ABSTRACT
Oxidative damage by photodynamic therapy (PDT) can lead to direct cytotoxicity in any tissue, malignant or stromal, that is illuminated following its accumulation of photosensitizer. In this chapter, the mechanisms and consequences of PDT-mediated cytotoxicity are initially considered, followed by a more specific emphasis on how damage to the vasculature of malignant or otherwise diseased tissue contributes to the successful application of PDT. We describe how changes in tumor blood flow report on the extent and therapeutic significance of PDT vascular damage. Lastly, tumor oxygenation, vascular composition, and other features of the tumor microenvironment are discussed in the context of how they affect the potential for PDT to create cellular and vascular damage.
