Novel light delivery method for performing transbronchial photodynamic therapy ablation to treat peripheral lung cancer: A pilot study

Background: Photodynamic therapy involves using a photosensitizer with l illumination and is recommended for treating early, centrally located lung cancers, but it is not a standard treatment for peripheral lung tumor.. We previously proposed a novel light delivery method, in which lipiodol is perfused into the bronchial tree to increase the scope of illumination via the fiber effect. Herein, we attempted this novel technique under electromagnetic bronchoscope guidance in a hybrid operation room where lipiodol facilitated light diffusion, and evaluated the effectiveness and feasibility of this technique for peripheral lung cancers. Methods: This phase 0 pilot study included three patients with peripheral lung cancers (primary tumors ≤20-mm diameter). The photodynamic therapy was administered using Porfimer sodium as the photosensitizer, and an electromagnetic navigation bronchoscope in a hybrid operating room to guide the catheter to the tumor. This facilitated lipiodol infusion to encase the tumor and permit the transbronchial photodynamic therapy ablation. Results: Administering 630 nm 200 J/cm (400mW/500sec) energy through a 3-cm cylindrical diffusing laser fiber was safe; no significant acute complications were observed. Although the treatment outcome was unsatisfactory due to the low light dose, tumor pathology in one case revealed tumor necrosis, with no significant damage to the surrounding lung tissue. Conclusions: Novel light delivery transbronchial photodynamic therapy ablation for peripheral lung tumors is feasible and safe. Additional clinical trials may help determine the best illumination plan and light dose through multiple deliveries from multiple angles. Keywords: Electromagnetic navigation bronchoscope; Lipiodol; Peripheral lung cancer; Photodynamic therapy; Porfimer sodium.