Photodynamic therapy for hypoxic tumors: Advances and perspectives.

This tutorial review summarizes the strategies for improving the efficacy of PDT in hypoxic tumor therapy. The advantages of combining PDT with other therapeutics, such as chemotherapy, chemodynamic therapy, gas therapy, immunotherapy and gene therapy, are also demonstrated. Finally, the existing challenges and future perspectives on clinical PDT for hypoxic tumors are discussed. [Display omitted] • Advanced materials and strategies for PDT to overcome hypoxia are classified. • Novel nano-systems in enhancing anti-tumor effects are summarized. • Combining PDT with other therapeutics to achieve synergetic effects are reported. • The current challenges and further opportunities are discussed. Photodynamic therapy (PDT) has been a preferred clinical technology for treating superficial tumors due to its advantages of high selectivity, non-invasiveness and negligible drug resistance. However, the hypoxic tumor microenvironment weakens the efficiency of O 2 -dependent PDT. Moreover, the PDT process consumes a large amount of O 2 and destroys the tumor blood vessels and further blocks the O 2 supply to tumor sites. Therefore, developing more advanced materials and methods for PDT of the hypoxic tumor is an essential scientific significance. This tutorial review summarizes the strategies for improving the efficacy of PDT in hypoxic tumor therapy, which is categorized into three sections: (I) enhancing O 2 concentration in the tumor; (II) disregarding hypoxia; and (III) exploiting hypoxia. The advantages of combining PDT with other therapeutics, such as chemotherapy, chemo-dynamic therapy, gas therapy, immunotherapy and gene therapy, are also demonstrated. Finally, the existing challenges and future perspectives on clinical PDT for hypoxic tumors are discussed. [ABSTRACT FROM AUTHOR]