoscopy revealed a 1 cm endobronchial mass obstructing the left upper lobe bronchus. Histopathological examination was consistent with a pulmonary hamartoma. This lesion was successfully debulked endoscopically with the use of a flexible cryoprobe without any complications. This case highlights both the importance of investigating recurrent pneumonia and the usefulness of endoscopic recanalisation in an obstructed segmental bronchus.

Bronchoscopic navigation and tissue diagnosis

Diagnosis of early-stage lung cancer has become increasingly important as the detection of peripheral pulmonary lesions (PPLs) grows with widespread adoption of CT-based lung cancer screening. Although CT-guided transthoracic needle aspiration has been the standard diagnostic approach for PPLs, transbronchial sampling by bronchoscopy is often performed due to its reduced rate of adverse events. However, the diagnostic yield of conventional bronchoscopy is often poor. Various bronchoscopic technologies have emerged over recent years to address this limitation, including thin/ultrathin bronchoscopes, radial probe endobronchial ultrasound (RP-EBUS), virtual navigation bronchoscopy (VBN), electromagnetic navigation bronchoscopy (ENB), and robotic bronchoscopy. Bronchoscopic transparenchymal nodule access (BTPNA) and transbronchial access tool (TBAT) are novel techniques that leverage navigational bronchoscopic technologies to further improve access to lesions throughout the lung. The devices used for sampling tissue have similarly evolved, such as the introduction of cryobiopsy. These innovative bronchoscopic techniques allows higher diagnostic yield even in small PPLs. Given the complexity of these new techniques and technologies, it is important for physicians to understand their strengths and limitations.

Blood clot removal by cryoextraction in critically ill patients with pulmonary hemorrhage

Background

Severe pulmonary hemorrhage is a life-threatening complication in critically ill patients. Due to tracheobronchial obstruction, ventilation is often impaired. Traditionally, rigid bronchoscopy is an option for recanalization. However, in comparison to flexible bronchoscopy, the application of rigid bronchoscopy is more complex. Against this background we evaluated the use of flexible cryo-probes for blood clot removal in critically ill patients.

Methods

Retrospectively, we identified 16 patients (median age: 60 years, 69% male patients), who suffered from severe airway obstruction due to blood clots. All patients required invasive ventilation and 11 patients depended on extracorporeal membrane oxygenation (ECMO). To remove blood clots, flexible bronchoscopic cryoextraction was performed in n=27 cases, whereas rigid bronchoscopy was only needed in two cases.

Results

Whereas in 9 cases single flexible cryoextraction was successful immediately, the procedure had to be repeated again in 7 patients. In all cases, tracheobronchial obstruction was treated with success and conditions of invasive ventilation were improved. In no case severe complications were observed.

Conclusions

In consideration of the underlying evaluation, we highly recommend flexible cryoextraction as both a safe and less complex technique for blood clot removal in critically ill patients.

An Open-label, Single-arm Study of CRYO2 for Debulking at the Site of Central Airway Obstruction or Stenosis

BACKGROUND

An open-label, single-arm study was conducted to assess the safety of a cryosurgery unit named CRYO2 for debulking at the site of obstruction or stenosis.

PATIENTS AND METHODS

In order to treat central airway tumor-related stenosis, debulking at the stenotic site of the airway was performed using CRYO2 under general or local anesthesia. The primary endpoint was the incidence of moderate to massive hemorrhage.

RESULTS

Incidence of moderate to massive hemorrhage during surgery was 3.8% (1/26) (95% confidence interval(CI)=0.1-19.6%). Technical success was 96.2% (25/26), with a 95% confidence interval of 80.4-99.9%.

CONCLUSION

CRYO2 for debulking at the site of obstruction or stenosis can be performed safely.

Bronchoscopic ablation techniques in the management of lung cancer

Central airway involvement is a common manifestation of lung cancer during the disease course. Some patients will require bronchoscopic therapeutic interventions to palliate symptoms, or less commonly to provide more definitive therapy of airway involvement. We describe an overview specifically of bronchoscopic ablative techniques that are available for use in malignant airway obstruction. Techniques that are more commonly used include bronchoscopic application of laser, electrocautery, argon plasma coagulation (APC), cryotherapy and mechanical debulking techniques. Less commonly employed are brachytherapy and photodynamic therapy. These techniques may be applied via flexible or rigid bronchoscopy depending upon the clinical scenario. The choice of technique depends on available tools and expertise, the urgency of the clinical scenario, and whether the lesion is predominately endobronchial, extrinsic compression, or a combination of both. Malignant airway obstruction is a common finding in lung cancer and there are a number of effective bronchoscopic ablative techniques that may be employed safely to palliate patients with a significant symptom burden.

Endobronchial Ablative Therapies

Endobronchial ablative therapies, such as mechanical debulking, laser therapy, electrocautery, argon plasma coagulation, cryotherapy, brachytherapy, photodynamic therapy, microdebrider bronchoscopy, resector balloon deobstruction, and intratumoral chemotherapy, are performed through a rigid or flexible bronchoscope in palliating or curing symptomatic malignant and benign airway lesions to improve symptoms, quality of life, and survival. Technical factors together with patient- and lesion-specific features determine the therapy of choice, as each therapy is different in capacity, limitation, and complications. In this article, indications, contraindications, and complications of endobronchial ablative therapies as well as practical issues related to their rational and cost-effective use are reviewed.

Cryo-Assisted Resection En Bloc, and Cryoablation In Situ, of Primary Breast Cancer Coupled With Intraoperative Ultrasound-Guided Tracer Injection: A Preliminary Clinical Study

The aim of the study was to perform cryosurgery on a primary breast tumor, coupled with simultaneous peritumoral and intratumoral tracer injection of a blue dye, to evaluate lymphatic mapping. We explored the ability of our strategy to prevent tumor cells, but not that of injected tracers, to migrate to the lymphovascular drainage during conventional resection of frozen breast malignancies. Seventeen patients aged 51 (14) years (mean [standard deviation]), presenting primary breast cancer with stage I to IV, were randomly selected and treated in The Rudolfinerhaus Private Clinic in Vienna, Austria, and included in this preliminary clinical study. Under intraoperative ultrasound, 14 patients underwent curative cryo-assisted tumor resection en bloc, coupled with peritumoral tracer injection, which consisted of complete tumor freezing and concomitant peritumor injection with a blue dye, before resection and sentinel lymph node dissection (group A). Group B consists of 3 patients previously refused any standard therapy and had palliative tumor cryoablation in situ combined with intratumoral tracer injection. The intraoperative ultrasound facilitated needle positioning and dye injection timing. In group A, the frozen site extruded the dye that was distributed through the unfrozen tumor, the breast tissue, and the resection cavity for 12 patients. One to 4 lymph nodes were stained for 10 of 14 patients. The resection margin was evaluable. Our intraoperative ultrasound-guided performance revealed the injection and migration of a blue dye during the frozen resection en bloc and cryoablation in situ of primary breast tumors. Sentinel lymph node mapping, pathological determination of the tumor, and resection margins were achievable. The study paves the way for intraoperative cryo-assisted therapeutic strategies for breast cancer.

Effects of a Thermal Accelerant Gel on Microwave Ablation Zone Volumes in Lung: A Porcine Study

Background Thermal ablation of cancers may be associated with high rates of local tumor progression. A thermal accelerant gel has been developed to improve the transmission of microwave energy in biologic tissues with the aim of enlarging the thermal ablation zone. Purpose To determine the effects of a thermal accelerant gel on microwave ablation zone volumes in porcine lung and to compare percutaneous and endobronchial delivery methods. Materials and Methods Thirty-two consecutive microwave lung ablations were performed in nine 12-week-old domestic male swine under general anesthesia by using fluoroscopic guidance between September 2017 and April 2018. Experimental ablations were performed following percutaneous injection of thermal accelerant into the lung (n = 16) or after endobronchial injection by using a flexible bronchoscope (n = 8). Control ablations were performed without accelerant gel (n = 8). Lung tissue was explanted after the animals were killed, and ablation zone volumes were calculated as the primary outcome measure by using triphenyltetrazolium chloride vital staining. Differences in treatment volumes were analyzed by generalized mixed modeling. Results Thermal accelerant ablation zone volumes were larger than control ablations (accelerant vs control ablation, 4.3 cm³ [95% confidence interval: 3.4, 5.5] vs 2.1 cm³ [95% confidence interval: 1.4, 2.9], respectively; P < .001). Among ablations with the thermal accelerant, those performed following percutaneous injection had a larger average ablation zone volume than those performed following endobronchial injection (percutaneous vs endobronchial, 4.8 cm³ [95% confidence interval: 3.6, 6.4] vs 3.3 cm³ [95% confidence interval: 2.9, 3.8], respectively; P = .03). Ablation zones created after endobronchial gel injection were more uniform in size distribution (standard error, percutaneous vs endobronchial: 0.13 vs 0.07, respectively; P = .03). Conclusion Use of thermal accelerant results in larger microwave ablation zone volumes in normal porcine lung tissue. Percutaneous thermal accelerant injection leads to a larger ablation zone volume compared with endobronchial injection, whereas a more homogeneous and precise ablation zone size is observed by using the endobronchial approach. © RSNA, 2019 See also the editorial by Goldberg in this issue.

Non-linear association of plasma level of high-density lipoprotein cholesterol with endobronchial biopsy bleeding in patients with lung cancer

Background

Despite a large body of studies have demonstrated the multifaceted behavior of high-density lipoproteins (HDLs) in several physiological and pathological processes, the levels of plasma HDL-cholesterol (HDL-C) that may be associated with endobronchial biopsy (EBB)-related bleeding have never been examined.

Methods

We conducted a single-center retrospective cohort study of 628 consecutive patients with primary lung cancer who had undergone EBB at a large tertiary hospital between January 2014 and February 2018. Patients were divided into the bleeding group and the non-bleeding group according to the bronchoscopy report. The association between HDL-C levels and EBB-induced bleeding was evaluated using the LASSO regression analysis, multiple regression analysis and smooth curve fitting adjusted for potential confounders.

Results

There was an inverse association of plasma HDL-C concentration with the incidence of EBB-induced bleeding as assessed by univariate analysis (P < 0.05). However, in piecewise linear regression analysis, a non-linear relationship with threshold saturation effects was observed between plasma HDL-C concentrations and EBB-induced bleeding. The incidence of EBB-induced bleeding decreased with HDL-C concentrations from 1.5 mmol/L up to 2.0 mmol/L (adjusted OR, 0.39; 95% CI, 0.20–0.74), but increased with HDL-C levels above the inflection point (HDL-C = 2.0 mmol/L).

Conclusions

There was a non-linear association between plasma HDL-C concentrations and the risk of EBB-induced bleeding in patients with lung cancer. The plasma level of HDL-C above 2.0 mmol/L or below 1.5 mmol/L may increase the risk of EBB-induced bleeding.

An open-label, single-arm study of CRYO2 for tissue removal at the site of central airway obstruction or stenosis: study protocol

Argon-plasma coagulation, high-frequency electrosurgical snare, laser therapy, and microwave treatment are therapeutic options to reduce tumor-related stenosis of the central airway. These treatments may cause airway fire under a high concentration of oxygen, so FiO2 levels must be ≤40%. This restriction may be dangerous when treating patients with respiratory failure. The cryosurgery unit, ERBE-CRYO2, facilitates treatment under an FiO₂ level of 100%, safely reducing this risk. In Japan, CRYO2 has been approved for cryobiopsy and foreign body removal, but not for tissue removal at the site of obstruction or stenosis due to lack of sufficient evidence. Since CRYO2 may be useful for reducing airway stenosis, the present study was designed to increase indications for this unit in Japan.

Plasma apolipoprotein E level is associated with the risk of endobronchial biopsy-induced bleeding in patients with lung cancer

Background

Factors affecting the risk of bleeding by bronchoscopic biopsy in patients with lung cancer remain unclear. The levels of plasma apolipoprotein E (ApoE) that may be associated with endobronchial biopsy (EBB)-induced bleeding have never been examined.

Methods

This was a retrospective study using data collected from 615 consecutive patients who had undergone EBB and been diagnosed with primary lung cancer from January 2014 through February 2018. Patients were either classified as the bleeding group (n = 214) or the non-bleeding group (n = 391) based on the bronchoscopy report. Multiple regression analysis was done to estimate the independent relationship between ApoE levels and EBB-induced bleeding, with an adjustment for potential confounders.

Results

The mean plasma ApoE concentration was higher in the non-bleeding group compared to that in the bleeding group (P < 0.05). However, a non-linear relationship with threshold effects was observed between plasma ApoE levels and EBB-induced bleeding in a piecewise linear regression analysis. The risk of EBB-induced bleeding decreased with ApoE concentrations from 3.5 mg/dL up to 5.9 mg/dL (adjusted odds ratio, 0.64; 95% confidence interval, 0.43–0.94); however, the incidence of EBB-induced bleeding increased with ApoE levels above the turning point (ApoE = 5.9 mg/dL).

Conclusions

There was a non-linear association between plasma ApoE levels and the risk of EBB-induced bleeding. Higher plasma ApoE concentrations (> 5.9 mg/dL) are the independent risk factor for hemorrhage during EBB in patients with lung cancer.

Successful use of snare electrocautery via flexible fiberoptic bronchoscopy for removal of an endobronchial hamartoma causing chronic lung atelectasis and mimicking malignancy

We present a rare case of giant endobronchial hamartoma coexisting with lung atelectasis for more than 3 years. The small specimen initially biopsied via bronchoscope did not reveal tissue features, but some features were suspicious for squamous cell carcinoma. The lesion was removed completely using snare electrocautery combined with argon plasma coagulation via flexible fiberoptic bronchoscopy. The patient made a satisfactory recovery, and a pathological diagnosis was made. This could be a useful option in selected endobronchial tumors.

The location, histologic type, and stage of lung cancer are associated with bleeding during endobronchial biopsy

Background

Several risk factors have been proposed for bleeding during bronchoscopy, including immunosuppression, thrombocytopenia, pulmonary arterial hypertension, and mechanical ventilation. However, research on bronchoscopic biopsy-induced bleeding in the population of lung cancer without these “proposed risk factors” remains lacking.

Patients and methods

A total of 531 lung cancer patients with endobronchial biopsy (EBB) were enrolled in this retrospective observational study. Patients were divided into biopsy-induced bleeding group (n=162) and non-bleeding group (n=369). Using multiple logistic regression, independent risk factors for EBB bleeding were identified.

Results

The location, histologic type, and stage of lung cancer were independently associated with EBB bleeding, as assessed by multiple logistic regression (p<0.05) in patients with lung cancer. Moreover, during EBB, the risk of bleeding of endobronchial lesions located in the central airways was significantly higher when compared to that in peripheral bronchi (odds ratio [OR], 2.211; 95% CI, 1.276–3.830; p=0.005). In addition, squamous cell carcinoma and small-cell lung carcinoma were more susceptible to bleeding during biopsy when compared with adenocarcinoma (OR, 3.107, 2.389; 95% CI, 1.832–5.271, 1.271–4.489; p=0.000, p=0.007, respectively). Patients with advanced lung cancer were more prone to EBB bleeding compared to patients in the early stages of disease (OR, 1.583; 95% CI, 1.065–2.354; p=0.023).

Conclusion

Lesions located in the central airways, histologic types of squamous cell carcinoma and small-cell lung carcinoma, and stages of advanced lung cancer were the independent risk factors for hemorrhage in EBB.

Unimodality and Multimodality Cryodebridement for Airway Obstruction. A Single-Center Experience with Safety and Efficacy

RATIONALE

Cryodebridement (CD) refers to the removal of obstructive material from the lumen of the tracheobronchial tree by freezing with a cryoprobe, which is usually inserted through a flexible bronchoscope. This method of achieving instant recanalization of airways has been established for over 20 years, but published experience comprises limited case series.

OBJECTIVES

This study describes a single large-volume referral center experience, including clinical outcomes and safety profile.

METHODS

Electronic medical records of 156 patients who underwent bronchoscopic CD between December 2007 and March 2012 as the primary method to relieve airway obstruction were reviewed retrospectively.

MEASUREMENTS AND MAIN RESULTS

The most frequent cause of airway obstruction was malignancy (n = 88), with non-small-cell lung cancer and metastatic renal cell carcinoma being the most common etiologies. The site of obstruction was localized to the central airways in 63 patients (40%) and the distal airways in 44 patients (28%), and it was diffuse in 49 patients (32%). Bronchoscopic airway patency was achieved in 95% of patients, with the highest success rates found in those with obstruction localized in the central airways. Improvement in symptoms occurred in 118 (82%) of 144 symptomatic patients. Serious complications were reported in 17 patients (11%) and included respiratory distress, severe bleeding, airway injury, and hemodynamic instability. All patients responded to treatment, and no intra- or postoperative deaths were reported.

CONCLUSIONS

CD, when used alone or in combination with other endoscopic treatment modalities, appears to be safe and effective in treating endoluminal airway obstruction.

Catheter-based endobronchial electroporation is feasible for the focal treatment of peribronchial tumors

OBJECTIVE

To evaluate the feasibility of catheter-based endobronchial electroporation for the treatment of peribronchial tumors and assess the incidence of treatment-related adverse events.

METHODS

Cytotoxicity of electroporation with or without cisplatin or gefitinib was assessed in vitro with lung cancer and normal cell lines. A novel catheter was designed for endobronchial electroporation, and computer simulations were used to predict in vivo treatment effects. Electroporation with the test catheter was performed (2000 V, 70 pulses) in the main bronchus of 8 pigs at 11 locations. Computed tomography imaging was performed before they were killed at 4 hours (6 animals) or 4 weeks (2 animals) posttreatment. Treated airway and surrounding parenchyma were compared with sham treatment via gross and histopathology.

RESULTS

Significant cell death due to electroporation and increased cytotoxicity in combination with cisplatin or gefitinib were observed in cancer cells only (P < .05). Simulations predicted penetrative electroporation of peribronchial parenchyma without tissue heating. Electric pulse delivery in vivo induced transient venous and bronchial spasms that resolved without intervention. Cross-sectional measurement of electroporation effects on computed tomography (14.4 ± 1.4 by 10.5 ± 1.3 mm) and gross pathology (17.2 ± 3.0 by 8.8 ± 0.6 mm) were representative of values predicted by simulation (P < .001). Cell death due to irreversible electroporation was observed in bronchial and parenchymal tissue in acute tissue samples. Treated lung rapidly recovered from the effects of electroporation without change in bronchial patency at 4 weeks posttreatment.

CONCLUSIONS

Catheter-based endobronchial electroporation is a reproducible technique that can be used to treat peribronchial tumors in combination with cisplatin, without affecting patency of the treated bronchus.

Comparison of two new techniques for the management of malignant central airway obstruction: argon plasma coagulation with mechanical tumor resection versus cryorecanalization

BACKGROUND

The development of central airway obstruction during malignant diseases is an important cause of morbidity and mortality. Endobronchial therapies can decrease the patient's symptoms and improve quality of life. Here, we compare airway recanalization methods: argon plasma coagulation with mechanical tumor resection (APC + MTR) and cryorecanalization (CR efficiency, complications, restenosis rate, and time to restenosis) in patients with malignant exophytic endobronchial airway obstruction.

METHODS

A total of 89 patients were included who were admitted to our hospital between 2005 and 2012. The data were analyzed retrospectively. Initially, a CR procedure was performed in 52 patients using rigid bronchoscopy under general anesthesia; the APC + MTR procedure was performed in 37 patients with malignant airway obstruction.

RESULTS

The airway patency rate with APC + MTR was 97.3% (n = 36) and CR was 80.8% (n = 42). The APC + MTR procedure was more effective than CR for recanalization of malignant endobronchial exophytic airway obstruction. Additionally, the achievement rate of airway patency with APC + MTR was significantly higher in tumors with distal bronchial involvement. There was no statistically significant difference between groups in terms of complications, restenosis rate, and time to restenosis.

CONCLUSIONS

The APC + MTR procedure is preferred over CR to introduce and maintain airway patency in patients with malignancy-related endobronchial exophytic airway obstruction.

Malignant central airway obstruction

This review comprehensively describes recent advances in the management of malignant central airway obstruction (CAO). Malignant CAO can be a dramatic and devastating manifestation of primary lung cancer or metastatic disease. A variety of diagnostic modalities are available to provide valuable information to plan a therapeutic intervention. Clinical heterogeneity in the presentation of malignant CAO provides opportunities to adapt and utilize endoscopic technology and tools in many ways. Mechanical debulking, thermal tools, cryotherapy and airway stents are methods and instruments used to rapidly restore airway patency. Delayed bronchoscopic methods, such as photodynamic therapy (PDT) and brachytherapy can also be utilized in specific non-emergent situations to establish airway patency. Although data regarding the success and complications of therapeutic interventions are retrospective and characterized by clinical and outcome measure variability, the symptoms of malignant CAO can often be successfully palliated. Assessment of risks and benefits of interventions in each individual patient during the decision-making process forms the critical foundation of the management of malignant CAO.

[Endoscopic interventions in pulmonology]

Bronchoscopy plays a significant role in the diagnosis and treatment of pulmonary diseases. Hemoptysis, or central airway obstruction, is a common indication for interventional bronchoscopy. In addition, the treatment of early lung cancer is the domain of bronchoscopy in inoperable patients. In recent years, endoscopic techniques have also been established as new therapeutic options in advanced chronic obstructive pulmonary disease and uncontrolled bronchial asthma.

Comparison of the efficacy of four endobronchial ablation techniques in dogs

The present study aimed to evaluate the safety and efficacy of four commonly used ablation techniques, namely neodymium-doped yttrium aluminium garnet (Nd:YAG) laser therapy, argon plasma coagulation (APC), high-frequency electrocautery and CO₂ cryotherapy. The techniques were performed at various powers or impedance settings, and for various durations, on the trachea of beagle dogs. Pathological changes of the tracheal wall were assessed by bronchoscopy. The endoscopic gross appearance of lesions induced by ablation treatments was consistent with the histopathological changes. The results suggested that cryotherapy was relatively safe, whereas APC induced superficial tissue coagulative necrosis. Furthermore, Nd:YAG laser therapy was the most efficient technique and showed the greatest penetration potential. In general, tissue injury was exacerbated with extended application time, at constant power or impedance. The safest application parameters were 20 W for ≤1 sec for Nd:YAG laser therapy, 40 W for ≤3 sec for electrocautery, 40 W for ≤5 sec for APC and 100 Ω for ≤120 sec for cryotherapy. At the maximum times, these settings resulted in identical pathological changes. Healing of the lesions following ablation was achieved within 3 weeks. The Nd:YAG laser, APC, electrocautery and cryotherapy endobronchial ablation techniques differed according to their potential and limitations for application on the trachea. However, when applied at specific combinations of power or impedance and duration, they exhibited similar efficacies.

Recent advances in diagnostic bronchoscopy

The field of diagnostic bronchoscopy has been revolutionized in the last decade primarily with the advent of endobronchial ultrasound (EBUS) but also with the addition of multiple different techniques for "guided-bronchoscopy". These advances have had a substantial impact in the management of lung cancer with bronchoscopy now providing both diagnosis and mediastinal staging in a single procedure. EBUS has, in fact, become the first choice for staging of the mediastinum over cervical mediastinoscopy (CM). Although EBUS is now a well-established technique, there are continuous efforts from the scientific community to improve its diagnostic performance, and these will be reviewed in this manuscript. The term "guided-bronchoscopy" was recently coined to describe a myriad of techniques that guide our bronchoscopes or bronchoscopic tools into the periphery of the lungs in addition to our conventional fluoroscopy. Electromagnetic and non-electromagnetic navigation, thin and ultrathin scopes, as well as radial-probe EBUS have collectively increased our yield for smaller peripheral lung lesions and continue to evolve. Despite this improved diagnostic yield, there is still ample room for improvement and newer techniques are under way. With new therapies available for patients with interstitial lung disease, achieving a specific histologic diagnosis is now of paramount importance. Given the high morbidity and mortality of surgical biopsies, bronchoscopic cryobiopsy is being rapidly adopted as a safer and effective alternative, and it is likely going to play a major role in the management of these diseases in the near future. This manuscript we will focus on recent advances in EBUS, guided-bronchoscopy, and the use of cryobiopsy.

Endobronchial Ultrasound-Radial Probe-Assisted Cryobiopsy for Peripheral Lung Mass: A New Way for Better Yield?

Solitary pulmonary nodules pose a diagnostic challenge as traditional techniques like bronchoscopic transbronchial biopsies or percutaneous transthoracic needle biopsies suffer either from poor yield or unacceptable complications. The advent of endobronchial ultrasound (EBUS)-radial probe (RP) has helped to guide the operator to the lesion more accurately and thereby improve yield. Small biopsy forceps or cytology brushes can be passed through the guide sheath of the EBUS-RP, after removing the probe, to get specimens. However, a small specimen may sometimes prove inadequate for special molecular studies or genetic analysis. Recently, there have been feasibility reports of transbronchial cryobiopsies that can be safely performed with larger biopsy specimens. We report a case of solitary pulmonary nodules where EBUS-RP was used to guide a cryoprobe to get large transbronchial cryobiopsies successfully.

Use of cryoprobe for removal of a large tracheobronchial foreign body during flexible bronchoscopy

Foreign body (FB) inhalation in the tracheobronchial tree is an infrequently encountered event in adults. The diagnosis is suspected in the presence of a clinical history of aspiration and the presence of respiratory symptoms. Management involves confirmation by flexible bronchoscopy, which may be both diagnostic as well as therapeutic. However, in certain situations including those with large FB, FB embedded in granulation tissue or FB with very smooth margins, rigid bronchoscopy may be superior to flexible bronchoscopy in the retrieval of the FB. An alternative to rigid bronchoscopy in such situations may be the use of a cryoprobe. Herein, we describe a patient with a large tracheobronchial FB causing a complete collapse of the left lung and hypoxemia. The FB was successfully extracted using a cryoprobe during flexible bronchoscopy, obviating the need for rigid bronchoscopy.

Transbronchial Lung Cryobiopsy for Interstitial Lung Disease Diagnosis: A Perspective From Members of the Pulmonary Pathology Society

Transbronchial lung cryobiopsy involves using a cryoprobe rather than forceps to obtain a bronchoscopic biopsy. Recent studies have shown that transbronchial cryobiopsy provides a larger specimen than conventional transbronchial forceps biopsy, and that the interobserver agreement in the interpretation of cryobiopsy specimens is comparable to that of a surgical lung biopsy. This is encouraging, and transbronchial lung cryobiopsy clearly has a role in the workup and diagnosis of interstitial lung diseases. However, very few patients who have been studied underwent both transbronchial lung cryobiopsy and surgical lung biopsy, and the available data suggest that the diagnostic accuracy of cryobiopsy may not be similar to that of surgical lung biopsy. Further study is needed before transbronchial lung biopsy can be recommended as a replacement for surgical lung biopsy.

How many samples would be optimal for endobronchial cryobiopsy?

BACKGROUND

Cryobiopsy, which provides larger specimens without crush artifact, is a good option for the diagnosis of visible endobronchial tumors. While there are several papers on diagnostic performance, application protocols vary between centers. In this study, we aimed to find the optimal number of cryobiopsies in endobronchial tumors.

METHODS

We prospectively involved cases with a visible endobronchial tumor in which conventional diagnostic measures failed and/or a therapeutic interventional bronchoscopy was planned. Endobronchial tumor was visualized, and four cryobiopsies were taken with a dedicated flexible probe. The samples were evaluated by a pathologist who was blinded to the order of the biopsies. The cumulative performances of one to four cryobiopsies were compared, and a complication analysis was conducted.

RESULTS

A total of 50 patients were involved. Four cryobiopsies were taken from 49 patients, and a single biopsy was taken from one case. The sensitivities of one, two, three and four biopsies were 82, 93.9, 93.9 and 95.9 %, respectively. The difference in performance of one and two biopsies was significant (p = 0.031), but the third and fourth biopsies were found to be unnecessary (p = 1.0 for second versus third and p = 1.0 for second versus fourth). Bleeding risk increased when ≥3 cryobiopsies were taken (Odds Ratio 2.758).

CONCLUSIONS

When the diagnostic benefits and complication rates were considered, two cryobiopsies were found to be optimal for endobronchial tumors. In patients with non-diagnostic conventional bronchoscopy, endobronchial tumors may be diagnosed by cryobiopsy.

Integration of interventional bronchoscopy in the management of lung cancer

Tracheal or bronchial proximal stenoses occur as complications in 20-30% of lung cancers, resulting in a dramatic alteration in quality of life and poor prognosis. Bronchoscopic management of these obstructions is based on what are known as "thermal" techniques for intraluminal stenosis and/or placement of tracheal or bronchial prostheses for extrinsic compressions, leading to rapid symptom palliation in the vast majority of patients. This invasive treatment should only be used in cases of symptomatic obstructions and in the presence of viable bronchial tree and downstream parenchyma. This review aims to clarify 1) the available methods for assessing the characteristics of stenoses before treatment, 2) the various techniques available including their preferred indications, outcomes and complications, and 3) the integration of interventional bronchoscopy in the multidisciplinary management of proximal bronchial cancers and its synergistic effects with the other specific treatments (surgery, radiotherapy or chemotherapy).

Present and Future Application of Energy Devices in Thoracic Surgery

In the last decade, many energy devices have entered day-to-day practice in thoracic surgery. Some have proven and recognized applications, whereas others still require further trials. Nevertheless, currently used devices continue to be improved on and new applications for current devices will be evaluated. Ultimately, novel applications of energy in thoracic surgery and refinement in technology will hopefully allow for safer and less invasive techniques for patients requiring thoracic surgical procedures. In this article, we review the present and future applications of energy devices in thoracic surgery.

From electrocautery, balloon dilatation, neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) laser to argon plasma coagulation and cryotherapy

Over the past decade, there has been significant advancement in the development/application of therapeutics in thoracic diseases. Ablation methods using heat or cold energy in the airway is safe and effective for treating complex airway disorders including malignant and non-malignant central airway obstruction (CAO) without limiting the impact of future definitive therapy. Timely and efficient use of endobronchial ablative therapies combined with mechanical debridement or stent placement results in immediate relief of dyspnea for CAO. Therapeutic modalities reviewed in this article including electrocautery, balloon dilation (BD), neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) laser, argon plasma coagulation (APC), and cryotherapy are often combined to achieve the desired results. This review aims to provide a clinically oriented review of these technologies in the modern era of interventional pulmonology (IP).