Mechanisms of tumor necrosis induced by photodynamic therapy.

Despite great progress and promising results achieved in cancer treatment by photodynamic therapy (PDT), the exact mechanism of tumor photosensitization in vivo by porphyrins and related phototherapeutic agents has not been fully explored and understood. This review is an attempt to gather available data on various processes occurring in neoplastic cells, microvasculature, non-vascular stroma and circulating blood within PDT-treated tumors. This information is necessary to understand the mechanisms governing the very complex processes which eventually lead to tumor necrosis.