Photodynamic therapy in the treatment of prostate cancer

The prostate cancer constitutes the third death cause among neoplastic diseases (5%) in Poland. Despite of availability of many treatment options of prostate cancer, its morbidity and mortality dramatically increases. In this situation, it is necessary to find an efficient, safe and little-invasive method of treatment of these diseases. One of these methods is photodynamic therapy (PDT) whose mechanism relies on in situ generation of cytotoxic agents by the activation of light sensitive drugs in the presence of oxygen. The produced reactive oxygen species induce death of tumor tissue directly or by inhibition of angiogenesis due to the damage of tumor vessels. This paper is a review of experimental and clinical studies concerning application of PDT in the treatment of prostate cancer. The results of these studies show that PDT is a selective, well-tolerated and efficient method of primary and salvage therapy of prostate cancer, particularly in the case of cancer resistant to radiotherapy. Among studied photosensitizers, Foscan, Lu-Tex, and WST-09 revealed high efficiency in PDT of prostate cancer. The WST-09 action is focused on the tumor vessels which are a "focus" of disease. Such protocol, called focal therapy, is a new paradigm in treatment of prostate cancer. Comparing to cryotherapy and ultrasound therapy, PDT is more selective and similar in tolerability, while in terms of efficiency it cannot only be matched for cryotherapy in the treatment of higher stage cancer. Due to substantial individual differences in concentrations of photosensitizers and of oxygen and in intensity of absorbed light in tissues of prostate, monitoring of these parameters as well as of adverse effects to avoid damage of adjacent tissues during PDT sessions are recommended.