Thoracic: Lung Cancer
Endobronchial ultrasound-guided bipolar radiofrequency ablation for lung cancer: A first-in-human clinical trial

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Abstract

Objective

Percutaneous radiofrequency ablation (RFA) is a therapeutic option for lung tumors. However, percutaneous approaches have limited access to central lung regions and a relatively high complication rate. To overcome these limitations, a needle-type bipolar RFA device compatible with an endobronchial ultrasound (EBUS) bronchoscope was developed. The aim of this pilot study was to evaluate the immediate-term safety and ablation zone of lung tumor EBUS-guided RFA.

Methods

This was an ablate-and-resect study in patients scheduled for surgical resection of clinical stage I or II lung cancer or metastatic lung lesions ≥1 cm that were accessible using an EBUS bronchoscope. The RFA electrodes were placed within the lung nodule using EBUS guidance followed by ablation. Bronchoscopy and contrast-enhanced computed tomography were performed to evaluate for post-RFA complications. The resected lung underwent pathological assessment to characterize the ablation zone.

Results

A total of 5 primary lung cancers were ablated in 5 separate patients; no patients with metastatic lesions were recruited. For a total energy of 4 kJ (n = 3), 6 kJ (n = 1), and 8 kJ (n = 1) delivered, the ablation time was a mean of 13.8 (range, 10.3-16.0) minutes, 8.4 minutes, and 15.6 minutes, respectively, and the maximum ablation diameter was a mean of 1.8 (range, 1.3-2.1) cm, 2.7 cm, and 2.6 cm, respectively. No immediate post-RFA complications were observed.

Conclusions

EBUS-guided bipolar RFA can ablate lung tumors using real-time ultrasound guidance. EBUS-guided RFA might ultimately represent a minimally invasive therapy for lung cancer in patients unable to tolerate surgery. Longer-term safety will need to be evaluated.

Section snippets

Study Design and Subjects

This single-center, prospective, unblinded, single-arm interventional study was approved by the institutional review board of the University Health Network (REB 17-5442, approved on September 11, 2017), and conducted at Toronto General Hospital (Toronto, Ontario, Canada) between April 2018 and October 2019. This study was registered at the ClinicalTrials.gov registry (NCT03400748). Health Canada approved the use of the RFA device for this study (number 268397). Written informed consent was

Patient Information

A total of 5 primary lung cancers were ablated in 5 separate patients (Figure E2). Information of these patients is summarized in Table 1. There were 3 men and 2 women (mean age, 73.8 ± 8.7 years). Three of the 5 patients presented with clinical stage II disease at diagnosis. Histologic diagnosis was adenocarcinoma in 4 patients and squamous cell carcinoma in 1 patient. CT images at each tumor's maximum axial diameter are shown in Figure 1, A. The mean tumor diameter was 4.4 ± 1.6 cm, with all

Discussion

This pilot study showed that EBUS-guided RFA can access lung tumors adjacent to airways, as well as monitor the deployment of the electrode and ablation in real-time without any immediate complications (Figure 4). Although the trial inclusion criteria did permit recruitment of patients with metastatic lesions, all ablated lesions were primary lung cancers.

There were no major immediate complications from the procedure. However, there was 1 mortality case on postoperative day 8 due to hemothorax.

Conclusions

This first-in-human ablate-and-resect trial showed that EBUS-guided bipolar RFA can access and ablate centrally located lung tumors using real-time ultrasound guidance. There were no major immediate complications, but 1 mortality event due to hemothorax occurred on postoperative day 8. Although specimen pathology suggested this event was unlikely to be related to the RFA itself, further assessment including long-term observation post RFA is needed to conclude its safety.

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    The editorial review of this article was handled by Associate Editor Sudish C. Murthy, MD.

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