How to improve photodynamic therapy-induced antitumor immunity for cancer treatment?

Photodynamic therapy (PDT) is a promising method of tumor ablation and function-preserving oncological intervention, which is minimally invasive, repeatable, and has excellent function and cosmetic effect, with no cumulative toxicity. More importantly, PDT can induce immunogenic cell death and local inflammation, thus stimulating the body's immune response. However, the weak immunity induced by PDT alone is insufficient to trigger a systemic immune response towards cancer cells. To overcome this obstacle, multiple strategies have been investigated, including tumor microenvironment remodeling, tumor vaccines, subcellular-targeted PDT, and synergistic therapies. This review summarizes the latest progress in the development of strategies to improve the PDT-induced immune effect for enhanced cancer treatment.