Pulmonary Resection After Successful Downstaging with Photodynamic Therapy

"Two-Stage Rocket-Propelled" Strategy Boosting Theranostic Efficacy with Mitochondria-Specific Type I-II Photosensitizers

Imaging-guided photodynamic therapy (PDT) holds great potential for tumor therapy. However, achieving the synergistic enhancement of the reactive oxygen species (ROS) generation efficiency and fluorescence emission of photosensitizers (PSs) remains a challenge, resulting in suboptimal image guidance and theranostic efficacy. The hypoxic tumor microenvironment also hinders the efficacy of PDT. Herein, we propose a "two-stage rocket-propelled" photosensitive system for tumor cell ablation. This system utilizes MitoS, a mitochondria-targeted PS, to ablate tumor cells. Importantly, MitoS can react with HClO to generate a more efficient PS, MitoSO, with a significantly improved fluorescence quantum yield. Both MitoS and MitoSO exhibit less O2-dependent type I ROS generation capability, inducing apoptosis and ferroptosis. In vivo PDT results confirm that this mitochondrial-specific type I-II cascade phototherapeutic strategy is a potent intervention for tumor downstaging. This study not only sheds light on the correlation between the PS structure and the ROS generation pathway but also proposes a novel and effective strategy for tumor downstaging intervention.

Photodynamic therapy (PDT) for lung cancer

Clinical PDT began in the early 1980s and lung cancer was one of the first indications for which the procedure was tried. Initially patients with advanced inoperable cancer and major bronchial obstruction were targeted with the objective of relief of airway obstruction and symptom palliation. In the past 30 years, assisted by progress in imaging methods and advances of technological developments, PDT indications have expanded to incorporate a multitude of lung cancer presentations which this review aims to display. Locally advanced and early stage endobronchial cancer continues to be the major indications albeit with a more precise diagnostic and guided illumination devices. Peripheral parenchymal disease has been a technical challenge but there is still ongoing development. Multifocal synchronous, recurrence and metachronous endobronchial disease following lung resection are now an up and coming indication with rewarding outcome. More importantly PDTs role within a multi-disciplinary assault on lung cancer is receiving acceptance.