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

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.