Liposome-Based Photodynamic Therapy for Breast Cancer: Innovations in Targeted Delivery, Combination Strategies, and Clinical Translation.

Breast cancer remains a leading cause of cancer-related mortality worldwide, with treatment resistance, recurrence, and metastasis significantly limiting the effectiveness of conventional therapies. Photodynamic therapy (PDT) has emerged as a minimally invasive and highly selective approach, utilizing photosensitizer-generated reactive oxygen species (ROS) to achieve precise tumor cytotoxicity while preserving surrounding healthy tissue. However, clinical translation of PDT remains constrained by critical biological barriers within the tumor microenvironment, including tumor hypoxia, limited light penetration, poor photosensitizer stability, and inefficient cellular uptake. Antigen-targeted liposomal nanocarriers offer a compelling solution by enabling targeted drug delivery and tumor-specific photosensitizer accumulation, prolonged systemic circulation, and enhanced cellular internalization. Their multifunctional architecture uniquely supports combinational therapeutic strategies, integrating PDT with chemotherapy, photothermal therapy, gene therapy, X-ray-induced photodynamic therapy (X-PDT) and immune checkpoint blockade, thereby amplifying antitumor efficacy and overcoming drug resistance mechanisms. This review comprehensively summarizes recent advances in liposome-based PDT for breast cancer, highlighting multimodal therapeutic integration. Special emphasis is placed on preclinical and emerging clinical outcomes, pilot-scale manufacturing considerations, and strategies to minimize immune clearance.