Endobronchial Intratumoral Immuno- and Gene Therapies in Lung Cancer: Mechanisms of Local Delivery, Systemic Immune Effects, and Global Feasibility

Lung cancer remains the leading cause of cancer-related mortality worldwide, and durable benefit from immune checkpoint inhibitors is limited by immune exclusion, microenvironmental immunosuppression, and toxicity. This narrative translational review evaluates whether endobronchial intratumoral delivery of immuno- and gene-based therapies can transform bronchoscopic access into a therapeutic platform linking local tumour intervention with systemic antitumour immunity. We synthesise evidence on endobronchial ultrasound, electromagnetic navigation bronchoscopy, and robotic-assisted bronchoscopy, together with local checkpoint blockade, cytokine and mRNA-lipid nanoparticle constructs, oncolytic virotherapy, dendritic-cell approaches, viral and non-viral gene transfer, and enzyme- or metabolite-based strategies. Current clinical evidence remains preliminary, consisting mainly of Phase I trials, small prospective cohorts, and case-based signals, with feasibility and safety observations but no completed randomised trial demonstrating efficacy against standard-of-care systemic therapy. The most plausible candidates are patients with advanced or recurrent NSCLC, bronchoscopically accessible lesions, inadequate response to systemic immunotherapy, and immune-excluded or locally immunosuppressed tumours. Biomarkers such as PD-L1, tumour mutational burden, CD8+ infiltration, tertiary lymphoid structures, radiomics, and circulating tumour DNA require validation. This review integrates delivery technology, immune mechanisms, statistical evidence appraisal, biomarker limitations, AI-guided planning, and global feasibility.