Safety and feasibility of a novel externally cooled bronchoscopic radiofrequency ablation catheter for ablation of peripheral lung tumours: a first-in-human dose escalation study

Abstract

<b>Background:</b> Surgical lobectomy remains preferred therapy for early-stage non-small cell lung cancer (NSCLC). Comorbidities and advanced age preclude resection in many patients. Radiofrequency ablation (RFA) is an effective modality for percutaneous ablation of NSCLC. We have developed a novel RFA Catheter with externally cooled electrode for ablation of pulmonary lesions. <b>Methods:</b> Single arm treat-and-resect study. Biopsy-confirmed NSCLC. Procedures were performed under general anaesthesia with neuromuscular blockade. The RFA catheter was delivered bronchoscopically to peripheral parenchymal NSCLC lesions, guided by radial EBUS,&nbsp;and&nbsp;intra-procedural cone beam CT. Participants underwent lobectomy&nbsp;7 days&nbsp;post-ablation. Pre-op CT chest and histologic examination of resected specimens established distribution/uniformity of ablation and efficacy of tumour ablation. <b>Results:</b> Seven&nbsp;patients underwent RFA of NSCLC (median size 2.5cm, range 1.7-3.1cm) with sequential dose escalation. Uniform ablation was achieved within ablation zones, including tumour in all cases. Gravity-dependent extension of ablation was frequently seen. Proportion of tumour ablated ranged from 8-72%, a dose-response (energy-ablation volume) relationship was observed. <b>Conclusion:</b> Bronchoscopic RFA using externally cooled catheter is safe, feasible, and achieves uniform ablation within treatment zones at&nbsp;relatively low energy levels.&nbsp;Use of increased energy levels, and improved targeting/overlap of ablation zone to target lesion is expected to improve ablative efficacy. Future studies with a modified catheter are planned.